Chronic effects of therapeutic irradiation for localized prostatic carcinoma on anorectal function

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

“…The effect size for the maximal thickness of the external anal sphincter was in accordance with this result (effect size 0.14), but the effect size for the thickness of the internal anal sphincter suggests a moderate detrimental effect of RT (effect size −0.72). Similar conclusions were drawn from a prospective cohort study conducted by the same author; no differences were found between pre-and postradiation measures of maximal thickness of the external and internal anal sphincters in men treated for prostate cancer in acute [33] and chronic [34] conditions; however, no effect size could be calculated from available data. Another study by Gervaz et al [31] presented an interesting case study with measures until 4 years post-radiation.…”

“…Howbeit, there is also level 2B evidence that these RT-induced changes do not include anal sphincter thickness. Out of the eight articles studying these aspects, only two had excellent methodological quality [32,34]. The latter study showed no change of the maximal thickness of the external and internal anal sphincters of men irradiated for prostate cancer, which is corroborated in two other studies of good methodological quality [30,33].…”

“…However, these findings were not maintained after 1 year. In contrast, resting pressure was found to be increased with comparison to initial assessment [34], which the authors did not offer an explanation for. In their study, Allgayer et al [28] did not observe significant difference between radiated and non-irradiated patients for anal resting and maximal squeeze pressure for the same outcome measure.…”

“…Of the eight articles that studied PFM structure after RT, three compared the irradiated subjects to non-cancer, non-irradiated subjects [28][29][30], another one to a subject with cancer who did not receive radiation [31], and three compared to pre-radiation measures for their cohort study [32][33][34], and the last study had no control group [35]. In these studies, the effects of radiation were observed through evaluation of the changes in the muscle tissue itself, such as its dimension, morphology, or composition (Table 3).…”

“…Furthermore, the results of a cross-sectional study by Vordermark et al [29] demonstrated a decreased anal resting and maximal squeeze pressure through manometry for the RT group compared to healthy normals. Manometry was also used in the studies by Yeoh et al [30,33,34], where anal resting and maximal squeeze pressure were found decreased in chronic cervical cancer patients [30] 5 to 10 years post-RT compared to healthy volunteers. Strong detrimental effect sizes could be calculated from the data of the first study (between −0.94 and −1.3), except for resting pressure at anal sleeve where only a weak detrimental effect size was calculated (effect size −0.14), The same results were observed in a cohort of men treated for prostate cancer [33], between baseline and 4-6 weeks post-RT.…”