Anticancer Drugs Practice Questions

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

Tretinoin. ### **Explanation** The clinical presentation of chest pain, pulmonary infiltrates, and pleural effusion in a patient being treated for leukemia (specifically Acute Promyelocytic Leukemia - APL) describes **Differentiation Syndrome** (formerly known as Retinoic Acid Syndrome). **1. Why Tretinoin is Correct:** Tretinoin (All-Trans Retinoic Acid or ATRA) induces the maturation of malignant promyelocytes. During this process, these cells release inflammatory cytokines and express adhesion molecules, leading to massive pulmonary infiltration and capillary leak. This manifests clinically as fever, dyspnea, weight gain, pleural/pericardial effusions, and pulmonary infiltrates. * **Management:** High-dose intravenous **Dexamethasone** is the treatment of choice. **2. Why Other Options are Incorrect:** * **Daunorubicin:** An anthracycline primarily associated with **cardiotoxicity** (dilated cardiomyopathy and congestive heart failure) rather than acute pulmonary infiltrates. * **Hydroxyurea:** Primarily causes myelosuppression and cutaneous side effects (hyperpigmentation, leg ulcers). While it can cause rare interstitial pneumonitis, it is not the classic cause of this acute triad in leukemia treatment. * **Cytarabine:** Known for causing **"Ara-C Syndrome"** (fever, rash, conjunctivitis) and cerebellar toxicity at high doses. While it can cause non-cardiogenic pulmonary edema, the context of APL treatment strongly points toward Tretinoin. **3. High-Yield Clinical Pearls for NEET-PG:** * **APL Marker:** Associated with **t(15;17)** translocation, involving the PML-RARα gene. * **Differentiation Syndrome:** Can also be caused by **Arsenic Trioxide**, another first-line agent for APL. * **Emergency Management:** Do not wait for radiological confirmation; if Differentiation Syndrome is suspected, start steroids immediately to prevent mortality.

Q: Thalidomide was reintroduced for certain indications like multiple myeloma after being withdrawn due to side effects. Which of the following is NOT a side effect of thalidomide?

Diarrhea. **Explanation:** Thalidomide is an immunomodulatory drug (IMiD) used primarily in the treatment of Multiple Myeloma and Erythema Nodosum Leprosum (ENL). **Why Diarrhea is the correct answer:** Thalidomide is characteristically associated with **constipation**, not diarrhea. It has significant neurotoxic and sedative properties that slow down gastrointestinal motility. In contrast, its newer analogue, Lenalidomide, is more frequently associated with diarrhea. **Analysis of incorrect options:** * **Hypothyroidism:** Thalidomide can cause primary hypothyroidism. Patients on long-term therapy require regular monitoring of Thyroid Stimulating Hormone (TSH) levels. * **Teratogenicity:** This is the most infamous side effect of thalidomide. If taken during the first trimester of pregnancy, it causes **Phocomelia** (seal-like limbs) due to its anti-angiogenic properties. This led to its withdrawal in the 1960s (the "Thalidomide Tragedy"). * **Deep Vein Thrombosis (DVT):** Thalidomide significantly increases the risk of venous thromboembolism, especially when used in combination with high-dose dexamethasone or chemotherapy in myeloma patients. Prophylactic anticoagulation is often required. **High-Yield Clinical Pearls for NEET-PG:** 1. **Mechanism of Action:** It binds to a protein called **Cereblon**, part of the E3 ubiquitin ligase complex, leading to the degradation of transcription factors (IKZF1/3). 2. **Peripheral Neuropathy:** A common dose-limiting toxicity; it is usually a symmetrical, painful sensory neuropathy. 3. **STEPS Program:** Due to its teratogenic potential, it is distributed under a restricted program (System for Thalidomide Education and Prescribing Safety). 4. **Drug of Choice:** Thalidomide is the drug of choice for Type 2 Lepra Reaction (ENL).

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: Which of the following is a known side effect of the chemotherapeutic agent cyclophosphamide?

Hemorrhagic cystitis. **Explanation:** Cyclophosphamide is a nitrogen mustard alkylating agent widely used in oncology and rheumatology [1]. The correct answer is **Hemorrhagic cystitis**, a classic and high-yield side effect [1]. 1. **Why Option A is Correct:** Cyclophosphamide is a prodrug metabolized in the liver to form **Acrolein** (and phosphoramide mustard) [1]. Acrolein is a toxic metabolite excreted in the urine. It causes direct irritation and sloughing of the bladder mucosa, leading to gross hematuria and bladder inflammation, known as hemorrhagic cystitis. 2. **Why the Other Options are Incorrect:** * **Renal failure (B):** While some alkylating agents like Cisplatin are notorious for nephrotoxicity [2], Cyclophosphamide is more specifically associated with bladder toxicity rather than acute renal failure. * **Tympanic membrane fibrosis (C):** This is not a recognized side effect of cyclophosphamide. Ototoxicity (specifically sensorineural hearing loss) is a hallmark side effect of **Cisplatin**. * **Necrotizing enterocolitis (D):** This is primarily a neonatal gastrointestinal emergency and is not a specific complication associated with cyclophosphamide therapy. **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). MESNA contains a thiol group that binds to and neutralizes acrolein in the bladder. * **Other Side Effects:** Cyclophosphamide is also associated with **SIADH** (dilutional hyponatremia), alopecia, and long-term risks of **transitional cell carcinoma** of the bladder and infertility (premature ovarian failure/azoospermia). * **Mechanism:** It acts by cross-linking DNA at the **Guanine N-7** position [3].

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).

Question 1

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 2

Thalidomide was reintroduced for certain indications like multiple myeloma after being withdrawn due to side effects. Which of the following is NOT a side effect of thalidomide?

Accepted Answer

Diarrhea

Answer

Hypothyroidism

Answer

Teratogenicity

Answer

Deep Vein Thrombosis

Question 3

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 4

Which of the following is a known side effect of the chemotherapeutic agent cyclophosphamide?

Accepted Answer

Hemorrhagic cystitis

Answer

Renal failure

Answer

Tympanic membrane fibrosis

Answer

Necrotizing enterocolitis

Question 5

Which of the following causes minimum bone marrow suppression?

Accepted Answer

Bleomycin

Answer

5-Fluorouracil

Answer

Cytarabine

Answer

Topotecan

Question 6

What is the mechanism of anticancer action of fluorouracil?

Accepted Answer

Irreversible inhibition of dihydrofolic acid reductase.

Answer

Cross-linking of double-stranded DNA and the resulting inhibition of DNA replication and transcription.

Answer

Cytotoxicity resulting from a metabolite that interferes with the production of dTMP.

Answer

Selective action of DNA polymerase.

Question 7

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 8

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

Accepted Answer

Doxorubicin

Answer

Docetaxel

Answer

Rituximab

Answer

Carboplatin

Question 9

Toxicity of nitrogen mustards can be decreased by?

Accepted Answer

GM-CSF

Answer

Allopurinol

Answer

Folinic acid

Answer

All

Question 10

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

Accepted Answer

Carmustine

Answer

Vincristine

Answer

Carboplatin

Answer

Melphalan

Anticancer Drugs — MCQs

Anticancer Drugs — MCQs

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