Radiotherapy for Metastatic Carcinoma Prostate

Introduction to Radiotherapy

Radiotherapy plays a crucial role in metastatic prostate cancer management, particularly for palliating bone pain with a single 800 cGy fraction for non-vertebral metastases, while radiopharmaceuticals like radium-223 are indicated for patients with symptomatic bone metastases and no known visceral disease 1, 2

A short course of 800 cGy in a single fraction is as effective and less costly than 3000 cGy in 10 fractions for non-vertebral metastases 1
For painful bone metastases from castration-refractory disease, fractioning of 1×8 Gy or 10×3 Gy may be used with equal pain-relieving efficacy 3, 4

Radiopharmaceuticals are effective for patients with widespread metastatic disease, particularly when they are no longer candidates for effective chemotherapy 1
Radium-223 emits high-energy alpha particles with shorter path, reducing toxic effects on adjacent tissue 5
Radium-223 significantly improves overall survival (median 14.9 vs 11.3 months) and prolongs time to first skeletal-related event (median 15.6 vs 9.8 months) compared to placebo 5
Other radiopharmaceuticals commonly used include strontium-89 (89Sr) and samarium-153 (153Sm) 1, 3

For patients with bone pain resistant to palliative radiotherapy and conventional analgesics, intravenous bisphosphonates (e.g., pamidronate) should be considered 3, 4
Patients with castration-refractory disease should be managed in collaboration with dedicated palliative care services 3, 4

Radium-223 is well-tolerated with low rates of grade 3/4 hematologic toxicity (3% neutropenia, 6% thrombocytopenia, 13% anemia) 5
The safety of using chemotherapy after radium-223 has not been established, and preliminary data suggest combination with standard doses of docetaxel should not be undertaken 5