Umegaki T, et al. - In this large-scale multi-center retrospective cohort study, researchers compared in-hospital mortality among different underweight body mass index (BMI) categories in pancreatic cancer patients who underwent pancreatectomy between April 1, 2010 and March 31, 2016, in Japan. Based on BMI, the following groups of patients were formed: normal BMI (18.50–24.99 kg/m²), mild thinness (17.00–18.49 kg/m²), moderate thinness (16.00–16.99 kg/m²), and severe thinness (< 16.00 kg/m²). They also carried out a multivariable logistic regression analysis with in-hospital mortality as the dependent variable and BMI groups as the main independent variable of interest. They found a significant association of severe thinness with a higher risk of mortality. In pancreatectomy patients, extremely low BMI was recommended to be considered as a risk factor.