OBJECTIVES Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal disease. Diabetes mellitus (DM) is both a risk factor for and a sequela of PDAC. Metformin is a commonly prescribed biguanide oral hypoglycemic used for the treatment of type II DM. We investigated whether metformin use before PDAC diagnosis affected survival of patients with DM, controlling confounders such as diabetic severity. METHODS We used the Surveillance, Epidemiology, and End Results registry (SEER)-Medicare linked database to identify patients with PDAC diagnosed between 2007 and 2011. The diabetic comorbidity severity index (DCSI) controlled for DM severity. Inverse propensity weighted Cox Proportional-Hazard Models assessed the association between metformin use and overall survival adjusting for relevant confounders. RESULTS We identified 1,916 patients with PDAC and pre-existing DM on hypoglycemic medications at least 1 year before cancer diagnosis. Of these, 1,098 (57.3%) were treated with metformin and 818 (42.7%) with other DM medications. Mean survival for those on metformin was 5.5 months compared with 4.2 months for those not on metformin (P<0.01). After adjusting for confounders including DCSI, Charlson score, and chronic kidney disease (CKD), patients on metformin had a 12% decreased risk of mortality compared with patients on other medications (hazard ratio (HR): 0.88, 95% confidence interval (CI): 0.81–0.96, P<0.01). In stratified analysis, differences persisted regardless of the Charlson score, the DCSI score, the presence of kidney disease, or the use of insulin/other hypoglycemic medications (P<0.01 for all). CONCLUSIONS Metformin is associated with increased survival among diabetics with PDAC. If confirmed in a prospective study, then these results suggest a possible role for metformin as an adjunct to chemotherapy among diabetics with PDAC.

No abstract

BACKGROUND & AIMS:Although multiple studies have reported an increasing incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) over the past decades, there are limited national data on recent trends. Using a population-based registry, we evaluated GEP-NET incidence trends in the United States population from 1975 through 2012, based on age, calendar year at diagnosis, and year of birth. METHODS:GEP-NET cases from 1975 through 2012 were identified from the most recent version of the Surveillance, Epidemiology, and End Results registry using histologic and site codes. We calculated overall annual incidence, age-adjusted incidence (number of cases per 100,000), annual percent change (APC), and average APC by 5-year age intervals. We also evaluated the incidence rates by age, period, and birth year cohorts. RESULTS:We identified 22,744 patients with GEP-NETs. In adults 25-39 years old, GEP-NET incidence rates decreased from the mid-1970s to the early 1980s, then increased until 2012. In adults ages 40 years and older or young adults ages 15-24 years, incidence rates generally increased continuously from 1975 through 2012. Adults ages 40-69 years had the most rapid increases in average APC (approximately 4%-6% per year). Overall incidence rates were highest in adults 70-84 years old. Since the inception of the Surveillance, Epidemiology, and End Results registry, GEP-NET incidence has increased in consecutive birth cohorts. CONCLUSION:The incidence of GEP-NET continues to increase-particularly in older adults. More recent generations have had higher GEP-NET incidence rates than more distant generations.

ImportanceThe prognosis for patients with metastatic pancreatic ductal adenocarcinoma (PDAC) is dismal, due in part to chemoresistance. Bacteria-mediated mechanisms of chemoresistance suggest a potential role for antibiotics in modulating response to chemotherapy.ObjectiveTo evaluate whether use of peritreatment antibiotics is associated with survival among patients with metastatic PDAC treated with first-line gemcitabine or fluorouracil chemotherapy.Design, Setting, and ParticipantsUsing the population-based Surveillance, Epidemiology, and End Results–Medicare linked database, this retrospective cohort study analyzed data for patients diagnosed with PDAC between January 1, 2007, and December 31, 2017. Data analysis was conducted between September 1, 2021, and January 15, 2023. The population-based sample included 3850 patients with primary metastatic PDAC treated with first-line gemcitabine or fluorouracil chemotherapy. Patients who received antibiotics were matched based on propensity scores to patients who did not receive antibiotics.ExposuresReceipt of 5 or more days of oral antibiotics or 1 injectable antibiotic in the month before or after beginning first-line chemotherapy.Main Outcomes and MeasuresOverall survival and cancer-specific survival. The end of follow-up was December 31, 2019, for overall survival and December 31, 2018, for cancer-specific survival.ResultsOf the 3850 patients treated with first-line gemcitabine (3150 [81.8%]) or fluorouracil (700 [18.2%]), 2178 (56.6%) received antibiotics. The mean (SD) age at diagnosis was 74.2 (5.8) years and patients were predominantly women (2102 [54.6%]), White (3396 [88.2%]), and from metropolitan areas (3393 [88.1%]) in the northeastern or western US (2952 [76.7%]). In total, 1672 propensity-matched pairs were analyzed. Antibiotic receipt was associated with an 11% improvement in overall survival (hazard ratio [HR], 0.89; 95% CI, 0.83-0.96; P = .003) and a 16% improvement in cancer-specific survival (HR, 0.84; 95% CI, 0.77-0.92; P &amp;lt; .001) among patients treated with gemcitabine. In contrast, there was no association between antibiotic receipt and overall survival (HR, 1.08; 95% CI, 0.90-1.29; P = .41) or cancer-specific survival (HR, 1.12; 95% CI, 0.90-1.36; P = .29) among patients treated with fluorouracil. In a subgroup of gemcitabine-treated patients who received antibiotics, nonpenicillin β-lactams were associated with an 11% survival benefit (HR, 0.89; 95% CI, 0.81-0.97; P = .01).Conclusions and RelevanceIn this cohort study, receipt of perichemotherapy antibiotics was associated with improved survival among patients treated with gemcitabine, but not fluorouracil, suggesting that antibiotics may modulate bacteria-mediated gemcitabine resistance and have the potential to improve PDAC outcomes.

Objectives This study aimed to determine the prognostic utility of the extent of lymph node involvement in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) by analyzing population-based data. Methods Patients in the Surveillance, Epidemiology, and End Results (SEER) registry were identified with histologically confirmed, surgically resected GEP-NETs. We divided patients into three lymph node ratio (LNR) groups based on the ratio of positive lymph nodes to total lymph nodes examined: ≤0.2, >0.2–0.5, and >0.5. Disease-specific survival was compared according to LNR group. Results We identified 3,133 patients with surgically resected GEP-NETs. Primary sites included stomach (11% of the total), pancreas (30%), colon (32%), appendix (20%), and rectum (7%). Survival was worse in patients with LNRs of ≤0.2 (hazard ratio [HR], 1.5; 95% confidence interval [CI], 1.2–2.0), >0.2–0.5 (HR, 2.0; 95% CI, 1.6–2.5), and >0.5 (HR, 3.1; 95% CI, 2.5–3.9) compared to N0 patients. Ten-year disease-specific survival decreased as LNR increased from N0 (81%) to ≤0.2 (69%), >0.2–0.5 (55%), and >0.5 (50%). Results were consistent for patients with both low and high grade tumors from most primary sites. Conclusions Degree of lymph node involvement is a prognostic factor at the most common GEP-NET sites. Higher LNR is associated with decreased survival.