Preoperative risk factors for positivity of peritoneal lavage cytology in patients with pancreatic ductal adenocarcinoma in the era of neoadjuvant therapy.

ABSTRACT

BACKGROUND: The preoperative risk factors for positive peritoneal lavage cytology (CY) are unknown, especially in patients who received neoadjuvant therapy. In addition, the optimal indications for staging laparoscopy (SL) are still unclear. The aim of this study was to investigate the preoperative risk factors of CY positivity in patients with pancreatic ductal adenocarcinoma (PDAC) treated with surgical resection and to determine the optimal indications for SL. METHODS: We retrospectively analyzed 493 patients with PDAC, including 356 treated with upfront surgery and 137 treated with neoadjuvant chemotherapy (NAC). The preoperative risk factor for CY positivity was investigated along with stratification according to NAC. RESULTS: Among the 493 patients, 36 (7.3%) were CY-positive. The CY-positive frequency in patients who received and did not receive NAC was 9 (6.6%) and 27 (7.6%), respectively. In the multivariate analyses, no independent preoperative predictive factor was found in patients who received NAC, whereas body and tail PDAC were identified as an independent risk factor for CY positivity in patients who did not receive NAC. CONCLUSIONS: The preoperative risk factors of CY-positive PDAC are body and tail PDAC in 356 patients who did not receive NAC. However, there is no useful predictive factor for CY positivity in patients treated with NAC. Based on these results, it was difficult to determine the optimal indication for SL especially in NAC cases.