Lymph Node Harvest After Proctectomy for Invasive Rectal Adenocarcinoma Following Neoadjuvant Therapy

Abstract

The current standard of lymph node harvest should be applied to patients with poorly responding primary tumors after neoadjuvant therapy. However, a new standard may be necessary to define the adequate number of lymph nodes for tumors that respond well to neoadjuvant therapy.

Lymph node yield is an independent predictor of survival in rectal cancer regardless of receipt of neoadjuvant therapy

“…The traditional method of harvesting lymph nodes included palpation and direct visualisation, while the newer fat clearance method involves immersing the specimen in an adipose clearing solution prior to lymph node harvest. Wang et al 29 was able to demonstrate that in their cohort of patients, the fat clearance method yielded, on average, 22.6 lymph nodes compared with 6.9 using the traditional method (p<0.001). The issue of harvesting at least 12 lymph nodes in rectal cancer is debated, particularly in the population of patients that receive neoadjuvant treatment 6 13 30.…”

Lymph Node Ratio is an Independent Prognostic Factor in Node Positive Rectal Cancer Patients Treated with Preoperative Chemoradiotherapy Followed by Curative Resection

“…Many factors influence the number of lymph nodes retrieved, including tumor (size, stage) (Baxter et al, 2005), and the patient (age, sex) (Thorn et al, 2004;Gao et al, 2013), and neoadjuvant CRT (Rullier et al, 2008;Doll et al, 2009;Wang et al, 2009). Recent studies demonstrated that the total number of retrieved LNs was decreased due to preoperative chemoradiation, probably because of lymph node atrophy, fibrosis and lymphocyte depletion caused by radiotherapy or/and chemotherapy, and the number of harvested LNs was frequently less than12, despite the maintenance of vigorous surgical standards (Rullier et al, 2008;Doll et al, 2009;Wang et al, 2009;Lee et al, 2012). Lee et al (2012) found that <12 LNs were harvested in 30.5% patients after preoperative CRT.…”

“…These studies have found that, LNR is not only an important prognostic indicator, but also a more accurate stratification system than the current metastatic lymph node number-based staging system in colorectal cancer (Peschaud et al, 2008;Rosenberg et al, 2008;Kim et al, 2009;Moug et al, 2009). Preoperative chemoradiotherapy (CRT) followed by total mesorectal excision (TME) is the current standard of care for patients with T3 or T4 tumors and/or positive lymph nodes (Kapiteijn et al, 2001;Sauer et al, 2004). However, some studies have demonstrated that the number of harvested LNs is significantly decreased in rectal cancer patients received preoperative CRT (Rullier et al, 2008;Doll et al, 2009;Wang et al, 2009). The number of harvested LNs in rectal cancer patients treated with preoperative CRT is frequently fewer than 12, as recommend by the American Joint Committee on Cancer (AJCC) and the National Cancer Institute (Goldstein et al, 1996).…”

Ratio of metastatic lymph nodes is more important for rectal cancer patients treated with preoperative chemoradiotherapy

“…Furthermore, while a correlation between lymph node metastasis and poor oncologic outcome in patients treated with PCRT and radical resection has been suggested, the value of the LNR after PCRT remains controversial [14,15] . PCRT has been shown to result in a significant decrease in both the size and number of LNs available for examination after resection [16][17][18][19][20] . Consequently, the number of LNs examined could be below the recommended number in patients with rectal cancer.…”