Population-based study of trends and variations in radiotherapy as part of primary treatment of cancer in the southern Netherlands between 1988 and 2006, with an emphasis on breast and rectal cancer.
To explore current variations in the use of primary radiotherapy (RT) in a region with two RT departments with adjacent referral areas, one in the eastern and one in the western sector of the southern region of the Netherlands. We calculated the proportion of 147,588 patients with newly diagnosed cancer between 1988 and 2006 in the southern Netherlands who received primary RT. Especially for breast and rectal cancer patients we studied primary RT use according to stage (breast cancer) and age and separately for the eastern and western sectors. The number of patients with new diagnoses receiving primary RT increased from 1,668 patients in 1988 to 2,971 patients in 2006, with the proportion of the overall patients receiving RT remaining more or less unchanged (+/-30%). However, only 20% of elderly patients (75+ years) received primary RT. Over time, more patients with prostate and rectal cancer, fewer patients with lung and bladder cancer or Hodgkin's lymphoma, and, recently, more patients with cervical or endometrial cancer received RT. The proportion of patients with most other tumor types treated with RT remained more or less unchanged. The total RT rate was slightly higher for patients in the eastern sector. Of particular note, patients with breast or rectal cancer in the eastern sector were significantly more likely to receive primary RT than were their counterparts in the western sector (odds ratio = 1.4, 95% confidence interval =1.4-1.5, and odds ratio = 1.4, 95% confidence interval = 1.3-1.6, respectively). Although the number of RT-treated patients increased substantially during 1988 to 2006, the proportion remained essentially unchanged. In addition, large variations were found in referral rates for RT, especially in later years, between the eastern and the western sectors of the region.