Understanding of changes in salivary and lacrimal gland functions after radioiodine therapy (131I-therapy) remains limited; and, to-date no studies have evaluated dose-response relationships between absorbed dose from 131I-therapy and dysfunctions of these glands. This study investigates salivary/lacrimal dysfunctions in differentiated thyroid cancer (DTC) patients six months after 131I-therapy, identifies 131I-therapy related risk factors for salivary/lacrimal dysfunctions, and assesses the relationships between 131I-therapy radiation dose and these dysfunctions. A cohort study was conducted involving 136 DTC patients treated by 131I-therapy of whom 44 and 92 patients received 1.1 and 3.7 GBq, respectively. Absorbed dose to the salivary glands was estimated using a dosimetric reconstruction method based on thermoluminescent dosimeters measurements. Salivary and lacrimal functions were assessed at baseline (T0, i.e., immediately prior to 131I-therapy), and 6 months later (T6) using validated questionnaires and salivary samplings, with and without stimulation of the salivary glands. Statistical analyses included descriptive analyses and random-effects multivariate logistic and linear regressions. There was no difference between T0 and T6 in the level of parotid gland pain, nor was there difference in the number of patients with hyposalivation, but there were significantly more patients with dry mouth sensation and dry eyes after therapy compared to baseline. Age, menopause, depression and anxiety symptoms, history of systemic disease, and not taking painkillers in the last 3 months were found to be significantly associated with salivary or lacrimal disorders. Significant associations were found between 131I-exposure and salivary disorders adjusted on the previous variables: e.g. per 1-Gy increase in mean dose to the salivary glands, OR=1.43 (95%CI 1.02-2.04) for dry mouth sensation, ß=-0.08 (95%CI -0.12;-0.02) mL/min for stimulated saliva flow, and ß= 1.07 (95%CI 0.42;1.71) mmol/L for salivary potassium concentration. This study brings new knowledge on the relationship between the absorbed dose to the salivary glands from 131I-therapy and salivary/lacrimal dysfunctions in DTC patients 6 months after 131I-therapy. Despite the findings of some dysfunctions, the results do not show any obvious clinical disorders after the 131I-therapy. Nevertheless, this study raises awareness of the risk factors for salivary disorders, and calls for longer follow-up. Clinical trials registration: number NCT04876287 on ClinicalTrials.gov.

The current dogma is a life-long follow-up for patients treated for follicular-derived differentiated thyroid cancers (DTC). Our primary objective was to determine the time to recurrence in a series of DTC patients with an excellent response to therapy 6 months after total thyroidectomy and radioiodine therapy. The secondary objectives were to determine the time to suspicion of recurrence and to identify factors associated with recurrence. This retrospective cohort study included patients treated for DTC between 2008 and 2012 and in remission 6 months after total thyroidectomy and radioiodine treatment. The criteria for remission were negative imaging and suppressed thyroglobulin (Tg) < 0.2 ng/mL or rh-TSH-(recombinant human TSH) stimulated Tg < 1 ng/mL according to the 2015 ATA (American Thyroid Association) guidelines. Recurrence was defined by cytologically and/or histologically proven cervical lymph node metastasis or the administration of a second radioiodine treatment. Among 721 patients treated for DTC, 158 were excluded because of persistent disease at 6 months and 71 because of missing follow-up data and 492 were included. The mean and median follow-up time were 7.0 and 7.9 years [IQR 2.1-11.3]. Recurrence occurred for 7 patients (1.4%), 1 initially classified as high recurrence risk, 3 as intermediate and 3 as low risk according to the 2015 ATA guidelines. All relapses occurred within 10 years after initial management (4 within the first 5 years). For patients with recurrence, rise in Tg and/or suspicious lymph node were detected in 6 out of 7 cases in the first 8 years, and for the last case 10 years after initial surgery. Low and intermediate recurrence risk DTC patients with excellent response 6 months after total thyroidectomy and radioiodine and in remission 10 years later have an extremely low recurrence risk. Follow-up might be undertaken by primary care providers from this time point. These discharge recommendations should be confirmed by further prospective studies.

Breast metastasis from thyroid papillary carcinoma is an exceptional situation. Here, we present the diagnostic approach and the management of a 19-year-old woman with single breast metastasis from thyroid carcinoma. There was no extra thyroidal extension, neoplastic emboli, or lymph node invasion. The metastasis was revealed by whole-body radioactive ¹³¹I scan, explored by a fine-needle aspiration, and confirmed by elevated thyroglobulin in situ.