Oncology — MCQs

A 60-year-old woman presents with symptoms of muscle weakness and fatigue. Her examination reveals blood pressure of 110/80 mm Hg, pulse of 100/min, JVP of 1 cm, normal heart sounds, and clear lungs. Laboratory findings include serum potassium of 2.5 mEq/L, bicarbonate of 15 mEq/L, and a normal anion gap. Urine potassium is 10 mEq/L. For this patient with hypokalemia, what is the most likely diagnosis?

Q50Medium

A 35-year-old woman presents with several days of increasing fatigue and shortness of breath on exertion. She was recently diagnosed with Mycoplasma pneumoniae. Physical examination reveals BP 113/67, HR 114 beats/min, and respiratory rate 20 breaths/min. She appears icteric and in mild respiratory distress. Her hemoglobin is 9.0 g/dL and MCV is 110. Which of the following is the best next diagnostic test?

Oncology Indian Medical PG Practice Questions and MCQs

Question 41: Which of the following tumors is typically associated with lymph node metastasis?

A. Liposarcoma
B. Neurofibrosarcoma
C. Histiocytoma
D. Angiosarcoma (Correct Answer)

Explanation: In the study of soft tissue sarcomas, a fundamental rule is that they primarily spread via the **hematogenous route** (bloodstream), most commonly to the lungs. Lymph node involvement is rare, occurring in less than 5% of cases. However, there are specific exceptions to this rule that are frequently tested in NEET-PG. **Angiosarcoma (Option D)** is the correct answer because it is one of the few soft tissue sarcomas known for a higher propensity for lymphatic spread. Other sarcomas in this "exception" category include Clear cell sarcoma, Rhabdomyosarcoma, Epithelioid sarcoma, and Synovial sarcoma. **Analysis of Incorrect Options:** * **Liposarcoma (Option A):** The most common adult soft tissue sarcoma. It typically spreads via local invasion or hematogenously to the lungs and retroperitoneum, but rarely involves lymph nodes. * **Neurofibrosarcoma (Option B):** Also known as Malignant Peripheral Nerve Sheath Tumor (MPNST), it is often associated with NF-1. It spreads locally and via the bloodstream. * **Histiocytoma (Option C):** Specifically Malignant Fibrous Histiocytoma (now termed Pleomorphic Undifferentiated Sarcoma), it follows the classic hematogenous spread pattern. **NEET-PG High-Yield Pearls:** To remember the sarcomas that spread via lymph nodes, use the mnemonic **"CREST"**: * **C:** Clear cell sarcoma * **R:** Rhabdomyosarcoma (most common in children) * **E:** Epithelioid sarcoma * **S:** Synovial sarcoma * **T:** (Angio)**T**umors / Angiosarcoma **Clinical Note:** Angiosarcomas are aggressive endothelial cell malignancies. They are classically associated with chronic lymphedema (Stewart-Treves Syndrome) and prior radiation therapy.

Question 42: Superior vena cava syndrome is most commonly caused by which of the following malignancies?

A. Adenocarcinoma
B. Squamous cell carcinoma
C. Small cell carcinoma (Correct Answer)
D. Large cell carcinoma

Explanation: **Explanation:** Superior Vena Cava (SVC) syndrome results from the obstruction of blood flow through the SVC, typically due to external compression or direct invasion by a mediastinal mass. **Why Small Cell Carcinoma (SCLC) is the correct answer:** While Non-Small Cell Lung Cancer (NSCLC) as a broad group accounts for more total cases of SVC syndrome due to its higher overall prevalence, **Small Cell Carcinoma** is the single most common histological subtype associated with this condition. This is due to its biological behavior: SCLC is typically **centrally located** (near the hilum and mediastinum) and is characterized by rapid growth and early involvement of mediastinal lymph nodes, which directly compress the thin-walled SVC. **Analysis of Incorrect Options:** * **Adenocarcinoma:** This is the most common type of lung cancer overall, but it is typically **peripherally located**. Therefore, it is less likely to cause central venous compression compared to SCLC. * **Squamous Cell Carcinoma:** While often centrally located, it is more prone to cavitation and endobronchial obstruction rather than the massive mediastinal lymphadenopathy seen in SCLC. * **Large Cell Carcinoma:** This is a less common subtype of NSCLC and does not carry the same predilection for central mediastinal crowding as SCLC. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause overall:** Malignancy (70-90%), specifically Lung Cancer [1]. * **Most common non-malignant cause:** Iatrogenic (indwelling catheters/pacemaker wires) leading to thrombosis. * **Clinical Presentation:** Facial puffiness, "plethora" (redness), dilated neck veins (non-pulsatile), and Pemberton’s sign. * **Management:** SCLC is highly chemo-sensitive [1]; therefore, chemotherapy is often the primary treatment for SVC syndrome caused by SCLC, whereas radiation is preferred for NSCLC.

Question 43: A 69-year-old woman is taking large amounts of aspirin for osteoarthritis and now complains of ringing in her ears and nausea. What is the most likely acid-base disorder for this patient with new symptoms?

A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis (Correct Answer)

Explanation: **Explanation:** This patient is presenting with classic signs of **salicylate (aspirin) toxicity**, characterized by tinnitus (ringing in the ears) and nausea [1]. **Why Respiratory Alkalosis is Correct:** Salicylates act as a direct stimulant to the medullary respiratory center [2, 5]. This leads to hyperventilation (increased rate and depth of breathing), which causes an excessive loss of $CO_2$. According to the Henderson-Hasselbalch principle, a decrease in $pCO_2$ results in an increase in blood pH, leading to **primary respiratory alkalosis** [2]. This is typically the earliest acid-base disturbance seen in adults following an aspirin overdose [1]. **Why the other options are incorrect:** * **Metabolic Acidosis:** While salicylates eventually cause a High Anion Gap Metabolic Acidosis (HAGMA) by uncoupling oxidative phosphorylation and increasing organic acids (lactic acid, ketoacids), the *initial* and most characteristic direct effect on the respiratory center in early toxicity is respiratory alkalosis [1]. * **Metabolic Alkalosis:** Aspirin is an acid (acetylsalicylic acid); its toxicity does not lead to a primary increase in bicarbonate or loss of hydrogen ions. * **Respiratory Acidosis:** This occurs only in very late stages or severe pediatric toxicity where central nervous system depression leads to hypoventilation, which is not the case here. **NEET-PG High-Yield Pearls:** * **Mixed Acid-Base Disorder:** In adults, the most common presentation of salicylate poisoning is a **mixed respiratory alkalosis and metabolic acidosis** [1]. If a question asks for the *earliest* or *most likely* initial change, choose respiratory alkalosis. * **Tinnitus:** This is a highly specific early sign of salicylate toxicity ("Salicylism") [1]. * **Treatment:** Management involves **urinary alkalinization** with Sodium Bicarbonate ($NaHCO_3$) to enhance salicylate excretion (ion trapping) and hemodialysis in severe cases.

Question 44: Which type of Hodgkin disease (HD) is characterized by a particularly good prognosis?

A. Lymphocyte-predominant Hodgkin disease (HD) (Correct Answer)
B. Nodular-sclerosing HD
C. Mixed-cellularity HD
D. Lymphocyte-depleted HD, reticular type

Explanation: The prognosis of Hodgkin Lymphoma (HL) is traditionally linked to the ratio of reactive lymphocytes to Reed-Sternberg (RS) cells [1]. A higher number of lymphocytes generally correlates with a more indolent course and a better prognosis. **1. Why Lymphocyte-Predominant HD is Correct:** This subtype (specifically **Nodular Lymphocyte-Predominant HL**) is characterized by an abundance of small lymphocytes and rare malignant cells known as **"Popcorn cells"** (L&H variants). It typically presents in young males as localized (Stage I or II) peripheral lymphadenopathy. It has the **best overall prognosis** among all subtypes, often behaving like a low-grade B-cell lymphoma with a very high long-term survival rate. **2. Analysis of Incorrect Options:** * **Nodular Sclerosing HD:** This is the **most common** subtype overall. While it has an excellent prognosis, it is slightly less favorable than the lymphocyte-predominant type. It is characterized by collagen bands and **Lacunar cells**. * **Mixed-Cellularity HD:** This type features a diverse inflammatory background (eosinophils, plasma cells). It has an intermediate prognosis and is more frequently associated with **EBV infection** and constitutional "B" symptoms. * **Lymphocyte-Depleted HD:** This is the **rarest** and most aggressive form. It is characterized by numerous pleomorphic RS cells and few lymphocytes. It carries the **worst prognosis** and is often seen in elderly or HIV-positive patients. **High-Yield Clinical Pearls for NEET-PG:** * **Best Prognosis:** Lymphocyte Predominant. * **Worst Prognosis:** Lymphocyte Depleted. * **Most Common Subtype:** Nodular Sclerosis (especially in young females). * **Subtype with most Eosinophils:** Mixed Cellularity (due to IL-5 secretion). * **RS Cell Markers:** Classic HL is **CD15+ and CD30+**; Lymphocyte Predominant is **CD20+** (CD15/30 negative).

Question 45: In Tumor Lysis Syndrome, which of the following signs due to hypocalcemia is NOT typically seen?

A. Tetany
B. Myopathy
C. Parkinsonism
D. Cardiac arrhythmias (Correct Answer)

Explanation: In **Tumor Lysis Syndrome (TLS)**, rapid cell breakdown leads to hyperphosphatemia. Excess phosphate binds to calcium, forming calcium phosphate crystals, which results in **secondary hypocalcemia** [1]. ### Why "Cardiac Arrhythmias" is the Correct Answer While hypocalcemia *can* cause ECG changes (like QTc prolongation [1]), it is **not** typically the primary driver of life-threatening arrhythmias in the context of TLS. In TLS, the most dangerous and characteristic cause of cardiac arrhythmias is **Hyperkalemia** (due to the release of intracellular potassium). Since the question asks which sign is "not typically seen" *due to hypocalcemia* in this specific syndrome, cardiac arrhythmias are attributed to potassium derangements rather than calcium. ### Explanation of Incorrect Options * **Tetany (A):** This is a classic manifestation of hypocalcemia. Low extracellular calcium lowers the threshold for depolarization in peripheral nerves, leading to muscle spasms and carpopedal spasms. * **Myopathy (B):** Hypocalcemia can present as proximal muscle weakness or myopathic symptoms due to altered neuromuscular excitability. * **Parkinsonism (C):** Chronic or severe hypocalcemia can lead to calcification of the basal ganglia (Fahr’s syndrome), which manifests as extrapyramidal symptoms, including parkinsonism. ### High-Yield Clinical Pearls for NEET-PG * **TLS Metabolic Profile:** Hyperuricemia, Hyperkalemia, Hyperphosphatemia, and **Hypocalcemia** [1]. * **ECG in Hypocalcemia:** Look for **prolonged QT interval** (specifically the ST segment) [1]. * **Chvostek’s Sign:** Facial twitching when tapping the facial nerve (sign of hypocalcemia). * **Trousseau’s Sign:** Carpal spasm induced by inflating a BP cuff (more sensitive than Chvostek’s). * **Prophylaxis:** Aggressive hydration and **Rasburicase** (recombinant urate oxidase) are preferred over Allopurinol for high-risk patients.

Question 46: A 70-year-old male has been experiencing intermittent epistaxis, fatigue, and bone pain for the past 4 months. Laboratory investigations show serum calcium of 14.2 mg/dL (Normal 8.9-10.1 mg/dL). How should the above condition be treated?

A. Radiotherapy
B. Chemotherapy (Correct Answer)
C. Antibiotics
D. Antifungal therapy

Explanation: ### **Explanation** The clinical presentation of **epistaxis (bleeding diathesis), fatigue (anemia), bone pain, and severe hypercalcemia (14.2 mg/dL)** in an elderly male is highly suggestive of **Multiple Myeloma (MM)** [1]. #### **Why Chemotherapy is Correct** Multiple Myeloma is a plasma cell dyscrasia characterized by the "CRAB" features: **C**alcium elevation, **R**enal insufficiency, **A**nemia, and **B**one lesions. * **Systemic Nature:** MM is a systemic hematological malignancy, not a localized tumor [1]. Therefore, the primary treatment modality is **systemic chemotherapy** (e.g., Proteasome inhibitors like Bortezomib, Immunomodulators like Lenalidomide, and Corticosteroids). * **Hypercalcemia Management:** While acute hypercalcemia requires aggressive hydration and bisphosphonates [2], the definitive treatment for the underlying cause (malignant plasma cell proliferation) is chemotherapy. #### **Why Other Options are Incorrect** * **Radiotherapy:** Used primarily for localized complications, such as painful focal bone lesions or spinal cord compression [3], but it cannot treat the systemic disease or the generalized hypercalcemia. * **Antibiotics & Antifungal therapy:** While MM patients are immunocompromised and prone to infections, these do not treat the underlying malignancy or the metabolic emergency of hypercalcemia. #### **NEET-PG High-Yield Pearls** * **Hypercalcemia of Malignancy:** MM is a leading cause. Treat acutely with **IV Normal Saline** (first step) followed by **Zoledronic acid** or **Pamidronate** [2]. * **Diagnosis:** Look for **M-spike** on Serum Protein Electrophoresis (SPEP) and **>10% clonal plasma cells** on bone marrow biopsy [1]. * **Bone Pain:** In MM, bone lesions are **osteolytic** (punched-out lesions) [1]. Note: Bone scans are often negative because they detect osteoblastic activity; **Skeletal Survey (X-rays)** or MRI is preferred. * **Bence-Jones Proteins:** These are free light chains found in the urine, which can lead to "Myeloma Kidney."

Question 47: Which of the following statements about the treatment of Chronic Lymphocytic Leukemia (CLL) is true?

A. Treatment should be offered to all patients diagnosed with CLL.
B. Treatment can be withheld in asymptomatic patients. (Correct Answer)
C. The treatment for CLL is curative.
D. Combination chemoradiotherapy should be administered to patients above 50 years of age.

Explanation: **Explanation:** **1. Why Option B is Correct:** Chronic Lymphocytic Leukemia (CLL) is often an indolent malignancy characterized by the clonal proliferation of mature B-cells. Unlike many other cancers, early intervention in asymptomatic patients (Rai Stage 0 or Binet Stage A) does not improve overall survival [1]. Therefore, the standard of care is **"Watchful Waiting"** (observation). Treatment is only initiated when the patient becomes symptomatic or shows evidence of disease progression (e.g., "B" symptoms, progressive marrow failure, or massive lymphadenopathy). **2. Why the Other Options are Incorrect:** * **Option A:** Treatment is not universal. Approximately one-third of patients never require treatment during their lifetime. Initiating therapy prematurely exposes patients to unnecessary toxicity without clinical benefit. * **Option C:** Current standard therapies (including Targeted agents like Ibrutinib or Venetoclax and Chemoimmunotherapy like FCR) are highly effective at inducing remission but are generally **not curative** [2]. The only potentially curative treatment is Allogeneic Stem Cell Transplant, which is reserved for very specific, high-risk cases. * **Option D:** CLL is a systemic hematological malignancy; localized radiotherapy is rarely used except for palliative relief of bulky lymphadenopathy [1]. Furthermore, age alone does not dictate "chemoradiotherapy"; treatment choice depends on fitness, comorbidities, and genetic markers (e.g., 17p deletion). **3. NEET-PG High-Yield Pearls:** * **Indications for Treatment (iwCLL Criteria):** Progressive anemia/thrombocytopenia, massive/symptomatic splenomegaly or lymphadenopathy, lymphocyte doubling time <6 months, or severe constitutional symptoms. * **Most Common Leukemia in the West:** CLL (often presents as incidental lymphocytosis in elderly patients). * **Diagnosis:** Flow cytometry showing **CD5+, CD19+, CD20+(weak), and CD23+** B-cells. * **Peripheral Smear:** Characterized by **Smudge cells** (Basket cells). * **Richter Transformation:** Development of high-grade Large B-cell Lymphoma in a CLL patient (poor prognosis).

Question 48: A 40-year-old female patient presents with weakness and loss of appetite. She is a known case of non-Hodgkin's lymphoma, and lymph node examination shows involvement of Waldeyer's ring. What is the clinical stage for this patient?

A. Stage I (Correct Answer)
B. Stage II
C. Stage III
D. Stage IV

Explanation: ### Explanation The clinical staging of Non-Hodgkin’s Lymphoma (NHL) follows the **Ann Arbor Staging System** (modified by the Cotswolds criteria) [1]. **Why Stage I is Correct:** In the Ann Arbor system, **Stage I** is defined as the involvement of a single lymph node region or a single extralymphatic organ/site. **Waldeyer’s ring** (comprising the tonsils, adenoids, and lingual tonsils) is considered a **single lymphoid site** [1]. Since the question specifies involvement of Waldeyer's ring without mentioning any other nodal or extranodal sites, it is classified as Stage I. **Analysis of Incorrect Options:** * **Stage II:** Requires involvement of two or more lymph node regions on the **same side** of the diaphragm. * **Stage III:** Requires involvement of lymph node regions on **both sides** of the diaphragm (e.g., cervical and inguinal nodes). * **Stage IV:** Represents diffuse or disseminated involvement of one or more extralymphatic organs (like bone marrow or liver), with or without associated lymph node involvement [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Waldeyer’s Ring:** It is a common site for extranodal NHL (especially Diffuse Large B-Cell Lymphoma). For staging purposes, it is treated as a single nodal station [1]. * **"E" Suffix:** If a single extranodal site is involved (e.g., localized stomach involvement), it is Stage IE. * **"B" Symptoms:** Fever (>38°C), drenching night sweats, and weight loss (>10% in 6 months) [1]. Their presence adds a "B" suffix (e.g., Stage IB), while their absence adds "A". * **Spleen:** Involvement of the spleen is considered nodal involvement and is designated by the suffix "S" (Stage IIIS) [1].

Question 49: A 60-year-old woman presents with symptoms of muscle weakness and fatigue. Her examination reveals blood pressure of 110/80 mm Hg, pulse of 100/min, JVP of 1 cm, normal heart sounds, and clear lungs. Laboratory findings include serum potassium of 2.5 mEq/L, bicarbonate of 15 mEq/L, and a normal anion gap. Urine potassium is 10 mEq/L. For this patient with hypokalemia, what is the most likely diagnosis?

A. Lower gastrointestinal losses (Correct Answer)
B. Prior use of diuretics
C. Renal tubular acidosis
D. Current use of diuretics

Explanation: This clinical scenario tests the systematic approach to **hypokalemia** by evaluating urinary potassium excretion and acid-base status. ### **Explanation of the Correct Answer** The patient presents with hypokalemia (2.5 mEq/L) and metabolic acidosis (Bicarbonate 15 mEq/L). The key to the diagnosis lies in the **Urine Potassium level (10 mEq/L)** [1]. * In hypokalemia, the normal renal response is to conserve potassium. A **Urine K+ < 15–20 mEq/L** indicates **extra-renal losses** (the kidneys are functioning correctly by holding onto potassium) [1]. * Lower GI losses (e.g., chronic diarrhea, laxative abuse) result in the loss of potassium and bicarbonate. This leads to hypokalemia and a **Normal Anion Gap Metabolic Acidosis (NAGMA)** [1]. ### **Why Other Options are Incorrect** * **B & D (Diuretics):** Both current and prior diuretic use typically cause **increased** urinary potassium excretion (Urine K+ > 20 mEq/L) and are usually associated with metabolic **alkalosis**, not acidosis. * **C (Renal Tubular Acidosis):** While RTA (Types 1 and 2) causes NAGMA and hypokalemia, it is a **renal** cause of potassium loss. Therefore, the Urine K+ would be inappropriately **high** (> 20 mEq/L) despite the low serum potassium. ### **NEET-PG High-Yield Pearls** 1. **Urinary K+ Threshold:** Use **20 mEq/L** as the cutoff. < 20 mEq/L = Extra-renal loss (GI or skin); > 20 mEq/L = Renal loss (Diuretics, RTA, Hyperaldosteronism) [1]. 2. **Acid-Base Clues:** * Hypokalemia + Acidosis = Diarrhea or RTA [1]. * Hypokalemia + Alkalosis = Vomiting, Diuretics, or Conn’s Syndrome. 3. **Transtubular Potassium Gradient (TTPG):** A TTPG > 7 in a hypokalemic patient suggests renal potassium wasting.

Question 50: A 35-year-old woman presents with several days of increasing fatigue and shortness of breath on exertion. She was recently diagnosed with Mycoplasma pneumoniae. Physical examination reveals BP 113/67, HR 114 beats/min, and respiratory rate 20 breaths/min. She appears icteric and in mild respiratory distress. Her hemoglobin is 9.0 g/dL and MCV is 110. Which of the following is the best next diagnostic test?

A. Serum protein electrophoresis
B. Flow cytometry
C. Peripheral blood smear (Correct Answer)
D. Glucose-6-PD level

Explanation: **Explanation:** The clinical presentation is highly suggestive of **Cold Agglutinin Disease (CAD)**, a form of autoimmune hemolytic anemia (AIHA) triggered by **Mycoplasma pneumoniae**. The patient presents with acute anemia (Hb 9.0 g/dL), jaundice (icterus), and macrocytosis (MCV 110 fL). In CAD, IgM antibodies bind to RBCs at low temperatures, causing them to clump together [1]. **Why Peripheral Blood Smear is the best next step:** A peripheral blood smear is the most rapid and cost-effective initial test to confirm hemolysis and identify **RBC agglutination** (clumping). This clumping explains the falsely elevated MCV, as automated counters mistake RBC clusters for single large cells [1]. The smear will also show **spherocytes**, confirming an extravascular hemolytic process [2]. **Analysis of Incorrect Options:** * **A. Serum protein electrophoresis:** Used to detect monoclonal gammopathy (e.g., Multiple Myeloma). While CAD can be associated with Waldenström macroglobulinemia, it is not the immediate diagnostic step for acute hemolysis. * **B. Flow cytometry:** This is the gold standard for Paroxysmal Nocturnal Hemoglobinuria (PNH) (CD55/59 deficiency). PNH presents with intravascular hemolysis but is not typically triggered by Mycoplasma. * **C. Glucose-6-PD level:** G6PD deficiency causes hemolysis triggered by oxidative stress (drugs, fava beans) [3]. While it shows bite cells on a smear, it is not associated with Mycoplasma or high MCV due to agglutination. **NEET-PG High-Yield Pearls:** * **Cold AIHA (IgM):** Associated with *Mycoplasma pneumoniae* and Infectious Mononucleosis (EBV) [1]. * **Warm AIHA (IgG):** Associated with SLE, CLL, and drugs (α-methyldopa) [2]. * **Direct Coombs Test:** In CAD, it is positive for **C3b/complement** only (IgM dissociates at warmer temperatures) [1]. * **Management:** Avoid cold exposure; Rituximab is the preferred medical therapy if needed [1].

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Oncology — MCQs

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