Is the Multifocality Rate in Thyroid Cancer Patients Increasing Over the Years

INTRODUCTION: Papillary thyroid cancer (PTC) is the most common type of thyroid cancer, and its incidence continues to increase. Multifocality is common in PTC, and it has been suggested in many studies that multifocality may be associated with poor prognosis. In this study, data of patients followed with multifocal PTC were evaluated.
METHODS: Following the approval of the local ethics committee, the data of patients who received total thyroidectomy and subsequent radioactive iodine (RAI) treatment for thyroid cancer between 2012 and 2020 were evaluated.
RESULTS: Multifocality was detected in 142 (19.88%) of the 714 PTC patients studied. The rate of multifocality among PTC patients was 3.29% in 2012, 7.2% in 2013, 10.1% in 2014, 10.5% in 2015, 38.15% in 2016, 31.6% in 2017, 33.33% in 2018, 32.58% in 2019 and 22.22% in 2020. Of these patients, 52.1% had 2 foci, 20.4% had 3 foci, 15.5% had 4 foci, and 12% had 5 or more foci. Multifocality was observed in the right and left lobe in 54.2% of the patients, the right lobe in 21.1% of the patients and the left lobe in 12.7% of the patients. Multifocality was not detected in the isthmus only. It was found that as the number of tumor foci increased, differentiation decreased. It was observed that multifocality was more common in microcarcinomas.
DISCUSSION AND CONCLUSION: In our clinic, it has been observed that the rate of multifocal PTC has increased in recent years. This significant increase may be the result of morphological changes as well as improvements in diagnosis and treatment.