YpN0 rectal cancer patients with sterilized lymph nodes after neoadjuvant chemoradiotherapy are of greater risk of recurrence

Lymph node regression after neoadjuvant chemoradiotherapy in rectal cancer

AIMS

Lymph node metastases (LNM) are one of the most important prognostic indicators in solid tumours and a major component of cancer staging. Neoadjuvant therapy might influence nodal status by induction of regression. Our aim is to determine the prevalence and role of regression of LNM on outcomes in patients with rectal cancer.

METHODS AND RESULTS

Four independent study populations of rectal cancer patients treated with similar regimens of chemoradiotherapy were pooled together to obtain a total cohort of 469 patients. Post-treatment nodal status (ypN) and signs of tumour regression (Reg) were incorporated to form three-tiered (ypN- Reg+, ypN- Reg- and ypN+) and four-tiered (ypN- Reg+, ypN- Reg-, ypN+ Reg+ and ypN+ Reg-) classifications. In our cohort, 31% of patients presented with ypN+ rectal cancer. As expected, we found significantly worse overall survival (OS) in ypN+ patients compared to ypN- patients (P = 0.002). The percentage of ypN- patients with lymph nodes with complete regression was 20% in our cohort. While node-negative patients with and without regression had similar OS (P = 0.09), disease-free survival (DFS) was significantly better in node-negative patients with regression (P = 0.009).

CONCLUSIONS

Regression in lymph nodes is frequent, and node-negative patients with evidence of lymph node regression have better DFS compared to node-negative patients without such evidence.

Effects of neoadjuvant chemotherapy plus chemoradiotherapy on lymph nodes in rectal adenocarcinoma

The pathological nodal stage, determination of which requires examination of ≥ 12 lymph nodes, is one of the main prognostic factors in rectal cancer. Neoadjuvant chemoradiotherapy (CRT) may reduce the number of both lymph nodes retrieved and positive lymph nodes. Induction chemotherapy before CRT aimed at reducing the rate of distant metastases. However, the impact of this new treatment on number of lymph nodes retrieved and positive lymph nodes is unknown. This study was performed to evaluate the effects of neoadjuvant chemotherapy on lymph nodes in locally advanced rectal cancer treated by CRT. We retrospectively included patients with T2 - 4 Nx M0 rectal cancer and compared those receiving neoadjuvant chemotherapy plus CRT with those receiving CRT alone. From 2012 to 2019, 85 patients were treated with neoadjuvant chemotherapy + CRT and 189 with CRT alone. The number of lymph nodes retrieved (19 vs. 17, respectively, P = 0.434), the rate of specimens with ≥ 12 lymph nodes (92% vs. 88%, respectively, P = 0.397), and the median number of positive lymph nodes (1 vs. 2, respectively, P = 0.878) were similar between the two groups. However, the rate of pN0 was higher after neoadjuvant chemotherapy + CRT compared to CRT (75% vs. 62%, respectively, P = 0.030). Neoadjuvant chemotherapy before CRT for locally advanced rectal cancer did not modify the number of lymph nodes retrieved or the number of positive lymph nodes compared to CRT alone. However, it significantly increased the rate of tumors without any positive lymph nodes (ypN0).

Prognostic impact of sterilized lymph nodes in esophageal squamous cell carcinomas after neoadjuvant chemoradiotherapy

BACKGROUND

The prognostic importance of sterilized lymph nodes (SLN) remains unclear in patients with esophageal squamous cell carcinomas (ESCC) treated by neoadjuvant chemoradiotherapy (nCRT). This study aimed to determine whether SLN predicted disease-free survival (DFS) in ESCC.

METHODS

We enrolled 246 eligible patients who were divided into SLN (+) and SLN (-) group according to the presence or absence of fibrosis, necrosis, calcifications and/or foreign body giant cell reactions in the negative lymph nodes specimens. The prognostic value of SLN was determined using univariate and multivariate analyses. The prognostic strength of counting SLN as positive lymph nodes was evaluated using the difference of Akaike information criterion (ΔAIC).

RESULTS

A total of 61 SLN were identified in 38 (15.4%) patients. There was no significant difference in baseline characteristics between SLN (+) and SLN (-) group. The most frequently detected SLN in the thoracic cavity and abdominal cavity were those along bilateral recurrent laryngeal nerve (21/38,55.3%) and left gastric artery (13/24,60.9%), respectively. The univariate and multivariate analyses showed SLN was an independent prognostic factor for worse DFS in the whole cohort (HR = 2.05, 95%CI = 1.08-3.90, P = 0.029). The SLN (+) group additionally correlated with worse 5-year DFS than SLN (-) group in the ypT0, ypN0 and pCR subgroups. Counting SLN as positive lymph nodes showed better prognostic strength than ignoring them.

CONCLUSION

SLN was of prognostic significance for worse DFS in patients with ESCC, particularly in patients with good response to nCRT.