ORLANDO – Patients who undergo surgical resection with narrow distal margins for ultra low rectal cancers can have local control of disease and overall survival comparable to those in patients with wider resection margins, investigators reported at a symposium of the Society of Surgical Oncology.
Dr. Wim P. Ceelen and coauthors reviewed 109 patients who underwent neoadjuvant chemoradiation and surgery for rectal cancers 5 cm or less from the anal verge from 1998 to 2010. Overall survival and local control were found to be the same in a comparison of patients with distal resection margins 1 cm wide or less and those with margins greater than 1 cm.
"Close but free distal margins after neoadjuvant radiation and sphincter-saving surgery do not compromise local or systemic control," said Dr. Ceelen, a surgical oncologist at University Hospital in Ghent, Belgium.
Neoadjuvant chemoradiation has made sphincter-sparing procedures available to more patients, but the surgical results often leave distal margins that some surgeons find too close for comfort, because they fall short of the so-called "1-cm rule" holding that margins should be a minimum of 1 cm from the tumor.
"There is some controversy about the oncological safety of having very close margins, i.e., less than 1 cm," Dr. Ceelen said.
To see whether margins matter, he and colleagues reviewed records in a prospective database on the 109 patients with ultra-low rectal cancers (median pretreatment distance of 3 cm from the anal verge). All patients underwent neoadjuvant chemoradiation with 5-fluorouracil and 45 Gy radiation delivered in 25 fractions, followed by sphincter-saving surgery with R0 (cancer-free) resections. In all, 59% of the patients were clinically node positive.
Surgeries included intersphincteric resection and coloanal anastomosis in 38 patients, and stapled anastamosis in 71. The large majority of patients (98) had protective loop ileostomies.
Surgical specimens showed tumors were stage 0 (pathologic complete response to chemoradiation) in 16%, stage 1 (T1-T2) in 30%, stage II (T3-T4) in 21%, and stage III (node-positive) in 19%. The median distal resection margin was 10 mm.
At a median follow-up of 33 months, 5 patients (4.6%) had a local recurrence. Two of these patients had had surgical margins of 1 cm or less, and 3 had margin greater than 1 cm. Of the 30 patients (27.5%) who had a systemic recurrence, 12 had resections with margins of 1 cm or less, and 18 had margins greater than 1 cm. Neither difference was statistically significant.
Overall 5-year survival was 70%, and again there was no significant difference in survival by margin size.
Dr. Ceelen noted that the results echo those of a recently published systematic review (Ann. Surg. Oncol. 2012;19: 801-8).
The study was internally funded. Dr. Ceelen had no disclosures.