Radiation therapy in localized prostate cancer: long-term results and late toxicity

This study was performed to determine the long-term results of radiotherapy in localized prostate cancer. The frequency and severity of late gastrointestinal and genitourinary toxicities were also investigated. Between 1980 and 1991, 206 men with localized prostate cancer were treated with radiotherapy alone at our hospital. Biopsy, transurethral resection of the prostate, or both, confirmed the diagnosis. Overall survival, cancer-specific survival, disease-free survival, local recurrence-free survival and metastasis-free survival were determined and compared with age, stage, grade and diagnostic intervention. A change in treatment policy occurred in 1987. The treatment results of the two periods are compared. Late toxicity was registered according to the Radiation Therapy Oncology Group scale. The 8-year overall survival rates were 60%, 44% and 29% for Stages T1, T2 and T3 respectively (P=0.028). The 8-year cancer-specific survival rates were 86%, 66% and 34% for Stages T1, T2 and T3 respectively (P=0.002). Transurethral resection of the prostate had a negative influence on cancer-free and disease-free survivals, owing especially to an increased incidence of metastases. In the bladder and rectum, late toxicity of grade 2 or more occurred in 26 (13%) of the 199 patients who were alive at 6 months after radiotherapy. One of these patients developed late toxicity 5 years after the radiotherapy. Radiation dose and field size had no detectable influence on the development of late toxicity. The difference between overall survival and cancer-specific survival confirms that many of these patients die without any clinical signs of prostate cancer or metastases. This observation puts a question mark over whether a biochemical endpoint alone is of clinical relevance. Although not statistically significant, local recurrence-free, disease-free and cancer-specific free survivals from 1987 onwards improved for larger tumours, which was most likely due to the administration of higher doses of radiation.