Anticancer Drugs Practice Questions

Q: Which BCL-2 inhibitor is used in Chronic Lymphocytic Leukemia (CLL)?

Venetoclax. ### Explanation **Correct Answer: D. Venetoclax** **Mechanism and Rationale:** Venetoclax is a first-in-class, orally bioavailable, selective small-molecule inhibitor of **BCL-2 (B-cell lymphoma 2)**. BCL-2 is an anti-apoptotic protein that is frequently overexpressed in Chronic Lymphocytic Leukemia (CLL) cells. By binding to BCL-2, Venetoclax displaces pro-apoptotic proteins (like BIM), leading to mitochondrial outer membrane permeabilization, activation of caspases, and subsequent **programmed cell death (apoptosis)** of the leukemia cells. It is specifically indicated for CLL and Small Lymphocytic Lymphoma (SLL). **Analysis of Incorrect Options:** * **A. Fludarabine:** A purine analog that inhibits DNA polymerase and ribonucleotide reductase. It was historically a first-line treatment for CLL but acts as a cytotoxic antimetabolite, not a BCL-2 inhibitor. * **B. Cladribine:** Another purine analog resistant to adenosine deaminase. It is the **drug of choice for Hairy Cell Leukemia**, not primarily used for standard CLL. * **C. Pentostatin:** An adenosine deaminase inhibitor also used primarily in Hairy Cell Leukemia. **High-Yield Clinical Pearls for NEET-PG:** * **Tumor Lysis Syndrome (TLS):** Venetoclax is so potent that it can cause rapid cell death leading to severe TLS. A "ramp-up" dosing schedule and aggressive hydration/prophylaxis are mandatory. * **Resistance Mechanism:** Mutations in the BCL-2 protein (e.g., G101V) can lead to acquired resistance. * **Other "Clax" drugs:** Navitoclax is another BCL-2 inhibitor but causes dose-limiting thrombocytopenia (as it also inhibits BCL-XL, which is vital for platelet survival). Venetoclax is BCL-2 selective and spares platelets.

Q: What is the drug of choice for the treatment of gastrointestinal stromal tumors?

Imatinib mesylate. **Explanation:** **Imatinib mesylate** is the drug of choice for **Gastrointestinal Stromal Tumors (GIST)**. The underlying pathophysiology of GIST involves a gain-of-function mutation in the **c-KIT proto-oncogene** (a receptor tyrosine kinase). Imatinib acts as a potent selective inhibitor of the tyrosine kinase domain of c-KIT, as well as BCR-ABL (used in CML) and PDGFR. By blocking these receptors, it inhibits tumor cell proliferation and induces apoptosis. **Analysis of Incorrect Options:** * **Rituximab:** A monoclonal antibody against **CD20** found on B-cells. It is primarily used in Non-Hodgkin Lymphoma (NHL), Chronic Lymphocytic Leukemia (CLL), and certain autoimmune conditions. * **Anagrelide:** An orally active agent used to reduce platelet counts in patients with **Essential Thrombocythemia**. It works by inhibiting megakaryocyte maturation. * **Denileukin diftitox:** A fusion protein combining Interleukin-2 (IL-2) and diphtheria toxin. It targets the IL-2 receptor and is used for **Cutaneous T-cell lymphoma (Mycosis Fungoides)**. **High-Yield Clinical Pearls for NEET-PG:** * **Imatinib** is also the first-line treatment for **Chronic Myeloid Leukemia (CML)**, targeting the Philadelphia chromosome ($t[9;22]$ / BCR-ABL). * **Resistance:** Resistance to Imatinib in GIST often occurs due to secondary mutations in the c-KIT gene. In such cases, **Sunitinib** or **Regorafenib** are used as second-line agents. * **Adverse Effect:** A characteristic side effect of Imatinib is **periorbital edema** (fluid retention).

Q: Which neoadjuvant chemotherapy is used in esophageal cancer?

Cisplatin. **Explanation:** **1. Why Cisplatin is Correct:** Neoadjuvant chemotherapy (NACT) is the standard of care for locally advanced esophageal cancer (both Squamous Cell Carcinoma and Adenocarcinoma) to downstage the tumor before surgery. **Cisplatin**, a platinum-based alkylating-like agent, is the backbone of these regimens. It works by forming intra-strand cross-links in DNA, triggering apoptosis. The most common high-yield regimens used are **PF (Cisplatin + 5-Fluorouracil)** or the **CROSS regimen** (Carboplatin + Paclitaxel with radiotherapy). Cisplatin is preferred due to its high efficacy in aerodigestive tract malignancies. **2. Why the Other Options are Incorrect:** * **Cyclophosphamide (Option B):** This is an alkylating agent primarily used in the **CHOP** regimen for Non-Hodgkin Lymphoma, breast cancer, and as an immunosuppressant. It is not a standard treatment for esophageal cancer. * **Doxorubicin (Option C):** An anthracycline used for breast cancer, sarcomas, and lymphomas (e.g., **ABVD** for Hodgkin’s). While used in some gastric cancer protocols (ECF), it is not the primary neoadjuvant choice for the esophagus. * **Methotrexate (Option D):** An antimetabolite (DHFR inhibitor) used in leukemias, osteosarcoma, and ectopic pregnancy. It has no significant role in the modern management of esophageal carcinoma. **3. Clinical Pearls for NEET-PG:** * **Dose-limiting toxicity of Cisplatin:** Nephrotoxicity (prevented by aggressive hydration and Amifostine) and Ototoxicity. * **Most emetogenic drug:** Cisplatin is the prototype for highly emetogenic chemotherapy. * **Drug of choice for Esophageal Cancer:** Cisplatin + 5-FU (PF Regimen). * **Radiosensitizer:** Cisplatin also acts as a potent radiosensitizer, making it ideal for concurrent chemoradiotherapy.

Q: A patient undergoing cancer chemotherapy has an increase in urinary frequency with discomfort. No specific findings are apparent on physical examination. Laboratory results include hematuria and mild leukopenia but no bacteria or crystalluria. If the symptoms experienced by the patient are drug related, what is the most likely causative agent?

cyclophosphamide. ### Explanation The patient is presenting with symptoms of **Hemorrhagic Cystitis** (urinary frequency, discomfort, and hematuria without evidence of infection or crystals). This is a classic, dose-limiting adverse effect associated with oxazaphosphorine prodrugs, specifically **Cyclophosphamide** and Ifosfamide. **Why Cyclophosphamide is correct:** Cyclophosphamide is metabolized in the liver to form **Acrolein**, a toxic metabolite. Acrolein is excreted in the urine, where it causes direct irritation and sloughing of the bladder mucosal lining, leading to sterile hemorrhagic cystitis. The mild leukopenia mentioned is consistent with the drug’s primary side effect of bone marrow suppression. **Why the other options are incorrect:** * **5-Fluorouracil (5-FU):** Primarily causes GI toxicity (mucositis, diarrhea) and "Hand-Foot Syndrome" (palmar-plantar erythrodysesthesia). It does not cause bladder toxicity. * **Methotrexate:** Known for bone marrow suppression, hepatotoxicity, and nephrotoxicity (due to crystalluria at high doses), but it does not cause hemorrhagic cystitis. * **Prednisone:** A glucocorticoid used in chemotherapy to reduce inflammation or treat lymphoid malignancies. Common side effects include hyperglycemia, osteoporosis, and immunosuppression, but not hematuria. **High-Yield Clinical Pearls for NEET-PG:** * **Prevention:** Hemorrhagic cystitis can be prevented by aggressive **hydration** and the administration of **MESNA** (2-Mercaptoethane Sulfonate Na). * **Mechanism of MESNA:** It contains a free sulfhydryl (-SH) group that binds to and neutralizes acrolein in the bladder to form a non-toxic adduct. * **Differential:** If a patient on Cyclophosphamide develops hematuria years later, consider **Bladder Carcinoma**, as chronic irritation increases malignancy risk.

Q: A patient on treatment for leukemia develops chest pain, pulmonary infiltrates, and pleural effusion. What is the likely cause?

Tretinoin. ### Explanation The patient is experiencing **Differentiation Syndrome** (formerly known as Retinoic Acid Syndrome), a life-threatening complication specifically associated with **Tretinoin (All-trans Retinoic Acid - ATRA)** and Arsenic Trioxide. **1. Why Tretinoin is correct:** Tretinoin is the first-line treatment for **Acute Promyelocytic Leukemia (APL - M3)**. It works by forcing the malignant promyelocytes to differentiate into mature neutrophils. During this process, these cells release a massive amount of inflammatory cytokines and gain increased adhesion molecules, leading to pulmonary capillary leak. * **Clinical Triad:** Fever, respiratory distress (pulmonary infiltrates/pleural effusion), and weight gain (edema). * **Management:** High-dose intravenous **Dexamethasone** is the immediate treatment of choice. **2. Why other options are incorrect:** * **Daunorubicin:** An anthracycline primarily known for **cardiotoxicity** (dilated cardiomyopathy/congestive heart failure) rather than acute pulmonary infiltrates. * **Hydroxyurea:** Commonly causes myelosuppression and painful leg ulcers; it does not typically cause acute pleural effusions or pulmonary infiltrates. * **Cytarabine:** Its classic high-yield side effects include **cerebellar ataxia** and conjunctivitis. While it can cause "Ara-C lung," it is less common than Differentiation Syndrome in the context of leukemia induction. **3. High-Yield Clinical Pearls for NEET-PG:** * **APL Cytogenetics:** t(15;17) involving the PML-RARα gene. * **Differentiation Syndrome Timing:** Usually occurs within the first 2–21 days of starting ATRA. * **Prophylaxis:** If the initial WBC count is high (>5,000–10,000/µL), steroids are often started prophylactically. * **Other ATRA Side Effects:** Pseudotumor cerebri (idiopathic intracranial hypertension) and dry skin/mucosa.

Q: What is the active metabolite of azathioprine?

6-mercaptopurine. **Explanation:** **Azathioprine** is a prodrug belonging to the purine antimetabolite class of immunosuppressants. Upon administration, it undergoes non-enzymatic cleavage by glutathione and other sulfhydryl-containing compounds, primarily in the liver and red blood cells, to form its active metabolite, **6-mercaptopurine (6-MP)**. 6-MP is further converted into thioguanine nucleotides (TGNs), which incorporate into DNA/RNA, inhibiting purine synthesis and arresting the proliferation of T and B lymphocytes. **Analysis of Options:** * **Option A (6-thioguanine):** While 6-TG is a related purine analog used in leukemia, it is a downstream product of 6-MP metabolism, not the immediate metabolite of azathioprine. * **Option B (6-thiouracil):** This is a metabolite of propylthiouracil (antithyroid drug) and is not related to azathioprine metabolism. * **Option D (6-mercaptoguanine):** This is not a standard pharmacological metabolite in this pathway. **High-Yield Clinical Pearls for NEET-PG:** 1. **Drug Interaction with Allopurinol:** 6-MP is metabolized by the enzyme **Xanthine Oxidase**. Allopurinol (a xanthine oxidase inhibitor) significantly increases the levels of 6-MP, leading to life-threatening bone marrow suppression. If used together, the dose of azathioprine must be reduced by **50-75%**. 2. **TPMT Polymorphism:** The enzyme **Thiopurine Methyltransferase (TPMT)** also metabolizes 6-MP. Patients with a genetic deficiency in TPMT are at a high risk of severe myelosuppression when taking azathioprine. 3. **Clinical Use:** It is a "steroid-sparing" agent used in organ transplantation, SLE, and Inflammatory Bowel Disease (IBD).

Q: Choriocarcinoma is most sensitive to which chemotherapeutic agent?

Methotrexate. **Explanation:** **Methotrexate (MTX)** is the drug of choice for **Choriocarcinoma** because this tumor is highly sensitive to folate antagonists. Choriocarcinoma is a rapidly dividing gestational trophoblastic neoplasia; since MTX inhibits **Dihydrofolate Reductase (DHFR)**, it effectively halts DNA synthesis and cell replication in these malignant cells. In low-risk cases, MTX monotherapy often results in a near 100% cure rate. **Analysis of Incorrect Options:** * **Vincristine:** A Vinca alkaloid that inhibits microtubule assembly. While used in various pediatric tumors and lymphomas, it is not the primary treatment for choriocarcinoma. * **Bleomycin:** An antitumor antibiotic that causes DNA strand breaks. It is a cornerstone for testicular tumors and Hodgkin lymphoma but is not the first-line choice here. * **Busulfan:** An alkylating agent specifically used for Chronic Myeloid Leukemia (CML) and bone marrow ablation before transplants. It has no significant role in treating choriocarcinoma. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** MTX competitively inhibits DHFR, preventing the conversion of Dihydrofolate to Tetrahydrofolate. * **Rescue Therapy:** High-dose MTX toxicity is managed with **Leucovorin (Folinic acid)**, which bypasses the inhibited DHFR enzyme ("Leucovorin Rescue"). * **Other Uses:** MTX is also the first-line Disease-Modifying Antirheumatic Drug (DMARD) for Rheumatoid Arthritis and the drug of choice for Ectopic Pregnancy. * **Resistance:** The most common mechanism of resistance to MTX is a decrease in the transport of the drug into the cell or an increase in DHFR levels.

Q: Hand and foot syndrome can be caused by which of the following agents?

Capecitabine. **Explanation:** **Hand-Foot Syndrome (HFS)**, also known as **Palmar-Plantar Erythrodysesthesia**, is a distinct dermatological toxicity characterized by redness, swelling, and pain on the palms and soles. 1. **Why Capecitabine is correct:** Capecitabine is an oral prodrug of **5-Fluorouracil (5-FU)**. It is the most common agent associated with HFS. The underlying mechanism involves the high levels of the enzyme **thymidine phosphorylase** in the skin of palms and soles, which converts the prodrug into active 5-FU, leading to localized cytotoxic damage. Other drugs frequently causing HFS include **5-FU (infusion)** and **Liposomal Doxorubicin**. 2. **Why other options are incorrect:** * **Cisplatin:** Primarily known for **nephrotoxicity** (prevented by amifostine/hydration) and **ototoxicity**. * **Vincristine:** Characterized by **peripheral neuropathy** (stocking-glove pattern) and autonomic dysfunction (constipation/paralytic ileus). It is notably bone marrow sparing. * **Mitomycin-C:** Associated with **Delayed Myelosuppression** and **Hemolytic Uremic Syndrome (HUS)**. **High-Yield Clinical Pearls for NEET-PG:** * **Management of HFS:** Dose reduction/interruption and topical emollients (Urea cream) or Pyridoxine (Vitamin B6). * **Hand-Foot Skin Reaction (HFSR):** Distinct from HFS; it presents with hyperkeratosis/calluses and is caused by **Tyrosine Kinase Inhibitors (TKIs)** like **Sorafenib** and **Sunitinib**. * **5-FU Toxicity:** Deficiency of the enzyme **DPD (Dihydropyrimidine dehydrogenase)** increases the risk of severe toxicity.

Q: Which of the following anticancer drugs is known to cause bone marrow suppression?

Vinblastine. The correct answer is **Vinblastine**. Bone marrow suppression (myelosuppression) is the most common dose-limiting toxicity for the majority of cytotoxic anticancer drugs. However, certain drugs are specifically known for being "bone marrow sparing." [2] **1. Why Vinblastine is correct:** Both Vincristine and Vinblastine are Vinca alkaloids that inhibit microtubule assembly [1, 4]. Despite their structural similarity, their toxicity profiles differ significantly. **Vinblastine** is notorious for causing significant myelosuppression (primarily leukopenia) [2]. A common medical mnemonic to distinguish the two is: *"**B**lastine **B**lasts the **B**one marrow."* **2. Why other options are incorrect:** * **Vincristine:** This is a classic "bone marrow sparing" drug [2]. Its dose-limiting toxicity is **peripheral neuropathy** (paresthesia, loss of reflexes, and foot drop) rather than myelosuppression [1]. * **Bleomycin:** This is another major "bone marrow sparing" agent. Its dose-limiting toxicity is **pulmonary fibrosis** and skin hyperpigmentation. * **Option D:** Since Vincristine and Bleomycin do not typically cause significant marrow suppression, "All of the above" is incorrect. **Clinical Pearls for NEET-PG:** * **Marrow Sparing Drugs:** Remember the mnemonic **"V-B-C-L"** (Vincristine, Bleomycin, Cisplatin, L-Asparaginase). These drugs are often used in combination regimens because they do not add to the hematologic toxicity of other agents. * **Vincristine:** Associated with SIADH and paralytic ileus [1]. * **Bleomycin:** Acts by forming free radicals that cause DNA strand breaks; it is cell-cycle specific (G2 phase). * **Busulfan:** Known for causing "Busulfan Lung" (interstitial fibrosis) and adrenal insufficiency-like skin pigmentation.

Question 1

Which BCL-2 inhibitor is used in Chronic Lymphocytic Leukemia (CLL)?

Accepted Answer

Venetoclax

Answer

Fludarabine

Answer

Cladribine

Answer

Pentostatin

Question 2

What is the drug of choice for the treatment of gastrointestinal stromal tumors?

Accepted Answer

Imatinib mesylate

Answer

Rituximab

Answer

Anagrelide

Answer

Denileukin diftitox

Question 3

Which neoadjuvant chemotherapy is used in esophageal cancer?

Accepted Answer

Cisplatin

Answer

Cyclophosphamide

Answer

Doxorubicin

Answer

Methotrexate

Question 4

A patient undergoing cancer chemotherapy has an increase in urinary frequency with discomfort. No specific findings are apparent on physical examination. Laboratory results include hematuria and mild leukopenia but no bacteria or crystalluria. If the symptoms experienced by the patient are drug related, what is the most likely causative agent?

Accepted Answer

cyclophosphamide

Answer

5-FU

Answer

methotrexate

Answer

prednisone

Question 5

A patient on treatment for leukemia develops chest pain, pulmonary infiltrates, and pleural effusion. What is the likely cause?

Accepted Answer

Tretinoin

Answer

Daunorubicin

Answer

Hydroxyurea

Answer

Cytarabine

Question 6

What is the active metabolite of azathioprine?

Accepted Answer

6-mercaptopurine

Answer

6-thioguanine

Answer

6-thiouracil

Answer

6-mercaptoguanine

Question 7

Amifostine is protective to all EXCEPT:

Accepted Answer

CNS

Answer

Salivary glands

Answer

Skin

Answer

GIT

Question 8

Choriocarcinoma is most sensitive to which chemotherapeutic agent?

Accepted Answer

Methotrexate

Answer

Vincristine

Answer

Bleomycin

Answer

Busulfan

Question 9

Hand and foot syndrome can be caused by which of the following agents?

Accepted Answer

Capecitabine

Answer

Cisplatin

Answer

Vincristine

Answer

Mitomycin-C

Question 10

Which of the following anticancer drugs is known to cause bone marrow suppression?

Accepted Answer

Vinblastine

Answer

Vincristine

Answer

Bleomycin

Answer

All of the above

Anticancer Drugs — MCQs

Anticancer Drugs — MCQs

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