Surgical removal of tumor involving these structures is limited because of the proximity of large blood vessels. Analysis of surgical specimens that show the presence of positive margins, ie, retroperitoneal tumor extension, and lymph nodes is associated with poor local control and poor survival. Based on these patterns of failure, the rationale for aggressive c hemoradiation, including EB-IORT, is justified. In an effort to improve local control rates with higher doses of adjuvant external radiotherapy, a specialized boost technique like EB-IORT has been tried at various institutions. Preliminary results from several centers indicate that this combination of treatment is safe and that local control may be improved beyond what has been reported in the literature for adjuvant external radiotherapy alone.
Survival compares favorably to that achieved with regional pancreatectomy.
On digital examination, the tumor involved two thirds of the circumference of the bowel lumen and was fixed to the posterior pelvic tissues. The patient was staged as a T4 NX MO rectal cancer and entered on a preoperative chemoradiation protocol. The resected specimen showed gross residual tumor that extended through the bowel w all to less than a millimeter of the posterior resection margin. The tumor was a mucinous adenocarcinoma with involvement of all 5 lymph nodes in the specimen. A 10 Gy boost of intraoperative electrons was given to the presacral region at the area of th e close resection margin.