Oncology — MCQs

Oncology Indian Medical PG Practice Questions and MCQs

Question 381: What is the tumor marker that can be indicative of disease relapse in a 65-year-old male who was diagnosed with prostate cancer three years ago and treated with surgery and hormone therapy, and is now experiencing urinary symptoms and progressive backache?

A. CA 125
B. Beta-HCG
C. Carcinoembryonic antigen (CEA)
D. PSA (Correct Answer)

Explanation: ***PSA*** - **Prostate-specific antigen (PSA)** is the primary tumor marker for prostate cancer and is used for screening, monitoring treatment response [2], and detecting **disease relapse** [4]. - Rising PSA levels in a patient with a history of prostate cancer, especially with new urinary symptoms and backache (suggesting **metastasis**), are highly indicative of recurrence [1]. *CA 125* - **CA 125** is primarily a tumor marker for **ovarian cancer** and is not used for monitoring prostate cancer. - While it can be elevated in some non-malignant conditions, it has no diagnostic or prognostic value for prostate cancer. *Beta-HCG* - **Beta-HCG** is a tumor marker typically associated with **germ cell tumors** (e.g., testicular cancer) and **choriocarcinoma** [3]. - It is not used for the diagnosis or monitoring of prostate cancer [3]. *Carcinoembryonic antigen (CEA)* - **CEA** is a tumor marker often associated with **colorectal cancer**, and less commonly with other adenocarcinomas such as lung or breast cancer. - It is not a specific or reliable marker for prostate cancer [4].

Question 382: What is the best method for screening prostate cancer?

A. DRE and PSA together
B. PET scan
C. DRE
D. PSA test (Correct Answer)

Explanation: ***PSA test*** - The **prostate-specific antigen (PSA) test** is a blood test that measures the level of PSA, a protein produced by the prostate gland [2]. Elevated PSA levels can indicate prostate cancer, but can also be caused by other benign prostate conditions (e.g., benign prostatic hyperplasia, prostatitis). - The PSA test is widely used for **screening asymptomatic men** for prostate cancer. While its use in widespread screening is debated due to concerns about overdiagnosis and overtreatment, it remains the primary blood test for initial prostate cancer detection. *PET scan* - **Positron Emission Tomography (PET) scans** are sophisticated imaging tests primarily used for **staging cancer** that has already been diagnosed, to detect metastases, or to monitor treatment response. - PET scans are **not recommended for initial prostate cancer screening** because they are expensive, involve radiation exposure, and lack the sensitivity and specificity needed for early detection in asymptomatic men. *DRE* - A **Digital Rectal Examination (DRE)** involves a physician inserting a gloved, lubricated finger into the rectum to feel the prostate gland for abnormalities such as lumps, hard spots, or an enlarged prostate [1]. - While DRE can sometimes detect prostate abnormalities, it has **limited sensitivity** for early-stage or small tumors and is **less effective than PSA** as a standalone screening tool [1]. *DRE and PSA together* - The **combination of DRE and PSA** was historically a common approach for prostate cancer screening, aiming to improve detection rates. - While performing both tests together can slightly increase detection compared to either test alone, **current guidelines often prioritize the PSA test** as the primary screening tool due to its higher sensitivity, particularly in conjunction with shared decision-making regarding the risks and benefits of screening. The DRE is often used as a follow-up if PSA is elevated or as a component of a comprehensive examination.

Question 383: The commonest site of lymphoma in the gastrointestinal system is:

A. Stomach (Correct Answer)
B. Large intestine
C. Esophagus
D. Small bowel

Explanation: **Stomach** - The **stomach** is the most common primary site for lymphoma within the gastrointestinal tract [1], especially **MALT lymphoma**, which is strongly associated with *Helicobacter pylori* infection [1]. - Gastric lymphoma can present with symptoms similar to peptic ulcer disease, such as **epigastric pain**, nausea, and weight loss [1]. *Small bowel* - While the small bowel can be affected by lymphoma, especially **enteropathy-associated T-cell lymphoma (EATL)**, it is less common than gastric involvement. - Small bowel lymphomas often cause **obstruction**, bleeding, or malabsorption [2]. *Large intestine* - Lymphoma of the large intestine is relatively rare compared to the stomach and small bowel. - It may present with symptoms such as **abdominal pain**, changes in bowel habits, or bleeding. *Esophagus* - Primary esophageal lymphoma is extremely rare. - When present, it is more often a result of **secondary involvement** from widespread lymphoma rather than a primary tumor.

Question 384: PSA greater than 20 ng/mL is commonly seen in:

A. Prostate cancer (Correct Answer)
B. BPH
C. Prostatitis
D. Bladder cancer

Explanation: ***Prostate cancer*** - A **prostate-specific antigen (PSA)** level greater than **20 ng/mL** is highly suggestive of **prostate cancer**, especially advanced disease, and prompts further evaluation. - While other conditions can elevate PSA, such levels significantly increase the **positive predictive value** for malignancy. *BPH* - **Benign prostatic hyperplasia (BPH)** can elevate PSA, but levels typically remain below **10 ng/mL**, rarely exceeding **20 ng/mL**. - The PSA elevation in BPH is proportional to the **gland size**, which usually doesn't lead to such high values. *Prostatitis* - **Prostatitis** (inflammation of the prostate) can cause a transient, significant increase in PSA, sometimes above **20 ng/mL**. - However, the elevation typically **normalizes** after treatment of the infection or inflammation, unlike in prostate cancer. *Bladder cancer* - **Bladder cancer** does not typically cause an elevation in PSA unless there is concurrent **prostatic involvement** or other prostate pathology. - PSA is a **prostate-specific marker**, so its elevation is not directly indicative of bladder malignancy.

Question 385: What would be the most probable diagnosis for a 50-year-old chronic smoker who presents with hemoptysis, truncal obesity, and hypertension, and has an elevated ACTH level that is not suppressible with high-dose dexamethasone?

A. Ectopic ACTH producing lung cancer (Correct Answer)
B. Adrenal adenoma
C. Bilateral adrenal hyperplasia
D. Pituitary tumor

Explanation: ***Ectopic ACTH producing lung cancer*** - The combination of **hemoptysis** in a **chronic smoker** points towards a pulmonary malignancy, which can produce **ectopic ACTH**, leading to Cushing's syndrome symptoms [2, 5]. - The **elevated ACTH** that is **not suppressible with high-dose dexamethasone** is characteristic of ectopic ACTH production, as the tumor cells do not respond to feedback inhibition [1]. *Adrenal adenoma* - An **adrenal adenoma** causes **ACTH-independent Cushing's syndrome**, meaning ACTH levels would be low [1]. - While it can cause symptoms like truncal obesity and hypertension, it does not explain the hemoptysis or elevated ACTH. *Bilateral adrenal hyperplasia* - **Bilateral adrenal hyperplasia** can cause Cushing's syndrome, but it is typically **ACTH-dependent** and often responsive to high-dose dexamethasone if it's pituitary-driven [1]. - It does not account for the hemoptysis or the **non-suppressible ACTH** level in this particular presentation. *Pituitary tumor* - A **pituitary tumor** (Cushing's disease) produces ACTH, causing Cushing's syndrome, and typically shows **suppression with high-dose dexamethasone** (though not always fully). - It would not explain the symptom of **hemoptysis** associated with a chronic smoker [2].

Question 386: Malignancy-associated hypercalcemia is due to?

A. Vitamin D secretion by tumors
B. Cytokine-mediated osteoclast activation
C. Bone metastases causing osteolysis
D. Parathyroid hormone-related peptide (PTHrP) (Correct Answer)

Explanation: Malignancy-associated hypercalcemia is primarily due to **parathyroid hormone-related peptide (PTHrP)**, which mimics the action of parathyroid hormone, causing increased calcium release from bones [1][2]. This condition is often seen in **solid tumors**, particularly squamous cell carcinomas, and can lead to significant **hypercalcemia** [2][3]. *Tumor lysis syndrome* - Tumor lysis syndrome results from rapid cell lysis leading to **release of intracellular contents**, causing hyperuricemia, not directly hypercalcemia. - It is characterized by **electrolyte imbalances** such as hyperkalemia, hyperphosphatemia, but not primarily hypercalcemia. *IGF-b* - Insulin-like Growth Factor (IGF) is primarily involved in **growth processes** and does not lead to hypercalcemia. - While it has an association with cancer, it does not function in the pathway that elevates serum calcium levels. *IL-7* - Interleukin-7 (IL-7) is mainly related to **T-cell development** and does not play a role in hypercalcemia associated with malignancy. - While cytokines can influence various pathways in cancer, IL-7 is not implicated in **calcium metabolism**.

Question 387: Screening of prostate cancer is commonly done by

A. DRE (digital rectal exam) & PSA (Correct Answer)
B. MRI imaging
C. Surgical intervention
D. Ultrasound-guided procedure

Explanation: ***DRE (digital rectal exam) & PSA*** - **Digital Rectal Exam (DRE)** allows for palpation of the prostate gland to detect **nodules**, **hardness**, or **asymmetry** that may indicate cancer. [1] - **Prostate-Specific Antigen (PSA)** is a blood test that measures a protein produced by the prostate gland; elevated levels can suggest prostate cancer. *MRI imaging* - While **MRI** is used for **staging** and sometimes for **targeted biopsies** of suspicious lesions, it is not a primary screening tool due to its cost and limited availability for broad population screening. - It is typically used *after* abnormal DRE or PSA results, or for monitoring. *Surgical intervention* - **Surgical intervention** (e.g., radical prostatectomy) is a **treatment** for prostate cancer confirmed by biopsy, not a screening method. - Screening aims to *detect* the disease, not to treat it. *Ultrasound-guided procedure* - **Transrectal ultrasound (TRUS)** is primarily used to **guide prostate biopsies** and determine prostate volume, not as a standalone screening test. - It does not have sufficient sensitivity or specificity to be routinely used for initial cancer screening.

Question 388: What is the role of the HER2/neu receptor in breast cancer treatment?

A. Screening for breast cancer risk
B. Assessing tumor recurrence risk
C. Guiding treatment decisions (Correct Answer)
D. Diagnosis of breast cancer based on HER2 status

Explanation: ***Predicting response to targeted therapies in breast cancer*** - The **HER2/neu receptor** is a key biomarker used to determine the effectiveness of targeted therapies, such as trastuzumab (Herceptin), in HER2-positive breast cancer [1]. - Presence of HER2 overexpression directly impacts treatment strategies and overall patient outcomes [1]. *Risk assessment for breast cancer screening* - While risk factors are essential for screening, **HER2/neu** is not utilized for general risk assessment. - Other factors like **family history** and **BRCA mutations** play a more significant role in this context. *Histological diagnosis of breast cancer* - Histological diagnosis primarily relies on **tissue biopsy** and specific grading systems, not HER2 status per se. - While HER2 can be evaluated histologically, it is not a key method for initial diagnosis [1]. *Prognosis and recurrence prediction in breast cancer* - HER2 positivity can indicate a worse prognosis, but it is more directly linked to **treatment response** than recurrence prediction [1]. - Other factors like **tumor size** and **lymph node status** are more traditionally used in prognosis.

Question 389: Carcinoid tumor is diagnosed by what means?

A. Measurement of urinary 5-HIAA levels. (Correct Answer)
B. Serum Chromogranin A levels.
C. Serum Neuron-Specific Enolase (NSE) levels.
D. Measurement of urinary 5-HTP levels.

Explanation: ***Measurement of urinary 5-HIAA levels.*** - Carcinoid tumors actively produce **serotonin (5-HT)**, which is metabolized into **5-hydroxyindoleacetic acid (5-HIAA)**. - Elevated levels of **5-HIAA** in a 24-hour urine collection are highly indicative of a carcinoid tumor [1]. *Serum Chromogranin A levels.* - **Chromogranin A** is a general marker for **neuroendocrine tumors**, including carcinoids, but is less specific than **5-HIAA** [1]. - Its levels can be elevated in other conditions like **renal insufficiency, atrophic gastritis**, and with **proton pump inhibitor (PPI)** use, leading to false positives. *Serum Neuron-Specific Enolase (NSE) levels.* - **NSE** is a marker primarily used for **small cell lung cancer** and some other neuroendocrine tumors, but it is not the primary diagnostic test for carcinoid. - While it can be elevated in some carcinoid cases, it lacks the specificity and diagnostic value of **urinary 5-HIAA** for classic carcinoid syndrome. *Measurement of urinary 5-HTP levels.* - **5-hydroxytryptophan (5-HTP)** is a precursor to serotonin, and its measurement is not a standard or primary diagnostic test for carcinoid tumors. - Carcinoid tumors typically directly produce **serotonin**, which is then metabolized to **5-HIAA**, making **5-HIAA** a more direct and reliable marker.

Question 390: The most common cause of severe hypercalcemia is

A. Malignancy (Correct Answer)
B. Vitamin D toxicity
C. Sarcoidosis
D. Chronic renal failure

Explanation: ***Malignancy*** - **Malignancy** is the most frequent cause of **severe hypercalcemia**, often resulting from **parathyroid hormone-related peptide (PTHrP) secretion** (humoral hypercalcemia of malignancy) or **bone metastases** causing osteolysis [1]. - Cancers like **squamous cell carcinoma**, **breast cancer**, **multiple myeloma**, and **renal cell carcinoma** are commonly associated with severe hypercalcemia [1]. *Vitamin D toxicity* - While vitamin D toxicity can cause hypercalcemia, it typically leads to **moderate hypercalcemia** and is less common as a cause of **severe hypercalcemia** compared to malignancy [1]. - It usually occurs due to **excessive intake of vitamin D supplements** or activated vitamin D [1]. *Sarcoidosis* - Sarcoidosis can cause hypercalcemia due to **extrarenal production of 1,25-dihydroxyvitamin D** by activated macrophages [1]. - However, the hypercalcemia in sarcoidosis is usually **mild to moderate** and rarely reaches the severity seen with malignancy [1]. *Chronic renal failure* - **Chronic renal failure** is more commonly associated with **hypocalcemia** due to impaired vitamin D activation and hyperparathyroidism [2], [3]. - While some patients with end-stage renal disease and **adynamic bone disease** or **tertiary hyperparathyroidism** can develop hypercalcemia, it is not the most common cause of *severe* hypercalcemia in the general population.

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Oncology — MCQs

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