Levothyroxine Treatment for Subclinical Hypothyroidism After Head and Neck Surgery
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.
Background and Scope:

 Hypothyroidism is one of the most common complications following multimodality treatment for
 head and neck cancer, with an incidence of 7-58% depending on the subsite. The causes for
 this high rate of hypothyroidism following treatment for head and neck cancer are
 multifactorial. Patients treated for head and neck cancer often require radiation therapy
 (RT). The negative effects of RT on the thyroid are well published, and the resultant
 hypothyroidism can have widespread implications on a patient's physical and mental health.
 Head and neck surgery has also been hypothesized to devascularize and disturb the overall
 anatomical structure of the thyroid, thus contributing to the high incidence of
 hypothyroidism after surgery.

 Despite the literature demonstrating the connection between head and neck cancer treatment
 and hypothyroidism, complications from this illness after major head and neck surgery remain
 common. Decreased survival as well as increased rates of fistulas, infections, and wound
 breakdown are some of the physical consequences. Other possible issues include decreased
 functional outcomes and increased mental illness, as these are known consequences of
 untreated hypothyroidism. While several studies have examined the rate and timing of
 hypothyroidism after radiation to the head and neck, there is a paucity of literature on the
 effect of surgery on thyroid function. Specifically, in patients treated with single modality
 surgery, and in patients treated with primary surgery before the start of RT, when the risk
 of wound complications is high.

 Synthroid is a synthetic thyroid hormone, and is the mainstay of treatment of patients with
 proven hypothyroidism and after surgical thyroid removal. Its use has been in effect and
 studied for over fifty years. Side effects of the drug most commonly occur with overdosing
 and will mimic those of hyperthyroidism, which may include: heart palpitations, abdominal
 pain, nausea, anxiety, confusion, agitation, insomnia, weight loss, and increased appetite.
 There is a low chance (< 1%) of allergic reaction to the drug, which may include shortness of
 breath, swelling of the face and tongue.

 Whereas treatment algorithms for clinical hypothyroidism are well established, treatment of
 subclinical hypothyroidism remains controversial. Subclinical hypothyroidism refers to a
 state of elevated thyroid stimulating hormone (TSH), with normal or near-normal thyroid
 hormone levels (T3 and T4), or a lack of symptoms of hypothyroidism. Endocrinologists
 disagree on whether this disease should be treated, since it is almost always asymptomatic,
 and the treatment is mainly for relief of symptoms. Head and neck cancer patients, however,
 represent a special population, in which the effects of subclinical hypothyroidism can result
 in consequences besides symptoms, such as wound healing issues and fistula development as
 described above. Studies have shown that the rate of subclinical hypothyroidism during head
 and neck cancer treatment is high.

 Therefore the investigators propose a single blinded randomized controlled trial comparing
 outcomes of patients with subclinical hypothyroidism, who are given a standardized dose of
 synthroid treatment after head and neck surgery versus those treated with conventional
 therapy. A secondary goal of this study is to determine the rate of clinical and subclinical
 hypothyroidism after surgical treatment for head and neck cancer, without RT or before the
 start of RT.

 Objectives:

 Primary Objectives:

 -  To assess the effect synthroid treatment in patients with subclinical hypothyroidism
 following head and neck surgery and it's effects on survival, gastrostomy tube (G-tube)
 rates, fistula formation, wound breakdown, and infection.

 Secondary Objectives

 -  To determine the rate of clinical and subclinical hypothyroidism after surgery for head
 and neck cancer

 -  To determine the factors that are predictive of the development of clinical and
 subclinical hypothyroidism after surgery for head and neck cancer

 Methods:

 This is a single-center double blinded randomized placebo-controlled trial of the effects of
 synthroid treatment immediately after surgery for head and neck cancer. Patient meeting
 eligibility criteria will be identified at the time of booking for surgery and approached by
 a member of the research team.

 Data will be collected from the medical records on the variables under study in
 study-specific data sheets. Data sheets will then be de-identified and input into a secure
 database that will be password protected hard drive in a room that is locked. Data will then
 be exported for statistical analysis when collection is complete.

 The population will be comprised of patients who underwent surgery with or without a
 combination of RT and/or chemotherapy for the treatment of non-thyroid head and neck cancer.
 Surgery is defined as surgical resection with primary closure or reconstruction with
 loco-regional flaps or autogenous free tissue transfer. RT is defined as curative dose
 therapy. Chemotherapy is defined as any single agent therapy or combination of cisplatin or
 carboplatin. Patients will be prospectively enrolled starting from March 1, 2015 until March
 1, 2016. The expected accrual of this patient group will be 200 patients. The demographics of
 head and neck mucosal cancers indicate that the male : female ratio will be 3 : 1 and the
 mean age will be approximately 60 years with a range of 18 - 85 years.

 In order to assess pre- and post-operative thyroid function, each patient will undergo blood
 testing including TSH, free T3, and free T4 levels one week prior to surgery, and weekly
 following surgery, up to 8 weeks post-operatively (if not receiving radiation), or until 8
 weeks after the start of radiation (if receiving radiation therapy).

 Patients will be classified into "normal" (normal TSH and normal free T3 and free T4 levels),
 "hypothyroid" (elevated TSH, decreased free T3 and free T4), or "subclinical hypothyroid"
 (elevated TSH (4-10mIU/L), normal free T3 and free T4).

 Patients with "normal" thyroid function will not be randomized to any treatment arm, but
 their post-operative outcomes will be recorded, according to section 8.0. Patients who are
 "hypothyroid" will be treated for their hypothyroidism according to the standard of care, in
 keeping with American Thyroid Association (ATA) / American Association of Clinical
 Endocrinologists (AACE) guidelines.

 Patients with "subclinical hypothyroidism" will be randomized to either the treatment arm or
 placebo arm, at the time of discovery of subclinical hypothyroidism (lab value abnormalities
 as noted above). Patients who are randomized to the treatment arm will be treated with a
 standard dose of 1.6mcg/kg/day of synthroid, and the target of treatment will be a normalized
 TSH (0.2-4.0mIU/L), measured at 6 weeks after treatment, according to ATA/AACE guidelines.
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).