To the editor:Thank you for your kind interest. The Korea Central Cancer Registry (KCCR) reports the cancer characteristics for patients in Korea, but this analysis was restricted to the eight most-frequent cancers, such as stomach, colorectal, liver, lung, etc. cancers [1]. Thus, we used the KCCR to focus on uncommon cancers. As you mentioned anal canal cancer tends to present in the sixth and the seventh decades of life, and the median age at diagnosis was 65.2 years in our study population. There was no difference in mean age between males and females in the study.We reported a relatively lower proportion of squamous cell carcinomas among all anal cancers, which may be one of characteristics of anal cancer in Koreans that is different [2]. Additionally, an adenocarcinoma may include primary a low rectal cancer involving the anal canal [3]. We did not provide full information about the distribution or comparison among the different histologic types or stages. However, analysis of a small number of stratified patients, such as in our study, may lead to bias. As the data are collected, a detailed analysis can be addressed. Unfortunately, as you also pointed out, we did not obtain important data, such as treatment modalities. Chemo-radiation or surgery may be a treatment option in most patients, and both may be needed in some cases [4]. We have a plan to take more clinical information in the future and hope to be able to provide a more valuable report for anal cancer.I appreciate your additional table including a comparison with other reports. I add that the overall survival has improved with time.