Unnecessity of lymph node regression evaluation for predicting gastric adenocarcinoma outcome after neoadjuvant chemotherapy

BACKGROUND Neoadjuvant chemotherapy has been applied worldwide to improve the survival of patients with gastric adenocarcinoma(GAC). The evaluation of histological regression in primary tumors is valuable for predicting prognosis. However, the prognostic effect of regression change in lymph nodes(LNs) remains unclear.AIM To confirm whether the evaluation of regression change in LNs could predict the prognosis of GAC patients who received neoadjuvant chemotherapy followed by surgery.METHODS In this study, we evaluated the histological regression of resected LNs from 192 GAC patients(including those with esophagogastric junction adenocarcinoma)treated with neoadjuvant chemotherapy. We classified regression change and residual tumor in LNs into four groups:(A) true negative LNs with no evidence of a preoperative therapy effect,(B) no residual metastasis but the presence of regression change in LNs,(C) residual metastasis with regression change in LNs,and(D) metastasis with minimal or no regression change in LNs. Correlations between regression change and residual tumor groups in LNs and regression change in the primary tumor, as well as correlations between regression change in LNs and clinicopathological characteristics, were analyzed. The prognostic effect of regression change and residual tumor groups in LNs was also analyzed.RESULTS We found that regression change and residual tumor groups in LNs were significantly correlated with regression change in the primary tumor, tumor differentiation, ypT stage, ypN stage, ypTNM stage, lymph-vascular invasion,perineural invasion and R0 resection status. Regression change and residual tumor groups in LNs were statistically significant using univariate Cox proportional hazards analysis, but were not independent predictors. For patients who had no residual tumor in LNs, the 5-year overall survival(OS) rates were 67.5% in Group A and 67.4% in Group B. For the patients who had residual tumors in LNs, the 5-year OS rates were 28.2% in Group C and 39.5% in Group D.The patients in Groups A+B had a significantly better outcome than the patients in Groups C+D(P < 0.01). No significant differences in survival were found between Groups A and B, or between Groups C and D.CONCLUSION The existence of residual tumor in LNs, rather than regression change in LNs, is useful for predicting the prognosis after neoadjuvant chemotherapy in GAC patients. In practice, it may not be necessary to report regression change in LNs.

Impact of neoadjuvant chemoradiotherapy on the local recurrence and distant metastasis pattern of locally advanced rectal cancer: a propensity score-matched analysis

Background:Previous studies have demonstrated different predominant sites of distant metastasis between patients with and without neoadjuvant chemoradiotherapy(NCRT).This study aimed to explore whether NCRT could influence the metastasis pattern of rectal cancer through a propensity score-matched analysis.Methods:In total,1296 patients with NCRT or post-operative chemoradiotherapy(PCRT)were enrolled in this study between January 2008 and December 2015.Propensity score matching was used to correct for differences in baseline characteristics between the two groups.After propensity score matching,the metastasis pattern,including metastasis sites and timing,was compared and analyzed.Results:After propensity score matching,there were 408 patients in the PCRT group and 245 patients in the NCRT group.NCRT significantly reduced local recurrence(4.1%vs.10.3%,P=0.004),but not distant metastases(28.2%vs.27.9%,P=0.924)compared with PCRT.In both the NCRT and PCRT groups,the most common metastasis site was the lung,followed by the liver.The NCRT group developed local recurrence and distant metastases later than the PCRT group(median time:29.2[18.8,52.0]months vs.18.7[13.3,30.0]months,Z=–2.342,P=0.019;and 21.2[12.2,33.8]vs.16.4[9.3,27.9]months,Z=–1.765,P=0.035,respectively).The distant metastases occurred mainly in the 2nd year after surgery in both the PCRT group(39/114,34.2%)and NCRT group(21/69,30.4%).However,20.3%(14/69)of the distant metastases appeared in the 3rd year in the NCRT group,while this number was only 13.2%(15/114)in the PCRT group.Conclusions:The predominant site of distant metastases was the lung,followed by the liver,for both the NCRT group and PCRT group.NCRT did not influence the predominant site of distant metastases,but the NCRT group developed local recurrence and distant metastases later than the PCRT group.The follow-up strategy for patients with NCRT should be adjusted and a longer intensive follow-up is needed.