Preoperative irradiation of cancer of the rectum

Summary and Conclusions

Roentgen therapy given preoperatively to patients with cancer of the rectum in tumor doses of 1,200 to 1,600 roentgens has materially improved the survival rate of patients who have the poorest prognosis, that is, those with lymph node metastases.

Review of the pathologic material of patients with Dukes’ C lesions did not indicate that the grade, the growth pattern, the stromal reaction, the absence of necrosis in node metastases or the presence of gelatinous cancer had any bearing on prognosis following irradiation. While not statistically significant, irradiation had an effect only when not too many nodes were involved and when most of them were located adjacent to the primary tumor, actually in the primary field of irradiation.

A possible explanation of the effect of preoperative roentgen therapy is that it inhibits the ability of cancer cells to disseminate at the time of surgery and to implant themselves and grow.