Oncology Practice Questions

Q: Which of the following is NOT a feature of tumour lysis syndrome?

Hypernatremia. Explanation: Tumor Lysis Syndrome (TLS) is a metabolic emergency caused by the rapid breakdown of malignant cells, typically following chemotherapy for high-grade hematologic malignancies (e.g., Burkitt lymphoma, ALL). When cells lyse, they release their intracellular contents into the systemic circulation. Why Hypernatremia is the Correct Answer: Hypernatremia is not a feature of TLS. Sodium is the primary extracellular cation; therefore, the destruction of cells does not significantly increase serum sodium levels. In fact, aggressive hydration (the mainstay of TLS management) may sometimes lead to dilutional hyponatremia [1], but hypernatremia is not part of the classic metabolic triad. Why the other options are incorrect (Features of TLS): * Hyperuricemia (A): Catabolism of purines from released nucleic acids leads to high uric acid levels [2], which can cause acute kidney injury (urate nephropathy). * Hyperphosphatemia (C): Malignant cells contain significantly higher concentrations of intracellular phosphorus than normal cells. Rapid release leads to hyperphosphatemia. * Hypocalcemia (B): This is a secondary phenomenon. Excess phosphorus binds to serum calcium, forming calcium-phosphate crystals that deposit in soft tissues and the kidneys, leading to a drop in ionized calcium. * Hyperkalemia: (Though not an option, it is a hallmark) Release of intracellular potassium can lead to life-threatening arrhythmias. Clinical Pearls for NEET-PG: * Cairo-Bishop Definition: Used to classify laboratory vs. clinical TLS. * Prophylaxis: Aggressive IV hydration and Allopurinol (xanthine oxidase inhibitor). * Treatment of Choice for Hyperuricemia: Rasburicase (recombinant urate oxidase) which converts uric acid to the highly soluble allantoin. * The "TLS Triad + 1": Hyperkalemia, Hyperphosphatemia, Hyperuricemia, and Hypocalcemia.

Q: Hormonal treatment is given for which of the following malignancies?

Carcinoma of the prostate. **Explanation:** **1. Why Carcinoma of the Prostate is Correct:** Prostate cancer is a classic example of a **hormone-dependent malignancy**. The growth and survival of prostatic adenocarcinoma cells are largely driven by androgens (testosterone and dihydrotestosterone) [1]. Therefore, **Androgen Deprivation Therapy (ADT)** is a cornerstone of management, especially in metastatic or advanced stages [2]. This is achieved through surgical castration (orchiectomy) or medical castration using GnRH agonists (e.g., Leuprolide), GnRH antagonists (e.g., Degarelix), or androgen receptor blockers (e.g., Enzalutamide). **2. Analysis of Incorrect Options:** * **Choriocarcinoma (A):** This is a highly malignant germ cell tumor that is exquisitely sensitive to **chemotherapy** (specifically Methotrexate or the EMA-CO regimen). While it produces hormones (hCG), it is not treated with hormonal therapy [1]. * **Hepatoma (C):** Hepatocellular carcinoma (HCC) is primarily treated with surgical resection, liver transplantation, or targeted systemic therapies like Multikinase inhibitors (e.g., **Sorafenib**, Lenvatinib) and immunotherapy. It does not respond to hormonal manipulation. * **Teratoma (D):** Teratomas are germ cell tumors composed of multiple germ layers. Mature teratomas are treated with **surgical excision**, while malignant components (immature teratoma) require chemotherapy [1]. They are not hormone-sensitive. **Clinical Pearls for NEET-PG:** * **Other Hormone-Dependent Tumors:** Breast cancer (ER/PR positive), Endometrial cancer, and some Thyroid cancers (TSH suppression). * **First-line for Metastatic Prostate CA:** ADT is the standard of care. * **Tumor Flare:** GnRH agonists can cause a transient surge in testosterone; this is prevented by co-administering Flutamide (anti-androgen) for the first 2 weeks.

Q: What is the most common cause of ectopic ACTH production?

Small cell carcinoma of the lung. **Explanation:** **Ectopic ACTH Syndrome** occurs when a non-pituitary tumor secretes adrenocorticotropic hormone, leading to ACTH-dependent Cushing syndrome [1]. 1. **Why Small Cell Carcinoma of the Lung (SCLC) is correct:** SCLC is a neuroendocrine tumor and is the **most common cause** of ectopic ACTH production, accounting for approximately 50% of cases [2]. These tumors possess the cellular machinery to express the *POMC* gene, the precursor to ACTH. Clinically, these patients often present with rapid-onset hypertension, profound hypokalemia, and metabolic alkalosis, rather than the classic "cushingoid" physical features (like buffalo hump), due to the aggressive nature of the underlying malignancy. 2. **Why the other options are incorrect:** * **Renal cell carcinoma:** While RCC is known for various paraneoplastic syndromes (like EPO production leading to polycythemia or PTHrP leading to hypercalcemia), it is a very rare cause of ectopic ACTH [2]. * **Hepatocellular carcinoma:** Similar to RCC, HCC can cause paraneoplastic hypoglycemia or erythrocytosis, but it is not a classic source of ACTH [2]. * **Pheochromocytoma:** While pheochromocytomas are neuroendocrine tumors and *can* secrete ACTH, they are much rarer causes compared to SCLC. **NEET-PG High-Yield Pearls:** * **Most common cause of Ectopic ACTH:** Small cell carcinoma of the lung [2]. * **Second most common cause:** Carcinoid tumors (especially bronchial carcinoids). * **Diagnostic clue:** High ACTH levels that are **not suppressed** by high-dose dexamethasone (8mg), unlike Pituitary Cushing’s (Cushing Disease). * **Classic Lab Finding:** Severe hypokalemia is a hallmark of ectopic ACTH due to the mineralocorticoid effects of high cortisol levels.

Q: What is the primary treatment modality for extragonadal germ cell tumors?

Chemotherapy. **Explanation:** Extragonadal Germ Cell Tumors (EGGCTs) are rare neoplasms that arise from primordial germ cells that failed to migrate to the gonadal ridges during embryogenesis. They are typically found in midline structures such as the mediastinum, retroperitoneum, and pineal gland. **Why Chemotherapy is Correct:** The primary treatment modality for EGGCTs is **platinum-based chemotherapy** (typically the BEP regimen: Bleomycin, Etoposide, and Cisplatin) [1]. Germ cell tumors are highly chemosensitive. Because EGGCTs are often bulky, located in surgically challenging midline areas, and have a high propensity for systemic micrometastasis, systemic chemotherapy is required as the first-line treatment to downstage the tumor and address potential spread [1]. **Why Other Options are Incorrect:** * **Radiotherapy:** While some dysgerminomas/seminomas are radiosensitive, radiation is generally reserved for specific sites (like intracranial germinomas) or palliative care [1]. It is not the primary modality for systemic or bulky EGGCTs. * **Surgery:** In EGGCTs, surgery is rarely the primary treatment. It is usually performed **post-chemotherapy** to resect residual masses (especially in non-seminomatous types) to check for viable tumor or teratoma [1]. * **Immunotherapy:** This is currently not a standard first-line treatment for germ cell tumors, though it is being investigated for refractory cases. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** The mediastinum is the most common extragonadal site in adults [1]. * **Tumor Markers:** Always check **AFP** (elevated in Yolk Sac Tumors) and **β-hCG** (elevated in Choriocarcinomas). * **Association:** Mediastinal non-seminomatous GCTs are associated with hematologic malignancies (e.g., Acute Myeloid Leukemia). * **Klinefelter Syndrome (47, XXY):** There is a strong clinical association between Klinefelter syndrome and the development of mediastinal EGGCTs.

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

Small cell carcinoma. **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 1

Which of the following is NOT a feature of tumour lysis syndrome?

Accepted Answer

Hypernatremia

Answer

Hyperuricemia

Answer

Hypocalcemia

Answer

Hyperphosphatemia

Question 2

A 70-year-old intensive care unit patient complains of fever and shaking chills. The patient develops hypotension, and blood cultures are positive for gram-negative bacilli. The patient begins bleeding from venipuncture sites and around his Foley catheter. Laboratory studies show: Hct: 38%, WBC: 15,000/mL, Platelet count: 40,000/mL, fragmented RBCs on peripheral blood smear, elevated PT, elevated PTT, plasma fibrinogen: 70 mg/dL. Which of the following is the best course of therapy in this patient?

Accepted Answer

Treat underlying disease

Answer

Begin heparin

Answer

Begin plasmapheresis

Answer

Give vitamin K

Question 3

Hormonal treatment is given for which of the following malignancies?

Accepted Answer

Carcinoma of the prostate

Answer

Choriocarcinoma

Answer

Hepatoma

Answer

Teratoma

Question 4

A 42-year-old man is on amitriptyline for depression. Recently he has been feeling more lethargic and unwell. His clinical examination is normal. Serum sodium is 125 mEq/L and osmolality is 260 mOsm/kg, and urine sodium is 40 mEq/L and osmolality is 450 mOsm/kg. For the above patient with hyponatremia, select the most likely diagnosis.

Accepted Answer

Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

Answer

Congestive heart failure (CHF)

Answer

Extrarenal sodium and fluid losses

Answer

Polydipsia

Question 5

What is the commonest site of extramedullary relapse?

Accepted Answer

Central Nervous System (CNS)

Answer

Lung

Answer

Liver

Answer

Testis

Question 6

Which of the following statements regarding cancer therapy with interleukin 2 (IL-2) is true?

Accepted Answer

It induces a major response in patients with metastatic melanoma

Answer

It is a B-cell growth factor

Answer

It induces a major response in patients with metastatic breast cancer

Answer

It induces a major response in patients with metastatic colon cancer

Question 7

What is the most common cause of ectopic ACTH production?

Accepted Answer

Small cell carcinoma of the lung

Answer

Renal cell carcinoma

Answer

Hepatocellular carcinoma

Answer

Pheochromocytoma

Question 8

What is the primary treatment modality for extragonadal germ cell tumors?

Accepted Answer

Chemotherapy

Answer

Radiotherapy

Answer

Surgery

Answer

Immunotherapy

Question 9

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

Accepted Answer

Small cell carcinoma

Answer

Adenocarcinoma

Answer

Squamous cell carcinoma

Answer

Large cell carcinoma

Question 10

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

Accepted Answer

Treatment can be withheld in asymptomatic patients.

Answer

Treatment should be offered to all patients diagnosed with CLL.

Answer

The treatment for CLL is curative.

Answer

Combination chemoradiotherapy should be administered to patients above 50 years of age.

Oncology — MCQs

Oncology — MCQs

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