A comparison of the stages at which cancer is diagnosed in physicians and in the general population in Taiwan

Background: Previous investigations have reported that physicians tend to neglect their own health care; however, they may also use their professional knowledge and networks to engage in healthier lifestyles or seek prompt health services. We sought to determine whether the stage at which cancer is diagnosed differs between physicians and nonphysicians. Methods: We conducted a nationwide matched cohort study over a period of 14 years in Taiwan. We accessed data from two national databases: the National Health Insurance Research Database and the Taiwan Cancer Registry File. We collected data on all patients with the 6 most common cancers in Taiwan (hepatoma, lung, colorectal, oral, female breast and cervical cancer) from 1999 to 2012. We excluded patients less than 25 years of age, as well as those with a history of organ transplantation, cancer or AIDS. We used propensity score matching for age, sex, residence and income to select members for the control (nonphysicians) and experimental (physicians) groups at a 5:1 ratio. We used χ² tests to analyze the distribution of incident cancer stages among physicians and nonphysicians. We compared these associations using multinomial logistic regression. We performed sensitivity analyses for subgroups of doctors and cancers. Results: We identified 274 003 patients with cancer, 542 of whom were physicians. After propensity score matching, we assigned 536 physicians to the experimental group and 2680 nonphysicians to the control group. We found no significant differences in cancer stage distributions between physicians and controls. Multinomial logistic regression and sensitivity analyses showed similar cancer stages in most scenarios; however, physicians had 2.64-fold higher risk of having stage IV cancer at diagnosis in cases of female breast and cervical cancer. Interpretation: In this cohort of physicians in Taiwan, cancer was not diagnosed at earlier stages than in nonphysicians, with the exception of stage IV cancer of the cervix and female breast.