Patient-Reported Treatment Side Effects
By: Dan Sperling, MD
The need for pre-treatment counseling of prostate cancer patients regarding possible side effects is recognized by physicians. As part of their decision-making, patients must take into account the potential for diminished quality of life (QOL) in terms of urinary, sexual and bowel functions, even if only temporarily. Tolerance for discomfort, inconvenience, embarrassment and reduced sexual pleasure will differ from one individual to another. Therefore, if a patient is faced with more than one treatment choice (with approximately equivalent probability of successful cancer control) the factor of impact on lifestyle may affect his choice of treatment. The potential for side effects is particularly concerning for men diagnosed with insignificant prostate cancer (PCa) which may never pose a threat to life during life expectancy at diagnosis. The prospect of overtreatment, with the risks of impaired QOL, complicates treatment decisions. Therefore, it is important that patients be given frank information about the possible side effects of all treatments. Since interventional physicians such as radiologists often do not track the long term impact of their treatment of patients, a good source of data comes from studies that track patient self-reports over time.
Two recent published articles discuss patient self-reporting of their experience of post-treatment side effects (also called morbidities or comorbidities). The first study by a German team used comprehensive questionnaires (core quality of life, sexual function, and prostate-specific quality of life) to assess and compare various treatment’ impact on patients’ QOL at 3, 6, 12 and 24 months after treatment.[i] The study involved 529 patients with localized PCa who underwent either radical prostatectomy (nerve-sparing or non-nerve-sparing RP) or radiation therapy (external beam, seed implants, or combination beam-implant). Generally, across all treatments patients experienced a downturn in their QOL during the first three months following therapy, after which recovery (full or partial) gradually occurred. Radiation patients reported increased symptoms of diarrhea as the most troublesome side effect; non-nerve-sparing prostatectomy patients reported greater decreases in prostate-specific QOL (urinary and sexual issues). According to the authors, prostatectomy patients “experienced considerable impairment in sexual functioning.”
Another study focused on before and after QOL among three different forms of radiation therapy.[ii] The purpose of the study was to assess whether or not stereotactic body radiotherapy (SBRT) offered a reduced side effect profile over intensity modulated radiation therapy (IMRT) and brachytherapy (seed implants). This multi-institutional study included the Cleveland Clinic, MD Anderson, and several major academic centers. The research began with baseline pre-radiation self-reports from 809 PCa patients, utilizing a version of the University of Michigan’s Expanded Prostate Cancer Index Composite (EPIC-26). This questionnaire is described as a “comprehensive instrument designed to evaluate patient function and bother after prostate cancer treatment.”[iii] Ultimately, 2-year post-treatment comparison data was available from 645 patients from the original cohort. Average (mean) 2-year declines reported as drop in score from baseline were:
- Urinary obstruction (-1.9)
- Urinary incontinence (-4.8)
- Bowel symptoms (-4.9)
- Sexual function (-13.3)
Brachytherapy demonstrated worse urinary irritation at 2 years following treatment, but no differences in other areas. QOL for SBRT was similar in the urinary and sexual domains, but had “better bowel score” results than IMRT and brachytherapy.
In describing erectile dysfunction as a “considerable impairment,” the German study points to a discrepancy between what patients tend to expect after prostatectomy and what in fact occurs more often than even doctors believe, especially after nerve-sparing prostatectomy. The radiation study from the U.S. researchers demonstrates the potential for radiation therapies to lead to gradual deterioration in urinary, sexual and bowel function as healthy tissues exposed to radiation form scarring and mutation over time. Neither study addressed the potential for radiation to lead to secondary cancers such as bladder or rectal cancer, though the increased risk for these is unique to prostate radiation, not surgery or thermal ablations.
Counseling patients on side effect rates as well as success rates for each prostate cancer treatment is of great help as patients weigh treatment options. Encouraging patients to attend support groups where they can meet men who have been through treatment, as well as to search online for a range of side effect occurrences and duration can also help patients discern which treatment meets their clinical as well as lifestyle needs and preferences.
[i] Eisemann N, Nolte S, Schnoor M et al. The ProCaSP study: quality of life outcomes of prostate cancer patients after radiotherapy or radical prostatectomy in a cohort study. BMC Urol. 2015 Apr 10;15:28. doi: 10.1186/s12894-015-0025-6.
[ii] Evans JR, Zhao S, Daignault S, Sanda MG et al. Patient-reported quality of life after stereotactic body radiotherapy (SBRT), intensity modulated radiotherapy (IMRT), and brachytherapy. Radiother Oncol. 2015 Aug 11. pii: S0167-8140(15)00368-0. doi: 10.1016/j.radonc.2015.07.016.
