We appreciate and thank Dr. Oxley et al. [1] for their interest in our work [2] and comments. Their involvement in this field makes them placed to contribute to these discussions. While we understand their concerns, we respectfully disagree with their interpretation of our analytic approach and conclusions.

One major concern was that the confidence of the findings was affected by inclusion criteria for uterine myoma and unmeasured confounders. However, a definitive diagnosis with International Classification of Diseases, 9th revision, clinical modification (ICD-9-CM) codes in the administrative data has important implications for the treatment of women with prior uterine myoma; thus, our patient selection criteria must be as precise as possible to weed out potential errors and increase diagnostic accuracy. In addition, to minimize selection bias, frequency matching can ensure that cases and controls have the same frequencies of exposure to potentially confounding factors for comparison [3]. Although other unmeasured factors may influence the results, these findings have important implications for understanding the impact of prior uterine myoma on the development of subsequent ovarian cancer.

Another concern was criticism of the results for ovarian cancer patients with prior uterine myoma and those who underwent myomectomy and their use of medical care services. However, this may be an over-interpretation of our results. In fact, Melin et al. [4] reported that women who underwent radical surgical extirpation of endometriosis had a lower risk of ovarian cancer. It is possible that removing endometriotic tissue would reduce inflammation in the pelvic cavity and then lower risk of developing ovarian malignant.

Their last concern was that exposure to negative information about uterine myoma risk may increase women's anxiety. Even if we cannot draw definitive conclusions, we believe that women with prior uterine myoma should be made aware of the potential conditions that result in an increased risk of ovarian cancer development. In addition, identification of patients at increased risk is essential and further studies are needed to clarify the mechanisms underlying the effects of uterine myoma on the pathogenesis of ovarian cancer.