Factors influencing the diagnostic basis in pancreatic cancer. A study within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort

Background and aims: Substantial differences have been reported in risk estimates for etiologic factors of pancreatic cancer among subjects with different degrees of diagnostic certainty. The aim of the study was to assess the influence of some personal and social characteristics on the diagnostic basis in individuals with pancreatic cancer. Methods: We analyzed 393 participants from the EPIC cohort with a diagnosis of pancreatic cancer and information on the basis of diagnosis. Two main groups of cases were compared: one in which microscopic confirmation (MC) was available to diagnose pancreatic cancer (including autopsy, histology, cytology or hematology), and one in which non-microscopic methods were used (biochemical, immunological or image tests, exploratory surgery, clinical observation, self-report, or death certificate). Results: The diagnosis of pancreatic cancer of 73% of participants was achieved through MC. While, overall, over 82% of men had MC, this figure was 65% in women (p<0.001). Subjects with MC, both men and women, were younger at diagnosis than participants diagnosed by non-microscopic methods. Younger women (<60 years) had a higher probability of having their cancer diagnosed with MC (OR=2.54, 95% CI 1.04-6.17) than women ≥70 years. After the year 2000 the chances of having the disease diagnosed through MC increased more than 2-fold in women and more than 5-fold in men. No significant differences in diagnostic basis were observed by educational level, comorbidities or established risk factors for pancreatic cancer. Conclusion: The rates of MC in subjects diagnosed with pancreatic cancer continued to be relatively low. Age and sex are the two main factors that powerfully influence MC. Hence, age and sex must be considered when designing and analyzing clinical and epidemiological studies, as well as in clinical practice. The consistently lower rates of MC in female patients suggest an ingrained sex-related diagnostic bias, which may require specific policies to be counterbalanced.