Competing risk analysis after radical prostatectomy for clinically nonmetastatic prostate adenocarcinoma according to clinical Gleason score and patient age

Abstract

Purpose: Factors important for determining appropriate therapy for localized prostate cancer are biopsy tumor grade, patient age and co-morbidity. We estimated the probability of dying from prostate cancer or other competing causes stratified by age at diagnosis and clinical histological grade in men diagnosed with clinically nonmetastatic prostate cancer who were treated with radical prostatectomy.

Materials and methods: A total of 751 men comprised a retrospective cohort with clinically nonmetastatic prostate cancer diagnosed and treated with bilateral pelvic lymphadenectomy and radical prostatectomy at our institution between 1971 and 1984. All patients were between 55 and 74 years old (median age 65) at diagnosis and they were followed a median of 14.7 years. The cumulative incidence of prostate cancer death or death from any cause was estimated using methods of competing risk survival analysis.

Results: Overall 435 men died with 32% of the deaths attributable to prostate cancer. In 62%, 27% and 11% of patients the Charlson co-morbidity score was 0, 1 and 2+, respectively. The only significant predictor of death from prostate cancer was clinical Gleason score (p <0.001), while only age and Charlson co-morbidity score were significant independent predictors of death from other causes (p <0.001). The estimated cumulative incidence of prostate cancer death after considering competing risks increased with Gleason score regardless of patient age. In men with Gleason scores 2 to 4, 5, 6, 7 and 8 to 10 disease the cumulative incidence of prostate cancer death within 20 years was 6% to 7%, 10% to 13%, 15% to 19%, 29% to 35% and 36% to 43%, respectively, depending on age at diagnosis. Clinical stages T2 and T3 outcomes were indistinguishable.

Conclusions: This study shows that for any given Gleason score the prostate cancer death rate is similar in older and younger patients with few to no co-morbidities. Men with a score of 7 to 10 were at 29% to 43% risk of death from prostate cancer even when cancer was diagnosed as late as age 74 years and treated surgically.