Irradiation in relapsing carcinoma of the prostate

Radiation therapy plays a major role in the management of patients with either locally recurrent or metastatic carcinoma of the prostate.

In 23 patients with isolated postprostatectomy local recurrences treated with doses of 60-65 Gy, 17 (74%) had tumor control, and 45% survived relapse-free for 5 years after treatment of the recurrence. Pelvic irradiation has been used to treat patients with elevated prostate-specific antigen (PSA) levels after radical prostatectomy. This was tried, and 17 of 24 patients (70%) showed a significant decrease in PSA levels after irradiation, in five without subsequent elevation. Two of the seven patients with elevated PSA levels later had distant metastases. Local irradiation has been reported to yield excellent relief of symptoms in 100% of patients with hematuria, 80% with urinary outflow obstruction, and 50-70% with ureteral obstruction or pelvic pain secondary to locally advanced prostatic carcinoma. Reirradiation, particularly with brachytherapy (in preliminary studies combined with hyperthermia) has been used in the management of postirradiation prostatic recurrences with satisfactory tumor regression in approximately 75% of patients. The Radiation Therapy Oncology Group (RTOG) reported on the palliative effects of external irradiation on patients with bony metastasis. Approximately 54% of such patients had complete relief, and 29% had partial relief of bone pain. However, the retreatment rate of the bony metastasis was lower in the patients receiving higher doses. In a RTOG protocol in which all patients received local irradiation for osseous metastases, 77 were randomized to receive elective hemibody irradiation and 69, local treatment only. The frequency of additional treatment at 1 year was lower in the hemibody irradiation group (54% versus 78%). Occasionally, brain, mediastinal, or liver metastasis can be treated with irradiation. Radioactive phosphorus-32 or strontium-89 has been administered for disseminated bony metastasis with improvement of bone pain in approximately 70-80% of treated patients.

The role of irradiation in the treatment of spinal cord compression is discussed. Significant improvement of neurologic function has been reported in 36-60% of the patients, depending on severity of deficit and promptness in instituting emergency treatment.