Dear Sir,
We would like to thank Shen et al. for their interest and comments on our study. They question the consistency of the results between our two studies comparing microwave ablation (MWA) with surgery for papillary thyroid microcarcinoma (PTMC).
We agree that propensity score matching analysis is a fine choice, but we elected to do a case-control study, matching gender and age and following cases up in chronological order. There were no significant differences in age, sex, or followup time between the two groups. We have to admit our studies were retrospective in nature. The ‘inconsistent’ results are because of different treatment intervals and followup lengths between the two studies. Compared to study A [Citation1], we expanded the time between treatment and followup in study B [Citation2], including when we initiated MWA (January 2013–February 2014) and the subsequent followup (August 2017–September 2018). As our MWA clinical research in PTMC progressed, we had many more patients available for enrollment in study B. We also found a few patients with central lymph node metastases and recurrence after MWA during 2018 (). We admit that preoperative examination (e.g., ultrasound) could not validly exclude lymphatic micrometastases or multifocality [Citation3,Citation4]. We still believe that MWA is superior to surgery for ultrasonically-detected PTMC in terms of the appearance of complications and its minimal invasiveness.
Figure 1. (A) This patient had PTMC (0.6 × 0.6 cm) in the right lobe of the thyroid before MWA. (B) The left lobe of the thyroid was intact. (C) MWA treatment of the right lobe. (D) 35 months after treatment, the patient developed PTMC in the left lobe.
We are further studying how to improve the accuracy of preoperative exploration [Citation5,Citation6].
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References
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- Li J, Liu Y, Liu J, et al. A comparative study of short-term efficacy and safety for thyroid micropapillary carcinoma patients after microwave ablation or surgery. Int J Hyperthermia. 2019;36(1):640–646.
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- Jianming L, Jibin L, Linxue Q. Suspicious ultrasound characteristics correlate with multiple factors that predict central lymph node metastasis of papillary thyroid carcinoma: Significant role of HBME-1. Eur J Radiol. 2020;123:108801.
- Li J, Li H, Yang Y, et al. The KWAK TI-RADS and 2015 ATA guidelines for medullary thyroid carcinoma: Combined with cell block-assisted ultrasound-guided thyroid fine-needle aspiration. Clin Endocrinol. 2019. DOI:10.1111/cen.14121. [Epub ahead of print]