As treatments for prostate cancer, brachytherapy and surgery share logistics in that they both involve a procedure that may be performed in one intervention. Beyond that, one sees similarities and differences depending on the point of comparison being examined. The ideal dataset to use for such a comparison would be from a well-done randomized trial.
Unfortunately, no such trial exists. Some trials along these lines have randomized patients to either surgery or external-beam radiotherapy, but they yielded results that are not widely accepted because of small sample sizes, significant imbalances in pretreatment characteristics between groups, and randomization artifacts.[1,2] An attempt to compare brachytherapy and surgery in a randomized setting was closed due to poor accrual.[3] Also, none of these trials made sufficient plans to assess toxicity beyond simple investigator-reported grading systems. As a result, one must appeal to less robust data for analysis.
Despite the lack of randomized data, it is possible to sift through the literature for good quality research that will provide a basis for analysis. If one limits the inclusion of such research to prospective trials as well as retrospective trials with adequate follow-up and sufficient numbers of patients, a solid comparison of brachytherapy and surgery for prostate cancer may be made. This report will focus the comparison on toxicity, biochemical relapse-free survival (bRFS), clinical relapse-free survival (cRFS), and prostate cancer–specific mortality.
Toxicity
Most major cooperative groups have toxicity grading systems that tend to suffer from the same flaw: they are physician/investigator-reported. One recently completed prospective trial—the Prostate Cancer Outcomes and Satisfaction with Treatment Quality Assessment (PROST-QA)—used a validated, patient-reported questionnaire on toxicity. The 2-year data from this trial were first reported in 2008.[4] A careful review of its findings will disclose the early toxicity profiles of each of the major modalities.
The Prost-QA trial is an inception cohort study in which the patient and partner were asked to answer a validated questionnaire that measured the change from baseline of various quality-of-life domains. The five specific domains were: sexual, urinary incontinence, urinary irritation or obstruction, bowel or rectal, and vitality or hormonal. Patients with localized prostate cancer were offered their choice of therapy and the option to participate in the trial at one of six major cancer centers nationwide. The questionnaire was given at baseline and then at months 2, 6, 12, and 24 after therapy. While the trial included patients treated with external-beam radiotherapy as well as brachytherapy and surgery, we will focus on just the results for the brachytherapy and surgery patients.
The common finding in assessing the brachytherapy and surgery patients is the consistent nadir in quality-of-life score at the 2-month point for each of the affected domains. Generally, the quality-of-life score rebounded in subsequent months. In the sexual domain a major difference was seen in the quality-of-life score between brachytherapy and surgery patients. The surgery patients had a higher baseline sexual score (70–80), while the brachytherapy patients had a baseline of 60–70. At the 2-month assessment, the surgery patients’ sexual score fell to ~20, and at 2 years it was 20–40 (with the lower number being for those who did not receive a nerve-sparing operation). In contrast, the brachytherapy patients’ score fell to 45–50 at 2 months and was about the same at 2 years. While both modalities suffered a loss in this domain, the surgery patients took a greater loss relative to baseline. At 2 years, both modalities had essentially the same sexual score.
Another quality-of-life domain in which there was a significant difference between surgery and brachytherapy is that of urinary incontinence. Both modalities started with the same baseline of ~95. The expected drop in the domain score was seen in both groups; however, the surgery patients’ score fell the furthest (~50 for surgery vs ~82 for brachytherapy). Recovery occurred for both groups, but the surgery patients were at ~75 at 2 years, whereas at the same point, the brachytherapy patients were at ~90.
In contrast to the two previously discussed domains, brachytherapy fared worse in both urinary irritation or obstruction and bowel or rectal symptoms. Specifically, while both modalities started at the same baseline of ~90 for the urinary irritation or obstruction domain, the surgery patients were still at baseline at 2 years whereas the brachytherapy patients fell to ~80 by 2 years. In the bowel or rectal domain, both modalities again began at ~97, but the brachytherapy patients’ score fell to ~90 at 2 years and the surgery patients maintained their baseline function.
