Effects of radiation therapy on the structure and function of the pelvic floor muscles of patients with cancer in the pelvic area: a systematic review

Radiation therapy (rt) is often recommended in the treatment of pelvic cancers. following rt, a high prevalence of pelvic floor dysfunctions (urinary incontinence, dyspareunia, and fecal incontinence) is reported. however, changes in pelvic floor muscles (pfms) after rt remain unclear. the purpose of this review was to systematically document the effects of rt on the pfm structure and function in patients with cancer in the pelvic area. an electronic literature search using pubmed central, cinahl, embase, and scopus was performed from date of inception up to 2014. the following keywords were used: radiotherapy, muscle tissue, and pelvic floor. two reviewers selected the studies in accordance with preferred reporting items for systematic reviews and meta-analyses statement (prisma). out of the 369 articles screened, 13 met all eligibility criteria. the methodological quality was assessed using the qualsyst scoring system, and standardized mean differences were calculated. thirteen studies fulfilled all inclusion criteria, from which four were of good methodological quality. one presented strong evidence that rt affects pfm structure in men treated for prostate cancer. four presented high-level evidence that rt affects pfm function in patients treated for rectal cancer. meta-analysis was not possible due to heterogeneity and lack of descriptive statistics. there is some evidence that rt has detrimental impacts on both pfms’ structure and function. a better understanding of muscle damage and dysfunction following rt treatment will improve pelvic floor rehabilitation and, potentially, prevention of its detrimental impacts.