The Geography of Cancer Mortality in Japan Focusing on Pancreatic Malignancies

To identify pancreatic cancer’s etiology and to better understand its pathogenesis, we assessed the association between pancreatic and other cancers by determining the standardized mortality ratios (SMRs). We calculated sex-specific and partial correlations (adjusting for lung cancer SMR) between pancreatic and other cancers in 47 Japanese prefectures. Comparing the results for the decades 1998-2007, 1988-1997, and 1978-1987 revealed that pancreatic cancer’s SMR associates with those of lung, laryngeal, and bladder cancer in males, and stomach, colon, and rectal cancer in both sexes, and with ovarian cancer. The association with lung, laryngeal, and bladder cancer in males implicates tobacco smoking as a risk factor. The association with stomach cancer implies that Helicobacter pylori is a common risk factor. The association with colorectal cancer likely indicates that common factors such as obesity and high dietary fat may play etiological role. These results provide the clue to clarify the etiology of pancreatic cancer.