Oncology Practice Questions

Q: A patient presents to the emergency room after a seizure. Laboratory investigations reveal SIADH, and a CT scan demonstrates a lung mass. Which of the following lung cancer subtypes is most likely to cause this electrolyte imbalance?

Small cell carcinoma. **Explanation:** **1. Why Small Cell Carcinoma (SCLC) is correct:** Small cell lung carcinoma is a neuroendocrine tumor derived from **Kulchitsky cells**. These cells have the metabolic machinery to produce various ectopic hormones. **SIADH (Syndrome of Inappropriate Antidiuretic Hormone)** is the most common paraneoplastic syndrome associated with SCLC, occurring in approximately 7–10% of patients [1]. It results in water retention and dilutional hyponatremia, which can manifest clinically as seizures, confusion, or coma [1]. **2. Why the other options are incorrect:** * **Adenocarcinoma (Option A):** This is the most common lung cancer overall (especially in non-smokers). While it is associated with hypertrophic osteoarthropathy (clubbing), it rarely causes SIADH. * **Bronchioloalveolar carcinoma (Option B):** Now classified under Adenocarcinoma in situ, it typically presents with voluminous watery sputum (bronchorrhea) rather than endocrine disturbances. * **Large cell carcinoma (Option C):** This is a diagnosis of exclusion. It is more commonly associated with gynecomastia due to beta-hCG production, not SIADH. **3. High-Yield Clinical Pearls for NEET-PG:** * **Small Cell Carcinoma:** Associated with "The 3 S's": **S**IADH, **S**ubacute cerebellar degeneration, and Lambert-Eaton **S**yndrome (and ACTH/Cushing’s) [1]. * **Squamous Cell Carcinoma:** Associated with "The 3 P's": **P**THrP (Hypercalcemia), **P**erypheral (actually Central, but often mnemonicized for **P**arathyroid-like), and **P**earl formation (keratin pearls) [1]. * **Location:** SCLC and Squamous cell are typically **Central** (hilar), while Adenocarcinoma is **Peripheral**. * **Management of SIADH:** Fluid restriction is the first-line treatment; Vaptans (Vasopressin antagonists) or Demeclocycline are used in refractory cases.

Q: What is the most common tumor that metastasizes to the brain?

Lung. **Explanation:** Brain metastases are the most common intracranial tumors in adults, occurring much more frequently than primary brain malignancies. **Correct Answer: C. Lung** Lung cancer is the most common primary source of brain metastases, accounting for approximately **40–50%** of all cases. This is due to the high incidence of lung cancer and the ability of tumor cells to enter the systemic circulation directly via the pulmonary veins, bypassing the initial filtration of the lungs and traveling straight to the cerebral vasculature. Both Small Cell Lung Cancer (SCLC) and Non-Small Cell Lung Cancer (NSCLC), particularly adenocarcinoma, have a high predilection for the brain. **Incorrect Options:** * **A. Breast:** This is the **second most common** source (approx. 15–25%). It is a frequent cause in females, but globally, lung cancer remains more common across both genders. * **B. Melanoma:** While melanoma has the **highest propensity** (highest percentage of patients with the disease developing brain spread), it is less common overall than lung cancer due to its lower general incidence. * **D. Prostate:** Prostate cancer rarely metastasizes to the brain parenchyma; it more commonly spreads to the bony calvarium or spinal column. **High-Yield Clinical Pearls for NEET-PG:** * **Most common source overall:** Lung > Breast > Melanoma > Renal Cell Carcinoma > GI tract. * **Highest propensity to bleed:** Melanoma, Choriocarcinoma, RCC, and Thyroid cancer (Mnemonic: **MCRT**). * **Location:** Most metastases occur at the **gray-white matter junction** due to the narrowing of blood vessels (vessel caliber change) trapping tumor emboli. * **Distribution:** 80% occur in the cerebral hemispheres, following the distribution of blood flow (Middle Cerebral Artery territory is most common).

Q: A 62-year-old man presents with dark tarry stools and light-headedness. Upper endoscopy finds an ulcerating lesion in his stomach and biopsies confirm gastric cancer. Which of the following is a risk factor for carcinoma of the stomach?

Helicobacter pylori infection. **Explanation:** **1. Why Helicobacter pylori is correct:** *H. pylori* is the most significant risk factor for non-cardia gastric adenocarcinoma [1]. It is classified as a **Group 1 Carcinogen** by the WHO. Chronic infection leads to a predictable histological progression known as the **Correa Pathway**: Chronic gastritis → Atrophic gastritis → Intestinal metaplasia → Dysplasia → Adenocarcinoma [1]. The chronic inflammation induced by the bacteria (specifically strains expressing **CagA** [1]) leads to DNA damage and the loss of acid-secreting parietal cells, creating an environment conducive to malignancy. **2. Why the other options are incorrect:** * **High socioeconomic status:** Gastric cancer is more prevalent in **low socioeconomic groups**, primarily due to overcrowding (increased *H. pylori* transmission) and poor access to fresh fruits/vegetables (refrigeration). * **High protein diet:** A high protein diet is not a recognized risk factor. However, diets high in **nitrates/nitrites** (found in smoked, salted, or cured meats) are strongly associated with gastric cancer as they are converted into carcinogenic nitrosamines. * **High alcohol consumption:** While alcohol is a major risk factor for esophageal and liver cancers, its link to gastric cancer is inconsistent and not as definitive as *H. pylori* or tobacco use. **3. NEET-PG High-Yield Pearls:** * **Blood Group A:** Associated with an increased risk of gastric cancer (specifically the diffuse type). * **Dietary Protective Factors:** High intake of Vitamin C and beta-carotene (fresh fruits/vegetables). * **Virchow’s Node:** Left supraclavicular lymphadenopathy indicating metastasis. * **Sister Mary Joseph Nodule:** Periumbilical metastasis. * **Krukenberg Tumor:** Metastasis to the ovaries (classically showing signet ring cells).

Q: What is the recent drug for metastatic hormone receptor-positive and HER2-negative metastatic breast cancer?

Palbociclib. **Explanation:** **Palbociclib** is the correct answer as it belongs to a class of drugs known as **CDK 4/6 inhibitors**. In Hormone Receptor-positive (HR+) breast cancer, the Cyclin D-CDK 4/6 pathway is often overactive, leading to uncontrolled cell proliferation. Palbociclib inhibits these kinases, effectively blocking the transition of the cell cycle from the G1 to the S phase. It is currently a standard-of-care first-line treatment for postmenopausal women with HR+/HER2- metastatic breast cancer, usually administered in combination with an aromatase inhibitor (like Letrozole). **Analysis of Incorrect Options:** * **Ipatasertib (B):** This is an investigational AKT inhibitor. While it shows promise in Triple-Negative Breast Cancer (TNBC) with PIK3CA/AKT1/PTEN alterations, it is not the standard "recent drug" for HR+/HER2- metastatic cases. * **Herceptin (Trastuzumab) (C):** This is a monoclonal antibody targeting the HER2/neu receptor. It is contraindicated or ineffective in HER2-negative breast cancer. * **Buparlisib (D):** This is a pan-PI3K inhibitor. Although studied in the BELLE trials, its clinical utility has been limited by significant toxicity (psychiatric side effects and liver toxicity) compared to more selective inhibitors like Alpelisib. **High-Yield Clinical Pearls for NEET-PG:** * **CDK 4/6 Inhibitors:** Include Palbociclib, Ribociclib, and Abemaciclib. * **Common Side Effect:** Neutropenia is the most common side effect of Palbociclib (unlike chemotherapy-induced neutropenia, it is rapidly reversible). * **Triple-Negative Breast Cancer (TNBC):** Often treated with PARP inhibitors (Olaparib) if BRCA mutations are present. * **HER2+ Treatment:** Trastuzumab and Pertuzumab are the mainstays.

Q: A 74-year-old man with a history of hypertension and benign prostatic hypertrophy presents with urinary retention. A Foley catheter is inserted, draining 1500 cc of urine. Subsequently, his urine output is 200 cc/h. Which of the following urine electrolyte values is most likely in keeping with post-obstructive diuresis?

High sodium. **Explanation:** **Post-obstructive diuresis (POD)** is a clinical condition characterized by polyuria (typically >200 mL/h) following the relief of a chronic, bilateral urinary tract obstruction. [1] **Why High Sodium is Correct:** The primary mechanism behind POD is a combination of **solute diuresis** and **tubular dysfunction**. During chronic obstruction, the accumulation of urea and other solutes creates an osmotic gradient. Once the obstruction is relieved, these solutes are excreted, dragging water with them [1]. More importantly, the prolonged high pressure in the renal pelvis causes damage to the distal tubules and collecting ducts, leading to an **impaired responsiveness to aldosterone and ADH** [2]. This results in a "salt-wasting" state where the kidneys cannot effectively reabsorb sodium, leading to **high urinary sodium levels** (often >40 mEq/L) [1]. **Why Other Options are Wrong:** * **Low Potassium:** While potassium is lost during diuresis, the hallmark of POD is the significant loss of sodium and water. Potassium levels in the urine are typically elevated (high), not low, due to the high flow rate. * **High Specific Gravity:** POD results in the excretion of large volumes of dilute urine because the kidneys lose their concentrating ability [2]. Therefore, the **specific gravity is low** (typically 200 mL/h for two consecutive hours or >3 L/24 hours. * **Management:** Most cases are self-limiting. Replace only **50% of hourly losses** with 0.45% saline to avoid perpetuating the diuresis, unless the patient is hemodynamically unstable. * **Risk Factors:** Chronic obstruction, congestive heart failure, and azotemia (high BUN/Creatinine).

Q: A 52-year-old man presents with a chronic cough and shortness of breath. He admits to smoking two packs of cigarettes a day for 30 years and has been diagnosed with chronic obstructive pulmonary disease. In counseling this patient, you advise him to stop smoking immediately and inform him that, in addition to emphysema, which of the following organs carries a significantly increased risk of smoking-related cancer?

Pancreas. **Explanation:** **1. Why Pancreas is Correct:** Smoking is the most significant avoidable risk factor for **Pancreatic Adenocarcinoma**. Carcinogens from tobacco smoke (such as N-nitrosamines and polycyclic aromatic hydrocarbons) are absorbed into the bloodstream and reach the pancreas via the blood or through bile reflux. Smoking is estimated to double the risk of pancreatic cancer and is responsible for approximately 20–25% of all cases. Other major smoking-related cancers include those of the lung [1], bladder, esophagus, kidney, and head/neck. **2. Why Other Options are Incorrect:** * **A. Brain:** While smoking increases the risk of cerebrovascular accidents (strokes), it is not a primary risk factor for primary brain tumors (like gliomas or meningiomas). * **B. Liver:** While some studies suggest a link between smoking and hepatocellular carcinoma (especially in patients with Hepatitis B or C), the association is not as classically emphasized or as strong as the link with pancreatic cancer in standard medical curricula. * **D. Skin:** Smoking is associated with premature skin aging and delayed wound healing, but the primary risk factors for skin cancers (Basal Cell, Squamous Cell, and Melanoma) are UV radiation and genetic predisposition, not tobacco. **3. NEET-PG High-Yield Pearls:** * **Most common genetic mutation in Pancreatic Cancer:** *KRAS* (found in >90% of cases). * **Classic Presentation:** Painless jaundice, weight loss, and **Courvoisier’s Law** (palpable gallbladder in a jaundiced patient suggests malignancy rather than gallstones). * **Trousseau Sign of Malignancy:** Migratory thrombophlebitis, often associated with pancreatic cancer. * **Tumor Marker:** **CA 19-9** (used for monitoring response to therapy, not for primary screening). **Smoking and COPD:** Cigarette smoking represents the most significant risk factor for COPD, and the risk relates to both the amount and duration of smoking [2].

Q: Which is the most common metastatic disease causing Superior Vena Cava (SVC) syndrome?

Metastatic breast carcinoma. **Explanation:** Superior Vena Cava (SVC) syndrome results from the external compression or internal thrombosis of the SVC, leading to venous congestion in the head, neck, and upper extremities. **1. Why Metastatic Breast Carcinoma is correct:** While **Bronchogenic carcinoma** is the most common *overall* cause of SVC syndrome (accounting for ~75% of cases), the question specifically asks for the most common **metastatic** disease. In the context of secondary spread from a distant primary site (excluding direct extension from the lung), **Breast carcinoma** is the most frequent metastatic malignancy to cause SVC syndrome [1]. This typically occurs via mediastinal lymph node metastasis or direct compression from metastatic masses. **2. Analysis of Incorrect Options:** * **A. Bronchogenic carcinoma:** This is the most common **primary** malignancy causing SVC syndrome. It is categorized as a primary intrathoracic tumor rather than a "metastatic disease" in this context [2]. * **C. Metastatic vertebral carcinoma:** While vertebral metastases are common in many cancers, they rarely involve the anterior mediastinal space or the SVC directly [3]. * **D. Gastric carcinoma:** Though it can metastasize to Virchow’s node (supraclavicular), it rarely involves the mediastinal nodes to a degree that causes SVC obstruction. **3. NEET-PG High-Yield Pearls:** * **Most common cause overall:** Bronchogenic carcinoma (Small Cell Lung Cancer > Non-Small Cell). * **Second most common cause:** Lymphoma (especially Non-Hodgkin Lymphoma). * **Most common benign cause:** Iatrogenic (indwelling central venous catheters or pacemakers). * **Clinical Sign:** Pemberton’s sign (facial flushing/cyanosis when arms are raised). * **Management:** Emergency radiotherapy is indicated if there is airway compromise or cerebral edema; otherwise, stenting and treating the underlying malignancy is the mainstay.

Question 1

Which acid-base disturbance is most commonly associated with hepatic cirrhosis complicated by acute kidney injury?

Accepted Answer

Metabolic acidosis and respiratory alkalosis

Answer

Metabolic acidosis and respiratory acidosis

Answer

Metabolic alkalosis and respiratory acidosis

Answer

Metabolic alkalosis and respiratory alkalosis

Question 2

A patient presents to the emergency room after a seizure. Laboratory investigations reveal SIADH, and a CT scan demonstrates a lung mass. Which of the following lung cancer subtypes is most likely to cause this electrolyte imbalance?

Accepted Answer

Small cell carcinoma

Answer

Adenocarcinoma

Answer

Bronchioloalveolar carcinoma

Answer

Large cell carcinoma

Question 3

What is the most common tumor that metastasizes to the brain?

Accepted Answer

Lung

Answer

Breast

Answer

Melanoma

Answer

Prostate

Question 4

A 62-year-old man presents with dark tarry stools and light-headedness. Upper endoscopy finds an ulcerating lesion in his stomach and biopsies confirm gastric cancer. Which of the following is a risk factor for carcinoma of the stomach?

Accepted Answer

Helicobacter pylori infection

Answer

High socioeconomic status

Answer

High protein diet

Answer

High alcohol consumption

Question 5

What is the recent drug for metastatic hormone receptor-positive and HER2-negative metastatic breast cancer?

Accepted Answer

Palbociclib

Answer

Ipataseib

Answer

Herceptin

Answer

Buparlisib

Question 6

Which of the following is a clinical feature often associated with a tumour?

Accepted Answer

Hypertrophic osteoarthropathy

Answer

Grotton's papules

Answer

Acanthosis nigricans

Answer

Dermatomyositis

Question 7

A 74-year-old man with a history of hypertension and benign prostatic hypertrophy presents with urinary retention. A Foley catheter is inserted, draining 1500 cc of urine. Subsequently, his urine output is 200 cc/h. Which of the following urine electrolyte values is most likely in keeping with post-obstructive diuresis?

Accepted Answer

High sodium

Answer

Low potassium

Answer

High specific gravity

Answer

Low pH

Question 8

A 52-year-old man presents with a chronic cough and shortness of breath. He admits to smoking two packs of cigarettes a day for 30 years and has been diagnosed with chronic obstructive pulmonary disease. In counseling this patient, you advise him to stop smoking immediately and inform him that, in addition to emphysema, which of the following organs carries a significantly increased risk of smoking-related cancer?

Accepted Answer

Pancreas

Answer

Brain

Answer

Liver

Answer

Skin

Question 9

Which of the following is NOT included in the management of febrile neutropenic patients receiving anti-cancer therapy?

Accepted Answer

Transfusion of granulocytes

Answer

Colony stimulating factors

Answer

Antibiotic prophylaxis

Answer

Repeated hand washing

Question 10

Which is the most common metastatic disease causing Superior Vena Cava (SVC) syndrome?

Accepted Answer

Metastatic breast carcinoma

Answer

Bronchogenic carcinoma

Answer

Metastatic vertebral carcinoma

Answer

Gastric carcinoma

Oncology — MCQs

Oncology — MCQs

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