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Background: Patients with limited distant metastatic disease, also known as oligometastasis, show better survival rates than polymetastatic patients, and may be amenable for curative‐intent treatment. The definition of oligometastasis, however, is unknown, and no quantitative analyses on the cutoff value for oligometastasis have been performed before. This study aims to derive specific threshold values for the number of metastases and affected locations that defines oligometastatic disease in head and neck squamous cell carcinoma. Methods: A retrospective cohort study was conducted including all patients diagnosed with distant metastases between 2006 and 2021. For each patient, the number of distant metastases and affected locations was recorded on the basis of the available imaging at the time of diagnosis. Cox regression analyses and a machine‐learning k‐means algorithm were used to determine threshold values. Results: A total of 384 patients untreated for their metastatic foci were analyzed. Most patients (n = 207; 53.9%) had metastasis to one anatomic location, followed by metastases in two anatomic locations (n = 62; 16.1%). The majority of patients had ≥9 metastatic foci (n = 174; 45.3%), followed by one focus (n = 74; 19.3%) and two foci (n = 32; 8.3%). Cox regression and machine‐learning k‐means models showed that although the number of metastases did not predict survival, the number of affected locations did significantly (p <.001), by identifying a threshold of two locations. Conclusions: Contrary to the prevalent dogma, the definition of oligometastasis should not be defined by the number of metastases but rather by the number of affected locations, with a maximum number of affected locations set at two. In this retrospective cohort study that included 384 patients with head and neck squamous cell carcinoma who were untreated for their metastatic foci, quantitative analyses showed that oligometastasis should be defined as distant metastatic dissemination to a maximum of two anatomic locations. In the context of survival, the number of distant metastatic foci was not a significant predictor. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether tangential versus segmental portomesenteric venous resection (PVR) impacts surgical and oncological outcome in patients undergoing pancreatoduodenectomy for pancreatic cancer with portomesenteric vein (PMV) involvement., Summary Background Data: Current comparative studies on tangential versus segmental PVR as part of pancreatoduodenectomy for pancreatic cancer include all degrees of PMV involvement, including cases where tangential PVR may not be a feasible approach, limiting the clinical applicability., Methods: International retrospective study in 10 centers from 5 countries, including all consecutive patients after pancreatoduodenectomy with PVR for pancreatic cancer with ≤180° PMV involvement on cross-sectional imaging at diagnosis (2014-2020). Cox and logistic regression analyses were performed to investigate the association of tangential versus segmental PVR with overall survival (OS) from surgery, recurrence-free survival (RFS), locoregional recurrence, and in-hospital/30-day major morbidity, adjusting for potential confounders., Results: Overall, 357 patients who underwent pancreatoduodenectomy with PVR were included (42% tangential PVR, 58% segmental PVR). The adjusted risk for in-hospital/30-day major morbidity was 23% (95%CI, 17-32) after tangential and 23% (95%CI, 17-30) after segmental PVR (P=0.98). After adjusting for confounders, PVR type was not associated with OS (HR=0.94 [95%CI, 0.69-1.30]), RFS (HR=0.94 [95% CI, 0.69 to 1.28), and locoregional recurrence (OR=0.76 [95%CI, 0.40-1.46])., Conclusions: In patients undergoing pancreatoduodenectomy for pancreatic cancer with ≤180° PMV involvement, the type of PVR (i.e., tangential vs. segmental) was not associated with differences in surgical and oncological outcome. This suggest that if both procedures are technically feasible, surgeons can choose the type of PVR based on their preference., Competing Interests: Financial disclosure/conflicts of interest: (1) Marco Del Chiaro has been awarded an industry grant (Haemonetics, Inc) to conduct a multicenter study to evaluate the prognostic implications of TEG in pancreatic cancer. (2) Marco Del Chiaro is co-principal investigator of a Boston Scientific sponsored international multicenter study on the use of intraoperative pancreatoscopy of patients with IPMN. (3) Atsushi Oba has been awarded with a grant (Bayer Yakuhin, Ltd.) to conduct an observational study to investigate the clinical impact of EOB-MRI in pancreatic cancer. (4) Asif Halimi is consultant for Olympus with regard to organizing pancreas surgery courses., (Copyright © 2025 The Author(s). Published by Wolters Kluwer Health, Inc.)