Management of radioiodine refractory differentiated thyroid cancer: the Latin American perspective

Radioiodine (RAI) refractory differentiated thyroid cancer is an uncommon and challenging situation that requires a multidisciplinary approach to therapeutic strategies. The definition of RAI-refractoriness is usually a clear situation in specialized centers. However, the right moment for initiation of multikinase inhibitors (MKI), the time and availability for genomic testing, and the possibility of prescribing MKI and selective kinase inhibitors differ worldwide.Latin America (LA) refers to the territories of the world that stretch across two regions: North America (including Central America and the Caribbean) and South America, containing 8.5% of the world's population. In this manuscript, we critically review the current standard approach recommended for patients with RAI refractory differentiated thyroid cancer, emphasizing the challenges faced in LA. To achieve this objective, the Latin American Thyroid Society (LATS) convened a panel of experts from Brazil, Argentina, Chile, and Colombia. Access to MKI compounds continues to be a challenge in all LA countries. This is true not only for MKI but also for the new selective tyrosine kinase inhibitor, which will also require genomic testing, that is not widely available. Thus, as precision medicine advances, significant disparities will be made more evident, and despite efforts to improve coverage and reimbursement, molecular-based precision medicine remains inaccessible to most of the LA population. Efforts should be undertaken to alleviate the discrepancies between the current state-of-the-art care for RAI-refractory differentiated thyroid cancer and the present situation in Latin America.

[Frey syndrome secondary to submaxillectomy and botulinic treatment]

A case of Frey syndrome (FS) secondary to submaxillar gland exeresis is presented and the results of the treatment with botulinum toxin (BTX) type A. FS is a condition of sweating cheek and preauricular area during realtime as a sequel detected in about 20-60% of patients after parotidectomy. The clinical symptoms include swelling, flushing and hyperhidrosis. The treatment choice for this condition is intracutaneous injection of BTX type A which blocks acetylcholine release at the sweat glands. A 30-year-old man, with thyroid medullar carcinoma diagnosed in 2002 received 6 cicles of cisplatin plus doxorubicin previous to the thyroidectomy with anterolateral neck dissection. During surgery the left ramus marginalis mandibulae was damaged. Two years later the patient referred sweating in submaxillar region during meals. CT scan demonstrated the absence of left submaxillar gland. Minor's test disclosed the affected area and BTX type A was injected (2.5 U/cm2/17 points). A twenty-one-day control showed a 95% reduction of the affected skin area. Persistent efficacy was observed up to one year follow-up time when he was reinjected. The FS, also known as "gustatory hyperhidrosis", was probably first reported by M. Duphenix in 1757. Lucja Frey considered its physiopathology as a disorder of both sympathetic and parasympathetic innervation. In our case the FS was caused by a misdirected regeneration of postganglionic parasympathetic nerve fibers that arrised from the nervus lingualis rami ganglionares of the nervus trigeminus. After nerve injury the colinergic parasympathetic fibers seek out colinergic receptors--sympathetic receptors of the skin--innervating sweat glands and small skin vessels. All previous cases were located at masseter region post-parotidectomy. We have not found any description of FS in the submaxillary region. The self-assessed efficacy of the treatment with a hyperhidrosis disease severity scale revealed a very satisfied patient at 20 months follow-up after being injected twice with BTX type A.