Patients with rectal cancer who completed neoadjuvant therapy with a clinical complete response but did not undergo rectal resection had similar 4-year survival rates as patients who chose to undergo immediate surgery, according to the results of a retrospective study (abstract #509) presented during a press briefing ahead of the American Society of Clinical Oncology (ASCO) 2015 Gastrointestinal Cancers Symposium.
“Nonoperative management appears to be a safe and effective treatment strategy and achieves a high rate of rectal preservation,” said study presenter Philip B. Paty, MD, of Memorial Sloan Kettering Cancer Center.
According to Paty, research has shown that at the time of rectal surgery pathologic analysis has shown that 12% to 38% of patients will have no cancer cells in the final specimen. Because of this Memorial Sloan Kettering has used selective nonoperative management in patients with rectal cancer with clinical complete response after neoadjuvant therapy since 2006.
This study evaluated a group of patients with stage I–III rectal cancer who underwent neoadjuvant therapy with radiation and chemotherapy. The researchers evaluated the safety and efficacy of nonoperative management in 73 patients who had achieved clinical complete response and compared outcomes with 72 patients who achieved pathologic complete response and underwent rectal resection.
A durable complete response was achieved in 74% of patients who underwent rectal preservation with the watch-and-wait approach. Nineteen patients (26%) who underwent organ preservation did have local regrowth: 16 patients had mucosal/intramural growth and 3 had mesenteric/nodal growth. Of those 19 patients, two were able to undergo local excision only, equating to a total rectal preservation rate of 77%.
No significant differences in 4-year disease-specific survival and overall survival were found between patients who underwent organ preservation and those who had immediate surgery.
Commenting on these results, press briefing moderator Smitha S. Krishnamurthi, MD, of Case Western Reserve University, said, “These are important findings for patients with rectal cancer because removal of rectum can result in altered bowel habits or the need for permanent colostomy. This study set the bar high comparing the results of nonoperative management to the results seen in patients who had no cancer left under the microscope at time of surgery and, in this setting, the nonoperative management appears to compare favorably.”
Both Paty and Krishnamurthi added that longer follow-up will be needed to be sure that these patients achieve a disease-specific survival that equals what is achieved with surgery in the long term.