One-level step section histological analysis is insufficient to confirm complete pathological response after neoadjuvant chemoradiation for rectal cancer

Lymph node regression after neoadjuvant chemotherapy: A predictor of survival in gastric cancer

BACKGROUND AND OBJECTIVE

Neoadjuvant chemotherapy (nCMT) has been increasingly used in advanced gastric cancer (GC). However, the prognostic impact of tumor response remains unclear. This study aimed to evaluate if tumor response at the primary site and lymph nodes (LN) correlate with survival in GC patients after nCMT.

METHODS

Patients with gastric adenocarcinoma treated with nCMT followed by gastrectomy were evaluated. Residual tumor was graded from 0% to 100%, defining two groups: poor (PR) and major response (MR). LN regression rate (LNRR) was determined based on tumor/fibrosis examination at each LN and a cutoff value established by receiver operating characteristic curve.

RESULTS

Among 62 cases, 20 (32.2%) had MR and 42 (67.7%) PR. Smaller size, diffuse histology, lower ypT status and less advanced stage were associated with the MR group. Based on cutoff value of 57, 45.6% and 54.4% patients were classified as low-LNRR and high-LNRR. High-LNRR correlated with absence of venous, lymphatic and perineural invasion, and less advanced stage. Survival was equivalent between MR and PR (P = .956). High-LNRR had better disease-free survival (DFS) than low-LNRR (P < .001). In multivariate analysis, only LNRR associated with DFS.

CONCLUSION

High-LNRR associates with DFS in GC treated with nCMT. Response at the primary site does not correlate with survival.

Lymph Node Yield After Neoadjuvant Chemoradiotherapy in Rectal Cancer Specimens: A Randomized Trial Comparing Two Fixatives

BACKGROUND

It is widely reported that neoadjuvant chemoradiation reduces lymph node yield in rectal cancer specimens. Some have questioned the adequacy of finding ≥12 lymph nodes for accurate staging, and fewer nodes were correlated with good response. Others reported that low lymph node count raises the chance for understaging and correlates with worse survival. In addition, a few studies demonstrated that diligent specimen analysis increases lymph node count.

OBJECTIVE

The aim of this study was to compare Carnoy's solution and formalin concerning lymph node yield in specimens of patients with rectal cancer after neoadjuvant chemoradiation.

DESIGN

This is a prospective randomized trial that was conducted from 2012 to 2015.

SETTINGS

This study was performed in a reference cancer center in Brazil.

PATIENTS

Patients who underwent low anterior resection with total mesorectal excision after neoadjuvant chemoradiation for rectal adenocarcinoma were included.

INTERVENTION

Rectosigmoid specimens were randomized for fixation with Carnoy's solution or formalin.

MAIN OUTCOME MEASURES

A total of 130 specimens were randomized. After dissection, the residual fat from the formalin group was immersed in Carnoy's solution in search for missed lymph nodes (Revision).

RESULTS

The Carnoy's solution group had superior lymph node count (24.0 vs 16.3, p < 0.01) and fewer cases with <12 lymph nodes (6 vs 22, p = 0.001). The Revision group found lymph nodes in all cases (mean, 11.1), retrieving metastatic lymph nodes in 6 patients. It reduced the formalin cases with <12 lymph nodes from 33.8% to 4.6% and upstaged 2 patients. Tumor response to neoadjuvant chemoradiotherapy was not associated with lymph node count.

LIMITATIONS

This was a unicentric study.

CONCLUSIONS

Compared with formalin, the Carnoy's solution increases lymph node count and reduces the cases with <12 lymph nodes. Harvested lymph nodes are missed following routine analysis and this is clinically relevant. Finding <12 lymph nodes is not a sign of good response to neoadjuvant chemoradiation (www.clinicaltrials.gov. Unique identifier: NCT02629315). See Video Abstract at http://links.lww.com/DCR/A694.