Conservative alternatives to radical surgery for favorable rectal cancers.

Selected cases of favorable rectal cancer can be treated with less than radical surgery. The literature demonstrates that excellent local control can be achieved using either local excision or carefully confined high dose radiation to treat the primary tumor site. Two treatments to the tumor site appear equally effective: local excision (usually a full thickness en bloc procedure) or low energy (50 kVp) endocavitary radiation. For many patients treated conservatively there is also a role for external beam radiation to the pelvis-this treats subclinical disease in regional nodes and around the tumor bed. The locoregional control for T1 lesions is excellent. For T2 lesions about 15% of patients can experience recurrence after conservative treatment. Close follow up of these patients is important, since local failures after conservative treatment are more amenable to salvage surgery than failures after standard radical surgery. Careful selection of cases, using endorectal ultrasound or MRI whenever possible, is important. The incidence of unexpected T3 disease or tumor at the margin of resection has been reported as high as 40% in series that do not utilize endorectal T staging.