Prognostic Significance of Intraoperative Peritoneal Lavage Cytology in Patients with Pancreatic Ductal Adenocarcinoma: A Single-Center Experience and Systematic Review of the Literature

Peritoneal washing cytology status as a crucial prognostic determinant in patients with localized pancreatic ductal adenocarcinoma who underwent curative-intent resection following preoperative chemoradiotherapy

BACKGROUND

Prognostic implications of peritoneal washing cytology (CY) in patients with localized pancreatic ductal adenocarcinoma (PDAC) undergoing surgical resection following preoperative chemoradiotherapy (CRT) remain unclear. This study aimed to elucidate the prognostic significance and predictors of a positive CY status (CY+) after preoperative CRT.

METHODS

Clinical data from 141 patients with localized PDAC who underwent curative-intent resection after preoperative CRT were retrospectively analyzed to examine the association between CY+ and clinicopathological factors and survival.

RESULTS

CY+ was observed in six patients (4.3%). The CY+ group exhibited significantly higher preoperative serum levels of CA19-9 and a substantially greater incidence of tumor location in the pancreatic body or tail, along with pathological invasion to the anterior pancreatic capsule, than the CY- group. The CY+ group had a significantly higher incidence of peritoneal recurrence compared with the CY- group (83.3% vs. 18.5%, p = 0.002). Overall survival (OS) and recurrence-free survival (RFS) after surgery were significantly shorter in the CY+ group than in the CY- group (CY+ vs. CY-: 18.3 vs. 46.2 months, p = 0.001, and 8.9 vs. 17.7 months, p = 0.009, respectively). Multivariate analyses identified CY+ as an independent prognostic factor for worse OS (hazard ratio 5.00, 95% confidence interval 1.03-12.31) and RFS (hazard ratio 2.58, 95% confidence interval 1.04-6.43). Local invasion grade on imaging before CRT, limited histological response to CRT, and absence of adjuvant chemotherapy were independent predictors of worse OS and RFS.

CONCLUSION

Despite the relatively low incidence of CY+ after preoperative CRT, it emerged as an independent prognostic factor in patients with localized PDAC undergoing curative-intent resection following preoperative CRT.

The Shorr Versus Modified Ultrafast Papanicolaou Method for Intraoperative Diagnosis of Peritoneal Washing Cytology in Advanced Gastric Cancer: A Phase II Study

PURPOSE

According to the American Joint Committee on Cancer cancer staging system, positive peritoneal washing cytology (PWC) indicates stage IV gastric cancer. However, rapid intraoperative diagnosis of PWC has no established reliable method. This study evaluated and compared the diagnostic accuracy of the Shorr and the modified ultrafast Papanicolaou (MUFP) methods for intraoperative PWC.

MATERIALS AND METHODS

This study included patients with gastric cancer who were clinically diagnosed with stage cT3 or higher. The Shorr and MUFP methods were performed on all PWC specimens, and the results were compared with those of conventional Papanicolaou (PAP) staining with carcinoembryonic antigen immunohistochemistry. Sensitivity, specificity, and partial likelihood tests were used to compare the 2 methods.

RESULTS

Forty patients underwent intraoperative PWC between November 2019 and August 2021. The average time between specimen reception and slide preparation using Shorr and MUFP methods was 44.4±4.5 minutes, and the average time between specimen reception and pathologic diagnosis was 53.9±8.9 minutes. Eight patients (20.0%) had positive cytology in PAP staining. The Shorr method had a sensitivity of 75.0% and specificity of 93.8%; the MUFP method had 62.5% sensitivity and 100.0% specificity. The area under the curve was 0.844 for Shorr and 0.813 for MUFP. In comparing the C-indices of each method with overall survival, no difference was found among the Shorr, MUFP, and conventional PAP methods.

CONCLUSIONS

The Shorr and MUFP methods are acceptable for the intraoperative diagnosis of PWC in advanced gastric cancer.