MINNEAPOLIS – Increasing the surgical margin length up to 15 mm during wedge resection of small lung cancer tumors significantly lowered the risk of local recurrence among 474 consecutive patients.
No additional benefit was observed, however, beyond 15 mm, said Dr. Kamran Mohiuddin, a surgical research fellow at Brigham and Women’s Hospital, Boston.
Compared with a margin length of 5 mm, the adjusted risk of local recurrence was estimated to be 45% lower with a margin length of 10 mm (hazard ratio, 0.55), 59% lower with a 15-mm margin (HR, 0.41), and 54% lower with a 20-mm margin (HR, 0.46).
"The downward trend flattens out, indicating diminished benefit of increasing the margin length," he said at the annual meeting of the American Association for Thoracic Surgery.
Patrice Wendling/IMNG Medical Media
Dr. Kamran Mohiuddin
Currently, the data are unclear regarding the optimal margin length for wedge resection of small non–small cell lung cancer (NSCLC) tumors of less than 2 cm. Wedge resections are associated with margins less than 1 cm and a high risk for locoregional recurrence (Ann. Surg. Oncol. 2007;14:2400-5), with a multicenter, prospective study suggesting that the optimal margin length should be larger than the maximum tumor diameter (Ann. Thorac. Surg. 2004;77:415-20).
When asked during a discussion of the analysis whether a more aggressive resection or segmentectomy would be performed if margins are found in the operating room to be inadequate based on the current results, senior author Dr. Scott J. Swanson, an ACS Fellow and director of minimally invasive thoracic surgery at the hospital, said they are taking the results forward into practice, but that it’s unclear whether 15 mm is the optimal number to target.
"Is 15 mm the correct margin? I am not sure we know the answer in all cases, but it is a useful number to keep in the surgeon’s head when we are doing resections for tumors that are 2 cm or less," he said in an interview. "A 15-mm margin seems to be a better target to aim for than margin length to tumor diameter ratio of greater than 1, as suggested by other investigators."
The current analysis included data from all patients, aged 21-85 years, who underwent wedge resection for NSCLC 2 cm or less at their institution between January 2001 and August 2011. Margin length, defined as the distance from the tumor to the closest stapled resection margin, was 0.1-0.5 cm in 36%, 0.6-1.0 cm in 25.5%, 1.1-2.0 cm in 28.5%, and greater than 2 cm in 10%.
The mean tumor size was 1.33 cm, the location of the tumor was the right upper lobe in the majority (36%), and video-assisted thoracic surgery (VATS) was used in 57.5%. The patients’ mean forced expiratory volume in 1 second (FEV1) was 79.8%, and the mean age was 68.5 years.
Perioperative death occurred in 1 patient and at least one major complication in 41 patients, Dr. Mohiuddin said.
The local recurrence rate was 5.8% at 1 year, 11.3% at 2 years, and 16.8% at 3 years. Median follow-up was 3.9 years.
In multivariate regression analysis, increased margin length was significantly associated with a lower risk of local recurrence, with evidence of diminished additional benefit beyond a length of 15 mm (P = .031), he said. The analysis adjusted for FEV1, chronic obstructive pulmonary disease, smoking, diabetes, tumor size, tumor lobe location, location within the hemothorax, surgeon, whether VATS or open surgery was used, and whether or not nodes were sampled.
Dr. Mohiuddin and his coauthors reported having no financial disclosures.