Historical Prostate Cancer Screening and Treatment Outcomes from a Single Institution

Objective: To quantify outcomes of individuals diagnosed and treated for prostate cancer in a single institution. Design: Retrospective electronic chart abstraction. Setting: Marshfield Clinic, the largest private multispecialty group practice in Wisconsin, and one of the largest in the United States, provides health care services annually to approximately 385,000 unique patients through 1.8 million annual patient encounters. Participants: Individuals within the Marshfield Clinic cancer registry who had been diagnosed with prostate cancer between 1960 and 2009. Methods: Electronic chart abstraction from the cancer registry and the electronic medical record was conducted (N=6,181). Data abstracted included age at diagnosis; stage and grade of tumor; prostate specific antigen (PSA) values before, at, and after diagnosis; initial cancer treatment; follow-up time; subsequent cancer treatments; evidence of metastasis; age of death; and cause of death, if known. Results: The average age of prostate cancer diagnosis has decreased from 70-71 years in the 1960's and 1970's to an average age at diagnosis of 67 years in the 2000's (P < 0.001). This decrease in age occurred within the decades of implementation of PSA screening. Approximately 74% of men diagnosed with prostate cancer within the PSA screening era had at least one PSA test, and the presence of a PSA test did not appear to change treatment outcome. Age, grade, and stage were the biggest predictors of prostate cancer outcome. There was no difference in event-free survival between current treatment types (radical prostatectomy, brachytherapy, photon treatment, or intensity-modulated radiation therapy) (2003 or later) when stratified by age (greater than 85%, 5-year event-free survival P=0.85); however, more events occurred with older external beam radiation treatment regimens (1993-2003) (70% to 75%, 5-year event-free survival P=0.001). Conclusion: Individuals diagnosed and treated for prostate cancer within the Marshfield Clinic comprehensive care setting follow national trends with a decreased age of diagnosis since the advent of PSA screening. Outcomes for individuals treated within the Clinic system are also comparable to national trends.