Timing of surgery after neoadjuvant treatment matters in rectal carcinoma: study

Last Updated: 2015-05-08

By Reuters Staff

NEW YORK (Reuters Health) - It's best to wait at least eight weeks between neoadjuvant chemoradiotherapy (nCRT) and surgery, if possible, in patients with clinical stage II-III rectal cancer, a new study suggests.

In what the study team says is the "largest and most direct examination of this topic to date," they observed that a nCRT-surgery interval of greater than eight weeks is independently associated with an increased likelihood of both pathological complete response (pCR) and tumor downstaging after neoadjuvant radiation.

"Our data suggest an optimal interval of 10-11 weeks with no observed impact on patient safety," write Dr. Christian Probst of University of Rochester Medical Center, New York, and the Consortium for Optimizing the Surgical Treatment of Rectal Cancer (OSTRiCh) in the Journal of the American College of Surgery, online April 22.

"This study also demonstrates that the association between longer intervals and increased pCR persists in a 'real-world', population-based sample of rectal cancer patients, not only in highly specialized centers with carefully defined patient cohorts," they note.

Prior single-center studies with small sample sizes have suggested that the time interval from nCRT completion to surgery has an impact on tumor response including pCR. To investigate further, they analyzed data from the National Cancer Data Base on more than 17,000 patients with clinical stage II-III rectal cancer treated with nCRT and surgery between 2006 and 2011.

An nCRT-surgery interval time of more than eight weeks (compared with six to eight weeks) was associated with a "small but real" increase in odds of pCR (OR, 1.12; 95% CI: 1.01-1.25) and tumor downstaging (OR, 1.11; 95% CI: 1.02-1.25) and with lower odds of 30-day readmission (OR, 0.82; 95% CI: 0.70-0.92), they report.

Further analysis showed that patients who had an nCRT-surgery interval of 10 to 11 weeks had 27% greater likelihood of pCR than those with an interval of six to eight weeks.

"These data provide strong support for consideration of extending the duration to surgery following the completion of neoadjuvant therapy," Dr. Probst and colleagues say.

The study "strongly suggests that interval assessment of tumor response following neoadjuvant therapy to decide on an extended interval after neoadjuvant therapy should become the standard of care, allowing rational choices to be made between radical resection and potentially non-operative management," they add.

The authors have no disclosures. They did not respond to request for comment by press time.

SOURCE: http://bit.ly/1dQRXkm

J Am Coll Surg 2015.