Anticancer Drugs — MCQs

Anticancer Drugs Indian Medical PG Practice Questions and MCQs

Question 561: Mechanism of action of actinomycin D is ?

A. Inhibits RNA-dependent DNA synthesis
B. Activates RNA-dependent DNA synthesis
C. Inhibits DNA-dependent RNA synthesis (Correct Answer)
D. Activates DNA-dependent RNA synthesis

Explanation: ***Inhibits DNA-dependent RNA synthesis*** - **Actinomycin D** (dactinomycin) is a chemotherapeutic agent that primarily acts by intercalating into the **DNA double helix** [1]. - This intercalation selectively inhibits the movement of **RNA polymerase**, thereby blocking **DNA-dependent RNA synthesis** (transcription) and subsequently protein synthesis [1]. *Inhibits RNA-dependent DNA synthesis* - This mechanism describes the action of drugs targeting **reverse transcriptase**, such as those used in **HIV treatment** [2]. - Actinomycin D does not affect enzymes involved in synthesizing DNA from an RNA template [1]. *Activates RNA-dependent DNA synthesis* - There are no known therapeutic drugs that deliberately activate **RNA-dependent DNA synthesis**. - Such an action would typically promote viral replication in the context of **retroviruses**. *Activates DNA-dependent RNA synthesis* - Activating **DNA-dependent RNA synthesis** (transcription) would increase gene expression and protein synthesis. - Actinomycin D is an **anti-cancer drug** designed to suppress cell growth by *inhibiting* this process, not activating it [1].

Question 562: Which chemotherapy agents are commonly used for the treatment of retinoblastoma?

A. vincristine, carboplatin and etoposide (Correct Answer)
B. vinblastine, etoposide and bleomycin
C. vinblastine, vincristine and etoposide
D. vinblastine, vincristine and cisplatin

Explanation: ***Vincristine, carboplatin and etoposide*** - This combination is a well-established and commonly used **chemotherapy regimen** for the systemic treatment of retinoblastoma, particularly when there is significant intraocular disease or extraocular extension. - **Vincristine** targets microtubules, **carboplatin** is an alkylating agent, and **etoposide** is a topoisomerase inhibitor, working together to achieve a synergistic antineoplastic effect. *Vinblastine, etoposide and bleomycin* - While etoposide is used, **vinblastine** is not a primary agent for retinoblastoma, and **bleomycin** is more commonly associated with germ cell tumors or lymphomas, not retinoblastoma. - This combination lacks the broad spectrum of activity and specific targeting for retinoblastoma that is present in the standard regimen. *Vinblastine, vincristine and etoposide* - Although vincristine and etoposide are used, **vinblastine** is not typically included in the first-line systemic chemotherapy for retinoblastoma. - The absence of a platinum agent like carboplatin would make this regimen less effective for retinoblastoma, which often requires a strong alkylating agent. *Vinblastine, vincristine and cisplatin* - While vincristine is appropriate, **vinblastine** is not a standard component, and **cisplatin** is an alkylating agent but **carboplatin** is generally preferred in retinoblastoma due to its similar efficacy and a more favorable toxicity profile, especially regarding nephrotoxicity. - The use of cisplatin can lead to more significant **renal toxicity** and potentially ototoxicity compared to carboplatin, which is often avoided in a pediatric population when alternatives exist.

Question 563: Which of the following is an aromatase inhibitor?

A. Letrozole (Correct Answer)
B. Tamoxifen
C. Danazol
D. Taxane

Explanation: ***Letrozole*** - **Letrozole** is a commonly used **aromatase inhibitor**, which works by blocking the enzyme **aromatase** that converts androgens into estrogens [1]. - This reduction in estrogen levels is crucial in treating **hormone-sensitive breast cancers** [1]. *Tamoxifen* - **Tamoxifen** is a **selective estrogen receptor modulator (SERM)**, not an aromatase inhibitor [2]. - It acts by blocking estrogen receptors in breast tissue while potentially stimulating them in other tissues like bone and uterus [2]. *Danazol* - **Danazol** is a synthetic androgen that suppresses the hypothalamic-pituitary-gonadal axis, leading to **decreased estrogen production**. - It works by inhibiting gonadotropin release and directly inhibiting ovarian steroidogenesis, rather than blocking the aromatase enzyme directly. *Taxane* - **Taxanes** are a class of **chemotherapy drugs** that interfere with cell division by stabilizing microtubules. - They are used to treat various cancers, including breast cancer, but do not act as aromatase inhibitors.

Question 564: Which anticancer drug is known to inhibit spindle formation during cell division?

A. Busulfan
B. Vinca alkaloids (Correct Answer)
C. 5-FU
D. Methotrexate

Explanation: ***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.

Question 565: Which drug is primarily used in the treatment of breast cancer?

A. Tamoxifen (Correct Answer)
B. Cyproterone
C. Testosterone
D. Chlorambucil

Explanation: ***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.

Question 566: Which of the following medications is relevant in the management of prostatic carcinoma?

A. Clomiphene
B. Finasteride (Correct Answer)
C. None of the options
D. Danazol

Explanation: ***Finasteride*** - **Finasteride** is a **5α-reductase inhibitor** that blocks the conversion of testosterone to dihydrotestosterone (DHT), which is crucial for prostate growth and development. - It is used in the **chemoprevention of prostatic carcinoma** in high-risk individuals, as demonstrated by the **Prostate Cancer Prevention Trial (PCPT)**, which showed a **25% reduction in prostate cancer risk**. - While finasteride is primarily used for **benign prostatic hyperplasia (BPH)** and **androgenetic alopecia**, its role in reducing prostate cancer risk makes it relevant in prostatic carcinoma management. - It is the only medication among the options with established relevance to prostate cancer. *Danazol* - **Danazol** is an attenuated androgen used primarily for **endometriosis**, **fibrocystic breast disease**, and **hereditary angioedema**. - It suppresses the pituitary-ovarian axis and has **no role in prostatic carcinoma management**. *Clomiphene* - **Clomiphene** is a selective estrogen receptor modulator (SERM) used to induce **ovulation in women** with infertility. - It stimulates gonadotropin release and is **not applicable to prostatic carcinoma** treatment or management. *None of the options* - This is incorrect because **finasteride has an established role** in prostate cancer chemoprevention and is relevant in the broader management of prostatic conditions including carcinoma risk reduction.

Question 567: What is the primary indication for the use of Erlotinib?

A. Colon cancer
B. Gall bladder cancer
C. Pancreatic cancer
D. NSCLC (Correct Answer)

Explanation: ***NSCLC (Non-Small Cell Lung Cancer)*** - **Erlotinib** is primarily indicated for patients with advanced **non-small cell lung cancer (NSCLC)**, particularly those with activating mutations in the **epidermal growth factor receptor (EGFR)**. - It functions as an **EGFR tyrosine kinase inhibitor**, blocking the signaling pathways essential for cancer cell growth and survival. - This is the **FDA-approved primary indication** and where Erlotinib shows the most significant clinical benefit. *Pancreatic cancer* - While Erlotinib has been used in combination with gemcitabine for **locally advanced, unresectable or metastatic pancreatic cancer**, it is not its primary or most prominent indication. - Its efficacy in pancreatic cancer is generally modest and overshadowed by its dramatic impact in EGFR-mutated NSCLC. *Colon cancer* - **Erlotinib** is **not a primary treatment** for **colon cancer**. - Other targeted therapies (such as anti-EGFR monoclonal antibodies like cetuximab) or chemotherapy regimens are typically used for colorectal cancer. *Gall bladder cancer* - **Erlotinib** is generally **not indicated** for the treatment of **gallbladder cancer**. - Treatment often involves surgery, chemotherapy, or radiation, with targeted therapies being less established for this malignancy.

Question 568: Which of the following medications is known to cause peripheral neuropathy?

A. Sulfonamide
B. Vincristine (Correct Answer)
C. Amiodarone
D. Paclitaxel

Explanation: ***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.

Question 569: Which of the following statements is FALSE regarding vincristine?

A. Its use is associated with neurotoxicity.
B. It is an alkaloid.
C. It is a useful drug for induction of remission in acute lymphoblastic leukemia.
D. It does not cause alopecia. (Correct Answer)

Explanation: ***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.

Question 570: Peripheral neuropathy as a side effect is caused by which of the following anticancer drugs?

A. Cyclophosphamide
B. Etoposide
C. Irinotecan
D. Vincristine (Correct Answer)

Explanation: ***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.

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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