SAN DIEGO (EGMN) – Radiotherapy is correlated with superior disease-specific and overall survival in clinically staged, lymph node–positive prostate cancer that is not metastatic, according to a retrospective analysis of more than 1,000 patients.
Dr. Jonathan Tward
The number needed to treat to prevent one prostate cancer death in 10 years is eight persons, Dr. Jonathan Tward reported at the annual meeting of the American Society for Radiation Oncology.
"Radiotherapy should be strongly considered for all men with clinically node-positive, nonmetastatic prostate cancer, and is consistent with National Comprehensive Cancer Network guidelines," said Dr. Tward, a radiation oncologist at Huntsman Cancer Hospital in Salt Lake City.
Clinically staged, lymph node–positive prostate cancer is rare, accounting for fewer than 2% of new diagnoses, he said. The Cancer Staging Manual (7th ed.) of the American Joint Committee on Cancer classifies clinically staged, lymph node–positive prostate cancer as stage IV, implying incurability.
"In spite of that dismal prognosis, retrospective data in the postoperative setting [suggest] that adding radiotherapy to androgen deprivation therapy improves overall survival in pathologically node-positive patients after prostatectomy," Dr. Tward noted. "Interestingly, NCCN guidelines offer definitive radiotherapy with androgen deprivation therapy for clinically node-positive patients as an option."
To evaluate the role of definitive radiotherapy in clinically node-positive prostate cancer, Dr. Tward and his associate, Dr. Dennis C. Shrieve, reviewed data from 1,082 patients in the National Cancer Institute’s SEER (Surveillance, Epidemiology, and End Results) program who were diagnosed with prostate cancer in 1988-2006. They included patients with clinically staged, node-positive disease, and excluded patients who had undergone surgery, those who had nonregional lymphadenopathy, and those with metastatic disease.
The median age of the 1,082 patients was 69 years, and the median follow-up of patients who did not die from any cause was 91 months. Of the 1,082 patients, 377 had external-beam radiotherapy, 703 had no radiation, and 20 had external-beam radiation plus brachytherapy.
Dr. Tward reported that prostate cancer–specific survival significantly favored patients who underwent radiotherapy (hazard ratio, 0.66; P = .0002). Overall survival also significantly favored patients who underwent radiotherapy (HR, 0.70; P less than .0001). This translated into a number needed to treat of seven patients in 10 years to prevent one death.
After factoring in heart disease and other competing causes of death, the researchers still found a significant survival benefit among those who received radiotherapy compared with those who did not (P less than .05).
Definitive radiotherapy with androgen deprivation therapy is the institutional standard of care at the University of Utah, Dr. Tward said.
He acknowledged certain limitations of the study, including that the data were retrospective and no information was available about the use of androgen deprivation therapy, chemotherapy, or radiation therapy parameters.
Dr. Tward said that he had no relevant financial conflicts to disclose.