Which is the best approach for treating lateral lymph node metastasis in locally advanced rectal cancer?

This study evaluated the best approach for treating lateral lymph node (LLNs) metastasis in patients with locally advanced rectal cancer (LARC). The data showed that a radiation dose boost is an effective way of increasing the response rate and decreasing recurrence rates in these patients.

Rectal cancer (RC) is one of the most common types of cancer worldwide. RC involves the final part of the large intestine or rectum. The first choice for treatment of RC is usually surgery. Often, patients are given chemotherapy (CT) after surgery to make sure any remaining cancer cells are killed. However, in more advanced stages, chemotherapy with radiation is given before surgery (neoadjuvant chemoradiotherapy; nCRT) to shrink the cancer so that it can be completely removed by surgery.

Prior studies have shown that LARC spreads to the lateral lymph nodes (LLN) in 10-25% of the cases. Treatment of LLNs metastasis differs around the world. LLNs metastasis is treated with nCRT followed by rectal surgery with or without lymph node surgery. However, the best approach for treating LLN metastasis in patients with LARC in still unknown.

This study involved 202 patients with LARC and LLN metastasis. Patients were divided into 3 groups based on the treatment they received before surgery. Group 1 included 94 patients who received nCT. Group 2 included 60 patients who received nCRT. Group 3 included 48 patients who received nCRT with a boost RT dose on the LLNs. The average follow-up time was 35 months.

The shrinkage of LLNs tumors was significantly greater for group 3 than in groups 1 and 2. The overall response rate (ORR; partial or complete disappearance of cancer) was also higher for group 3 (72.9%) compared to group 1 (48.9%) and group 2 (65%).

The 3-year local recurrence (cancer coming back) rate was 2.3% in group 3 which was significantly lower compared to group 1 (68.2%) and group 2 (29.5%). There were no differences in the radiation-related side effects among the 3 groups.

This study concluded that a radiation dose boost to the LLNs is an effective way of increasing the response rate and decreasing recurrence rates for the treatment of patients with LARC and LLN metastasis.

This study looked back in time at medical records. The sample size was very small and only included patients from a single institution in China. Larger studies with longer follow-up are necessary to validate the conclusions.