THURSDAY, Jan. 21, 2016 (HealthDay News) -- Researchers say they've pinpointed the best length of time to wait to perform surgery for rectal cancer after chemotherapy and radiation treatment have been completed.
The researchers examined outcomes among 11,760 U.S. patients with stage 2 or 3 localized rectal cancer who had combined chemotherapy and radiation therapy (chemoradiotherapy) and surgery between 2006 and 2012.
Patients who had surgery precisely eight weeks (56 days) after they completed chemoradiotherapy had the best survival rates and successful removal of their tumors. Waiting any longer may increase the risk of tumor regrowth, the study found.
The time between chemoradiotherapy and surgery ranged from 43 to 63 days in the study.
Compared to those who had surgery within 55 days of chemoradiotherapy, those who had surgery after 56 days were slightly older (59 versus 58 years of age) and more likely to be black (9.5 percent versus 8 percent). In addition, they were more likely to be treated at an academic hospital, less likely to have private insurance, and more likely to have stage 3 cancer, the findings showed.
The study was published in the Jan. 20 online edition of the Journal of the American College of Surgeons.
The findings may help guide doctors when deciding how long patients should wait for surgery after chemoradiotherapy, said study leader Dr. Christopher Mantyh of Duke University, in Durham, N.C.
"In the global picture, there's a lot of discussion about if waiting longer for surgery is better, and if you don't wait as long there's less chance of tumor spreading, but none of it is backed up on good modeling data like we have in this study," he said in a news release from the American College of Surgeons.
"This kind of analysis is what we need in medicine and surgery. We need to have good population-based data," Mantyh added.
Colon and rectal cancers are the third most common cancers in the United States, with about 135,000 new cases and 51,000 deaths per year, according to the U.S. Centers for Disease Control and Prevention.
Patients with many types of cancers have chemoradiotherapy prior to having surgery to remove tumors.
The U.S. National Cancer Institute has more about rectal cancer.