Low-dose preoperative radiation postpones recurrences in operable rectal cancer: results of a randomized multicenter trial in Western Norway

Article Abstract:

In Norway, only about 40 percent of patients with operable rectal cancers survive five years after surgery. Among the patients who relapse after surgery, from 30 to 60 percent experience recurrence of tumor in the locoregional area only, with no metastatic disease. These patients represent a population of patients who may well be cured if improvements in surgical treatment can be achieved. One method to improve the success of potentially curative surgery for rectal cancer that is under investigation is preoperative radiation. Several preliminary trials have suggested that preoperative radiation may provide some survival benefit for these patients. To objectively evaluate the benefits of preoperative radiotherapy, a controlled study was designed to examine survival of patients with operable rectal cancer with or without preoperative radiation. A total of 145 patients received surgical treatment only, and 155 patients received preoperative radiation consisting of a dose of 3,150 cGy in 18 fractions two to three weeks prior to surgery. (A Gy, or Gary, is 1 joule of energy absorbed per kilogram of tissue.) Overall, the five-year survival of the patients was 57.5 percent and 56.7 percent for the control and the radiation groups. For those patients for whom the surgery was regarded as possibly curative, the five-year survival rates were 60.9 percent in the control group and 64.2 percent in the group receiving radiation therapy.These differences were not statistically significant. It was observed that while the proportion of patients in relapse was the same in both groups, the duration of the response prior to relapse was not the same. Patients in the control group relapsed after an average of 13.3 months, while patients treated with preoperative radiation enjoyed remissions lasting an average of 27.1 months. It should be mentioned that the rectum is relatively resistant to the harmful effects of radiation, and a dose of 3,150 cGy is significantly less than the area is capable of tolerating. Considering the extension of remission as a result of the preoperative radiation, it is plausible that higher radiation doses, perhaps around 5,600 cGy, may provide improved long-term survival. (Consumer Summary produced by Reliance Medical Information, Inc.)

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Preoperative short-term radiation therapy in operable rectal carcinoma: a prospective randomized trial

Article Abstract:

Rectal cancer is common in western nations, and even when the tumor is surgically removable, the 5-year survival rate is roughly 50 percent. The most common cause of death is the metastatic spread of cancer, but it should not be overlooked that many patients die of local disease recurrence, without any metastatic spread. Therefore, there is some rationale for including adjuvant radiotherapy with surgery for patients who have resectable rectal cancer. Some researchers have advocated preoperative radiation, and some postoperative. In addition, some studies have demonstrated an advantage to radiation, but others have not. The point remains controversial. In order to shed more light on these questions, a randomized, prospective trial was carried out over an 8-year period on 849 patients with rectal cancer. Surgery was considered curative in 679 patients, i.e. it appeared that the entire tumor was successfully removed. Among these patients, 37 of 331 who received adjuvant preoperative radiotherapy developed local recurrence, in contrast with 86 of 348 who did not receive radiotherapy. There were no significant differences in the rate of metastatic disease, nor were there differences in overall survival. Postoperative illness and death were significantly greater for the patients who received preoperative radiotherapy. Thirty-five of 424 patients receiving radiation therapy died within 30 days after surgery; cardiovascular disease was the most common cause. In contrast, only 7 of 425 patients, whose only treatment was surgery, died within that period. (Consumer Summary produced by Reliance Medical Information, Inc.)

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The safe and effective use of postoperative radiation therapy in modified Astler Coller Stage C3 rectal cancer

Article Abstract:

Virtually 100 percent of patients with Stage C3 rectal cancer will experience recurrence in the local region if surgery is not supplemented with postoperative radiation. Unfortunately, the therapeutic doses of radiation may cause severe toxic effects resulting from damage to the small bowel. Several patients have died from radiation enteritis (inflammation of the intestines). However, it is possible to use a sling made of absorbable polyglycolic acid mesh to suspend the intestines out of the way of the postoperative pelvic radiation. This technique has permitted the evaluation of radiation doses greater than 5500 cGy in 19 patients with C3 rectal cancer. Of the 19 patients treated, only two experienced local recurrences after a mean follow-up of 33 months, indicating that the radiation was effective. Similar patients without radiation treatment have a 80 percent chance of recurrence within 24 months. Eleven of the patients experienced distant tumor spread, but seven have lived disease-free for a mean of 35 months. The sling procedure permits the application of tumoricidal radiation doses without risk of small bowel injury, and is effective in suppressing local regional recurrence for at least 33 months. (Consumer Summary produced by Reliance Medical Information, Inc.)

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