What is the physician’s approach to stage IV differentiated thyroid cancer? How to choose a treatment plan? Let’s start with two typical cases. The FAQs at the end of this article may answer your questions.
Case A:
Ms. A, age 58, presented with a 2-month history of an anterior cervical mass with no relevant family history or history of radiation exposure. She subsequently underwent thyroid function, ultrasound, CT, and fine needle aspiration. The results suggested bilateral papillary thyroid cancer, bilateral multiple lymph node metastases in the neck, and bilateral pulmonary metastases.
The doctor recommended that she be admitted to the hospital for surgery. After completing the tests and excluding contraindications to surgery, she underwent total thyroidectomy + bilateral lymph node dissection in the central region + bilateral lymph node dissection in the neck.
Postoperative pathology suggested bilateral papillary thyroid carcinoma with multiple lesions, the largest lesion 1.6 cm in diameter, multiple lymph node metastases in the central and lateral neck regions bilaterally, stage T1N1bM1 (tumor no more than 2 cm, within the thyroid, metastasis to ipsilateral or contralateral or bilateral neck lymph nodes in the lateral neck region, and distant metastasis), stage IV.
Postoperative radioiodine scan showed radiological coalescence in both pulmonary nodes, considering pulmonary metastasis of thyroid cancer.
Because of the good iodine uptake capacity of the pulmonary metastases, she was recommended to receive 3 treatments of radioactive iodine (RAI) with a total dose of 600 curies (mCi) within 2 years postoperatively. After RAI treatment, the metastatic lung lesions were significantly smaller than before.
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Ms. A is still on regular review and taking oral eugenol (levothyroxine tablets).
Case B:
Ms. B, age 61, was found to have bilateral thyroid nodules on physical examination with no relevant family history or history of radiation exposure. After coming to the hospital and completing various tests, the physician considered a possible bilateral papillary thyroid carcinoma with no obvious cervical lymph node metastasis and multiple nodules in both lungs, possibly metastatic thyroid cancer.
The doctor recommended surgery first, and Ms. B was admitted to the hospital and underwent total thyroidectomy + bilateral lymph node dissection in the central region after preoperative tests were completed and contraindications to surgery were ruled out.
Postoperative pathology suggested bilateral papillary microcarcinoma of the thyroid with bilateral central lymph node metastases (2/2, meaning that 2 lymph nodes were cleared and metastatic cancer was found in both lymph nodes), stage T1N1aM1 (tumor no more than 2 cm in the thyroid, metastasis to the pre-tracheal, paratracheal, and anterior laryngeal lymph nodes, and distant metastasis), stage IV.
Postoperative radioiodine scan showed no radioactive coalescence in both pulmonary nodes, and the lung metastases were not considered to be iodine uptake, so no RAI treatment was done.
Postoperatively, Ms. B took oral eugenol. The metastases have not progressed significantly during regular follow-up.
Frequently asked questions about the management of stage IV differentiated thyroid cancer
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Q1: Why is Ms. B’s lymph node metastasis in the neck less severe and Ms. A’s more severe when she has stage IV differentiated thyroid cancer and both have lung metastases?
These are the most common types of thyroid cancer.
The common routes of metastasis for differentiated thyroid cancer include metastasis to lymph nodes via the lymphatic tract and distant metastases via the bloodstream, with cervical lymph node metastases being the most common. Although the probability of distant metastasis is low, approximately 1% to 4% of patients with papillary carcinoma have distant metastasis at the time of initial presentation, and another 2.5% to 5% have distant metastasis after initial surgery, with the most common sites of metastasis being lung (50%), bone (25%), simultaneous lung-bone metastasis (20%), and other sites (5%). Both of these patients had distant metastases, although severity of lymph node metastases in the neck is not absolutely related to the occurrence of distant metastases.
Q2: Ms. B’s lung metastases are not iodine ingested, are there other treatment options if they progress further?
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For differentiated thyroid cancer that does not uptake iodine, there are options for radiation, chemotherapy, and new targeted therapies, but treatment outcomes are not yet certain. Of these, targeted therapy may offer more hope in the future.
Q3: In both cases, the metastases were not surgically resected, so which case of metastatic lesions is preferred for surgery?
The lung metastases in both patients were multiple and inoperable. There are generally two types of metastases that can be considered for surgery: 1) a single lesion; and 2) multiple lesions but the presence of a single lesion that causes significant clinical symptoms and is operable. For example, multiple metastases in the lung and the presence of a single metastasis in the lumbar spine that causes severe bone pain or pathologic fracture can be surgically treated for a lumbar spine lesion.
Q4: How long can a patient with stage IV differentiated thyroid cancer live?
The overall survival rate is reduced with the development of distant metastases. One study suggested that patients without distant metastases had 5- and 10-year survival rates of 95.3% and 88.9%, respectively, while those with distant metastases had lower rates of 74.9% and 53.1%, respectively. However, survival may vary widely for each patient, even in the same stage IV, and is closely related to age, physical condition, histological characteristics of the primary site, number, size, and distribution of metastases (lung, bone, brain), and the response of metastases to therapy. Even if certain therapies do not improve survival, they may still significantly alleviate clinical symptoms or delay progression.
Overall, thyroid cancer has a good outcome, especially in differentiated thyroid cancer, and most patients have a long survival even with distant metastases. Please don’t be discouraged; aggressive treatment, caring for yourself, and an optimistic mindset can all help prolong survival.
Disclaimer:
Tumor disease and treatment options are extremely complex, and treatment should be individualized, and this case does not represent a treatment decision for a “similar patient. Please seek professional advice from a competent physician regarding your specific treatment plan.
Co-written by Dr. Tingting Zhang, Fudan University Cancer Hospital