An excisional biopsy is performed and the diagnosis of superficial spreading melanoma is confirmed. The lesion is 1.1 mm thick. Which of the following is the most appropriate next step in management?
Q2
A 57-year-old woman with non-small cell lung cancer comes to the physician 4 weeks after her tumor was resected. She takes no medications. The physician starts her on a treatment regimen that includes vinblastine. This treatment puts the patient at highest risk for which of the following?
Q3
A 64-year-old woman presents to the surgical oncology clinic as a new patient for evaluation of recently diagnosed breast cancer. She has a medical history of type 2 diabetes mellitus for which she takes metformin. Her surgical history is a total knee arthroplasty 7 years ago. Her family history is insignificant. Physical examination is notable for an irregular nodule near the surface of her right breast. Her primary concern today is which surgical approach will be chosen to remove her breast cancer. Which of the following procedures involves the removal of a portion of a breast?
Q4
A 60-year-old female presents to her primary care physician complaining of bloating and fatigue over the past year. On examination, she has abdominal distension and ascites. Abdominal imaging reveals a mass-like lesion affecting the left ovary. A biopsy of the lesion demonstrates serous cystadenocarcinoma. She is subsequently started on a chemotherapeutic medication known to stabilize polymerized microtubules. Which of the following complications should this patient be monitored for following initiation of this medication?
Q5
Patient 1 – A 26-year-old woman presents to her primary care physician for an annual exam. She currently does not have any acute concerns and says her health has been generally well. Medical history is significant for asthma, which is managed with an albuterol inhaler. Her last pap smear was unremarkable. She is currently sexually active with one male and consistently uses condoms. She occasionally smokes marijuana and drinks wine once per week. Her mother recently passed away from advanced ovarian cancer. Her sister is 37-years-old and was recently diagnosed with breast cancer and ovarian cancer. Physical examination is remarkable for a mildly anxious woman.
Patient 2 – A 27-year-old woman presents to her primary care physician for an annual exam. She says that she would like to be screened for breast cancer since two of her close friends were recently diagnosed. She noticed she has a small and mobile mass on her left breast, which increases in size and becomes tender around her time of menses. Family history is remarkable for hypertension in the father. The physical exam is significant for a small, well-defined, and mobile mass on her left breast that is not tender to palpation.
Which of the following is the best next step in management for patient 1 and 2?
Q6
A 46-year-old woman comes to the physician because of increasingly severe lower back pain for the past week. The pain is constant, and she describes it as 9 out of 10 in intensity. Six months ago, she underwent a lumpectomy for hormone receptor-negative lobular carcinoma of the right breast. She has undergone multiple cycles of radiotherapy. Vital signs are within normal limits. Examination shows a well-healed surgical incision over the right breast. There is severe tenderness to palpation over the 12th thoracic vertebra. The straight-leg raise test is negative. The remainder of the examination shows no abnormalities. Serum studies show:
Glucose 76 mg/dL
Creatinine 1 mg/dL
Total bilirubin 0.8 mg/dL
Alkaline phosphatase 234 U/L
Aspartate aminotransferase (AST, GOT) 16 U/L
Alanine aminotransferase (ALT, GPT) 12 U/L
γ-Glutamyltransferase (GGT) 40 U/L (N=5–50)
Which of the following is the most appropriate next step in management?
Q7
A 62-year-old woman presents to her oncologist to discuss the chemotherapy options for her newly diagnosed breast cancer. During the meeting, they discuss a drug that inhibits the breakdown of mitotic spindles in cells. Her oncologist explains that this will be more toxic to cancer cells because those cells are dividing more rapidly. Which of the following side effects is closely associated with the use of this chemotherapeutic agent?
Q8
A parent presents to her pediatrician requesting information about immunizations for her newborn. The pediatrician explains about basic principles of immunization, types of vaccines, possible adverse effects, and the immunization schedule. Regarding how immunizations work, the pediatrician explains that there are mainly 2 types of vaccines. The first type of vaccine provides stronger and more lasting immunity as it induces both cellular and humoral immune responses. The second type of vaccine produces mainly a humoral response only, and its overall efficacy is less as compared to the first type. Which of the following vaccines belongs to the first type of vaccine that the pediatrician is talking about?
Q9
A 50-year-old obese woman presents for a follow-up appointment regarding microcalcifications found in her left breast on a recent screening mammogram. The patient denies any recent associated symptoms. The past medical history is significant for polycystic ovarian syndrome (PCOS), for which she takes metformin. Her menarche occurred at age 11, and the patient still has regular menstrual cycles. The family history is significant for breast cancer in her mother at the age of 72. The review of systems is notable for a 6.8 kg (15 lb) weight loss in the past 2 months. The vital signs include: temperature 37.0°C (98.6°F), blood pressure 130/70 mm Hg, pulse 82/min, respiratory rate 17/min, and oxygen saturation 98% on room air. On physical examination, the patient is alert and cooperative. The breast examination reveals no palpable masses, lymphadenopathy, or evidence of skin retraction. A biopsy of the left breast is performed, and histologic examination demonstrates evidence of non-invasive malignancy. Which of the following is the most appropriate definitive treatment for this patient?
Q10
A 62-year-old man presents to his primary care physician. He was brought in by his daughter as he has refused to see a physician for the past 10 years. The patient has been having worsening abdominal pain. He claims that it was mild initially but has gotten worse over the past week. The patient has been eating lots of vegetables recently to help with his pain. The patient has a past medical history of constipation and a 50 pack-year smoking history. He is not currently taking any medications. On review of systems, the patient endorses trouble defecating and blood that coats his stool. His temperature is 99.5°F (37.5°C), blood pressure is 197/128 mmHg, pulse is 100/min, respirations are 17/min, and oxygen saturation is 98% on room air. On abdominal exam, the patient complains of right upper quadrant tenderness and a palpable liver edge that extends 4 cm beneath the costal margin. Murphy's sign is positive. HEENT exam is notable for poor dentition, normal sclera, and normal extraocular movements. There are no palpable lymph nodes. Laboratory studies are ordered as seen below.
Hemoglobin: 9 g/dL
Hematocrit: 30%
Leukocyte count: 7,500/mm^3 with normal differential
Platelet count: 199,000/mm^3
Serum:
Na+: 140 mEq/L
Cl-: 101 mEq/L
K+: 4.0 mEq/L
HCO3-: 23 mEq/L
BUN: 29 mg/dL
Glucose: 197 mg/dL
Creatinine: 1.4 mg/dL
Ca2+: 10.2 mg/dL
Total bilirubin: 1.1 mg/dL
AST: 150 U/L
ALT: 112 U/L
Which of the following is the most likely diagnosis?
Neoadjuvant and adjuvant therapy timing US Medical PG Practice Questions and MCQs
Question 1: An excisional biopsy is performed and the diagnosis of superficial spreading melanoma is confirmed. The lesion is 1.1 mm thick. Which of the following is the most appropriate next step in management?
A. Surgical excision with 0.5-1 cm safety margins only
B. Surgical excision with 1 cm safety margins only
C. Surgical excision with 1-2 cm safety margins only
D. Surgical excision with 0.5-1 cm safety margins and sentinel lymph node study
E. Surgical excision with 1-2 cm safety margins and sentinel lymph node study (Correct Answer)
Explanation: ***Surgical excision with 1-2 cm safety margins and sentinel lymph node study***
- A melanoma with a **Breslow thickness between 1.01 mm and 2.0 mm** (like this 1.1 mm lesion) requires a recommended surgical margin of **1 to 2 cm**.
- For melanomas **≥0.8 mm thickness** (or those with ulceration), a **sentinel lymph node biopsy (SLNB)** is recommended to assess for micrometastasis, as it helps in staging and prognosis.
*Surgical excision with 0.5-1 cm safety margins only*
- A 0.5 cm margin is typically reserved for melanoma *in situ* or extremely thin melanomas (less than or equal to 0.5 mm), and 1 cm for lesions 0.51 to 1.0 mm, which is too narrow for a 1.1 mm lesion.
- This option incorrectly omits the **sentinel lymph node study**, which is indicated for a melanoma of this thickness.
*Surgical excision with 1 cm safety margins only*
- While 1 cm is a common margin for lesions up to 1.0 mm, a 1.1 mm melanoma usually warrants a slightly wider margin, ideally 1-2 cm.
- This option also fails to include the **sentinel lymph node study**, which is crucial for staging melanomas ≥0.8 mm thickness.
*Surgical excision with 0.5-1 cm safety margins and sentinel lymph node study*
- The recommended surgical margin for a 1.1 mm melanoma is at least **1 cm, preferably between 1 and 2 cm**, making a 0.5-1 cm range insufficient.
- Although it correctly includes the sentinel lymph node study, the **surgical margin is inadequate** for the given Breslow thickness.
*Surgical excision with 1-2 cm safety margins only*
- While the **1-2 cm surgical margin** is appropriate for a 1.1 mm melanoma, this option **incorrectly excludes the sentinel lymph node study**.
- The sentinel lymph node biopsy is a critical part of the staging and management plan for melanomas of this thickness to detect potential nodal involvement.
Question 2: A 57-year-old woman with non-small cell lung cancer comes to the physician 4 weeks after her tumor was resected. She takes no medications. The physician starts her on a treatment regimen that includes vinblastine. This treatment puts the patient at highest risk for which of the following?
A. Pulmonary embolism
B. Invasive fungal infection (Correct Answer)
C. Progressive multifocal leukoencephalopathy
D. Pulmonary fibrosis
E. Heart failure
Explanation: ***Invasive fungal infection***
- Vinblastine is an **antimitotic chemotherapy agent** that, like other chemotherapeutic agents, can cause **myelosuppression**.
- **Myelosuppression** (particularly **neutropenia**) severely compromises the immune system, making patients highly susceptible to **opportunistic infections**, including invasive fungal infections.
*Pulmonary embolism*
- While cancer itself is a risk factor for **venous thromboembolism**, including pulmonary embolism, vinblastine itself **does not directly increase the risk** more than other chemotherapy agents.
- The highest risk with vinblastine specifically relates to its impact on bone marrow.
*Progressive multifocal leukoencephalopathy*
- This is a rare, severe opportunistic infection of the brain caused by the **JC virus**, primarily seen in patients with **severe immunosuppression**, such as those with HIV/AIDS or on chronic immunosuppressive therapy (e.g., natalizumab).
- While chemotherapy can cause immunosuppression, PML is not the most common or highest specific risk directly associated with vinblastine or its immediate, acute side effects compared to myelosuppression and opportunistic infections.
*Pulmonary fibrosis*
- **Pulmonary fibrosis** is a known side effect of certain chemotherapeutic agents like **bleomycin** and **busulfan**, but it is **not a primary or common adverse effect of vinblastine**.
- The side effect profile of vinblastine primarily involves myelosuppression, neurotoxicity, and gastrointestinal effects.
*Heart failure*
- **Cardiotoxicity leading to heart failure** is a significant concern with certain chemotherapy drugs, particularly **anthracyclines** (e.g., doxorubicin) and some tyrosine kinase inhibitors.
- **Vinblastine is not typically associated with cardiotoxicity or heart failure** as a primary or high-risk adverse effect.
Question 3: A 64-year-old woman presents to the surgical oncology clinic as a new patient for evaluation of recently diagnosed breast cancer. She has a medical history of type 2 diabetes mellitus for which she takes metformin. Her surgical history is a total knee arthroplasty 7 years ago. Her family history is insignificant. Physical examination is notable for an irregular nodule near the surface of her right breast. Her primary concern today is which surgical approach will be chosen to remove her breast cancer. Which of the following procedures involves the removal of a portion of a breast?
A. Arthroplasty
B. Lumpectomy (Correct Answer)
C. Vasectomy
D. Mastectomy
E. Laminectomy
Explanation: ***Lumpectomy***
- A **lumpectomy** is a surgical procedure that removes the **breast cancer tumor** and a small margin of surrounding healthy tissue, preserving most of the breast.
- This procedure is a common treatment for early-stage breast cancer and is often followed by radiation therapy.
*Arthroplasty*
- **Arthroplasty** is a surgical procedure to **repair or replace a joint**, typically due to arthritis or injury.
- The patient's history of a total knee arthroplasty indicates this procedure was performed on her knee, not her breast.
*Vasectomy*
- A **vasectomy** is a surgical procedure for **male sterilization**, involving the cutting and sealing of the vas deferens.
- This procedure is unrelated to breast cancer treatment or breast surgery.
*Mastectomy*
- A **mastectomy** involves the **complete surgical removal of the entire breast**, often including the nipple and areola.
- While it is a breast surgery, it removes the *entire* breast, not just a portion.
*Laminectomy*
- A **laminectomy** is a surgical procedure that removes a portion of the **vertebra (lamina)** to relieve pressure on the spinal cord or nerves.
- This procedure is for spinal conditions and is entirely unrelated to breast cancer surgery.
Question 4: A 60-year-old female presents to her primary care physician complaining of bloating and fatigue over the past year. On examination, she has abdominal distension and ascites. Abdominal imaging reveals a mass-like lesion affecting the left ovary. A biopsy of the lesion demonstrates serous cystadenocarcinoma. She is subsequently started on a chemotherapeutic medication known to stabilize polymerized microtubules. Which of the following complications should this patient be monitored for following initiation of this medication?
A. Peripheral neuropathy (Correct Answer)
B. Pulmonary fibrosis
C. Acoustic nerve damage
D. Hemorrhagic cystitis
E. Cardiotoxicity
Explanation: ***Peripheral neuropathy***
- The chemotherapeutic medication described, which stabilizes **polymerized microtubules**, is likely a **taxane** (e.g., paclitaxel, docetaxel), often used for ovarian cancer.
- Taxanes are well-known to cause **dose-dependent peripheral neuropathy** due to their effects on microtubule dynamics in neuronal axons.
*Pulmonary fibrosis*
- **Pulmonary fibrosis** is a significant side effect associated with certain chemotherapeutic agents like **bleomycin** or **busulfan**, but not typically with taxanes.
- Monitoring for this would involve assessing breath sounds, oxygen saturation, and potentially imaging for interstitial changes.
*Acoustic nerve damage*
- **Acoustic nerve damage** and ototoxicity are characteristic side effects of **platinum-based chemotherapy agents** (e.g., cisplatin), which are also used in ovarian cancer but have a different mechanism of action than microtubule stabilizers.
- This typically manifests as **tinnitus** or **hearing loss**.
*Hemorrhagic cystitis*
- **Hemorrhagic cystitis** is a common and severe side effect of **cyclophosphamide** and **ifosfamide**, alkylating agents, due to the accumulation of their metabolite **acrolein** in the bladder.
- It is not associated with microtubule-stabilizing agents like taxanes.
*Cardiotoxicity*
- **Cardiotoxicity**, including dilated cardiomyopathy, is a serious side effect primarily associated with **anthracyclines** (e.g., doxorubicin), which generate free radicals and damage cardiac myocytes.
- While some taxanes can cause cardiovascular effects, severe cardiotoxicity like that seen with anthracyclines is not their primary or most concerning side effect.
Question 5: Patient 1 – A 26-year-old woman presents to her primary care physician for an annual exam. She currently does not have any acute concerns and says her health has been generally well. Medical history is significant for asthma, which is managed with an albuterol inhaler. Her last pap smear was unremarkable. She is currently sexually active with one male and consistently uses condoms. She occasionally smokes marijuana and drinks wine once per week. Her mother recently passed away from advanced ovarian cancer. Her sister is 37-years-old and was recently diagnosed with breast cancer and ovarian cancer. Physical examination is remarkable for a mildly anxious woman.
Patient 2 – A 27-year-old woman presents to her primary care physician for an annual exam. She says that she would like to be screened for breast cancer since two of her close friends were recently diagnosed. She noticed she has a small and mobile mass on her left breast, which increases in size and becomes tender around her time of menses. Family history is remarkable for hypertension in the father. The physical exam is significant for a small, well-defined, and mobile mass on her left breast that is not tender to palpation.
Which of the following is the best next step in management for patient 1 and 2?
A. Patient 1 – Breast ultrasound. Patient 2 – Return in 3 months for a clinical breast exam
B. Patient 1 – Reassurance. Patient 2 – Breast ultrasound
D. Patient 1 – BRCA testing. Patient 2 – Breast ultrasound (Correct Answer)
E. Patient 1 – Breast and ovarian ultrasound. Patient 2 – Mammography
Explanation: ***Patient 1 – BRCA testing. Patient 2 – Breast ultrasound***
- Patient 1 has a strong family history of early-onset **breast and ovarian cancer** (**mother and sister**), suggesting a high probability of an inherited genetic mutation, such as **BRCA1/2**, which warrants genetic testing.
- Patient 2 presents with a **small, mobile, well-defined breast mass** that is likely benign, and a **breast ultrasound** is the appropriate initial imaging for further characterization in a young woman.
*Patient 1 – Breast ultrasound. Patient 2 – Return in 3 months for a clinical breast exam*
- Patient 1's primary concern is genetic predisposition due to family history, an **ultrasound** is not the initial or primary screening method for future cancer risk.
- Patient 2 has a palpable mass; waiting 3 months for a **clinical breast exam** without initial imaging (ultrasound) is not appropriate for evaluating a new breast lump.
*Patient 1 – Reassurance. Patient 2 – Breast ultrasound*
- Patient 1's family history of **early-onset breast and ovarian cancer** is a significant risk factor; therefore, simple **reassurance** without further investigation is inappropriate.
- While a **breast ultrasound** is appropriate for Patient 2, the recommendation for Patient 1 is incorrect.
*Patient 1 – CA-125 testing. Patient 2 – BRCA testing*
- **CA-125** is a tumor marker primarily used for monitoring ovarian cancer treatment or recurrence, not for initial screening in asymptomatic individuals, especially in a young woman with no active symptoms.
- **BRCA testing** is indicated for Patient 1 due to family history, but not for Patient 2 who has a likely benign breast mass and no significant family history.
*Patient 1 – Breast and ovarian ultrasound. Patient 2 – Mammography*
- Regular **breast and ovarian ultrasounds** are not recommended as primary screening tools for genetic risk in asymptomatic high-risk individuals like Patient 1.
- **Mammography** is less sensitive in young women (under 30) due to higher breast tissue density, making **ultrasound** the preferred initial imaging for Patient 2.
Question 6: A 46-year-old woman comes to the physician because of increasingly severe lower back pain for the past week. The pain is constant, and she describes it as 9 out of 10 in intensity. Six months ago, she underwent a lumpectomy for hormone receptor-negative lobular carcinoma of the right breast. She has undergone multiple cycles of radiotherapy. Vital signs are within normal limits. Examination shows a well-healed surgical incision over the right breast. There is severe tenderness to palpation over the 12th thoracic vertebra. The straight-leg raise test is negative. The remainder of the examination shows no abnormalities. Serum studies show:
Glucose 76 mg/dL
Creatinine 1 mg/dL
Total bilirubin 0.8 mg/dL
Alkaline phosphatase 234 U/L
Aspartate aminotransferase (AST, GOT) 16 U/L
Alanine aminotransferase (ALT, GPT) 12 U/L
γ-Glutamyltransferase (GGT) 40 U/L (N=5–50)
Which of the following is the most appropriate next step in management?
A. Bone biopsy
B. Positron emission tomography
C. MRI of the spine (Correct Answer)
D. Bone scintigraphy
E. X-ray of the spine
Explanation: ***MRI of the spine***
- The patient's history of **breast carcinoma**, severe localized back pain, and **elevated alkaline phosphatase** strongly suggest **vertebral metastasis**. MRI is the most sensitive and preferred imaging modality for detecting **spinal cord compression** or bone metastases in such cases.
- **MRI** provides detailed soft tissue contrast, allowing for precise visualization of the spinal cord, nerve roots, and extent of tumor involvement, which is crucial for treatment planning.
*Bone biopsy*
- While a bone biopsy can confirm the diagnosis of metastasis, it is an **invasive procedure** and usually performed after less invasive imaging has identified a suspicious lesion.
- It is not the most appropriate *initial* step, especially when rapid assessment for **spinal cord compression** (a neurosurgical emergency) is needed.
*Positron emission tomography*
- **PET scans** are useful for detecting distant metastases and assessing metabolic activity of tumors, but they provide less detailed anatomical information than MRI regarding **spinal cord compromise**.
- Although it can detect bone metastases, its utility is more in systemic staging rather than immediate evaluation of severe localized spinal pain and potential compression.
*Bone scintigraphy*
- **Bone scintigraphy** (bone scan) is sensitive for detecting increased bone turnover associated with metastases, but it has **lower spatial resolution** than MRI and cannot directly visualize the spinal cord.
- It may miss purely lytic lesions and is less specific for evaluating the extent of soft tissue involvement or risk of **spinal cord compression**.
*X-ray of the spine*
- **Plain radiographs** are often the *first* imaging study for back pain, but they have **low sensitivity** for detecting early bone metastases, especially before significant bone destruction has occurred.
- X-rays would likely miss small lesions or those infiltrating the bone marrow and are inadequate for assessing **spinal cord compression**.
Question 7: A 62-year-old woman presents to her oncologist to discuss the chemotherapy options for her newly diagnosed breast cancer. During the meeting, they discuss a drug that inhibits the breakdown of mitotic spindles in cells. Her oncologist explains that this will be more toxic to cancer cells because those cells are dividing more rapidly. Which of the following side effects is closely associated with the use of this chemotherapeutic agent?
A. Photosensitivity
B. Peripheral neuropathy (Correct Answer)
C. Paralytic ileus
D. Hemorrhagic cystitis
E. Pulmonary fibrosis
Explanation: ***Peripheral neuropathy***
- Drugs that inhibit the breakdown of **mitotic spindles** are **microtubule-targeting agents** (e.g., **taxanes** like paclitaxel/docetaxel, **vinca alkaloids** like vincristine/vinblastine).
- These agents interfere with **microtubule function** in neurons, leading to **axonal damage** and **peripheral neuropathy**.
- This is the **most characteristic and common dose-limiting toxicity** of microtubule inhibitors, affecting sensory and motor nerves (numbness, tingling, weakness in extremities).
*Photosensitivity*
- **Photosensitivity** is a common adverse effect associated with certain chemotherapeutic agents like **fluorouracil** (5-FU) or **methotrexate**, but is not linked to microtubule inhibitors.
- It involves an increased sensitivity to UV light, often manifesting as a rash or exaggerated sunburn.
*Paralytic ileus*
- **Paralytic ileus** can occur with **vinca alkaloids** (especially vincristine) due to autonomic neuropathy affecting the **enteric nervous system**.
- However, this is **less common** than peripheral neuropathy and occurs more specifically with vincristine rather than taxanes.
- **Peripheral neuropathy** is the more pervasive, dose-limiting, and universally characteristic side effect across all microtubule inhibitors.
*Hemorrhagic cystitis*
- **Hemorrhagic cystitis** is a classic side effect of **alkylating agents** like **cyclophosphamide** and **ifosfamide**, which produce the toxic metabolite **acrolein**.
- It is prevented/managed with **mesna**, which inactivates acrolein.
- Not associated with microtubule inhibitors.
*Pulmonary fibrosis*
- **Pulmonary fibrosis** is a known side effect of certain chemotherapeutic drugs, most notably **bleomycin** and **busulfan**.
- This adverse effect is not associated with agents that target **mitotic spindle breakdown**.
Question 8: A parent presents to her pediatrician requesting information about immunizations for her newborn. The pediatrician explains about basic principles of immunization, types of vaccines, possible adverse effects, and the immunization schedule. Regarding how immunizations work, the pediatrician explains that there are mainly 2 types of vaccines. The first type of vaccine provides stronger and more lasting immunity as it induces both cellular and humoral immune responses. The second type of vaccine produces mainly a humoral response only, and its overall efficacy is less as compared to the first type. Which of the following vaccines belongs to the first type of vaccine that the pediatrician is talking about?
A. Hepatitis A vaccine
B. Polio vaccine (Salk)
C. Yellow fever vaccine (Correct Answer)
D. Rabies vaccine
E. Hepatitis B vaccine
Explanation: ***Yellow fever vaccine***
- The Yellow fever vaccine is a **live-attenuated vaccine**, which mimics natural infection and effectively stimulates both **cellular and humoral immune responses**, leading to strong and long-lasting immunity.
- Live-attenuated vaccines contain a weakened form of the pathogen, allowing for replication within the host and robust immune system activation.
*Hepatitis A vaccine*
- The Hepatitis A vaccine is an **inactivated vaccine**, which primarily induces a **humoral (antibody-mediated) immune response**.
- Inactivated vaccines generally do not stimulate a strong cellular immune response and often require booster doses to maintain protective immunity.
*Polio vaccine (Salk)*
- The Salk polio vaccine is an **inactivated polio vaccine (IPV)**, meaning it contains killed viral particles.
- As an inactivated vaccine, it mainly elicits a **humoral immune response** producing circulating antibodies but less mucosal or cellular immunity.
*Rabies vaccine*
- The Rabies vaccine is an **inactivated vaccine** given after exposure or for pre-exposure prophylaxis.
- It primarily induces a **humoral antibody response** rather than a strong cellular immune response.
*Hepatitis B vaccine*
- The Hepatitis B vaccine is a **recombinant vaccine**, containing only a portion of the viral antigen (HBsAg).
- This type of vaccine primarily stimulates a **humoral immune response** leading to antibody production, which is effective but does not typically induce a strong cellular response like live vaccines.
Question 9: A 50-year-old obese woman presents for a follow-up appointment regarding microcalcifications found in her left breast on a recent screening mammogram. The patient denies any recent associated symptoms. The past medical history is significant for polycystic ovarian syndrome (PCOS), for which she takes metformin. Her menarche occurred at age 11, and the patient still has regular menstrual cycles. The family history is significant for breast cancer in her mother at the age of 72. The review of systems is notable for a 6.8 kg (15 lb) weight loss in the past 2 months. The vital signs include: temperature 37.0°C (98.6°F), blood pressure 130/70 mm Hg, pulse 82/min, respiratory rate 17/min, and oxygen saturation 98% on room air. On physical examination, the patient is alert and cooperative. The breast examination reveals no palpable masses, lymphadenopathy, or evidence of skin retraction. A biopsy of the left breast is performed, and histologic examination demonstrates evidence of non-invasive malignancy. Which of the following is the most appropriate definitive treatment for this patient?
A. Tamoxifen
B. Observation with bilateral mammograms every 6 months
C. Lumpectomy (Correct Answer)
D. Radiotherapy
E. Bilateral mastectomy
Explanation: ***Lumpectomy***
- This patient has **non-invasive malignancy**, likely **ductal carcinoma in situ (DCIS)**, identified through microcalcifications and confirmed by excisional biopsy. For DCIS without gross invasion, the primary treatment is **surgical excision**, often a lumpectomy.
- A lumpectomy, also known as **breast-conserving surgery**, aims to remove the cancerous tissue with a margin of healthy tissue while preserving the rest of the breast.
*Tamoxifen*
- **Tamoxifen** is an **estrogen receptor modulator** used as **adjuvant therapy** for hormone-receptor-positive breast cancer, primarily after surgical removal of the tumor. It is not a primary treatment for removing the malignancy itself.
- While it might be considered after surgery depending on receptor status, it does not address the need for initial excision of the non-invasive malignancy.
*Observation with bilateral mammograms every 6 months*
- **Observation** is insufficient for confirmed non-invasive malignancy, which carries a risk of progression if untreated. **Active intervention** is required once malignancy is histologically confirmed.
- This approach might be considered for high-risk lesions or atypical hyperplasia, but not for confirmed carcinoma in situ.
*Radiotherapy*
- **Radiotherapy** is often used as **adjuvant therapy** after lumpectomy for DCIS to reduce the risk of local recurrence. It is not a standalone primary treatment for removing the initial non-invasive malignancy.
- The first step is always surgical removal of the cancerous tissue.
*Bilateral mastectomy*
- **Bilateral mastectomy** is a more aggressive surgical intervention, typically reserved for **invasive breast cancer**, widespread DCIS, or cases with very high genetic risk (e.g., BRCA mutations).
- For localized non-invasive malignancy identified through microcalcifications, a lumpectomy is generally the **most appropriate and less invasive initial surgical approach**.
Question 10: A 62-year-old man presents to his primary care physician. He was brought in by his daughter as he has refused to see a physician for the past 10 years. The patient has been having worsening abdominal pain. He claims that it was mild initially but has gotten worse over the past week. The patient has been eating lots of vegetables recently to help with his pain. The patient has a past medical history of constipation and a 50 pack-year smoking history. He is not currently taking any medications. On review of systems, the patient endorses trouble defecating and blood that coats his stool. His temperature is 99.5°F (37.5°C), blood pressure is 197/128 mmHg, pulse is 100/min, respirations are 17/min, and oxygen saturation is 98% on room air. On abdominal exam, the patient complains of right upper quadrant tenderness and a palpable liver edge that extends 4 cm beneath the costal margin. Murphy's sign is positive. HEENT exam is notable for poor dentition, normal sclera, and normal extraocular movements. There are no palpable lymph nodes. Laboratory studies are ordered as seen below.
Hemoglobin: 9 g/dL
Hematocrit: 30%
Leukocyte count: 7,500/mm^3 with normal differential
Platelet count: 199,000/mm^3
Serum:
Na+: 140 mEq/L
Cl-: 101 mEq/L
K+: 4.0 mEq/L
HCO3-: 23 mEq/L
BUN: 29 mg/dL
Glucose: 197 mg/dL
Creatinine: 1.4 mg/dL
Ca2+: 10.2 mg/dL
Total bilirubin: 1.1 mg/dL
AST: 150 U/L
ALT: 112 U/L
Which of the following is the most likely diagnosis?
A. Hepatocellular carcinoma
B. Colon cancer (Correct Answer)
C. Pancreatic cancer
D. Acute cholecystitis
E. Acute appendicitis
Explanation: ***Colon cancer***
- The patient's presentation with **worsening abdominal pain**, chronic constipation, **blood coating the stool (hematochezia)**, and **significant anemia** (hemoglobin 9 g/dL, hematocrit 30%) are highly suggestive of **colorectal malignancy**. His **50 pack-year smoking history** is a significant risk factor for colon cancer.
- The **palpable liver edge extending 4 cm below the costal margin** and **elevated AST/ALT** (150/112 U/L) suggest **hepatic metastases**, which are common with advanced colon cancer and explain the hepatomegaly and liver enzyme elevation.
- While the positive Murphy's sign suggests concurrent **acute cholecystitis**, the constellation of chronic GI symptoms (constipation, hematochezia, anemia) indicates that **colon cancer is the underlying primary diagnosis**, with possible complications including liver metastases and secondary cholecystitis (which can occur in cancer patients due to biliary obstruction from liver metastases or other factors).
- This is the **most likely unifying diagnosis** that explains the majority of clinical findings.
*Hepatocellular carcinoma*
- While **hepatocellular carcinoma (HCC)** can cause hepatomegaly, RUQ pain, and elevated liver enzymes, it does not explain the pronounced lower GI symptoms such as **chronic constipation** and **blood coating the stool (hematochezia)**.
- HCC typically requires risk factors like **chronic viral hepatitis (HBV/HCV)** or **cirrhosis**, which are not mentioned in this case. The patient's presentation is more consistent with a primary GI malignancy with hepatic metastases.
*Pancreatic cancer*
- **Pancreatic cancer** typically presents with **epigastric pain radiating to the back**, weight loss, and **painless jaundice** (courvoisier sign), but the bilirubin is only minimally elevated (1.1 mg/dL) here.
- It does not typically cause **hematochezia** or the pattern of **chronic constipation** seen in this patient, making it less likely than colon cancer.
*Acute cholecystitis*
- **Acute cholecystitis** would explain the **RUQ pain**, **positive Murphy's sign**, and **low-grade fever** (99.5°F), and may indeed be present concurrently.
- However, it does NOT explain the **chronic constipation**, **hematochezia**, **significant anemia** (Hgb 9 g/dL), or the chronic nature of symptoms. These findings point to an underlying GI malignancy as the primary diagnosis.
- Acute cholecystitis alone would not cause blood in the stool or chronic anemia, making it less likely to be the primary/most likely diagnosis.
*Acute appendicitis*
- **Acute appendicitis** presents with **acute onset right lower quadrant (RLQ) pain**, rebound tenderness, fever, and typically **leukocytosis** (WBC often >10,000/mm³).
- This patient has **normal WBC** (7,500/mm³), **RUQ pain** (not RLQ), chronic symptoms, and findings suggesting liver involvement, making appendicitis highly unlikely.
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