Lymph Node Yield Is a Less Reliable Prognostic Marker Following Neoadjuvant Chemoradiotherapy Compared to Primary Surgery for Rectal Cancer

International guidelines recommend a minimum lymph node yield (LNY) of ≥ 12 for adequate oncological resection in colorectal cancer. Neoadjuvant chemoradiotherapy (NACRT) in rectal cancers decreases LNY, which questions its ability to provide accurate prognostic information in this setting. The consensus of this significance remains undetermined. The aim of this study is to investigate the significance of LNY on 3-year recurrence and survival following anterior resection and abdominoperineal resection with or without NACRT for rectal cancer. Prospectively collected data on patients diagnosed with rectal cancer in a tertiary referral centre was analysed. Patients were divided into primary surgery and NACRT groups. Univariable and multivariable analyses were used for analysis. Disease recurrence and survival were analysed with logrank test and Kaplan–Meier curves. One hundred forty-eight patients were included (56.1% ( n = 83) receiving NACRT). The median LNY of the primary surgery group was 14 (interquartile range (IQR) 11–19) and for the NACRT group was 12 (IQR 8–14) ( p < 0.001). LNY < 12 was significantly associated with higher 3-year recurrence rates compared in the primary surgery group ( p = 0.013), but not in the NACRT group ( p = 0.055) and similar findings for disease-free survival (primary surgery group ( p = 0.042); NACRT ( p = 0.172)). In the NACRT group, recurrence was observed as LNY < 8 no recurrence, LNY8–11 11.11% and LNY ≥ 12 17.77% ( p = 0.050) and disease-free survival as LNY < 8 100%, LNY8–11 100% and LNY ≥ 12 93.79% ( p = 0.393). On multivariable analysis, LNY was not significantly associated with 3-year cancer outcomes. LNY < 12 was not a negative prognostic indicator following NACRT and surgery for rectal cancer, but remains prognostic in patients who undergo primary surgery.