## **Core Concept**
The management of prostate cancer, especially in the context of metastatic disease, involves considering the patient's symptoms, the extent of disease, and the tumor's characteristics, such as Gleason score and PSA levels. For a 70-year-old man with well-differentiated adenocarcinoma of the prostate and osteoblastic metastases, treatment aims to alleviate symptoms, slow disease progression, and improve quality of life.

## **Why the Correct Answer is Right**
The correct approach for this patient, who has well-differentiated adenocarcinoma of the prostate with osteoblastic metastases, involves hormonal therapy. **Androgen deprivation therapy (ADT)** is a cornerstone in the management of metastatic prostate cancer. Since the cancer is well-differentiated (implying a lower Gleason score and less aggressive disease), and given the presence of osteoblastic metastases which are characteristic of prostate cancer, ADT is aimed at reducing testosterone levels, which prostate cancer cells depend on for growth. This approach can help in reducing symptoms, slowing disease progression, and delaying the onset of castration-resistant prostate cancer.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because, although surgery (prostatectomy) might be considered in localized disease, it's not the ideal treatment for a 70-year-old man with metastatic disease.
- **Option B:** This option is incorrect as radiation therapy, while useful for palliation of bone pain and for localized disease, is not the primary treatment for widespread metastatic disease.
- **Option C:** This option is incorrect because chemotherapy might be considered in castration-resistant prostate cancer or in symptomatic metastatic hormone-sensitive prostate cancer, but it's not the first line for well-differentiated metastatic disease.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **osteoblastic metastases** are commonly associated with prostate cancer. Also, the management of metastatic prostate cancer often involves **androgen deprivation therapy (ADT)** as a first-line treatment to reduce testosterone levels and slow disease progression.

## **Correct Answer:** . Androgen Deprivation Therapy (ADT)