Patients with Multifocal Macroscopic Papillary Thyroid Carcinoma Have a Low Risk of Recurrence at Early Follow-Up after Total Thyroidectomy and Radioactive Iodine Treatment.

Background: Multifocal thyroid cancer involvement is a common presentation in papillary thyroid cancer. The risk of recurrence of intrathyroidal multifocal papillary microcarcinoma (<1 cm) is documented to be low. However, the risk of recurrence of multifocal macroscopic thyroid cancer is not known. Prior studies have suggested that both the number of foci and the presence of nodal involvement at diagnosis are important predictors of recurrence in multifocal papillary thyroid carcinoma (PTC).

Objectives: In this retrospective review of 99 patients presenting with multifocal macroscopic PTC (with 2 tumor foci >1 cm) without gross extrathyroidal extension, we examined the clinical outcomes of patients in the first 2 years after the initial therapy and at the end of the follow-up period (median: 5 years).

Results: Half of the patients presenting with multifocal macroscopic PTC had nodal involvement at diagnosis. Only 4 patients had a recurrence on long-term follow-up, all with classic or tall-cell variant PTC with bulky nodal involvement at diagnosis. The number of tumor foci did not influence the risk of recurrence in this cohort. The median time to recurrence in these 4 patients was 11 years, with all patients having a recurrence after 9 years of follow-up. None of patients developed distant metastasis or died from thyroid cancer.

Conclusions: Patients presenting with multifocal macroscopic papillary thyroid cancer without bulky nodal involvement or gross extrathyroidal extension have a low risk of thyroid cancer recurrence.