[Papillary and follicular cancers of the thyroid]

MANAGEMENT STRATEGIES: Management of papillary and follicular cancer of the thyroid varies somewhat between centers because of the generally good prognosis and the absence of well-controlled therapeutic trials. The internationally recognized TNM system is widely used to modulate treatment and follow-up to the individual situation.

Surgery is indicated in well-differentiated thyroid cancer. Total thyroidectomy is required for clinically patent tumors (> or = 1 cm) and small tumors (< 1 cm) recognized prior to surgery. For small tumors found at histology examination, reoperation is discussed in terms of prognosis. Post-operative 131-iodine is indicated when surgical resection is incomplete or in case of unfavorable prognosis. External radiotherapy is currently reserved for exceptional cases with unremoved tumoral tissue unresponsive to 131-iodine.

All operated patients are given L-thyroxine to achieve euthyroidism and low TSH levels (< 0.1 microU/ml). Early detection of relapse is based on combined thyroglobulin assay and whole body 131-iodine scintigraphy. Both are performed during the first year of follow-up after a period of thyroid hormone withdrawal. Human recombinant TSH will soon be available allowing selection of patients with a detectable thyroglobulin level after stimulation; these patients should have a 131-iodine scintigram. If thyroglobulin remains undetectable during L-thyroxine treatment, an annual dosage is indicated and other exams are unwarranted.

Surgery is indicated in case of small areas of active recurrent tumoral tissue in a cervical location. If a high-sensitivity scintigram does not show iodine uptake, the surgical procedure is completed by radiotherapy or possibly chemotherapy with doxorubicin. Small recurrent tumors in other areas respond to 131-iodine (3.7 GBq). Surgery, 131-iodine and radiotherapy are usually indicated for large ectopic recurrences. Chemotherapy is ineffective.

Standard primary therapy generally provides cure and most patients are followed by annual thyroglobulin and TSH assays. Other explorations beginning with a whole-body 131-scintigram may be indicated in selected patients.