Source: DGNews  |  Posted 2 years ago

By Gabe Waggoner

PHOENIX, Ariz -- March 8, 2009 -- Short-course radiation therapy after excision may not improve the rate of recurrence nor the rate of overall survival for patients with lower rectal cancer treated with abdominoperineal excision of the rectum, researchers stated here at the Society of Surgical Oncology (SSO) 62nd Annual Cancer Symposium. Short-course radiotherapy, in fact, may cause more complications after surgery.

Mohammad Tayyab, MD, University of Hull, Cottingham, United Kingdom, and colleagues sought to assess both surgical outcomes and long-term survival of patients with rectal cancer who underwent short-course radiation therapy after abdominoperineal excision of the rectum. They presented their findings here in a poster discussion session on March 6.

The authors retrospectively analysed patients with stage T2 and T3 operable rectal cancers who had been treated with abdominoperineal excision of the rectum during a 16-year period (January 1992 through April 2008).

Using a multivariate regression, the researchers found that a statistical correlation existed between neoadjuvant short-course radiation therapy and several other factors, including positivity of circumferential resection margins, invasion of extramural large vessels, involvement of the anterior quadrant, complications after surgery, delayed healing of the perineal wound, recurrence of disease, and the number of positive lymph nodes.

Of the 220 patients who had undergone abdominoperineal excision of the rectum, 126 were ultimately analysed. Thirty-three of these patients had been treated with short-course radiation therapy after excision, whereas the remaining 93 had not. The 2 groups were matched for age, sex, and T stage.

The authors monitored patients in the radiotherapy group for a median of 24 months and followed patients in the excision-only group for a median of 45 months.

Analysis revealed that overall survival in both groups was not statistically significantly different. The 2 groups also had similar rates of recurrence-free survival. The 5-year local recurrence rates of 17% (radiation therapy group) and 36% (no radiation therapy) were also not statistically significantly different (P = .7).

Dr. Tayyab noted that in other studies, “short-course radiotherapy has been shown to improve relapse-free survival following surgery for rectal cancer.” Nevertheless, in this particular study, the radiation therapy given to patients with rectal cancer appeared to have no effect on either recurrence or overall survival. Moreover, he pointed out, patients with low rectal cancers who were treated with neoadjuvant short-course radiation therapy tended to have more postsurgical complications.

[Presentation title: Analysis of Impact of Short Course Pre Operative Radiotherapy on Local Relapse and Survival Outcomes in Patients Following Abdominoperineal Excision for Rectal Adenocarcinoma. Abstract P137]