Preoperative staging and radiotherapy in rectal cancer surgery

Abstract: Background: Rectal cancer affects approximately 2 000 people in Sweden every year. The overall survival rate is approximately 50% after five years. During the last decades the survival has increased and the local recurrence rate has declined. This can be attributed to improved surgical techniques and introduction of preoperative radiotherapy. The improved surgical technique includes specimen oriented surgery and introduction of the total mesorectal excision-technique (TME). The long-term complications of radiotherapy in rectal cancer are largely unknown. Prior to deciding on administration of preoperative radiotherapy, a preoperative staging is needed, using endorectal ultrasound, MRI or CT. The aims of the present thesis were to determine the accuracy of endorectal ultrasonography in preoperative staging of rectal tumors and to evaluate the long-term consequences of preoperative radiotherapy in rectal cancer with or without TME-surgery. Patients & Methods. The results from preoperative endorectal ultrasound staging of 545 patients with rectal tumors were compared with postoperative pathoanatomical staging. From 1980 through 1993, 1 406 patients were randomly assigned to either preoperative (5x5 Gy) radiotherapy and surgery, or to surgery alone, within the Stockholm I & II trials. These patients were operated with standard surgical technique prior to the TME-era. 139 of these patients were alive and available for follow-up at mean 14 years after surgery. Patients were examined with questionnaires regarding hospital admissions, medication used, bowel and urinary function and quality of life. Patients were also examined clinically, including rigid proctoscopy and anorectal manometry in those without a colostomy. Anorectal function in 68 patients operated with TME after a mean follow-up of 8 years was evaluated with identical questionnaires and examinations. Comparisons on anorectal function at longterm follow-up were made between patients operated with or without TME and with or without preoperative radiotherapy. Results: The accuracy of endorectal ultrasound for preoperative staging was 69% for depth of bowel wall penetration with 13% of tumors understaged and 18% of tumors overstaged. The overall accuracy for perirectal lymph-nodes was 64% with 11% of tumors understaged and 25% overstaged. The accuracy for distinguishing a noninvasive from an invasive rectal tumor was 87%. Patients treated with preoperative radiotherapy had significantly more cardiovascular disease, anal incontinence and urinary incontinence than patients treated with surgery alone. Patients operated with TME and preoperative radiotherapy had significantly more anal incontinence, compared to patients treated with TME alone. In a multivariate analysis of possible risk factors for developing anal incontinence, only preoperative radiotherapy was an independent risk factor (RR 2.78, 95% CI: 1.236.29). Patients with anal incontinence had a lower quality of life score compared to continent patients. The global QoL score did not differ between irradiated and nonirradiated patients. Conclusions: Endorectal ultrasonography is useful in preoperative staging of rectal tumors. It identifies transmural invasion and reliably distinguishes between noninvasive and invasive rectal tumors. Preoperative short-course, high-dose radiotherapy in rectal cancer increases the incidence of bowel, anal and urinary dysfunction, and may increase the risk for cardiovascular morbidity. The potential benefits of preoperative radiotherapy therefore need to be balanced against the risk for increased morbidity when tailoring the treatment for the individual patient.