Thyroid Cancer and NodulesOpen AccessOpen Access license
Active Surveillance Versus Immediate Surgery: Questionnaire Survey on the Current Treatment Strategy for Adult Patients with Low-Risk Papillary Thyroid Microcarcinoma in Japan
Background: Two Japanese prospective trials of active surveillance (AS) for adult patients with low-risk papillary thyroid carcinoma (PTC) ≤1 cm (cT1aN0M0 PTMC) have verified the safety of AS in oncological control and its superiority over immediate surgery with respect to unfavorable outcomes. Thus, AS has been accepted as an alternative to immediate surgery for asymptomatic papillary thyroid microcarcinomas (PTMCs). However, the real-world clinical approach for PTMC is unknown. Thus, this study aimed to investigate the current state of management of asymptomatic PTMCs in Japan.
Methods: We conducted a questionnaire survey on the actual treatment patterns for adult patients with low-risk PTMCs. The subjects were member institutions of the Japan Association of Endocrine Surgery (JAES) or Japanese Society of Thyroid Surgery (JSTS), including the departments of surgery and head and neck surgery (HNS).
Results: Responses were obtained from 134 institutes, where 72.4% of Japanese thyroid cancer cases operated by surgeons were treated. For suspicious tumors on ultrasound, 18 responders (13.4%) conducted cytological examination routinely, while 69 (51.5%) and 40 (27.8%) conducted it only for tumors >5 and >10 mm, respectively. After the diagnosis, 42 responders (31.3%) recommend AS, 35 (26.1%) recommend immediate surgery as the management, and 52 (38.8%) allowed patients to decide the treatment course. The present responders tended to recommend surgery for PTMCs that were located adjacent to the dorsal surface of the thyroid, were multiple, or measured almost 10 mm in size. At these institutions, 1176 patients with PTMC underwent surgery in 2017, accounting for 18.1% of surgeries for PTC. During the succeeding three months, 310 of 576 (53.8%) PTMC patients underwent AS. The treatment strategies did not differ between the departments (Surgery or HNS). The institutions that have six or more surgeons, that were located in metropolitan areas, or that were certified by JAES or JSTS performed AS more actively.
Conclusion: More than 50% of low-risk PTMCs are on AS in Japan. However, the indication and recommendation for AS vary significantly between institutions. To improve the implementation of this management modality, physicians and patients should be further educated, and the sociomedical environment should be improved.
The incidence of thyroid carcinoma has rapidly increased recently in many developed countries (1–4) owing to the increase in the detection of small papillary thyroid carcinomas (PTCs), most of which are 10 mm or smaller and are called papillary thyroid microcarcinomas (PTMCs). The advances in and widespread use of imaging modalities including ultrasound and ultrasound-guided fine-needle aspiration cytology (FNAC) and the increased access to such imaging studies have led to the detection of low-risk PTMC (cT1aN0M0), which was previously mostly detected only on autopsy (5). Despite the increase in incidence, the mortality from thyroid carcinoma has remained stable (1–4), raising a question of whether surgical treatment of low-risk PTMCs is beneficial.
In Japan, a screening study of thyroid cancer among adult women using ultrasound revealed a 3.5% incidence of small PTC (6), which was >1000 times higher than the prevalence of clinical thyroid cancer in Japanese women being reported at that time (7). This prompted the two high-volume centers, Kuma Hospital (beginning in 1993) and Cancer Institute Hospital of Japanese Foundation for Cancer Research (beginning in 1995), to initiate a clinical trial of active surveillance (AS) of low-risk PTMC (i.e., PTMC without high-risk features such as clinical node or, although rare, distant metastasis, and symptoms of carcinoma extension such as recurrent laryngeal nerve paralysis and tracheal invasion). PTMCs attaching to the trachea or located in the course of the recurrent laryngeal nerve were regarded unsuitable for AS, although these features are not necessarily biologically aggressive. Long-term large-scale prospective studies from these two institutions showed favorable outcomes (8–11). AS of low-risk PTMC was then included in the guidelines developed by the Japan Association of Endocrine Surgery (JAES)/Japanese Society of Thyroid Surgery (JSTS) (12) and the American Thyroid Association (ATA) (13). Favorable results of AS from other countries such as the United States and Korea have also been reported (14–16).
However, even in Japan, it remains unclear how asymptomatic PTMCs are managed. Therefore, we performed this questionnaire survey for member institutions of JAES and/or JSTS to investigate the current state of the management of asymptomatic PTMCs in Japan.