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

Abstract

Background: 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.Materials and Methods: 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.Results: 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 (P = 0.06) and disease-free survival (DFS) was 64 vs. 76%, respectively (P = 0.09). Five-year overall survival was similar between groups (73 vs. 80%, respectively; P = 0.90).Conclusions: 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.

Combination of extramural venous invasion and lateral lymph node size detected with magnetic resonance imaging is a reliable biomarker for lateral lymph node metastasis in patients with rectal cancer

“…On the other hand, even with the performance of both neoadjuvant chemoradiotherapy (NACRT) and ME, metastasis to the LLN remains a significant clinical concern [ 38 ]. Haanappel et al [ 39 ] demonstrated that compared to patients without LLN metastases, patients with clinically suspected LLN metastases exhibited a clinically relevant trend toward worse 5-year local recurrence-free and disease-free survival. They suggested that in cases with clinically suspected LLN metastases, NACRT alone might not be sufficient treatment and that the addition of LLN dissection should be considered.…”

Management of Clinically Involved Lateral Lymph Node Metastasis in Locally Advanced Rectal Cancer: A Radiation Dose Escalation Study

“…A cut-off value of 5 mm was selected for our study, and the LR rate was 25.1%. There was a need for a consensus in selecting LLND for the patients based on the restaging imaging findings of LLNs (10,12,13,25,26). A study conducted at the MD Anderson Cancer Center found that after nCRT, none of the patients with LLN <5 mm had pathologically positive LLNs (13).…”

Positive lateral pelvic lymph nodes in low rectal cancer: should we change our practice now?

“…This includes surgical technique, systemic treatment regimens and radiological reporting. Larger studies in Western and European cohorts 19,21–23 are multicentric in order to mitigate low event rates. However, the compromise is variation in diagnostics, classifications and treatments according to local practices.…”

“…The primary endpoint was LR. This was diagnosed radiologically and defined as tumour regrowth at the anastomotic site, within the pelvis involving urological, gynaecological organs or the sacrum, or in the lateral pelvic sidewall 19 . Secondary outcomes included distant metastases, disease‐free survival (DFS) and overall survival (OS).…”