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Introduction:The role of parenchyma-sparing resections (PSR) and lymph node dissection in small (< 3 cm) nonfunctional pancreatic neuroendocrine tumors (PNET) is unlikely to be studied in a prospective randomized clinical trial. By combining data from 4 high-volume pancreatic centers we compared postoperative and long-term outcomes of patients who underwent PSR with patients who underwent oncologic resections. Methods: Retrospective review of prospectively collected clinicopathologic data of patients who underwent pancreatectomy between 2000 and 2021 was collected from 4 high-volume institutions. PSR and lymph nodesparing resections (enucleation and central pancreatectomy) were compared to those who underwent oncologic resections with lymphadenectomy (pancreaticoduodenectomy, distal pancreatectomy). Statistical testing was performed using χ 2 test and t test, survival estimates with Kaplan-Meier method and multivariate analysis using Cox proportional hazard model. Results: Of 810 patients with small sporadic nonfunctional PNETs, 121 (14.9%) had enucleations, 100 (12.3%) had central pancreatectomies, and 589 (72.7%) patients underwent oncologic resections. The median age was 59 years and 48.2% were female with a median tumor size of 2.5 cm. After case-control matching for tumor size, 221 patients were selected in each group. Patients with PSR were more likely to undergo minimally invasive operations (32.6% vs 13.6%, P < 0.001), had less intraoperative blood loss (358 vs 511 ml, P < 0.001) and had shorter operative times (180 vs 330 minutes, P < 0.001) than patients undergoing oncologic resections. While the mean number of lymph nodes harvested was lower for PSR (n = 1.4 vs n = 9.9, P < 0.001), the mean number of positive lymph nodes was equivalent to oncologic resections (n = 1.1 vs n = 0.9, P = 0.808). Although the rate of all postoperative complications was similar for PSR and oncologic resections (38.5% vs 48.2%, P = 0.090), it was higher for central pancreatectomies (38.5% vs 56.6%, P = 0.003). Long-term median disease-free survival (190.5 vs 195.2 months, P = 0.506) and overall survival (197.9 vs 192.6 months, P = 0.372) were comparable. Of the 810 patients 136 (16.7%) had no lymph nodes resected. These patients experienced less blood loss, shorter operations (P < 0.001), and lower postoperative complication rates as compared to patients who had lymphadenectomies (39.7% vs 56.9%, P = 0.008). Median disease-free survival (197.1 vs 191.9 months, P = 0.837) and overall survival (200 vs 195.1 months, P = 0.827) were similar for patients with no lymph nodes resected and patients with negative lymph nodes (N0) after lymphadenectomy. Conclusion: In small <3 cm nonfunctional PNETs, PSRs and lymph node-sparing resections are associated with lower blood loss, shorter operative times, and lower complication rates when compared to oncologic resections, and have similar long-term oncologic outcomes.

Predicting R status before surgery for pancreatic cancer (PDAC) patients with upfront surgery and neoadjuvant therapy. Summary Background Data: Negative surgical margins (R0) are a key predictor of long-term outcomes in PDAC. Methods: Patients undergoing pancreatic resection with curative intent for PDAC were identified. Using the CT scans from the time of diagnosis, the 2019 NCCN borderline resectability criteria were compared to novel criteria: presence of any alteration of the superior mesenteric-portal vein (SMPV) and perivascular stranding of the superior mesenteric artery (SMA). Accuracy of predicting R status was evaluated for both criteria. Patient baseline characteristics, surgical, histopathological parameters, and long-term overall survival (OS) after resection were evaluated. Results: A total of 593 patients undergoing pancreatic resections for PDAC between 2010 and 2018 were identified. Three hundred and twenty-five (54.8%) patients underwent upfront surgery, whereas 268 (45.2%) received neoadjuvant therapy. In upfront resected patients, positive SMA stranding was associated with 56% margin positive resection rates, whereas positive SMA stranding and SMPV alterations together showed a margin positive resection rate of 75%. In contrast to these criteria, the 2019 NCCN borderline criteria failed to predict margin status. In patients undergoing neoadjuvant therapy, only perivascular SMA stranding remained a predictor of margin positive resection, leading to a rate of 33% R+ resections. Perivascular SMA stranding was related to higher clinical T stage (P = 0.003) and clinical N stage (P = 0.043) as well as perineural invasion (P = 0.022). SMA stranding was associated with worse survival in both patients undergoing upfront surgery (36 vs 22 months, P = 0.002) and neoadjuvant therapy (47 vs 34 months, P = 0.050). Conclusions: The novel criteria were accurate predictors of R status in PDAC patients undergoing upfront resection. After neoadjuvant treatment, likelihood of positive resection margins is approximately halved, and only perivascular SMA stranding remained a predictive factor.