Objective  To identify the clinical characteristics of pancreatic cancer (PC) with diabetes mellitus (DM) and to analyze impact of different factors on the onset age of PC.

  Methods  We collected the patients with PC and DM who were treated in Peking Union Medical College Hospital within the period from January1985 to October 2014 and met the inclusion criteria. We collected and analyzed basic information of the patients. The patients were divided into two subgroups according to the duration of DM:new-onset DM (≤ 2 years) and long-term DM (>2 years). We analyzed the clinical characteristics, cancer features, medical history, and medication history of the two subgroups, and the association between the onset age of PC and various factors including sex, life style, family history, past history, and medication.

  Results  A total of 327 cases of PC with DM were included in this study. The proportion of male was higher and with a younger age of onset compared with female(60.2±9.5)years vs. (65.7±8.5)years, P < 0.001. Compared with the patients with long-term DM, the new-onset DM patients were younger at onset of PC(60.6±9.5)years vs. (64.4±9.0)years, P < 0.001, with a lower proportion of positive family history of DM (13.8% vs. 24.3%, P=0.016), more loss of weight (9.0 kg vs. 5.0 kg, P=0.003), lower fasting blood glucose (8.2 mmol/L vs. 9.1 mmol/L, P=0.003), larger average tumor diameter(4.0 cm vs. 3.5 cm, P=0.007), and a lower proportion of taking insulin and anti-hypertensive drugs (41.9% vs. 71.3%, P < 0.001; 32.9% vs. 49.6%, P=0.004). The onset age of PC were younger in patients who were male (P < 0.001), smokers (P < 0.001), drinkers (P < 0.001), having family history of DM (P=0.048), and taking metformin (P=0.046), while the patients taking acarbose had older onset age of PC (P=0.042).

  Conclusions  Patients newly diagnosed with DM might be at a high risk to develop PC if they have no family history of DM, experienced obvious weight loss, or are drinkers or smokers, thus demanding further investigation for PC.