Drug used for estrogen dependent breast cancer?

Chitranjjan National Cancer Institute Kolkata - 2021

Pharmacology

Easy

Appeared in: Chitranjjan National Cancer Institute Kolkata - 2021

Explanation

Tamoxifen is a Selective Estrogen Receptor Modulator (SERM) used as a primary hormonal therapy for estrogen-receptor-positive (ER+) breast cancer.
It acts as an estrogen antagonist in breast tissue, competitively blocking estrogen from binding to its receptor on cancer cells.
By blocking the receptor, it inhibits the growth-promoting effects of estrogen on the tumor, making it a targeted and effective treatment.
It is effective in both premenopausal and postmenopausal women for treating early and advanced breast cancer.

Option B: Clomiphene citrate is also an antiestrogen, but its primary clinical use is to treat infertility in women with anovulation, not breast cancer.
Option C: Administering estrogen to a patient with estrogen-dependent breast cancer is contraindicated as it would stimulate the growth of the cancer cells.
Option D: Adriamycin (Doxorubicin) is a potent cytotoxic chemotherapy agent (an anthracycline), not a hormonal therapy. It kills all rapidly dividing cells and is not specific to estrogen-dependent cancers.

Clinical Relevance

Nursing practice connection: Knowing Pharmacotherapy for Hormone-Sensitive Cancers helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses must educate patients on the signs and symptoms of serious adverse effects of Tamoxifen, particularly deep vein thrombosis (DVT) and pulmonary embolism (PE). Symptoms include leg swelling/pain, sudden chest pain, and shortness of breath, which require immediate medical attention.
Patients should be advised about the increased risk of endometrial cancer, and any unusual vaginal bleeding should be reported promptly.
What if the patient was a postmenopausal woman with ER+ breast cancer? While Tamoxifen is an option, an Aromatase Inhibitor (e.g., Letrozole, Anastrozole) is often the first-line hormonal therapy in postmenopausal women, as they can be more effective and have a different side-effect profile (e.g., no increased risk of endometrial cancer, but higher risk of osteoporosis).

How to Approach the Question

First, identify the core of the question: it asks for a drug to treat a specific type of cancer, 'estrogen-dependent breast cancer'.
This keyword 'estrogen-dependent' points towards a hormonal therapy that targets the estrogen pathway.
Evaluate the options based on their drug class and primary mechanism. Ask yourself: 'Which of these drugs interferes with estrogen?'
Tamoxifen and Clomiphene are anti-estrogens. Estrogen is a hormone itself. Adriamycin is a general chemotherapy drug.
Differentiate between the anti-estrogens. Recall that Tamoxifen is specifically indicated for breast cancer, while Clomiphene is for infertility.
Conclude that Tamoxifen is the correct targeted therapy for estrogen-dependent breast cancer.

Concept Tested & Keywords

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E6 Pharmacology KD Tripathi Essentials 9e Part 1 pp. 365-367, 366-368

E6 Gynecology Williams p. 183-219