Abstract Background
The treatment strategy for differentiated thyroid cancer differs from that in Western countries in Japan. While radioactive iodine therapy after total thyroidectomy is the standard of care in Western countries, limited thyroidectomy has been widely accepted in Japan. Our new clinical practice guidelines build on previous publications and on data accumulated from clinical treatment of thyroid cancer in Japan. We recommend treatment recommendations based on these guidelines to patients with thyroid cancer. Methods We selected 55 clinical questions for the treatment of differentiated thyroid cancer and compared them with the corresponding Western guidelines. Results
We strongly or moderately recommended total thyroidectomy for patients with papillary thyroid cancer larger than 4 cm, with clinical consideration of lymph node metastasis, distant metastasis, or significant invasion of extrathyroidal tissue; and total thyroidectomy for patients with T1 N0M
0 patients a lobectomy on one side of the thyroid is acceptable. In contrast to Western guidelines, our guidelines routinely perform central group lymph node dissection for papillary carcinoma. For patients with a preoperative diagnosis of follicular neoplasia for lobectomy on one side, we recommend total thyroidectomy if intraoperative pathology confirms follicular carcinoma with extensive infiltration or poor differentiation. We also recommend radioiodine therapy for patients with differentiated thyroid cancer with aggressive clinicopathological features, but with stricter indications than Western guidelines; this is not only limited by the requirements of radioiodine therapy, but also based on our strategy of not requiring radiation therapy for non-high-risk patients. Conclusion
Individualized rather than one-size-fits-all treatment for patients with DTC is important, and we hope to find the best compromise between Japanese strategies and Western guidelines in the future for the benefit of thyroid cancer patients worldwide. Background Thyroid cancer is a common disease in Japan, with an incidence rate of 3.25 per 100,000 men and 9.26 per 100,000 women in 2003, and an age-corrected incidence rate of 2.56 per 100,000 men and 7.17 per 100,000 women. according to a survey conducted by the Japanese Society for Thyroid Surgery in 2004, 92.5% of these cancers were papillary, 4.8% follicular, 1.3 The incidence of papillary carcinoma is higher than that in the West. The higher incidence of papillary carcinoma than in the West may be explained by the adequate iodine intake in the Japanese diet. Papillary carcinoma and follicular carcinoma are often classified as differentiated thyroid cancer. The treatment strategy for differentiated thyroid cancer in Japan is different from that in the West. In the West, total thyroidectomy, postoperative iodine 131 therapy and TSH suppression therapy are the standard of care. In contrast, in Japan, restricted thyroid surgery, such as lobectomy of one side of the thyroid gland plus isthmus, and subtotal thyroidectomy are more widely used for various reasons. First, restricted thyroid surgery reduces the occurrence of serious complications, such as bilateral recurrent laryngeal nerve palsy, permanent hypocalcemia, and possibly avoidance of replacement therapy with levothyroxine tablets. Second, only some patients can receive radioactive iodine treatment due to legal restrictions on radioactive iodine treatment. Third, Japanese endocrine surgeons empirically believe that differentiated thyroid cancer is not highly malignant and has a good prognosis even without total thyroidectomy and radioactive iodine therapy or TSH suppression. However, since the common site of recurrence is in the lymph nodes, prophylactic lymphatic dissection is rather aggressive in Japan, not only in the central region but also in the lateral cervical region, even in patients without significant lymph node metastases on preoperative imaging evaluation. According to the latest guidelines of the British Thyroid Association, there are still questions regarding the indication for postoperative radioiodine nail clearance in low-risk patients. In Japan, total thyroidectomy is usually performed for high-risk patients, and extended prophylactic lymph node dissection is also considered unnecessary for low-risk patients. Thus, it appears that Western and Japanese treatment strategies are converging on each other. In the West, various authoritative guidelines have been established, such as the American Thyroid Association (ATA), the International Union of Cancer (NCCN), the BTA, and the American Association for Clinical Endocrinology/Surgery (AACE/AAES). Recently, JSTS and JSES have also updated their guidelines for the treatment of thyroid tumors.