The influence of irradiation on the clinical severity of incontinence, sphincter function, morphologic features and short/long-term treatment effects of sphincter training therapy is still insufficiently understood in irradiated patients with fecal incontinence after surgery for colorectal cancer. These parameters were compared in irradiated and non-irradiated patients and followed prospectively with regard to short- and long-term training effects.
Forty-one patients having been irradiated after surgery (50.0+/-5.0 Gy) and 54 non-irradiated patients with fecal incontinence participated in this prospective, non-randomized trial. Baseline evaluation included a semiquantitative severity assessment score of fecal incontinence (modified Cleveland Incontinence Score (MCIS)), rectal manometry and endoscopy. After 3 weeks (short term) of intensive in-hospital pelvic floor exercise combined with biofeedback training, a second evaluation was made. In addition, anal endosonography (EUS) was performed in cases of treatment failure. After one year (long term) a third evaluation was made clinically (MCIS score).
Irradiated patients presented with a significantly higher degree of fecal incontinence (lower MCIS) compared to non-irradiated patients: 7.4+/-2.2 versus 8.7+/-2.7 points (p<0.001). Rectosigmoidal inflammation was more frequent in irradiated than non-irradiated patients (26.9% versus 9.3%) (p<0.03). Sphincter pressure, sensation/pain threshold and the rectoanal inhibitory reflex were similar in both groups. A significant short-term training effect was observed in both groups following sphincter training therapy in terms of an increase in MCIS from 7.4+/-2.2 to 9.4+/-2.7 points in the irradiated group and from 8.7+/-2.7 to 11.4+/-2.5 points in the non-irradiated group (p<0.0001). After one year the scores were 8.2+/-3.8 and 10.7+/-4.4 points, respectively (p<0.0001). There was a significant correlation (p<0.001) between baseline MCIS and the short- and long-term MCIS. In patients with short-term treatment failure (16.6%) anal EUS revealed structural defects of the external sphincter in four patients. There was no association of sphincter diameter with sphincter pressure, sensation/pain threshold and short/long-term MCIS.
The main result of this study is that irradiated patients show short- and long-term training effects comparable with those of non-irradiated patients despite the higher degree of incontinence at baseline. The correlation between the initial MCIS and short- and long-term treatment effects may be regarded as an important clinical predictor for treatment outcome. Functional and morphologic features are less suitable for this purpose.