Lateral lymph node (LLN) metastasis in locally advanced rectal cancer is associated with patient prognosis. However, the clinical significance of lateral lymph node dissection (LLND) has always been a matter of debate in the academic community. We have invited Dr. Petrv Tsarkov from Chechenov State Medical University in Moscow to share his insights and thoughts on the clinical controversies surrounding lymph node dissection in colorectal cancer.

Oncology Frontier: How should the extent of lymphadenectomy be clinically defined in colorectal cancer?

Dr. Petrv Tsarkov:The clinical indications for extensive lymphadenectomy remain highly controversial due to the current limitations of our diagnostic tools. For example, the predictive value of lymph node positivity assessed by CT or MRI in colorectal cancer is quite low, ranging from only 10% to 30%. While artificial intelligence is being explored to improve diagnostic accuracy, these tools still offer limited reliability. Consequently, decisions regarding the extent of lymphadenectomy must often be made both before and during surgery.

From the perspective of Russian surgeons, prophylactic lymphadenectomy is recommended for patients with T2–T4 stage colon and rectal cancers due to its potential benefits. Approximately 30% of these tumors exhibit lymph node metastasis, suggesting that extended lymph node dissection could play a role in improving patient outcomes.

Oncology Frontier: Given that lateral lymph node (LLN) metastasis in locally advanced rectal cancer is associated with patient prognosis, how should we define lateral lymph node dissection (LLND)?

Dr. Petrv Tsarkov: If a patient has positive lateral lymph nodes, their prognosis is certainly worsened. However, by treating these positive lymph nodes, even if we cannot completely cure the patient, we can improve survival rates and extend overall survival. At our institution, we have been performing LLND since 2000. We likely have the largest group of Caucasian patients who have undergone lateral lymph node dissection, which differs from the situation in Asian countries like Japan, China, and South Korea, where this surgical procedure is widely and frequently practiced. In Western countries, however, this approach is much less common.

Our observations show that patients with metastasis confined to the internal iliac lymph nodes have significantly better outcomes—about 60% of these patients survive. In contrast, patients with positive lymph node spread beyond the internal iliac region to the external iliac lymph nodes have poorer survival rates, with survival dropping to around 30%–35%.

Oncology Frontier: What are the current controversies surrounding treatment strategies for locally advanced mid to low rectal cancer?

Dr. Petrv Tsarkov: In my opinion, the main controversy lies in how we should treat low rectal cancer. For mid-rectal cancer, it is well-established that most patients undergo standard total mesorectal excision (TME). Even without any adjuvant therapy, over 90% of these patients likely won’t experience local recurrence after surgery alone.

However, for low rectal cancer, several contentious issues remain. The first major point of debate is survival rates and the factors influencing them. I believe that lateral lymph node dissection (LLND) is critical here because approximately 30% of low rectal cancer patients have positive external iliac lymph nodes. This highlights the need to address this issue more carefully.

The second controversy concerns functional outcomes. In cases of localized rectal cancer, we often perform abdominoperineal resection (APR), which results in a permanent colostomy for the patient. To avoid such invasive procedures, there is a growing global interest in the “watch-and-wait” approach, also known as the organ-preservation strategy.

However, if a patient does not achieve a complete response within eight weeks following chemoradiotherapy, we must be very cautious with this strategy. In cases of incomplete response, surgical intervention should be strongly considered.