[Sportschosun] Reporter Jang Jong-ho — A domestic multicenter study has found that the long-debated question of whether to remove lateral pelvic lymph nodes during rectal cancer surgery can be decided selectively, based on how the nodes respond to preoperative chemoradiation therapy. The analysis showed that lymph nodes that shrank after treatment did not lead to worse recurrence or survival rates even when they were left in place.
A joint research team from eight university hospitals in South Korea, led by Professor Oh Heung-kwon of the Department of Surgery at Seoul National University Bundang Hospital, analyzed data from 844 rectal cancer surgery patients and released the findings. The study involved Seoul National University Bundang Hospital, Seoul National University Hospital, Asan Medical Center, Severance Hospital, NCC, Chilgok Kyungpook National University Hospital, Korea University Anam Hospital, and The Catholic University of Korea, Seoul St. Mary's Hospital.
Rectal cancer can spread to the lateral pelvic lymph nodes on the sides of the pelvis, so surgeons often remove these nodes along with the standard rectal cancer operation. The goal is to reduce the risk of metastasis, but a wider surgical scope also increases the burden on patients. Surgery takes longer, and there is a higher risk of complications, including nerve damage that can affect urinary and sexual function.
For that reason, lateral pelvic lymph node dissection has remained a long-standing controversy in rectal cancer surgery. In Western countries, surgeons tend to remove the nodes selectively when imaging suggests metastasis, while in Japan, bilateral lateral lymph node dissection has been broadly recommended for mid- and low-rectal cancer. In particular, there has been insufficient evidence on whether patients whose lymph nodes shrink after preoperative treatment still need surgery, or whether the procedure can be omitted based on treatment response.
The research team therefore examined whether additional resection could be skipped without compromising outcomes in patients whose lateral lymph nodes had shrunk sufficiently after preoperative chemoradiation therapy. The study included 844 patients whose lateral lymph node metastasis was suspected on preoperative MRI but whose nodes had shrunk to less than 5 mm after chemoradiation therapy. The patients were divided into a resection group and a non-resection group, and their outcomes were compared.
The analysis found some numerical differences in the 5-year oncologic outcomes between the resection and non-resection groups, but no statistically significant evidence that the results were affected by whether surgery was performed. The 5-year disease-free survival rates were 77.1% and 71.4%, respectively, while overall survival was 87.0% and 86.9%. Local recurrence rates were 3.1% and 5.3%, and local recurrence in the lateral lymph node area was 1.9% and 3.1%.
The surgical burden, however, was clearly different. The average operation time in the non-resection group was 237.9 minutes, about 41 minutes shorter than the 279.3 minutes in the resection group. The rate of early complications within 30 days after surgery was also higher in the resection group, at 27.0%, compared with 19.6% in the non-resection group.
This suggests that for lateral lymph nodes that respond well to preoperative treatment, additional resection does not provide a clear benefit in terms of survival or recurrence, while it can add longer surgery times and a greater risk of early complications for patients.
However, the study suggested that resection may still be helpful in patients with elevated CEA levels in pre-treatment blood tests, which can indicate cancer activity, or in those with low rectal cancer where preserving the anus is difficult. In the end, the key message of the study is not to reduce resection uniformly, but to adjust the surgical scope by considering both treatment response and risk factors.
As the medical community increasingly embraces 'de-escalation' and 'response-adapted' treatment strategies that preserve efficacy while reducing the use of drugs, radiation, and surgery, this study is meaningful in that it provides evidence for extending that trend to rectal cancer care.
Professor Oh Heung-kwon said, "Rather than applying the same surgery to every patient, we presented evidence for 'response-based personalized surgery' that adjusts the surgical scope according to how the tumor responds to preoperative treatment." He added, "As total neoadjuvant therapy, in which systemic chemotherapy is given before surgery for advanced rectal cancer, is rapidly becoming the international standard, an approach that determines the surgical scope based on treatment response will become even more important."
Oh added, "In an area where Eastern and Western recommendations have long diverged, this domestic cohort has laid a stepping stone, and we hope it will serve as evidence to reduce the surgical burden on patients."
Meanwhile, Hwang Seong-seo, a surgical resident at Seoul National University Bundang Hospital, was the first author of the study. The findings were published in Annals of Surgery, a leading international journal in the field of surgery.
Jang Jong-ho, bellho@sportschosun.com
This article has been translated by GripLabs Mingo AI.
