From the Guidelines
No, a patient with papillary thyroid carcinoma should not stop taking Synthroid (levothyroxine). In fact, after thyroid surgery for papillary thyroid cancer, patients typically need to continue levothyroxine therapy for life, often at a higher dose than what would be used for simple hypothyroidism. The standard approach is to maintain TSH levels at the low end of normal or even slightly suppressed (typically between 0.1-0.5 mIU/L for intermediate-risk patients), depending on the stage and risk of cancer recurrence, as recommended by the NCCN guidelines 1. This suppression therapy helps prevent cancer recurrence by reducing TSH stimulation of any remaining thyroid tissue or cancer cells. Levothyroxine also replaces the thyroid hormone that the body can no longer produce after partial or complete thyroidectomy. Stopping Synthroid would lead to hypothyroidism symptoms and potentially increase cancer recurrence risk. Dosing is individualized based on body weight, age, and other medical conditions, and requires regular blood tests to monitor thyroid function. Any adjustments to levothyroxine therapy should only be made under medical supervision.
Some key points to consider:
- The NCCN guidelines recommend maintaining TSH levels at the low end of normal or even slightly suppressed for patients with papillary thyroid carcinoma 1.
- The goal of levothyroxine therapy is to replace thyroid hormone and suppress TSH stimulation of any remaining thyroid tissue or cancer cells 1.
- The duration of suppression therapy is currently being debated, but it is generally recommended to maintain suppressive doses of levothyroxine for 3-5 years in high-risk patients 1.
- Patients who remain disease-free for several years can probably have their TSH levels maintained within the reference range 1.
Overall, the evidence suggests that patients with papillary thyroid carcinoma should continue taking Synthroid (levothyroxine) to maintain TSH levels at the low end of normal or even slightly suppressed, depending on the stage and risk of cancer recurrence.
From the Research
Patient Considerations
- The patient's current medication, Synthroid (levothyroxine), is a common treatment for hypothyroidism, often resulting from thyroid cancer treatment 2, 3.
- The decision to continue or stop Synthroid depends on the patient's individual case, including the type and stage of thyroid cancer, as well as their overall health status.
Thyroid Cancer and Levothyroxine Treatment
- Research suggests that levothyroxine (L-T4) treatment can benefit high-risk thyroid cancer patients by decreasing progression and recurrence rates, and cancer-related mortality 3.
- However, for low-risk patients, the goal of L-T4 treatment is to obtain a TSH level in the normal range (0.5-2.5 mU/l), rather than suppressing TSH 3.
- A study found that levothyroxine supplementation reduced recurrence risk in patients with papillary thyroid carcinoma, without suppressing TSH 4.
Specific Considerations for Papillary Thyroid Carcinoma
- For patients with low-risk papillary thyroid microcarcinoma, levothyroxine treatment may be associated with decreased tumor growth during active surveillance 5.
- Another study found that TSH suppression has a variable effect on the growth of existing tumors and the incidence of recurrent disease, but there is a sound rationale for long-term TSH suppression in all patients with differentiated tumors of the thyroid 6.