Lateral Lymph Node Metastases in Locally Advanced Low Rectal Cancers May Not Be Treated Effectively With Neoadjuvant (Chemo)Radiotherapy Only

• Published in: Frontiers in oncology Vol. 9; p. 1355
• Main Authors: Haanappel, Anouck, Kroon, Hidde M, Schaap, Dennis P, Bedrikovetski, Sergei, Dudi-Venkata, Nagendra N, Lee, Hong X, Thomas, Michelle L, Liu, Jianliang, van der Valk, Maxime J M, Rutten, Harm J T, Beets, Geerard L, Kusters, Miranda, Sammour, Tarik
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 03.12.2019
• Subjects: lateral lymph nodes; locally advanced low rectal cancer; neoadjuvant (chemo)radiotherapy; oncological outcomes; Oncology; survival; oncological outcomes; neoadjuvant (chemo)radiotherapy; lateral lymph nodes; locally advanced low rectal cancer; survival
• ISSN: 2234-943X; 2234-943X
• DOI: 10.3389/fonc.2019.01355

In the West, pre-treatment abnormal lateral lymph nodes (LLN+) in patients with a low locally advanced rectal cancer (AJCC Stage III), are treated with neoadjuvant (chemo)radiotherapy (nCRT), without a lateral lymph node dissection (LLND). It has been suggested, however, that LLN+ patients have higher local recurrence (LR) rates than similarly staged patients with abnormal mesorectal lymph nodes only (LLN-), but no comparative data exist. Therefore, we conducted this international multi-center study in the Netherlands and Australia of Stage III rectal cancer patients with either LLN+ or LLN- to compare oncological outcomes from both groups. Patients with Stage III low rectal cancer with (LLN+ group) or without (LLN- group) abnormal lateral lymph nodes on pre-treatment MRI were included. Patients underwent nCRT followed by rectal resection surgery with curative intent between 2009 and 2016 with a minimum follow-up of 2-years. No patient had a LLND. Propensity score matching corrected differences in baseline characteristics. Two hundred twenty-three patients could be included: 125 in the LLN+ group and 98 in the LLN- group. Between groups, there were significant differences in cT-stage and in the rate of adjuvant chemotherapy administered. Propensity score matching resulted in 54 patients in each group, with equal baseline characteristics. The 5-year LR rate in the LLN+ group was 11 vs. 2% in the LLN- group ( = 0.06) and disease-free survival (DFS) was 64 vs. 76%, respectively ( = 0.09). Five-year overall survival was similar between groups (73 vs. 80%, respectively; = 0.90). In Western patients with Stage III low rectal cancer, there is a trend toward worse LR rate and DFS rates in LLN+ patients compared to similarly staged LLN- patients. These results suggest that LLN+ patients may currently not be treated optimally with nCRT alone, and the addition of LLND requires further consideration.