Anticancer Drugs Practice Questions

Q: Which chemotherapeutic drug inhibits the polymerization of microtubules but is not associated with causing bone marrow suppression?

Vincristine. **Explanation:** The correct answer is **Vincristine**. This question tests the ability to differentiate between drugs within the same class based on their side-effect profiles, a common high-yield theme in NEET-PG. **1. Why Vincristine is correct:** Vincristine belongs to the **Vinca Alkaloids** class. Its mechanism of action involves binding to tubulin dimers, which **inhibits the polymerization** of microtubules, leading to mitotic arrest in the M-phase. A unique clinical feature of Vincristine is that it is **bone marrow sparing** (minimal myelosuppression). However, its dose-limiting toxicity is **peripheral neuropathy** (paresthesia, loss of reflexes, and foot drop). **2. Why the other options are incorrect:** * **Vinblastine:** Although it is also a Vinca alkaloid with the same mechanism (inhibiting polymerization), it is notorious for causing significant bone marrow suppression. (Mnemonic: **B**lastine **B**lasts the **B**one marrow). * **Cisplatin:** This is a platinum compound that acts by cross-linking DNA. It is highly emetogenic and nephrotoxic but does not act on microtubules. * **5-Fluorouracil:** This is an antimetabolite (pyrimidine analog) that inhibits thymidylate synthase. It causes significant myelosuppression and GI toxicity. **3. NEET-PG High-Yield Pearls:** * **Microtubule Inhibitors:** Remember that **Vinca alkaloids** (Vincristine, Vinblastine) inhibit *polymerization*, whereas **Taxanes** (Paclitaxel, Docetaxel) inhibit *depolymerization* (they "freeze" the spindle). * **Vincristine Side Effects:** Apart from neuropathy, it can cause **SIADH** and paralytic ileus. * **Fatal Administration:** Vincristine is **fatal if given intrathecally**; it must only be administered intravenously. * **Marrow Sparing Drugs:** Other notable marrow-sparing anticancer drugs include **Bleomycin** (pulmonary fibrosis) and **L-Asparaginase** (pancreatitis).

Q: Sipuleucel-T is a vaccine indicated for which condition?

Prostate carcinoma. **Explanation:** **Sipuleucel-T** is a revolutionary immunotherapy, specifically an **autologous cellular immunotherapy**, used in the management of advanced prostate cancer. **Why Prostate Carcinoma is Correct:** Sipuleucel-T is the first "cancer vaccine" approved by the FDA for the treatment of **asymptomatic or minimally symptomatic metastatic castrate-resistant prostate cancer (mCRPC)**. The process involves collecting a patient's own peripheral blood mononuclear cells (including antigen-presenting cells) via leukapheresis. These cells are activated ex-vivo with a recombinant fusion protein (PA2024) consisting of **Prostatic Acid Phosphatase (PAP)** linked to Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF). When re-infused, these "primed" cells stimulate a T-cell immune response against prostate cancer cells expressing PAP. **Why Other Options are Incorrect:** * **Renal Cell Carcinoma (RCC):** While RCC is highly immunogenic, standard immunotherapies involve Tyrosine Kinase Inhibitors (TKIs) or Checkpoint Inhibitors (Nivolumab/Pembrolizumab), not Sipuleucel-T. * **Testicular Tumor:** These are primarily treated with surgery (Radical Orchidectomy) and platinum-based chemotherapy (BEP regimen). * **Bladder Carcinoma:** Intravesical BCG is the standard immunotherapy for non-muscle invasive bladder cancer; Sipuleucel-T has no role here. **High-Yield Clinical Pearls for NEET-PG:** * **Indication:** Metastatic Castrate-Resistant Prostate Cancer (mCRPC) that is asymptomatic/minimally symptomatic. * **Target Antigen:** Prostatic Acid Phosphatase (PAP). * **Mechanism:** Active cellular immunotherapy (not a preventive vaccine). * **Survival:** It has been shown to improve overall survival (OS) but does not typically result in a decrease in PSA levels or tumor shrinkage on imaging.

Q: Which of the following causes minimum bone marrow suppression?

Bleomycin. **Explanation:** The correct answer is **Bleomycin**. Most conventional cytotoxic anticancer drugs are "myelosuppressive," meaning they target rapidly dividing cells in the bone marrow, leading to leukopenia, anemia, and thrombocytopenia. However, certain drugs are known for their **"bone marrow sparing"** properties. **1. Why Bleomycin is correct:** Bleomycin is a glycopeptide antibiotic that works by inducing free radical formation, causing single and double-strand DNA breaks. Its dose-limiting toxicity is **pulmonary fibrosis**, not myelosuppression. This is because the enzyme that inactivates the drug (bleomycin hydrolase) is present in high concentrations in the bone marrow but is deficient in the lungs and skin. **2. Why the other options are incorrect:** * **5-Fluorouracil (5-FU):** An antimetabolite (pyrimidine analog) that inhibits thymidylate synthase. It causes significant myelosuppression (nadir at 9–14 days) and GI toxicity. * **Cytarabine (Ara-C):** A potent S-phase specific antimetabolite. It is notorious for causing severe, prolonged bone marrow suppression, which is actually the therapeutic goal when treating acute myeloid leukemia (AML). * **Topotecan:** A Topoisomerase I inhibitor. Its primary dose-limiting toxicity is neutropenia (up to 80% of patients). **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Bone Marrow Sparing Drugs:** "**B**etter **V**ictory **L**ess **C**omplications" → **B**leomycin, **V**incristine, **L**-asparaginase, **C**isplatin (Cisplatin is relatively less myelosuppressive compared to Carboplatin). * **Specific Toxicities to Remember:** * Bleomycin: Pulmonary fibrosis & Skin hyperpigmentation. * Vincristine: Peripheral neuropathy (Microtubule inhibitor). * L-asparaginase: Pancreatitis & Clotting factor deficiency. * Cyclophosphamide: Hemorrhagic cystitis (prevented by **MESNA**).

Q: Hydroxyurea's mechanism of action in cancer is by inhibiting which enzyme?

Ribonucleotide diphosphate reductase. **Explanation** **Mechanism of Action** Hydroxyurea is an S-phase specific antimetabolite. Its primary mechanism of action is the inhibition of the enzyme **Ribonucleotide diphosphate reductase (RNR)**. This enzyme is responsible for the rate-limiting step in DNA synthesis: the conversion of ribonucleoside diphosphates (NDPs) to deoxyribonucleoside diphosphates (dNDPs). By inhibiting RNR, hydroxyurea depletes the intracellular pool of deoxyribonucleotides, thereby halting DNA synthesis and repair. **Analysis of Options** * **Option A (Correct):** Ribonucleotide diphosphate reductase is the specific target. Hydroxyurea acts by scavenging the tyrosyl free radical required for the enzyme's catalytic activity. * **Option B:** Ribonucleotide oxidase is not a recognized enzyme in the de novo synthesis of nucleotides. * **Option C & D:** DNA lyase and DNA synthetase (often referred to as DNA Polymerase/Ligase) are involved in the later stages of DNA strand assembly and repair, but they are not the targets of hydroxyurea. **Clinical Pearls for NEET-PG** * **Sickle Cell Anemia:** Hydroxyurea is the drug of choice to reduce the frequency of painful crises. It works by **increasing the levels of Fetal Hemoglobin (HbF)**, which inhibits the polymerization of HbS. * **Myeloproliferative Disorders:** It is used in the management of Chronic Myeloid Leukemia (CML), Polycythemia Vera, and Essential Thrombocythemia to rapidly lower cell counts. * **Radiation Sensitizer:** It is used in cervical and head/neck cancers to synchronize cells in the G1 phase, making them more sensitive to radiotherapy. * **Side Effect:** The most common dose-limiting toxicity is **myelosuppression** (leukopenia). It can also cause macrocytosis and cutaneous ulcers.

Q: Which of the following is a significant cause of alopecia (epilation)?

Doxorubicin. **Explanation:** **Doxorubicin (Option A)** is the correct answer. Alopecia (hair loss) is a common side effect of cytotoxic chemotherapy because these drugs target rapidly dividing cells [1]. Hair follicle matrix cells have a high mitotic index, making them highly susceptible. Doxorubicin, an anthracycline, is notorious for causing **complete and severe alopecia** (often occurring within 2–3 weeks of the first cycle). It works by intercalating DNA and inhibiting Topoisomerase II, leading to significant damage in the hair bulb. **Analysis of Incorrect Options:** * **Docetaxel (Option B):** While taxanes do cause significant alopecia, Doxorubicin is classically associated with the most profound and rapid epilation in pharmacological literature and exams. * **Rituximab (Option C):** This is a monoclonal antibody targeting CD20 on B-cells. Unlike cytotoxic drugs, it does not typically affect hair follicles and rarely causes alopecia. * **Carboplatin (Option D):** While platinum compounds can cause hair thinning [1], the incidence and severity are significantly lower compared to anthracyclines like Doxorubicin. **High-Yield NEET-PG Pearls:** * **"Red Devil":** Doxorubicin is nicknamed the "Red Devil" due to its red color and significant toxicities, including **cardiotoxicity** (dilated cardiomyopathy) and severe alopecia. * **Prevention:** Scalp cooling (cold caps) is used to induce vasoconstriction, reducing the delivery of chemotherapy to hair follicles. * **Other high-alopecia drugs:** Cyclophosphamide, Vincristine, and Paclitaxel. * **Minimal-alopecia drugs:** Methotrexate (low dose), Fluorouracil (5-FU), and Bleomycin.

Q: Toxicity of nitrogen mustards can be decreased by?

GM-CSF. ### Explanation **Correct Answer: C. GM-CSF** **Mechanism and Rationale:** Nitrogen mustards (e.g., Cyclophosphamide, Ifosfamide, Mechlorethamine) are potent alkylating agents. Their most common dose-limiting toxicity is **bone marrow suppression (myelosuppression)**, leading to severe neutropenia and increased risk of infections. **GM-CSF (Granulocyte-Macrophage Colony-Stimulating Factor)**, such as Sargramostim, or G-CSF (Filgrastim), stimulates the production and differentiation of myeloid progenitor cells in the bone marrow. By accelerating the recovery of neutrophil counts, GM-CSF directly mitigates the hematological toxicity caused by nitrogen mustards. **Analysis of Incorrect Options:** * **A. Allopurinol:** While used in cancer patients, it is specifically indicated to prevent **Tumor Lysis Syndrome** (hyperuricemia) resulting from rapid cell kill. It does not reduce the direct cytotoxic damage of nitrogen mustards on healthy tissues. * **B. Folinic acid (Leucovorin):** This is the specific "rescue" agent for **Methotrexate** (a folate antagonist) toxicity. It has no role in reversing the DNA alkylation caused by nitrogen mustards. **High-Yield Clinical Pearls for NEET-PG:** * **Mesna:** Specifically used to prevent **Hemorrhagic Cystitis** caused by the metabolite *Acrolein* during Cyclophosphamide or Ifosfamide therapy. * **Amifostine:** A cytoprotective agent used to reduce renal toxicity from Cisplatin. * **Dexrazoxane:** Used to prevent cardiomyopathy caused by Anthracyclines (Doxorubicin). * **Nitrogen Mustard Mnemonic:** *Mechlorethamine* was the first non-hormonal anticancer drug developed from mustard gas used in WWI.

Q: Which of the following drugs can cause delayed bone marrow suppression leading to sustained neutropenia?

Carmustine. **Explanation:** The correct answer is **Carmustine (Option D)**. **1. Why Carmustine is correct:** Carmustine (BCNU) and Lomustine (CCNU) are **Nitrosoureas**, a class of alkylating agents. Unlike most cytotoxic drugs that cause a nadir (lowest point of blood counts) at 7–14 days, Nitrosoureas are notorious for causing **delayed and cumulative bone marrow suppression**. The neutropenia and thrombocytopenia typically occur **4 to 6 weeks** after administration and can be prolonged. This delay is due to their action on early hematopoietic stem cells rather than rapidly dividing committed progenitors. **2. Analysis of Incorrect Options:** * **Vincristine (A):** A Vinca alkaloid known for being **"bone marrow sparing."** Its dose-limiting toxicity is peripheral neuropathy (paresthesia, foot drop), not myelosuppression. * **Carboplatin (B):** While it causes significant thrombocytopenia, the suppression is typically not "delayed" in the 6-week timeframe characteristic of Nitrosoureas. * **Melphalan (C):** An alkylating agent used in Multiple Myeloma. While it causes myelosuppression, it follows a more standard recovery timeline compared to the profound delay seen with Carmustine. **3. High-Yield Clinical Pearls for NEET-PG:** * **Nitrosoureas (Carmustine/Lomustine):** Highly lipid-soluble; they cross the Blood-Brain Barrier (BBB) and are the drugs of choice for **Glut-4/Brain tumors (Gliomas)**. * **Busulfan:** Another alkylating agent known for "prolonged" marrow suppression and a specific side effect called **"Busulfan Tan"** (skin hyperpigmentation) and pulmonary fibrosis. * **Marrow Sparing Drugs:** Remember the mnemonic **"VBC"** — Vincristine, Bleomycin, and Cisplatin (Cisplatin is more nephrotoxic/emetogenic than myelotoxic).

Q: Which of the following agents is known to cause epilation?

Adriamycin. **Explanation:** **Adriamycin (Doxorubicin)**, an anthracycline antibiotic, is notorious for causing significant **alopecia (epilation)**. The underlying mechanism involves the drug’s interference with rapidly dividing cells. Hair follicles have a high mitotic index; Adriamycin inhibits Topoisomerase II and generates free radicals, leading to DNA damage in the hair bulb. This results in an "anagen effluvium," where hair loss is often complete and occurs within 1–3 weeks of treatment. **Analysis of Incorrect Options:** * **5-Fluorouracil (5-FU):** While it can cause thinning of hair, its hallmark toxicity is **Hand-Foot Syndrome** (palmar-plantar erythrodysesthesia) and GI mucosal ulceration. * **Cisplatin:** This platinum compound is primarily known for its dose-limiting **nephrotoxicity** and severe **emetogenicity**. It causes minimal hair loss compared to anthracyclines. * **Methotrexate:** An antimetabolite that primarily causes **myelosuppression** and **mucositis**. While it can cause some hair thinning, it rarely leads to the total epilation characteristic of Adriamycin. **High-Yield Clinical Pearls for NEET-PG:** 1. **Anthracycline Toxicity:** Apart from epilation, the most specific side effect is **Cardiotoxicity** (dilated cardiomyopathy). This is mediated by iron-dependent superoxide free radicals. 2. **Dexrazoxane:** An iron chelator used to prevent Adriamycin-induced cardiotoxicity. 3. **Radiation Recall:** Adriamycin can cause inflammatory skin reactions in previously irradiated areas. 4. **Red Urine:** Patients should be counseled that Adriamycin can cause harmless red discoloration of urine (not hematuria).

Q: Which of the following chemotherapeutic drugs has selective action on hypoxic tumor cells?

Mitomycin C. **Explanation:** **Mitomycin C** is the correct answer because it acts as a **bioreductive alkylating agent**. It is a prodrug that requires enzymatic activation (reduction) to form a highly reactive DNA-crosslinking species. This activation process is significantly more efficient in **hypoxic environments** (low oxygen levels) compared to well-oxygenated tissues. Since the core of solid tumors is often poorly vascularized and hypoxic, Mitomycin C exhibits selective toxicity toward these cells, making it a unique tool in treating solid tumors like those of the stomach, pancreas, and bladder. **Analysis of Incorrect Options:** * **B. Cisplatin:** A platinum compound that causes DNA cross-linking. Its efficacy is actually **reduced** in hypoxic conditions because hypoxia can lead to decreased drug uptake and slower cell cycling. * **C. Doxorubicin:** An anthracycline that inhibits Topoisomerase II and generates free radicals. Its free-radical-mediated damage requires **oxygen**, making it less effective in hypoxic tumor zones. * **D. 5-Fluorouracil (5-FU):** An antimetabolite (pyrimidine analog) that inhibits thymidylate synthase. It is most effective against rapidly dividing cells in the S-phase and does not have a selective mechanism for hypoxia. **High-Yield Clinical Pearls for NEET-PG:** * **Dose-Limiting Toxicity:** Mitomycin C causes delayed and prolonged **bone marrow suppression** (thrombocytopenia and leukopenia). * **Specific Side Effect:** It is associated with **Hemolytic Uremic Syndrome (HUS)** and pulmonary fibrosis. * **Clinical Use:** Often used intravesically for superficial bladder cancer to prevent recurrence. * **Concept:** Tumors with high hypoxic fractions are generally resistant to radiotherapy; Mitomycin C is often used as a "hypoxic cell sensitizer" to bridge this gap.

Q: Bevacizumab is:

Monoclonal antibody against VEGF. **Explanation:** **Bevacizumab** is a recombinant humanized monoclonal antibody that acts as a potent **angiogenesis inhibitor**. It works by specifically binding to and neutralizing **Vascular Endothelial Growth Factor (VEGF-A)**. By preventing VEGF from binding to its receptors (VEGFR-1 and VEGFR-2) on the surface of endothelial cells, it inhibits the formation of new blood vessels (neovascularization), thereby "starving" the tumor of oxygen and nutrients required for growth and metastasis. **Analysis of Incorrect Options:** * **Option B (Anti-IL-2):** Drugs like **Daclizumab** and **Basiliximab** are monoclonal antibodies against the IL-2 receptor (CD25), primarily used as immunosuppressants in renal transplants. * **Option C (Anti-FGFR):** While Fibroblast Growth Factor Receptor (FGFR) inhibitors exist (e.g., **Erdafitinib**), they are typically small molecule tyrosine kinase inhibitors rather than widely used monoclonal antibodies in standard NEET-PG curricula. * **Option D (Anti-EGFR):** Monoclonal antibodies against the Epidermal Growth Factor Receptor (EGFR) include **Cetuximab** and **Panitumumab**, commonly used in colorectal and head/neck cancers. **High-Yield Clinical Pearls for NEET-PG:** 1. **Clinical Uses:** Bevacizumab is used in metastatic colorectal cancer, non-small cell lung cancer (NSCLC), glioblastoma, and renal cell carcinoma. 2. **Ocular Use:** It is frequently used **off-label** (intravitreal injection) for **Wet Age-Related Macular Degeneration (ARMD)** and diabetic retinopathy to reduce macular edema. 3. **Key Side Effects:** The most characteristic adverse effects include **hypertension**, impaired wound healing, arterial thrombosis, and **proteinuria**. 4. **Suffix Tip:** Monoclonal antibodies ending in **"-umab"** are human, while **"-ximab"** are chimeric.

Question 1

Which chemotherapeutic drug inhibits the polymerization of microtubules but is not associated with causing bone marrow suppression?

Accepted Answer

Vincristine

Answer

Cisplatin

Answer

Vinblastine

Answer

5-Fluorouracil

Question 2

Sipuleucel-T is a vaccine indicated for which condition?

Accepted Answer

Prostate carcinoma

Answer

Renal cell carcinoma

Answer

Testicular tumor

Answer

Bladder carcinoma

Question 3

Which of the following causes minimum bone marrow suppression?

Accepted Answer

Bleomycin

Answer

5-Fluorouracil

Answer

Cytarabine

Answer

Topotecan

Question 4

Hydroxyurea's mechanism of action in cancer is by inhibiting which enzyme?

Accepted Answer

Ribonucleotide diphosphate reductase

Answer

Ribonucleotide oxidase

Answer

DNA lyase

Answer

DNA synthetase

Question 5

Which of the following is a significant cause of alopecia (epilation)?

Accepted Answer

Doxorubicin

Answer

Docetaxel

Answer

Rituximab

Answer

Carboplatin

Question 6

Toxicity of nitrogen mustards can be decreased by?

Accepted Answer

GM-CSF

Answer

Allopurinol

Answer

Folinic acid

Answer

All

Question 7

Which of the following drugs can cause delayed bone marrow suppression leading to sustained neutropenia?

Accepted Answer

Carmustine

Answer

Vincristine

Answer

Carboplatin

Answer

Melphalan

Question 8

Which of the following agents is known to cause epilation?

Accepted Answer

Adriamycin

Answer

5-Flurouracil

Answer

Cisplatin

Answer

Methotrexate

Question 9

Which of the following chemotherapeutic drugs has selective action on hypoxic tumor cells?

Accepted Answer

Mitomycin C

Answer

Cisplatin

Answer

Doxorubicin

Answer

5-Fluorouracil

Question 10

Bevacizumab is:

Accepted Answer

Monoclonal antibody against VEGF

Answer

Anti-IL-2 monoclonal antibody

Answer

Monoclonal antibody against FGFR

Answer

Monoclonal antibody against EGFR

Anticancer Drugs — MCQs

Anticancer Drugs — MCQs

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