Levothyroxine Treatment for Subclinical Hypothyroidism After Head and Neck Surgery

Patients that require treatment for cancers of the head and neck often require a combination of surgery and/or radiation and chemotherapy. Hypothyroidism is one of the most common complications, and has been associated with post-operative complications such as wound healing problems, fistula formation, and decreased quality of life and survival. Several studies have examined hypothyroidism after radiation to the head and neck, but few have examined this after non-thyroid head and neck surgery. Head and neck resection is theorized to devascularize the thyroid, thus resulting in post-operative hypothyroidism. Synthroid is a synthetic thyroid hormone often used in cases of patients with proven hypothyroidism and after surgical thyroid removal. It's use has been in effect and studied for over fifty years. Treatment algorithms for hypothyroidism are well published. However, treatment of subclinical hypothyroidism (elevated TSH with normal or near-normal T3/T4) is controversial. The rate of subclinical hypothyroidism after non-thyroid head and neck surgery is high (up to 20%), and is associated with post-operative complications as noted above. Therefore the investigators propose a double blinded randomized controlled trial comparing outcomes of patients that develop subclinical hypothyroidism after head and neck surgery, who are given a standardized dose of synthroid treatment versus those treated with placebo. The main outcomes to be examined are post-operative complications (wound healing issues, fistula formation), survival, and quality of life measures.

Sex

All

Minimum age

18 Years

Maximum age

80 Years

Inclusion Criteria:

* Biopsy proven head and neck cancer, as defined by AJCC staging system
* Treated with surgery in Edmonton, Alberta
* Treated with curative intent
* Diagnosis of sub-clinical hypothyroidism after head and neck surgery (TSH 4-10mIU/L, and free T4 10-24pmol/L)

Exclusion Criteria:

* Head and neck cancer of the thyroid gland, or other subsite involving the thyroid gland
* Underwent previous treatment for a different head and neck cancer
* History of radiation therapy and or chemotherapy to the head and neck
* History of thyroid disease as follows:
* Hypothyroidism
* Hyperthyroidism
* Autoimmune thyroid disease including Grave's disease and Hashimoto's thyroiditis
* History of thyroiditis
* History of diabetes mellitus
* History of long term steroid usage
* History of immunocompromise
* History of thyroid surgery
* History of ischemic heart disease
* Age \>80
* Patients taking a medication that may alter the metabolism or interact with levothyroxine, which they cannot safely stop (see Appendix A).