This trial develops and studies how well a patient decision aid works in supporting decision-making about when to start or stop new drugs, join clinical trials, or continue active cancer monitoring for patients with medullary thyroid cancer and their caregivers. Developing a patient decision aid may help patients with medullary thyroid cancer make well-informed decisions about their cancer care and be able to discuss their preferences with their doctors.

PRIMARY OBJECTIVES:

I. To assess patient/survivor, caregiver/family member, and provider decision-making needs.

II. To design and develop an initial patient decision aid prototype. III. To pilot test its acceptability. IV. To evaluate the acceptability and usability of the decision aid prototype from patients/survivors, caregivers and providers in a real world environment.

OUTLINE:

Participants use decision aid and complete questionnaire.

Inclusion Criteria:

• Aged 18 years old or older
• Have or will face(d) this decision, including: Patient/survivor - who has medullary thyroid carcinoma, as determined by a clinician or documented in the Genetics of Endocrine Neoplasia Registry or sporadic (medullary thyroid carcinoma) MTC database; Caregiver/family member - of patient/survivor who has medullary thyroid carcinoma, as nominated by the patient/survivor; and Provider - who treats patients/survivors who have medullary thyroid carcinoma, as described above
• Able to speak, read, and write English
• Pregnant patients are included

Exclusion Criteria:

--Individuals with cognitive or psychological impairment (e.g., depression, anxiety, severe mental illness; as documented in the registry)