Short term outcomes of minimally invasive selective lateral pelvic lymph node dissection for low rectal cancer.

BACKGROUND

Pelvic recurrence after rectal cancer surgery is still a significant problem despite the introduction of total mesorectal excision and chemoradiation treatment (CRT), and one of the most common areas of recurrence is in the lateral pelvic lymph nodes. Hence, there is a possible role for lateral pelvic lymph node dissection (LPND) in rectal cancer.

AIM

To evaluate the short-term outcomes of patients who underwent minimally invasive LPND during rectal cancer surgery. Secondary outcomes were to evaluate for any predictive factors to determine lymph node metastases based on pre-operative scans.

METHODS

From October 2016 to November 2019, 22 patients with stage II or III rectal cancer underwent minimally invasive rectal cancer surgery and LPND. These patients were all discussed at a multidisciplinary tumor board meeting and most of them received neoadjuvant chemoradiation prior to surgery. All patients had radiologically positive lateral pelvic lymph nodes on the initial staging scans, defined as lymph nodes larger than 7 mm in long axis measurement, or abnormal radiological morphology. LPND was only performed on the involved side.

RESULTS

Majority of the patients were male (18/22, 81.8%), with a median age of 65 years (44-81). Eighteen patients completed neoadjuvant CRT pre-operatively. 18 patients (81.8%) had unilateral LPND, with the others receiving bilateral surgery. The median number of lateral pelvic lymph nodes harvested was 10 (3-22) per pelvic side wall. 8 patients (36.4%) had positive metastases identified in the lymph nodes harvested. The median pre-CRT size of these positive lymph nodes was 10mm. Median length of stay was 7.5 d (3-76), and only 2 patients failed initial removal of their urinary catheter. Complication rates were low, with only 1 lymphocele and 1 anastomotic leak. There was only 1 mortality (4.5%). There have been no recurrences so far.

CONCLUSION

Chemoradiation is inadequate in completely eradicating lateral wall metastasis and there are still technical limitations in accurately diagnosing metastases in these areas. A pre-CRT lymph node size of ≥ 10 mm is suggestive of metastases. LPND may be performed safely with minimally invasive surgery.