Anticancer Drugs — MCQs
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Which of the following anticancer drugs is not derived from plants?
Alkylating drugs attach an alkyl group to which position of guanine?
A young male was diagnosed with acute myeloid leukemia and successfully completed induction chemotherapy. Two months later, he presents with bilateral pedal edema and dyspnea on exertion (waking up multiple times due to breathlessness). Which of the following anticancer drugs is most likely responsible for these symptoms?
Which of the following statements is true regarding intravenous administration of chemotherapy?
Which anticancer drug belongs to the class of inorganic metal complexes?
Which of the following is associated with neutropenia?
A female patient with a mechanical heart valve who is taking warfarin informs you that she hopes to get pregnant in the near future. What advice do you give her regarding her antithrombotic medication during the anticipated pregnancy?
Which of the following is a monoclonal antibody against IL-5?
Ifosfamide belongs to which group of anticancer drugs?
Which of the following is an antimitotic drug of plant origin?
Anticancer Drugs Indian Medical PG Practice Questions and MCQs
Question 61: Which of the following anticancer drugs is not derived from plants?
- A. Irinotecan
- B. Doxorubicin (Correct Answer)
- C. Paclitaxel
- D. Etoposide
Explanation: The correct answer is **Doxorubicin** because it is an **anthracycline antibiotic** derived from the bacterium *Streptomyces peucetius*, not from a plant source. ### **Explanation of Options:** * **Doxorubicin (Option B):** It is a microbial product. It acts by inhibiting Topoisomerase II, intercalating between DNA base pairs, and generating free radicals. Its major dose-limiting toxicity is cardiotoxicity (dilated cardiomyopathy). * **Irinotecan (Option A):** This is a semi-synthetic derivative of **Camptothecin**, which is obtained from the Chinese ornamental tree *Camptotheca acuminata*. It acts by inhibiting Topoisomerase I. * **Paclitaxel (Option C):** This is a **Taxane** derived from the bark of the Pacific Yew tree (*Taxus brevifolia*). It acts by stabilizing microtubules (preventing depolymerization), leading to mitotic arrest. * **Etoposide (Option D):** This is a semi-synthetic derivative of **Podophyllotoxin**, which is extracted from the Mayapple plant (*Podophyllum peltatum*). It acts by inhibiting Topoisomerase II. ### **High-Yield Clinical Pearls for NEET-PG:** 1. **Vinca Alkaloids (Vincristine/Vinblastine):** Derived from *Catharanthus roseus* (Periwinkle). They inhibit microtubule assembly (polymerization). 2. **Taxanes vs. Vincas:** Taxanes "freeze" microtubules (prevent breakdown), while Vincas "dissolve" them (prevent formation). 3. **Topoisomerase Inhibitors:** * **Type I:** Irinotecan, Topotecan (Plant-derived). * **Type II:** Etoposide (Plant-derived) and Doxorubicin (Microbial-derived). 4. **Antitumor Antibiotics:** Most (Doxorubicin, Bleomycin, Mitomycin C) are derived from *Streptomyces* species.
Question 62: Alkylating drugs attach an alkyl group to which position of guanine?
- A. N3
- B. N5
- C. N7 (Correct Answer)
- D. N9
Explanation: **Explanation:** **Mechanism of Action:** Alkylating agents (e.g., Cyclophosphamide, Chlorambucil) are cell cycle-nonspecific drugs that act by forming highly reactive carbonium ion intermediates. These intermediates form covalent bonds with electron-rich nucleophilic sites on DNA bases. The **N7 position of Guanine** is the most nucleophilic (electron-dense) site in DNA, making it the primary target for alkylation. **Why N7 is Correct:** When an alkyl group attaches to the N7 position of guanine, it leads to: 1. **Cross-linking:** Formation of intra-strand or inter-strand bridges (especially with bifunctional alkylators), which prevents DNA strand separation during replication. 2. **Base-pairing errors:** Guanine may mispair with Thymine. 3. **Depurination:** The imidazole ring destabilizes, leading to excision of the guanine base and subsequent DNA strand breakage. **Why Other Options are Incorrect:** * **N3 of Guanine:** While alkylation can occur at the N3 position of Adenine, it is not the preferred or most common site for Guanine. * **N5:** This is not a standard site for DNA alkylation by these agents. * **N9:** The N9 position of guanine is the site where the base attaches to the deoxyribose sugar (forming the N-glycosidic bond), making it unavailable for alkylation in a DNA polymer. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** N7 of Guanine (Primary target). * **Other targets:** N1 and N3 of Adenine, N3 of Cytosine. * **Cyclophosphamide:** A prodrug activated by Cytochrome P450 in the liver. Its metabolite **Acrolein** causes hemorrhagic cystitis, which is prevented by **MESNA** (Mercaptoethane sulfonate) and aggressive hydration. * **Resistance:** Often occurs due to increased production of Glutathione or enhanced DNA repair enzymes (e.g., MGMT).
Question 63: A young male was diagnosed with acute myeloid leukemia and successfully completed induction chemotherapy. Two months later, he presents with bilateral pedal edema and dyspnea on exertion (waking up multiple times due to breathlessness). Which of the following anticancer drugs is most likely responsible for these symptoms?
- A. Cisplatin
- B. Methotrexate
- C. Doxorubicin (Correct Answer)
- D. Vincristine
Explanation: ### Explanation The clinical presentation of bilateral pedal edema, dyspnea on exertion, and paroxysmal nocturnal dyspnea (waking up breathless) points toward **Congestive Heart Failure (CHF)**. In a patient treated for Acute Myeloid Leukemia (AML), this is a classic manifestation of **Anthracycline-induced cardiotoxicity**. **1. Why Doxorubicin is correct:** Doxorubicin (an Anthracycline) causes cardiotoxicity through the generation of **iron-dependent free radicals** (superoxide anions) that cause lipid peroxidation of the myocardial membranes. Since the heart has low levels of protective enzymes like catalase, it is highly susceptible. This toxicity is **dose-dependent and cumulative**. It typically presents as dilated cardiomyopathy leading to heart failure months after treatment. **2. Why other options are incorrect:** * **Cisplatin:** Primarily known for **Nephrotoxicity** (prevented by aggressive hydration/Amifostine) and Ototoxicity. It does not typically cause heart failure. * **Methotrexate:** Associated with **Myelosuppression**, Mucositis, and Hepatotoxicity. High doses can cause nephrotoxicity due to crystalluria. * **Vincristine:** Its hallmark side effect is **Peripheral Neuropathy** (paresthesia, loss of deep tendon reflexes, and autonomic dysfunction like constipation). It is "bone marrow sparing." **3. High-Yield Clinical Pearls for NEET-PG:** * **Monitoring:** Periodic **Echocardiography** or MUGA scans to monitor Left Ventricular Ejection Fraction (LVEF) is mandatory. * **Prevention:** **Dexrazoxane** (an iron chelator) is used to reduce the risk of doxorubicin-induced cardiotoxicity. * **Cumulative Dose:** The risk of CHF increases significantly once the cumulative dose of Doxorubicin exceeds **550 mg/m²**. * **Histology:** On biopsy, look for "Myofibrillar loss and cytoplasmic vacuolization."
Question 64: Which of the following statements is true regarding intravenous administration of chemotherapy?
- A. Subcutaneous extravasation of carmustine (BCNU) or 5-fluorouracil (5-FU) usually causes ulceration.
- B. Extravasation of doxorubicin rarely causes serious ulceration because the agent binds quickly to tissue nucleic acid.
- C. Serious and progressive ulceration can be expected following extravasation of vincristine or vinblastine.
- D. Problems of wound healing should be anticipated if systemic 5-FU therapy is begun less than 2 weeks postoperatively. (Correct Answer)
Explanation: ### Explanation **Correct Option: D** Antimetabolites like **5-Fluorouracil (5-FU)** inhibit DNA synthesis and cell proliferation, which are essential processes for tissue repair and collagen formation [2]. If administered systemically within 10–14 days of surgery, 5-FU can significantly impair fibroblast activity and wound contraction, leading to dehiscence or delayed healing. Therefore, a postoperative "waiting period" of at least 2 weeks is clinically recommended. **Analysis of Incorrect Options:** * **Option A:** Carmustine (BCNU) and 5-FU are generally classified as **non-vesicants** (or irritants). While they may cause local inflammation or phlebitis, their extravasation does not typically lead to deep tissue necrosis or ulceration. * **Option B:** Doxorubicin is a potent **vesicant**. Contrary to the statement, it causes severe, progressive, and chronic ulceration because it remains bound to tissue proteins and DNA for long periods, causing continuous cell death in the surrounding area. * **Option C:** While Vincristine and Vinblastine are vesicants, their extravasation typically causes localized pain and inflammation that is usually **self-limiting** and less severe than the progressive necrosis seen with Anthracyclines (like Doxorubicin) [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Vesicants vs. Irritants:** Vesicants (e.g., Doxorubicin, Vinca alkaloids, Mechlorethamine) cause necrosis; Irritants (e.g., 5-FU, Cyclophosphamide, Platinum drugs) cause inflammation without necrosis. * **Antidote for Anthracyclines (Doxorubicin):** Dexrazoxane or topical DMSO; apply **cold** compresses. * **Antidote for Vinca Alkaloids (Vincristine):** Hyaluronidase; apply **warm** compresses (to increase drug dispersion). * **5-FU Toxicity:** Hand-foot syndrome (palmar-plantar erythrodysesthesia) and mucositis are common side effects.
Question 65: Which anticancer drug belongs to the class of inorganic metal complexes?
- A. Dacarbazine
- B. Cisplatin (Correct Answer)
- C. Methotrexate
- D. Vincristine
Explanation: ### Explanation **Correct Answer: B. Cisplatin** **Mechanism and Classification:** Cisplatin is the prototype of the **platinum coordination complexes**, which are inorganic metal complexes. Unlike organic molecules, cisplatin consists of a central platinum atom surrounded by two ammonia molecules and two chloride atoms in a *cis* configuration. * **Mechanism of Action:** It acts as a cell-cycle non-specific alkylating-like agent. Inside the cell, chloride ions are displaced by water, forming a reactive species that binds to DNA (primarily at the N7 position of guanine). This creates **intrastrand cross-links**, leading to DNA bending, inhibition of replication, and apoptosis. **Analysis of Incorrect Options:** * **A. Dacarbazine:** An organic alkylating agent belonging to the **Triazene** group. It is a prodrug activated in the liver to MTIC, used primarily in melanoma and Hodgkin lymphoma. * **C. Methotrexate:** A classic **Antimetabolite**. It is a folate analogue that inhibits the enzyme dihydrofolate reductase (DHFR), thereby arresting DNA synthesis. * **D. Vincristine:** A **Vinca Alkaloid** derived from the periwinkle plant (*Catharanthus roseus*). It is a microtubule inhibitor that binds to tubulin and prevents polymerization (M-phase specific). **High-Yield Clinical Pearls for NEET-PG:** * **Toxicity Profile:** Cisplatin is notorious for "the three Ns": **N**ephrotoxicity (prevented by aggressive hydration and Amifostine), **N**eurotoxicity (peripheral neuropathy), and severe **N**ausea/vomiting (highly emetogenic). It is also **Ototoxic**. * **Indications:** It is the cornerstone of treatment for solid tumors, especially testicular, ovarian, and lung cancers. * **Resistance:** Often occurs due to increased DNA repair or increased intracellular levels of glutathione.
Question 66: Which of the following is associated with neutropenia?
- A. Doxorubicin
- B. Vinblastine
- C. Cisplatin
- D. Methotrexate (Correct Answer)
Explanation: **Explanation:** **1. Why Methotrexate is the Correct Answer:** Methotrexate (MTX) is a folate antimetabolite that inhibits the enzyme **dihydrofolate reductase (DHFR)**. This inhibition prevents the conversion of dihydrofolate to tetrahydrofolate, which is essential for DNA synthesis (thymidylate synthesis). Because it acts on rapidly dividing cells, the bone marrow is highly susceptible. **Myelosuppression**, specifically **neutropenia**, is the dose-limiting toxicity of Methotrexate. This can be mitigated by "Leucovorin rescue" (folinic acid), which bypasses the inhibited DHFR enzyme. **2. Analysis of Incorrect Options:** * **Doxorubicin:** While it can cause myelosuppression, its most characteristic and high-yield side effect is **cardiotoxicity** (dilated cardiomyopathy) due to free radical generation. * **Vinblastine:** Although Vinblastine is more bone-marrow toxic than Vincristine ("Blast the marrow"), it is not the primary answer when compared to the systemic antimetabolic effect of Methotrexate in many standardized contexts. However, in clinical practice, many of these drugs cause neutropenia; the question focuses on the classic association with antimetabolites. * **Cisplatin:** The hallmark toxicities of Cisplatin are **nephrotoxicity** and **ototoxicity**. It is considered relatively "bone marrow sparing" compared to other cytotoxic agents. **3. NEET-PG High-Yield Pearls:** * **Mnemonic for Vinca Alkaloids:** **V**in**b**lastine **B**lasts the **B**one marrow; **V**incristine **C**onstricts the **C**ranials (Neurotoxicity/Peripheral neuropathy). * **Methotrexate Toxicity:** Always remember the triad of Myelosuppression, Mucositis, and Hepatotoxicity (cirrhosis with long-term use). * **Antidote:** **Glucarpidase** can be used for methotrexate toxicity in patients with renal failure. * **Cisplatin:** Prevent nephrotoxicity with aggressive hydration and **Amifostine** (a cytoprotective agent).
Question 67: A female patient with a mechanical heart valve who is taking warfarin informs you that she hopes to get pregnant in the near future. What advice do you give her regarding her antithrombotic medication during the anticipated pregnancy?
- A. Continue with warfarin until the third trimester.
- B. Replace warfarin with aspirin at analgesic doses.
- C. Discontinue all medications that affect the blood.
- D. Replace warfarin with heparin. (Correct Answer)
Explanation: ### Explanation **1. Why the correct answer is right:** Warfarin is a small, lipid-soluble molecule that easily crosses the placenta. It is highly **teratogenic**, especially during the first trimester (6th–9th week), leading to **Fetal Warfarin Syndrome** (characterized by nasal hypoplasia, stippled epiphyses, and CNS defects). In contrast, **Heparin** (both Unfractionated Heparin and LMWH) is a large, polar molecule that **does not cross the placenta** and is therefore safe for the fetus. For patients with mechanical heart valves, anticoagulation must be maintained throughout pregnancy to prevent valve thrombosis, making heparin the safest substitute. **2. Why the incorrect options are wrong:** * **Option A:** Continuing warfarin until the third trimester exposes the fetus to the highest risk of malformations in the first trimester and intracranial hemorrhage during labor in the third trimester. * **Option B:** Aspirin at analgesic doses is not a substitute for anticoagulation in mechanical valves and can cause premature closure of the *ductus arteriosus*. * **Option C:** Discontinuing all medications is life-threatening for the mother, as pregnancy is a hypercoagulable state; a mechanical valve without anticoagulation will almost certainly thrombose. **3. Clinical Pearls for NEET-PG:** * **Fetal Warfarin Syndrome:** Look for keywords like "Chondrodysplasia punctata" or "stippled epiphyses." * **LMWH vs. UFH:** LMWH (e.g., Enoxaparin) is generally preferred in pregnancy due to a lower risk of Heparin-Induced Thrombocytopenia (HIT) and osteoporosis, but it requires monitoring of **Factor Xa levels**. * **The "Switch":** Common practice involves switching to Heparin before conception or as soon as pregnancy is confirmed, though some guidelines allow warfarin between 13–36 weeks if the dose is low (<5mg/day). However, for MCQ purposes, **Heparin is the drug of choice in pregnancy.**
Question 68: Which of the following is a monoclonal antibody against IL-5?
- A. Omalizumab
- B. Mepolizumab (Correct Answer)
- C. Tocilizumab
- D. Alemtuzumab
Explanation: **Explanation:** **Mepolizumab** is a humanized monoclonal antibody that directly binds to and inhibits **Interleukin-5 (IL-5)**. IL-5 is the primary cytokine responsible for the growth, activation, and survival of eosinophils. By neutralizing IL-5, mepolizumab reduces eosinophilic inflammation, making it a key treatment for **severe eosinophilic asthma** and Hypereosinophilic Syndrome. **Analysis of Incorrect Options:** * **A. Omalizumab:** This is a monoclonal antibody against **IgE**. It prevents IgE from binding to mast cells and basophils, used primarily in severe allergic asthma. * **C. Tocilizumab:** This is an **IL-6 receptor antagonist**. It is used in Rheumatoid Arthritis, Giant Cell Arteritis, and was notably used in managing the "cytokine storm" in severe COVID-19. * **D. Alemtuzumab:** This is a monoclonal antibody against **CD52**, found on mature lymphocytes. It is used in the treatment of Chronic Lymphocytic Leukemia (CLL) and Multiple Sclerosis. **High-Yield NEET-PG Pearls:** 1. **IL-5 Inhibitors:** Remember the "mabs" for eosinophilic asthma: **Mepolizumab** and **Reslizumab** (bind to IL-5) and **Benralizumab** (binds to the IL-5 receptor). 2. **Dupilumab:** Often confused with these, it targets the **IL-4 receptor alpha subunit** (inhibiting both IL-4 and IL-13) and is used for atopic dermatitis and asthma. 3. **Suffix Clue:** "-li-" in Mepo**li**zumab stands for "limbic/immune system," while "-tu-" in Toci**tu**zumab (though often shortened) or Rituximab refers to "tumor."
Question 69: Ifosfamide belongs to which group of anticancer drugs?
- A. Alkylating agents (Correct Answer)
- B. Antimetabolites
- C. Mitotic inhibitors
- D. Topoisomerase inhibitors
Explanation: **Explanation:** **Ifosfamide** is a nitrogen mustard derivative and a structural isomer of cyclophosphamide. It belongs to the **Alkylating Agents** group (specifically the Oxazaphosphorine subclass). These drugs work by attaching alkyl groups to DNA bases (primarily at the N7 position of guanine), leading to DNA cross-linking, strand breakage, and inhibition of DNA synthesis. Like cyclophosphamide, ifosfamide is a **prodrug** that requires hepatic activation by the Cytochrome P450 system (CYP3A4 and CYP2B6) to form its active metabolite, ifosfamide mustard. **Why other options are incorrect:** * **Antimetabolites (e.g., Methotrexate, 5-FU):** These interfere with metabolic pathways (like folic acid or pyrimidine synthesis) and are S-phase specific. * **Mitotic Inhibitors (e.g., Vincristine, Paclitaxel):** These target microtubules during the M-phase of the cell cycle. * **Topoisomerase Inhibitors (e.g., Etoposide, Irinotecan):** These inhibit enzymes responsible for DNA winding/unwinding. **High-Yield Clinical Pearls for NEET-PG:** 1. **Hemorrhagic Cystitis:** Ifosfamide produces **Acrolein**, a toxic metabolite that causes bladder irritation. This risk is significantly higher with ifosfamide than with cyclophosphamide. 2. **Mesna (2-Mercaptoethane sulfonate):** Always co-administered with ifosfamide to neutralize acrolein in the bladder and prevent hemorrhagic cystitis. 3. **Encephalopathy:** Ifosfamide can cause CNS toxicity (confusion, seizures) due to the production of **chloroacetaldehyde**. This is a unique side effect compared to cyclophosphamide. 4. **Cell Cycle Non-Specific (CCNS):** Like most alkylating agents, ifosfamide acts throughout the cell cycle.
Question 70: Which of the following is an antimitotic drug of plant origin?
- A. Vincristine (Correct Answer)
- B. Isotretinoin
- C. Bleomycin
- D. Methotrexate
Explanation: **Explanation:** **Vincristine** is the correct answer because it is a natural alkaloid derived from the **Periwinkle plant (*Vinca rosea*)**. It functions as an **antimitotic agent** by binding to tubulin, preventing the polymerization of microtubules. This inhibits the formation of the mitotic spindle, leading to cell cycle arrest in the **M-phase**. **Analysis of Incorrect Options:** * **Isotretinoin:** A retinoid (Vitamin A derivative) primarily used in severe acne. While retinoids are used in some cancers (like APL), it is not an antimitotic drug of plant origin. * **Bleomycin:** An antitumor antibiotic derived from the bacterium *Streptomyces verticillus*. It acts by inducing DNA strand breaks through free radical formation (G2 phase specific), not by inhibiting mitosis. * **Methotrexate:** An antimetabolite that acts as a **dihydrofolate reductase (DHFR) inhibitor**. It is cell cycle-specific for the **S-phase** and is a synthetic compound, not plant-derived. **High-Yield Clinical Pearls for NEET-PG:** 1. **Vinca Alkaloids vs. Taxanes:** Both are plant-derived antimitotics. Vincas (Vincristine, Vinblastine) **inhibit polymerization**, while Taxanes (Paclitaxel, Docetaxel) **inhibit depolymerization** ("freeze" the spindle). 2. **Dose-Limiting Toxicity:** The major side effect of Vincristine is **peripheral neuropathy** (paresthesia, loss of reflexes), whereas Vinblastine is more associated with **bone marrow suppression** ("Blast" the marrow). 3. **Vincristine is "Bone Marrow Sparing":** It is a preferred component in regimens like MOPP or CHOP because it causes minimal myelosuppression.
Practice by Chapter
Principles of Cancer Chemotherapy
Practice Questions
Alkylating Agents
Practice Questions
Antimetabolites
Practice Questions
Antitumor Antibiotics
Practice Questions
Plant Alkaloids
Practice Questions
Topoisomerase Inhibitors
Practice Questions
Hormonal Agents
Practice Questions
Targeted Therapy
Practice Questions
Immunotherapy
Practice Questions
Management of Chemotherapy Side Effects
Practice Questions
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