METASTATIC ‘EARLY’ COLORECTAL CANCER

Radiation treatment for rectal cancer

Radiation treatment is widely used in the management of adenocarcinomas of the rectum, either alone or more frequently as part of multimodality treatment protocols. External beam radiation is capable of eradicating about one-third of bulky but mobile primary rectal cancers and is an alternative to be considered when standard surgery is not possible. Endorectal irradiation, either alone or combined with external beam treatment, has proved highly effective for selected superficial cancers of the distal rectum. Irradiation alone or in conjunction with cytotoxic chemotherapy appears to reduce the risk of tumor progression at the primary site or in regional lymph nodes when combined with local surgical excisions that preserve anorectal function. The treatment of recurrent and metastatic cancer frequently provides palliation, although cure by irradiation is rare.

Local excision of rectal carcinoma

Sixteen published series were reviewed in which local excision was used as definitive treatment for patients with invasive rectal carcinoma located within 6 cm of the anal verge. Ninety-four percent of tumors were T1 or T2 adenocarcinomas with no identified regional metastases. Five-year cancer-specific survival was 89%. Local recurrence was 19%, although more than half of these patients were cured with additional surgery. These results were comparable with those for historical controls treated with abdominoperineal resection (APR). Four pathologic features of the surgical specimen were analyzed to assess their correlation with patient outcome. Positive surgical margins, poorly differentiated histology, and increasing depth of bowel wall invasion were associated with increased local recurrence and decreased survival. Tumor size greater than 3 cm was not a significant factor. When criteria for appropriate patient selection are followed, local excision may provide survival and recurrence rates comparable with those achieved with APR with less morbidity and operative mortality.

Curative local excision of rectal adenocarcinoma

The records of all 28 patients with rectal adenocarcinoma treated by potentially curative local excision by one surgeon (A.M.C.) between 1970 and 1984 were reviewed. Patient age, sex, tumour size, site, degree of differentiation and level of invasion are reported. The procedure was associated with no mortality and minimal morbidity. Twenty-two patients, followed for an average of 51 months, have either died of other causes or remain free of recurrent or disseminated malignancy. Six patients have required further surgery for local recurrence. Of these, one patient has had a repeat local excision while the remaining five patients have had an abdominoperineal excision of the rectum. All six patients, followed since the second operation for an average of 50 months, are free of further recurrent or disseminated disease. The results reported in this review suggest that in a selected group of patients with rectal adenocarcinoma curative local excision may offer a safe alternative to more radical forms of surgery.