Anticancer Drugs Practice Questions

Q: Mode of excretion of cyclophosphamide is?

Kidney. ***Kidney*** - Cyclophosphamide is a **prodrug** that undergoes metabolism in the liver to its active forms. However, both the parent drug and its active metabolites are primarily **excreted renally**. [1] - Renal excretion means that patients with **renal impairment** may require dose adjustments to prevent drug accumulation and increased toxicity. [3] *Lung* - The lungs are primarily involved in **gas exchange** and the elimination of volatile substances, not non-volatile drugs like cyclophosphamide. - While some drugs can be excreted to a minor extent via the lungs, it is not the primary route for **cyclophosphamide**. *Liver* - The liver is the primary site of **metabolism** for cyclophosphamide, where it is converted into active cytotoxic metabolites. [1], [2] - While metabolites are formed here, the liver is not the main organ for the final **elimination** (excretion) of the drug or its metabolites from the body. *Skin* - The skin's role in drug excretion is generally minimal, mainly involving substances excreted in **sweat**, and is not a significant route for cyclophosphamide. - Excretion via the skin is typically very limited for most drugs and does not play a major role in the elimination of **chemotherapeutic agents** like cyclophosphamide.

Q: Which of the following medications is known to cause peripheral neuropathy?

Vincristine. ***Vincristine*** - **Vincristine** is a **vinca alkaloid chemotherapeutic agent** that is **notorious** for causing **peripheral neuropathy** as its **dose-limiting toxicity**. - It interferes with **microtubule function** during mitosis, leading to **axonal damage** and predominantly **sensorimotor neuropathy**. - Peripheral neuropathy occurs in **virtually all patients** receiving vincristine and typically manifests as **distal paresthesias**, **loss of deep tendon reflexes**, and **motor weakness**. - This is the **most characteristic adverse effect** of vincristine. *Paclitaxel* - **Paclitaxel** is a **taxane chemotherapeutic agent** that also causes **peripheral neuropathy** as a significant adverse effect. - It stabilizes **microtubules**, preventing their depolymerization, leading to neurotoxicity. - While peripheral neuropathy is common with paclitaxel, it shares prominence with other major toxicities like **myelosuppression** and **hypersensitivity reactions**. *Sulfonamide* - **Sulfonamide antibiotics** are primarily associated with **hypersensitivity reactions**, **crystalluria**, **skin rashes**, and **hematologic abnormalities**. - Peripheral neuropathy is not a recognized or common adverse effect of sulfonamides. *Amiodarone* - **Amiodarone** is an **antiarrhythmic drug** with multiple adverse effects including **pulmonary fibrosis**, **thyroid dysfunction**, **corneal deposits**, and **hepatotoxicity**. - While rare cases of **peripheral neuropathy** have been reported, it is **not a characteristic or common adverse effect** of amiodarone.

Q: Which of the following statements is FALSE regarding vincristine?

It does not cause alopecia.. ***It does not cause alopecia.*** - This statement is **false** because vincristine, like many chemotherapeutic agents, commonly causes **alopecia** (hair loss) due to its impact on rapidly dividing cells, including hair follicle cells. - While it may be considered less myelosuppressive than some other anticancer drugs, its effect on hair follicles is well-documented. *It is an alkaloid.* - This statement is **true** because vincristine is a **vinca alkaloid**, derived from the Madagascar periwinkle plant (*Catharanthus roseus*). - Vinca alkaloids are a class of antineoplastic agents that target microtubules. *Its use is associated with neurotoxicity.* - This statement is **true** as **neurotoxicity** is a prominent and dose-limiting side effect of vincristine, manifesting as peripheral neuropathy (e.g., paresthesias, foot drop, constipation due to autonomic neuropathy). - This adverse effect arises from its mechanism of action, which involves disrupting microtubules critical for axonal transport. *It is a useful drug for induction of remission in acute lymphoblastic leukemia.* - This statement is **true**; **vincristine** is a cornerstone of combination chemotherapy regimens for **acute lymphoblastic leukemia (ALL)**, particularly during the induction phase. - Its efficacy in ALL is attributed to its ability to arrest cell division in metaphase.

Q: Which anticancer drug is known to inhibit spindle formation during cell division?

Vinca alkaloids. ***Vinca alkaloids*** - **Vinca alkaloids**, such as **vincristine** and **vinblastine**, bind to **tubulin** and prevent its polymerization into microtubules. - This action effectively **inhibits the formation of the mitotic spindle**, leading to metaphase arrest and ultimately cell death. *Busulfan* - **Busulfan** is an **alkylating agent** that **cross-links DNA**, thereby interfering with DNA replication and transcription. - Its primary mechanism is **DNA damage**, not direct inhibition of spindle formation. *5-FU* - **5-fluorouracil (5-FU)** is an **antimetabolite** that inhibits **thymidylate synthase**, thereby impairing DNA synthesis and repair. - It acts by **mimicking pyrimidine bases** and incorporating into DNA and RNA, leading to cellular dysfunction. *Methotrexate* - **Methotrexate** is an **antifolate** drug that inhibits **dihydrofolate reductase**, an enzyme crucial for the synthesis of purines and pyrimidines. - This enzyme inhibition leads to **impaired DNA and RNA synthesis**, impacting rapidly dividing cells.

Q: Which drug is primarily used in the treatment of breast cancer?

Tamoxifen. ***Tamoxifen*** - **Tamoxifen** is a **selective estrogen receptor modulator (SERM)** primarily used to treat and prevent **estrogen receptor (ER)-positive breast cancer**. - It works by blocking estrogen from binding to receptors in breast cancer cells, thereby inhibiting their growth. *Cyproterone* - **Cyproterone** is an **anti-androgen** and **progestogen** primarily used to treat conditions like **prostate cancer**, **acne**, and **hirsutism** in women. - Its main mechanism involves blocking androgen receptors and reducing androgen production, which is not the primary pathway for breast cancer. *Testosterone* - **Testosterone** is an **androgen** (male sex hormone) and is **not used** in the primary treatment of breast cancer. - In certain rare cases of severe metastatic breast cancer, androgens like high-dose testosterone have been historically used for palliation, but this is not standard therapy. *Chlorambucil* - **Chlorambucil** is an **alkylating agent** used primarily in the treatment of **chronic lymphocytic leukemia (CLL)** and certain **lymphomas**. - It works by interfering with DNA replication and transcription, but it is not a first-line or primary agent for breast cancer.

Q: Peripheral neuropathy as a side effect is caused by which of the following anticancer drugs?

Vincristine. ***Vincristine*** - **Vincristine** is a **vinca alkaloid** that works by inhibiting **microtubule formation**, which is essential for cell division [1], [3]. - Its major dose-limiting toxicity is **peripheral neuropathy**, manifesting as paresthesias, weakness, and loss of reflexes due to damage to neuronal microtubules [1], [2]. *Cyclophosphamide* - **Cyclophosphamide** is an **alkylating agent** that forms cross-links in DNA, leading to cell death. - Its most common side effects include **myelosuppression**, hemorrhagic cystitis, and alopecia; **peripheral neuropathy** is generally not a prominent adverse effect. *Etoposide* - **Etoposide** is a **topoisomerase II inhibitor** that causes DNA strand breaks. - Key toxicities include **myelosuppression** and **gastrointestinal disturbances**, but it is not typically associated with significant peripheral neuropathy. *Irinotecan* - **Irinotecan** is a **topoisomerase I inhibitor** that causes DNA damage during replication. - Its primary dose-limiting toxicities are **diarrhea** and **myelosuppression**, not peripheral neuropathy.

Q: Which of the following substances is known to cause predominantly sensory neuropathy?

Cisplatin. ***Cisplatin*** - **Cisplatin** is a platinum-based chemotherapy drug well-known for causing **dose-dependent peripheral neuropathy**, primarily affecting sensory neurons. - Patients often present with **numbness**, **tingling**, and **loss of proprioception** in a glove-and-stocking distribution. - This is the **most characteristic** drug for **predominantly sensory neuropathy** among chemotherapeutic agents. *Pyridoxine excess* - While **pyridoxine (vitamin B6) excess** can cause sensory neuropathy, it is less commonly observed as a primary cause compared to cisplatin in the context of drug-induced neuropathies. - High doses of pyridoxine can lead to **dorsal root ganglionopathy**, affecting sensory nerve fibers. *Suramin* - **Suramin** is an anthelmintic agent primarily used for treating sleeping sickness, and it is known to cause a variety of side effects, including **renal toxicity** and **neurological symptoms**. - While neurological side effects can occur, they are not typically characterized as a **predominantly sensory neuropathy** in the same way as cisplatin. *Vincristine* - **Vincristine** is a vinca alkaloid chemotherapy agent that causes peripheral neuropathy. - However, vincristine typically causes **mixed motor and sensory neuropathy** with prominent motor involvement (foot drop, wrist drop). - This differs from cisplatin's **predominantly sensory** presentation.

Q: Resistance to Methotrexate develops due to?

Increased production of dihydrofolate reductase (DHFR). ***Increased production of dihydrofolate reductase (DHFR)*** - Methotrexate acts by inhibiting **dihydrofolate reductase (DHFR)**, an enzyme essential for **folate metabolism** and DNA synthesis. - An **increased production of DHFR** (through gene amplification or overexpression) by cancer cells allows them to bypass the drug's inhibitory effects, leading to resistance. - This is the **most common mechanism** of methotrexate resistance. *Rapid proliferation of cancer cells* - While **rapid cell proliferation** is a characteristic of cancer, it doesn't directly explain resistance to methotrexate. - Methotrexate targets fast-dividing cells (S-phase specific), so rapid proliferation often makes them **more susceptible**, not resistant, as long as the drug's mechanism is effective. *Thymidylate kinase deficiency* - **Thymidylate kinase** is involved in the phosphorylation of **thymidine** to produce **dTMP** (deoxythymidine monophosphate). - A deficiency in this enzyme would likely hinder DNA synthesis, potentially increasing sensitivity to DNA-targeting agents, rather than causing resistance to methotrexate. *Thymidylate synthetase deficiency* - **Thymidylate synthetase** converts dUMP to dTMP using **5,10-methylene-THF** as a cofactor. - Methotrexate **indirectly inhibits** thymidylate synthetase by depleting tetrahydrofolate cofactor pools through DHFR inhibition. - A **deficiency** of this enzyme would not cause resistance; rather, **increased thymidylate synthetase** expression can be an alternative resistance mechanism, though less common than DHFR overexpression.

Q: All are true regarding Sunitinib except which of the following?

It is excreted primarily in urine. ***It is excreted primarily in urine*** - **Sunitinib** is predominantly metabolized in the **liver** by CYP3A4 and primarily excreted in the **feces**, not urine. - Its major active metabolite, N-desethyl sunitinib, is also primarily eliminated via the fecal route. *It inhibits tyrosine kinase receptors* - **Sunitinib** is a **multitargeted receptor tyrosine kinase (RTK) inhibitor**. - It blocks several RTKs involved in tumor growth, angiogenesis, and metastatic progression, such as **VEGFR, PDGFR, KIT, and FLT3**. *It is used for the treatment of GIST* - **Sunitinib** is approved for the treatment of **imatinib-refractory** or **imatinib-intolerant gastrointestinal stromal tumors (GIST)**. - Its mechanism in GIST involves inhibiting KIT and PDGFR, which are often mutated and constitutively active in this cancer. *It is used for renal cell carcinoma* - **Sunitinib** is a standard first-line treatment for **advanced renal cell carcinoma (RCC)**. - Its efficacy in RCC is primarily due to its inhibition of VEGFR, which targets the high vascularity characteristic of kidney tumors.

Q: Which of the following statements about vinca alkaloids is true?

Inhibits mitotic spindle. ***Inhibits mitotic spindle*** - **Vinca alkaloids** (e.g., vincristine, vinblastine) exert their cytotoxic effects by binding to **tubulin**, thereby inhibiting its polymerization into microtubules. - This disruption prevents the formation of the **mitotic spindle**, arresting cells in metaphase and leading to apoptosis. *Enhances polymerization of tubulin* - This statement describes the mechanism of action of **taxanes** (e.g., paclitaxel), which stabilize microtubules and prevent their depolymerization. - Vinca alkaloids, in contrast, **inhibit** tubulin polymerization, preventing microtubule assembly. *Inhibits topoisomerase I* - Inhibition of **topoisomerase I** is the mechanism of action for drugs like **irinotecan** and **topotecan**. - These agents cause single-strand breaks in DNA, which is distinct from the microtubule disruption caused by vinca alkaloids. *Inhibits topoisomerase II* - Drugs like **etoposide** and **teniposide** work by inhibiting **topoisomerase II**, leading to double-strand DNA breaks. - This mechanism is different from the disruption of microtubule dynamics seen with vinca alkaloids.

Question 1

Mode of excretion of cyclophosphamide is?

Accepted Answer

Kidney

Answer

Lung

Answer

Liver

Answer

Skin

Question 2

Which of the following medications is known to cause peripheral neuropathy?

Accepted Answer

Vincristine

Answer

Sulfonamide

Answer

Amiodarone

Answer

Paclitaxel

Question 3

Which of the following statements is FALSE regarding vincristine?

Accepted Answer

It does not cause alopecia.

Answer

Its use is associated with neurotoxicity.

Answer

It is an alkaloid.

Answer

It is a useful drug for induction of remission in acute lymphoblastic leukemia.

Question 4

Which anticancer drug is known to inhibit spindle formation during cell division?

Accepted Answer

Vinca alkaloids

Answer

Busulfan

Answer

5-FU

Answer

Methotrexate

Question 5

Which drug is primarily used in the treatment of breast cancer?

Accepted Answer

Tamoxifen

Answer

Cyproterone

Answer

Testosterone

Answer

Chlorambucil

Question 6

Peripheral neuropathy as a side effect is caused by which of the following anticancer drugs?

Accepted Answer

Vincristine

Answer

Cyclophosphamide

Answer

Etoposide

Answer

Irinotecan

Question 7

Which of the following substances is known to cause predominantly sensory neuropathy?

Accepted Answer

Cisplatin

Answer

Pyridoxine excess

Answer

Suramin

Answer

Vincristine

Question 8

Resistance to Methotrexate develops due to?

Accepted Answer

Increased production of dihydrofolate reductase (DHFR)

Answer

Rapid proliferation of cancer cells

Answer

Thymidylate kinase deficiency

Answer

Thymidylate synthetase deficiency

Question 9

All are true regarding Sunitinib except which of the following?

Accepted Answer

It is excreted primarily in urine

Answer

It inhibits tyrosine kinase receptors

Answer

It is used for the treatment of GIST

Answer

It is used for renal cell carcinoma

Question 10

Which of the following statements about vinca alkaloids is true?

Accepted Answer

Inhibits mitotic spindle

Answer

Enhances polymerization of tubulin

Answer

Inhibits topoisomerase I

Answer

Inhibits topoisomerase II

Anticancer Drugs — MCQs

Anticancer Drugs — MCQs

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