Ben Sischy

The use of radiation therapy combined with chemotherapy in the management of squamous cell carcinoma of the anus and marginally resectable adenocarcinoma of the rectum.

For many years surgery has been the treatment of choice for squamous cell carcinoma of the anus, but it is now becoming apparent that well-planned definitive radiation therapy combined with chemotherapy may obviate the need for an abdomino-perineal resection. Since 1976, 33 patients with this disease were treated at Highland Hospital by radiation therapy combined with 5-FU and Mitomycin-C for sensitization. Four of these patients underwent a planned abdomino-perineal resection following therapy; the operative specimens of all four patients were negative for tumor. Twenty-nine patients were treated by the above method without surgery in a definitive manner and local control was achieved in 89.6% of patients. Radiation therapy combined with 5-FU and Mitomycin-C for sensitization has also been used in an effort to improve the resectability rate of large rectal cancers and ultimately the 5-year survival of patients with this disease. Fifty-eight patients with marginally resectable carcinoma of the rectum were treated pre-operatively by this regimen. The method of administration of the chemotherapeutic agents used for sensitization appears to be an important factor in obtaining an increased therapeutic ratio. Thirty-three patients have been followed for a minimum of 5 years with an 84.9% local control rate; 63.7% are alive and well, and 9.1% have died of intercurrent disease. An additional 22 patients have been treated with this regimen for recurrent rectal disease and 9.9% are alive and well at 5 years. Radiation therapy combined with 5-FU and Mitomycin-C for sensitization purposes appears to be effective in downstaging rectal carcinoma at surgery with a resultant survival rate superior to that following surgery alone.

Definitive treatment of anal-canal carcinoma by means of radiation therapy and chemotherapy

In the light of the relatively poor response of squamous-cell carcinoma of the anus to surgery, an alternative method of treatment has been sought. During the past five years, in a series of 19 patients, the first four were treated by a combination of preoperative irradiation, 5-fluorouracil (5-FU) and mitomycin C as radiosensitizers plus surgery. As a result of complete responses at the time of surgery of all these patients, 15 additional patients have been treated by definitive radiotherapy combined with 5-FU and mitomycin C, thereby avoiding abdominoperineal resection. Eighteen patients had local control, and the one treatment failure is discussed. The method of treatment is described, and recommendations are made concerning techniques to be used or to be avoided.

Preoperative radiation therapy with sensitizers in the management of carcinoma of the rectum.

There is enough evidence to show that adjuvant radiation therapy contributes to the management of patients with carcinoma of the rectum. In an effort to improve resectability and possibly survival rates, the use of chemosensitizers, combined with moderate doses of radiation used presurgically, was introduced for carcinomas larger than 5 cm in diameter requiring abdominoperineal resection. Based on our experience and that of others, it is believed that the method of administration of 5FU and mitomycin-C is an important factor in obtaining an increased therapeutic ratio. Because of the locoregional pattern of spread of rectal cancer, this adjuvant approach would appear suitable. A series of approximately 60 patients is discussed and the surgical findings and five-year survival is reported.

Intraoperative electron beam radiation therapy with particular reference to the treatment of rectal carcinomas--primary and recurrent.

Radiation therapy is being used alone or in combination with surgery with increasing frequency in the treatment of colorectal malignancies. Preoperative or postoperative irradiation may be offered to patients with marginally resectable lesions who are at high risk for local recurrence. Dose levels required for cure, however, may be such that the complications are unaceeptable.The use of intraoperative radiation therapy (IORT) has increased the possibility of a higher local control rate and possible cure. The ability to increase the therapeutic ratio between local control and complications using IORT is achieved only with close interaction between the surgeon and radiation oncologist. Furthermore, intraoperative radiation therapy may be offered for patients with recurrent rectal tumors.The technique of intraoperative radiation therapy will be described briefly and recent results regarding colorectal cancers from larger centers will be reviewed. It apperas from many reports that the three-to-five-year results for marginally resectable disease are approximately 50 percent and for recurrent disease, approximately 40 percent.The incidence of complications following intraoperative radiation therapy does not appear to increase as a result of this aggressive treatment modality. The number of centers offering this modality is increasing rapidly.

Efficacy of 5-Fluorouracil by Continuous Infusion as a Radiopotentiator — Anal and Rectal Carcinoma

The conventional treatment for both rectal and anal carcinomas remains surgery, with a characteristic 5-year survival rate of approximately 50% at each disease site (Enbald and Adami 1988). The role of radiation therapy in the management of these diseases was not recognized until fairly recently; initially radiation therapy played a palliative role but was not regarded with favor as either a definitive or an adjunct modality. Early suboptimal equipment and poor quality of delivery, coupled with disappointing results and significant morbidity, caused surgeons to remain antagonistic. Once supervoltage irradiation became available, results improved and it was possible to treat patients to tumoricidal doses within normal tissue tolerance dose levels.