A 75-year-old man comes to the office due to 4 weeks of increased urinary hesitancy and progressive low back pain. Spinal imaging reveals multiple lesions suspicious for metastatic cancer. Biopsy of a bone lesion shows well-differentiated adenocarcinoma. Treatment with a medication that does which of the following would most likely reduce the spread of this patient's cancer?

Question

A 75-year-old man comes to the office due to 4 weeks of increased urinary hesitancy and progressive low back pain.  Spinal imaging reveals multiple lesions suspicious for metastatic cancer.  Biopsy of a bone lesion shows well-differentiated adenocarcinoma.  Treatment with a medication that does which of the following would most likely reduce the spread of this patient's cancer?

Quizplus · Accepted Answer

11ec160b_3c05_3c0f_9249_fd4ea347f35c_MD0001_00 This older patient with urinary hesitancy and multiple bone lesions has biopsy evidence of well-differentiated adenocarcinoma, raising strong suspicion for metastatic prostate adenocarcinoma. Prostate cancer is the most common non-skin cancer in men; it has a predilection for metastases to bone due to tumor surface proteins that bind to pericytes and bone marrow stromal cells. Prostate adenocarcinoma is generally an androgen-sensitive tumor. Because androgens in men are produced primarily in the testes, initial treatment for advanced disease usually involves medical or surgical orchiectomy to eliminate testicular production of androgens. However, androgens are also produced in the adrenal glands and tumor cells via the expression of 17-alpha-hydroxylase, a cytochrome P-450 enzyme that converts pregnenolone/progesterone into dehydroepiandrosterone (DHEA)/androstenedione. Because these extratesticular androgens can also drive tumor growth, patients with advanced disease and those with castration-resistant prostate cancer generally receive abiraterone, a medication that irreversibly inhibits 17-alpha-hydroxylase. This limits extratesticular androgen production, which slows the growth of the tumor. (Choice A) Because prostate cancer is an androgen-sensitive tumor, activation of the androgen receptor would worsen the disease. (Choice B) LH triggers Leydig cells in the testes to produce androgens. Therefore, activation of the LH receptor would worsen prostate cancer (increased androgen production). Medical orchiectomy involves the administration of GnRH analogues, which reduce LH levels by eliminating the pulsatile stimulation of pituitary gonadotrophs. (Choice C) Estrogen receptor blockade is used in the treatment of estrogen-sensitive breast and endometrial cancer. Prostate cancer is driven by androgens such as testosterone and DHEA, not estrogen. (Choice D) FSH induces spermatogenesis in men; LH is responsible for testicular androgen production. Therefore, blockade of FSH would not inhibit systemic androgen generation. Educational objective: Patients with advanced or castration-resistant prostate cancer are often treated with an 17-alpha-hydroxylase inhibitors (eg, abiraterone), which block the generation of androgens in the adrenal glands, testes, and tumor cells. This reduces systemic androgen levels, which limit prostate cancer growth.

A 75-Year-Old Man Comes to the Office Due to 4