Predictive factors of operability after neoadjuvant chemotherapy in resectable or borderline resectable pancreatic cancer: a single-center retrospective study

Background/Aims: Recently neoadjuvant chemotherapy (NAC) for pancreatic cancer has been shown to be superior to upfront surgery, but it remains a matter of debate for resectable cases. In clinical practice, some resectable cases may become unresectable after NAC. This study aimed to reveal the outcomes after NAC and to clarify the characteristics of unresected cases. Methods: The medical records of 142 patients who underwent NAC between 2016 and 2020 were retrospectively reviewed. Patient characteristics, effectiveness of NAC, and outcomes were compared between the surgical group and non-surgical group (NSG). Furthermore, the risk of recurrence limited to in the patients who received NAC with gemcitabine plus nab-paclitaxel, which were mostly administered in this cohort, following R0/R1 resection was assessed. Results: The overall and R0 resection rates after NAC were 89.1% and 79.7%, respectively. The neutrophil to lymphocyte ratio (NLR) > 2.78 (p = 0.0120) and anatomical borderline resectable pancreatic cancer (p = 0.0044) revealed a statistically significantly correlation with the NSG. On the other hand, NAC week < 8 (p = 0.0285), radiological response, stable disease or progression disease (p = 0.0212), and pathological stage > IIA (P = 0.0003) were significantly associated with recurrence. The tumor response rate was approximately 26.1%, and three patients with ≥ 30% reduction of primary tumor lost excision opportunities because of metastasis, interstitial pneumonia, and vascular invasion. Conclusions: This study shows incomplete tumor shrinkage benefits, but pre-NAC NLR is a predictive factor for predicting operability after NAC. The NLR can be easily calculated by normal blood test, and can be considered as a suitable marker of operability.