In reference to The increasing incidence of small thyroid cancers: Where are the cases coming from ?

Dear Editor: As faithful readers of the journal The Laryngoscope, we read with great interest the article titled ‘‘The Increasing Incidence of Small Thyroid Cancers: Where Are the Cases Coming From?’’ by Davies et al. In their cohort of 279 thyroidectomies, they found that 46% (44 cancers) of all identified cancers (95 cancers) were in the 127 thyroidectomies performed as a result of three trigger events: screening, serendipity, and diagnostic cascade. They concluded that the detection of these extra cancers leads to unnecessary surgery. We would like to compliment the authors on their research alerting us to the potential consequences from overtreatment of asymptomatic thyroid cancers. However, their inference that those extra-diagnosed cancers were never destined to cause symptoms in the patient’s lifetime is somewhat arbitrary. Therefore, we believe the value of detecting and treating asymptomatic thyroid cancer needs further discussion. First of all, the so-called extra-diagnosed cancers were not always small and not always papillary carcinoma. In Table II of Davies and colleagues’ article, the size of the medullary carcinoma was 2.3 cm in the serendipity group. The mean size of the follicular carcinoma was 3.5 cm in the serendipity group and 5.3 cm in the screening exam group. In our opinion, detection and surgery for those tumors should not be deemed unnecessary. In addition, although the mean size of the papillary carcinoma was 1.9 cm, the size ranged from 0.2 cm to 10 cm according to their results. It is hard to believe a 10-cm papillary carcinoma will never cause a problem in the future. Furthermore, if we recalculated the mean size of their 44 extra-diagnosed thyroid carcinomas, themean size would be 2.07 cm, and the tumors would be classified as T2 stage according to the TNMstaging system.We think it is inappropriate to ignore a T2 cancer simply because patients have no symptoms. If we do not treat the tumors until they cause symptoms, the T stage probably will be upgraded to T3 orT4 and the prognosiswill becomeworse. Second, even if the extra-diagnosed cancer is smaller than 2 cm, leaving it untreated invites debate. In the study series conducted by Pellegriti et al., the papillary carcinomas <1.5 cm were surprisingly aggressive, with multifocal disease found in about one-third of tumors, spreading to local lymph nodes in 30% of the cases and leading to extrathyroidal invasion in 20% and distant metastases in 3%. Orsenigo et al. also found that even papillary microcarcinoma (<1 cm) was associated with a 1% disease-related mortality and a 1% distant metastasis rate after treatment. It is obvious that leaving small thyroid cancers untreated does not guarantee patient safety. Ignoring small thyroid cancers may lead to surgeons running the risk of being sued for missing or undertreating a curable cancer. When facing the reality of increasing incidence of small asymptomatic thyroid tumors, we must improve our techniques to identify tumors with higher risk and appropriately treat them instead of ignoring them. For example, the positive predictive value of fine-needle aspiration cytology in malignancy was 86% in extra-diagnosed thyroid tumor patients without symptoms in Davies and colleagues’ study. The usefulness of fine-needle aspiration cytology to detect cancer in asymptomatic thyroid tumors should not be undervalued. Moreover, Ito et al. found that an ill-defined edge on ultrasonographic examination for thyroid microcarcinoma could be amarker of aggressiveness that indicates worse disease-free survival and higher lateral lymph nodemetastasis. In conclusion, extra-diagnosed asymptomatic carcinoma is not always small. Leaving small thyroid cancer untreated is not necessarily a safe option. How to improve our ability to differentiate high-risk thyroid tumors from low-risk thyroid tumors is the most important issue wemust address.