Authors’ reply to radiotherapy did not
increase thyroid cancer
risk among women with breast cancer: A
nationwide
population-based cohort study
Li-Min Sun1, Cheng-Li Lin2,3, Ji-An Liang3,4,5 and Chia-Hung Kao4,6
Thanks for Lin Wei et al. (IJC-15-0992.R2) asking regarding our recent published paper.1
First, we believed that our control group selected from
NHIRD was a highly representative sample of Taiwan’s general population because the reimbursement policy is universal
and operated by the government.2 The other two reports you
mentioned are also from NHIRD, but the control selection
was based on the matching to cases characteristics with different age, sex, index year distribution. Both the current
paper and the one regarding women alopecia3 are women
subjects, but the different study targets may make a little bit difference in the thyroid cancer incidence rates of control groups. Moreover, the paper published by Lin et al4 covered
both men and women participants, and the difference of thyroid cancer incidence rates of control groups between theirs
and the current paper could be expected.
According to your suggestion, we excluded thyroid cancer patients who were diagnosed in half a year after the index date and made a new analysis. The results are similar to the current article and do not change the conclusion. Please refer to the new Table 1.
Yes, we agreed with your opinion that the risk of thyroid cancer did increase in some sub groups, and RT may be involved in subsequent thyroid cancer development among
may be modified by other treatment factors, like
chemotherapy. We preferred to give a suggestion for the whole study subjects, and not specify the sub group findings in details because of the limitation length of discussion section.
Finally, we did an interaction analysis in the new Table 2 and it shows that RT and chemotherapy had a statistically significant interaction on risk of thyroid cancer in patients with breast cancer. Please refer to the new Table 2.
