A retrospective analysis of data from the National Cancer Data Base has found that patients who had cancer surgery at 56 days after the end of combined chemoradiotherapy presented with the best overall survival and successful removal of their residual tumors.
A retrospective analysis of data from the National Cancer Data Base (NCDB) has found that patients who had cancer surgery at precisely 8 weeks after the end of combined chemoradiotherapy presented with the best overall survival and successful removal of their residual tumors.
Colon and rectal cancers are the third most common cancers in the United States, according to the CDC, with about 135,000 new cases and 51,000 deaths per year.
Published in the Journal of the American College of Surgeons, the study included data from 11,760 patients with stage II and III rectal adenocarcinoma who went through chemoradiotherapy and surgical resection from 2006 to 2012. The primary outcomes that were evaluated were margin positivity, and tumor downstaging. Secondary outcomes evaluated were readmission and death rates within 30 days of hospital discharge and overall survival.
The study analysis divided patients into 2 groups: short-interval, those who underwent operations within 55 days of chemoradiotherapy; and long-interval, those who had an operation 56 days or more after radiotherapy. The long-interval group was slightly older (age 59 vs 58 years), more likely to be black (9.5% vs 8%), treated at an academic hospital, and less likely to have private insurance (50.2% vs 55.4%), and stage III disease (51.4% vs 54.2%).
The investigators found that the median time between chemoradiotherapy and surgery was 53 days, with a range of 43 to 63 days. After adjusting for patient demographic, clinical, tumor, and treatment characteristics, the period of 56 days was found to have the most impact on resection margin positivity and pathologic downstaging. Additionally, extending the delay beyond 56 days between radiation and surgery was associated with a higher likelihood of positive resection margins and compromised long-term survival, suggesting that longer waiting times may risk tumor regrowth.
“Due to its size, we thought NCDB was a perfect resource to answer the question about the timing of surgery after chemoradiotherapy for rectal cancer. The data set represented all types of hospitals,” said Christopher R. Mantyh, MD, FACS, senior author on the study, in a press release. According to Mantyh, the size of the study distinguishes the results from all previous studies that tried to answer the same question. The earlier studies, he said, had smaller patient cohorts and were from single institutions unlike the current study.
“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,” Mantyh said. “This kind of analysis is what we need in medicine and surgery. We need to have good population based data.”