Letter to the Editor: Reply to Topkan et al.

We appreciate the insightful letter from Topkan et al., which highlights important considerations regarding postoperative concurrent chemoradiotherapy (CCRT) in highrisk head and neck adenoid cystic carcinoma (ACC) and offers valuable perspectives on future directions. First of all, we agree that the standard use of CCRT cannot be recommended until prospective evidence is available. While chemotherapy may offer some benefit in local control and overall survival in ACC patients, it inevitably increases the risk of treatment-related toxicities. Therefore, the routine use of CCRT in ACC patients cannot be recommended unless sufficient survival benefit is demonstrated in prospective trials. Second, we recognize that one of the limitations of the study was the relatively small sample size, which may have limited its ability to detect statistically significant differences between the CCRT and RT-alone groups. Given the low incidence of ACC, recruiting an adequately large cohort across multiple centers would require substantial collaboration and coordination. This presents a significant challenge, as the rarity of ACC often results in slow patient recruitment, potentially affecting the generalizability of the findings. Nevertheless, with robust multi-institutional collaboration, such studies remain feasible and could yield valuable insights into treatment outcomes for this patient population.