Anticancer Drugs Practice Questions

Q: What is the drug of choice for Chronic Myeloid Leukemia (CML)?

Imatinib mesylate. **Explanation:** **Correct Answer: A. Imatinib mesylate** Imatinib is the first-line treatment (Drug of Choice) for Chronic Myeloid Leukemia (CML). The underlying pathophysiology of CML involves the **Philadelphia chromosome t(9;22)**, which creates the **BCR-ABL fusion gene**. This gene encodes a constitutively active **tyrosine kinase** protein that drives uncontrolled myeloid proliferation. Imatinib acts as a selective **Tyrosine Kinase Inhibitor (TKI)** by binding to the ATP-binding site of the BCR-ABL enzyme, effectively "turning off" the signal for cell division. **Analysis of Incorrect Options:** * **B. Fludarabine:** A purine analog primarily used as the drug of choice for **Chronic Lymphocytic Leukemia (CLL)**. * **C. All-trans retinoic acid (ATRA):** The specific targeted therapy for **Acute Promyelocytic Leukemia (AML-M3)**. It works by inducing the differentiation of leukemic promyelocytes. * **D. Methotrexate:** A folate antagonist used in various regimens for Acute Lymphoblastic Leukemia (ALL), ectopic pregnancy, and rheumatoid arthritis, but it does not target the specific molecular defect in CML. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Imatinib is a competitive inhibitor of the ATP-binding site on the BCR-ABL tyrosine kinase. * **Resistance:** Resistance to Imatinib often occurs due to a point mutation in the BCR-ABL gene (most notably the **T315I mutation**). * **Second-generation TKIs:** Dasatinib and Nilotinib are used if Imatinib fails or is not tolerated. **Ponatinib** is used specifically for the T315I mutation. * **Side Effects:** A characteristic side effect of Imatinib is **periorbital edema** (fluid retention).

Q: Cetuximab, an EGFR antagonist, can be used in which of the following conditions?

Palliation in head and neck cancer. **Explanation:** **Cetuximab** is a recombinant human/mouse chimeric monoclonal antibody that binds specifically to the extracellular domain of the **Epidermal Growth Factor Receptor (EGFR)**. By inhibiting EGFR, it blocks downstream signaling pathways (like KRAS/MAPK) that promote cell proliferation and survival. **1. Why Option A is correct:** Cetuximab is FDA-approved for use in **Squamous Cell Carcinoma of the Head and Neck (SCCHN)**. It is used in combination with radiotherapy for locally advanced disease or as a palliative monotherapy/combination therapy for recurrent or metastatic cases. It is also notably used in **metastatic colorectal cancer**, provided the tumor is **KRAS wild-type**. **2. Why other options are incorrect:** * **Anal canal carcinoma:** The standard of care (Nigro protocol) involves Mitomycin and 5-Fluorouracil (5-FU) with radiation. Cetuximab is not a primary indication here. * **Gastric carcinoma:** First-line targeted therapy usually involves **Trastuzumab** (for HER2-positive cases) or **Ramucirumab** (VEGFR2 antagonist). * **Lung carcinoma:** While EGFR mutations are common in Non-Small Cell Lung Cancer (NSCLC), the preferred agents are **Tyrosine Kinase Inhibitors (TKIs)** like Erlotinib, Gefitinib, or Osimertinib, rather than Cetuximab. **High-Yield Clinical Pearls for NEET-PG:** * **Dermatologic Toxicity:** The most common side effect is an **acneiform skin rash**. Interestingly, the severity of the rash often correlates with a *positive* therapeutic response. * **Genetic Testing:** Before starting Cetuximab in colorectal cancer, testing for **KRAS mutations** is mandatory. If a KRAS mutation is present, Cetuximab will be ineffective because the pathway is "turned on" downstream of the receptor. * **Hypomagnesemia:** Cetuximab can cause significant magnesium wasting, requiring monitoring of electrolytes.

Q: Which of the following is an antifolate cancer drug?

Methotrexate. ### Explanation **Correct Option: A. Methotrexate** Methotrexate is the prototypical **antifolate** antimetabolite. It acts by competitively inhibiting the enzyme **Dihydrofolate Reductase (DHFR)**. This inhibition prevents the conversion of dihydrofolate to tetrahydrofolate (THF), the active form of folic acid required for the synthesis of thymidylate and purines. Consequently, DNA synthesis is halted, leading to "thymineless death" of rapidly dividing cancer cells. **Analysis of Incorrect Options:** * **B. Azathioprine:** This is a **purine analog** (a prodrug of 6-mercaptopurine). While it is an antimetabolite used as an immunosuppressant, it does not target folate metabolism. * **C. Cyclosporin:** This is a **calcineurin inhibitor**. It acts by inhibiting T-cell activation via the suppression of IL-2 production. It is not a cytotoxic anticancer drug but an immunosuppressant. * **D. Vincristine:** This is a **Vinca alkaloid** that acts as a mitotic inhibitor. It binds to tubulin and prevents microtubule polymerization, arresting the cell cycle in the M-phase. **High-Yield Clinical Pearls for NEET-PG:** * **Rescue Therapy:** High-dose Methotrexate toxicity is managed with **Leucovorin (Folinic acid)**, which bypasses the inhibited DHFR enzyme to provide a source of active folate. * **Adverse Effects:** Notable for causing **mucositis**, bone marrow suppression, and nephrotoxicity (due to crystalluria). * **Resistance:** Often occurs due to decreased drug uptake or increased synthesis of the DHFR enzyme. * **Other Antifolates:** Pemetrexed and Pralatrexate are newer agents in this class.

Q: All the following drugs are used in the treatment of metastatic breast cancer except?

Sunitinib. **Explanation:** The correct answer is **Sunitinib**. **1. Why Sunitinib is the correct answer:** Sunitinib is a multi-targeted receptor tyrosine kinase inhibitor (TKI) that primarily inhibits VEGF receptors, PDGF receptors, and c-KIT [2]. It is the standard of care for **Metastatic Renal Cell Carcinoma (mRCC)**, Gastrointestinal Stromal Tumors (GIST), and Pancreatic Neuroendocrine Tumors (pNETs) [2]. It has no established role or FDA approval for the treatment of metastatic breast cancer. **2. Analysis of incorrect options:** * **Ixabepilone:** An **Epothilone B analog** that stabilizes microtubules (similar to taxanes but binds to a different site). It is specifically indicated for metastatic or locally advanced breast cancer, especially in patients resistant to anthracyclines and taxanes. * **Abemaciclib & Ribociclib:** These are **CDK 4/6 inhibitors**. They inhibit the cell cycle transition from G1 to S phase. Both are first-line treatments for Hormone Receptor (HR)-positive, HER2-negative metastatic breast cancer, usually in combination with aromatase inhibitors (e.g., Letrozole). **3. High-Yield Clinical Pearls for NEET-PG:** * **CDK 4/6 Inhibitors:** Palbociclib, Ribociclib, and Abemaciclib. *Mnemonic: "PAR" for Breast Cancer.* * **Ixabepilone:** Unique because it remains active in cells that overexpress P-glycoprotein (MDR1 gene), making it effective in taxane-resistant breast cancer. * **Sunitinib Side Effect:** Characteristically causes **Hand-Foot Syndrome** and yellowing of the skin/depigmentation of hair. * **Trastuzumab/Pertuzumab:** Targeted therapy for HER2-positive breast cancer [1], [2].

Q: All of the following statements about vincristine are true EXCEPT:

It is a drug of choice for choriocarcinoma.. **Explanation:** The correct answer is **D** because **Methotrexate** (a folate antagonist), not Vincristine, is the drug of choice for gestational choriocarcinoma. While Vincristine is used in various combination regimens for solid tumors and leukemias [2], it does not hold primary status for choriocarcinoma. **Analysis of Options:** * **Option A (True):** Vincristine is a **cell cycle-specific (CCS)** agent [1]. It binds to tubulin and inhibits its polymerization into microtubules, preventing the formation of the mitotic spindle [1]. This causes cell cycle arrest specifically in the **M phase (Mitosis)** [1]. * **Option B (False statement/True fact):** This is a tricky distractor. While Vincristine is famous for being **"bone marrow sparing"** (unlike Vinblastine) [3], it can still cause mild marrow suppression in some cases [3]. However, its **dose-limiting toxicity is peripheral neuropathy** (paresthesia, loss of reflexes, foot drop) [2], [3]. * **Option C (True):** Folic acid (Leucovorin) is used to "rescue" cells from Methotrexate toxicity. It has no biochemical role in reversing the microtubule inhibition caused by Vincristine. **Clinical Pearls for NEET-PG:** * **Vinca Alkaloids Mnemonic:** **V**incristine = **V**ery little marrow effect (Neurotoxicity); **V**inblastine = **B**lasts the **B**one marrow (Myelosuppression) [3]. * **Fatal Route:** Vincristine is for **Intravenous use ONLY**. Intrathecal administration is fatal due to ascending myeloencephalopathy. * **Syndrome of Inappropriate ADH (SIADH):** Vincristine is a well-known cause of drug-induced SIADH.

Q: For which condition is the drug Bozoib used?

Multiple myeloma. **Explanation:** **Bortezomib** (often referred to in shorthand or slightly modified names in exams) is a first-in-class **proteasome inhibitor**. It specifically targets the **26S proteasome** complex, leading to the inhibition of the degradation of pro-apoptotic proteins and the stabilization of **NF-κB** inhibitors (IκB). In malignant plasma cells, this results in the induction of apoptosis and inhibition of cell survival pathways. * **Why Multiple Myeloma is correct:** Multiple myeloma cells are highly dependent on the proteasome system to clear the excessive amounts of abnormal immunoglobulins (M-proteins) they produce. By blocking the proteasome, Bortezomib causes "proteotoxic stress" and unfolded protein responses, making it a cornerstone therapy for both newly diagnosed and relapsed **Multiple Myeloma**, as well as Mantle Cell Lymphoma. * **Why other options are incorrect:** * **Renal Cell Carcinoma (RCC):** Primarily treated with Tyrosine Kinase Inhibitors (TKIs) like Sunitinib or mTOR inhibitors like Everolimus. * **Hepatocellular Carcinoma (HCC):** The standard systemic therapy involves multikinase inhibitors like **Sorafenib** or Lenvatinib. * **Pancreatic Carcinoma:** Typically managed with cytotoxic regimens like Gemcitabine or FOLFIRINOX. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Reversible inhibition of the 26S proteasome. * **Key Side Effect:** **Peripheral Neuropathy** (often dose-limiting). * **Viral Reactivation:** It significantly increases the risk of **Herpes Zoster** reactivation; therefore, patients are often started on prophylactic Acyclovir. * **Route:** Subcutaneous administration is preferred over intravenous to reduce the incidence of neuropathy.

Q: What is the most common dose-limiting toxicity of chemotherapeutic agents?

Myelosuppression. **Explanation:** The most common dose-limiting toxicity (DLT) for the majority of cytotoxic chemotherapeutic agents is **Myelosuppression** (Bone Marrow Suppression). **Why Myelosuppression is the Correct Answer:** Cytotoxic drugs primarily target rapidly dividing cells by interfering with DNA synthesis or mitosis. Since the hematopoietic stem cells in the bone marrow have a high turnover rate, they are highly susceptible to these agents. This results in leucopenia (specifically neutropenia), thrombocytopenia, and anemia. Neutropenia is the most critical component, as it predisposes patients to life-threatening opportunistic infections, often necessitating dose reduction or treatment delay. **Analysis of Incorrect Options:** * **B. Gastrointestinal Toxicity:** While nausea, vomiting, and mucositis are very common side effects, they are usually manageable with antiemetics (like Ondansetron) and are rarely the primary factor that limits the maximum tolerated dose (except for specific drugs like Irinotecan or 5-FU). * **C. Neurotoxicity:** This is a specific DLT for certain classes (e.g., Vinca alkaloids like Vincristine, Taxanes, and Cisplatin) but is not the "most common" across the entire spectrum of chemotherapy. * **D. Alopecia:** Hair loss is a distressing side effect due to the high mitotic index of hair follicles, but it is cosmetic and never dose-limiting. **High-Yield Clinical Pearls for NEET-PG:** * **Exceptions:** Drugs that are **NOT** typically myelosuppressive include **Vincristine, Bleomycin, Cisplatin, and L-Asparaginase.** * **Nadir:** The point of lowest blood cell count after chemo, usually occurring 7–14 days post-treatment. * **Specific DLTs to remember:** * Cisplatin: Nephrotoxicity (prevented by aggressive hydration/Amifostine). * Doxorubicin: Cardiotoxicity (prevented by Dexrazoxane). * Bleomycin: Pulmonary Fibrosis. * Cyclophosphamide: Hemorrhagic Cystitis (prevented by MESNA).

Q: Erlotinib is used in which of the following cancers?

Pancreatic cancer. **Explanation:** **Erlotinib** is a small-molecule **Tyrosine Kinase Inhibitor (TKI)** that specifically targets the **Epidermal Growth Factor Receptor (EGFR/HER1)**. By inhibiting the intracellular phosphorylation of EGFR, it prevents the downstream signaling pathways responsible for cell proliferation and survival. **Why Pancreatic Cancer is correct:** Erlotinib is FDA-approved for use in combination with **Gemcitabine** as a first-line treatment for patients with locally advanced, unresectable, or metastatic **pancreatic cancer**. It is also a primary treatment for Non-Small Cell Lung Cancer (NSCLC), particularly in patients with specific EGFR mutations (Exon 19 deletions or Exon 21 L858R mutations). **Analysis of Incorrect Options:** * **A. Colon cancer:** The primary EGFR inhibitors used here are monoclonal antibodies like **Cetuximab** and **Panitumumab** (effective only in KRAS wild-type patients), not Erlotinib. * **C. Gall bladder cancer:** While research is ongoing, Erlotinib is not a standard-of-care or first-line therapy for biliary tract cancers. * **D. GIST (Gastrointestinal Stromal Tumor):** The drug of choice is **Imatinib**, which targets the **c-KIT** (CD117) tyrosine kinase, not EGFR. **High-Yield Clinical Pearls for NEET-PG:** * **Side Effects:** The most characteristic side effect of Erlotinib is an **acneiform skin rash**. Interestingly, the severity of the rash often correlates with a better therapeutic response. * **Metabolism:** It is metabolized by **CYP3A4**; therefore, smokers may require higher doses as smoking induces the metabolism of Erlotinib. * **Comparison:** Unlike Erlotinib (TKI), **Cetuximab** is a monoclonal antibody against EGFR. Both are distinct from **Trastuzumab**, which targets **HER2/neu**.

Q: Which of the following drugs is most emetogenic?

Cisplatin. **Explanation:** The emetogenic potential of chemotherapy is categorized into four levels: High (>90% risk), Moderate (30–90%), Low (10–30%), and Minimal ( 90% risk of emesis, it requires triple antiemetic therapy (5-HT3 antagonist + Dexamethasone + NK1 antagonist like Aprepitant). **Analysis of Incorrect Options:** * **Carboplatin:** While related to cisplatin, it is significantly less emetogenic and falls into the **Moderate** risk category. * **High-dose Cyclophosphamide:** Doses >1500 mg/m² are considered highly emetogenic, but **Cisplatin remains the gold standard** for the highest emetic risk in pharmacological comparisons. * **High-dose Methotrexate:** This is generally classified as having **Moderate** emetogenic potential. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of choice for Cisplatin-induced vomiting:** 5-HT3 antagonists (e.g., Ondansetron) for acute; NK1 antagonists (e.g., Aprepitant) for delayed. * **Other Highly Emetogenic Drugs:** Dacarbazine, Mechlorethamine, and high-dose Anthracyclines (Doxorubicin). * **Least Emetogenic (Minimal risk):** Vincristine, Vinblastine, and Bleomycin. * **Cisplatin Toxicity Profile:** Remember the mnemonic "3 N's" — **N**ephrotoxicity (prevented by Amifostine/hydration), **N**eurotoxicity (ototoxicity), and **N**ausea/vomiting.

Q: Bicalutamide is a specific inhibitor of which of the following?

Androgen receptors. **Explanation:** **Bicalutamide** is a potent, non-steroidal **Androgen Receptor (AR) antagonist**. It works by competitively inhibiting the binding of dihydrotestosterone (DHT) and testosterone to androgen receptors in target tissues, such as the prostate gland. By blocking these receptors, it prevents the growth-stimulating effects of androgens on prostate cancer cells. **Analysis of Options:** * **Option B (Correct):** Bicalutamide belongs to the "lutamide" family (including Flutamide and Enzalutamide), which are pure anti-androgens used primarily in the management of metastatic **Prostate Carcinoma**. * **Option A (Incorrect):** Inhibitors of 5-alpha reductase include **Finasteride** and **Dutasteride**. These drugs prevent the conversion of testosterone to the more potent DHT and are used for Benign Prostatic Hyperplasia (BPH) and alopecia. * **Option C (Incorrect):** Aromatase inhibitors include **Anastrozole**, **Letrozole**, and **Exemestane**. They block the conversion of androgens to estrogens and are used in postmenopausal breast cancer. * **Option D (Incorrect):** Estrogen receptor antagonists/modulators include **Tamoxifen** (SERM) and **Fulvestrant** (SERD), used primarily in breast cancer treatment. **High-Yield Clinical Pearls for NEET-PG:** * **Combined Androgen Blockade (CAB):** Bicalutamide is often used in combination with GnRH agonists (like Leuprolide) to prevent the **"testosterone flare"** (initial surge in testosterone) that occurs at the start of GnRH therapy. * **Advantages:** Compared to Flutamide, Bicalutamide has a longer half-life (allowing once-daily dosing) and a lower risk of hepatotoxicity. * **Side Effects:** Common side effects include gynecomastia, hot flashes, and hepatotoxicity (monitor LFTs).

Question 1

What is the drug of choice for Chronic Myeloid Leukemia (CML)?

Accepted Answer

Imatinib mesylate

Answer

Fludarabine

Answer

All-trans retinoic acid (for AML M3)

Answer

Methotrexate

Question 2

Cetuximab, an EGFR antagonist, can be used in which of the following conditions?

Accepted Answer

Palliation in head and neck cancer

Answer

Anal canal carcinoma

Answer

Gastric carcinoma

Answer

Lung carcinoma

Question 3

Which of the following is an antifolate cancer drug?

Accepted Answer

Methotrexate

Answer

Azathioprine

Answer

Cyclosporin

Answer

Vincristine

Question 4

All the following drugs are used in the treatment of metastatic breast cancer except?

Accepted Answer

Sunitinib

Answer

Ixabepilone

Answer

Abemaciclib

Answer

Ribociclib

Question 5

All of the following statements about vincristine are true EXCEPT:

Accepted Answer

It is a drug of choice for choriocarcinoma.

Answer

It is cell cycle specific and kills cells in the M phase.

Answer

Its toxicity primarily affects peripheral nerves and bone marrow.

Answer

Folic acid is not used to reverse its toxic effects.

Question 6

For which condition is the drug Bozoib used?

Accepted Answer

Multiple myeloma

Answer

Renal cell carcinoma

Answer

Hepatocellular carcinoma

Answer

Pancreatic carcinoma

Question 7

What is the most common dose-limiting toxicity of chemotherapeutic agents?

Accepted Answer

Myelosuppression

Answer

Gastrointestinal toxicity

Answer

Neurotoxicity

Answer

Alopecia

Question 8

Erlotinib is used in which of the following cancers?

Accepted Answer

Pancreatic cancer

Answer

Colon cancer

Answer

Gall bladder cancer

Answer

GIST

Question 9

Which of the following drugs is most emetogenic?

Accepted Answer

Cisplatin

Answer

Carboplatin

Answer

High dose cyclophosphamide

Answer

High dose methotrexate

Question 10

Bicalutamide is a specific inhibitor of which of the following?

Accepted Answer

Androgen receptors

Answer

5-alpha reductase

Answer

Aromatase

Answer

Estrogen receptor

Anticancer Drugs — MCQs

Anticancer Drugs — MCQs

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