Impact of comorbidity on health-related quality of life after prostate cancer treatment: combined analysis of two prospective cohort studies.

Objective: To improve and individualise estimates of treatment outcomes for men diagnosed with prostate cancer, we examined the impact of baseline comorbidity on health-related quality of life (HRQL) outcomes in an analysis of two pooled, prospective cohort studies.

Patients And Methods: We studied 697 patients from three academic hospitals who received radical prostatectomy (RP), external beam radiation therapy (EBRT), or brachytherapy (BT). Measures of patient-reported bowel, urinary, and sexual symptoms along with physical and mental health were prospectively collected before treatment and 3, 12, 24, and 36 months after treatment. We assessed baseline comorbidity by the validated Index of Co-Existent Disease (ICED), abstracted from medical records. Regression mixed-models were built for each treatment group and HRQL outcome controlling for baseline age, education, marital status, risk group and patient-reported general health.

Results: About 71% of patients had one or more comorbid conditions at baseline. After adjusting for covariates, we found baseline comorbidity was independently associated with poorer sexual function after BT (P = 0.04) and RP (P = 0.03) but not EBRT (P = 0.35). Physical health was significantly worse for men receiving BT with more comorbidities (P = 0.02). Baseline comorbid conditions were not associated with urinary incontinence or bowel functioning.

Conclusions: Comorbidity at baseline is significantly associated with poorer sexual function after prostate BT or RP. This information may help patients and their physicians anticipate outcomes after surgical and radiation treatments.