Do I have to take thyroxine for the rest of my life? How long do I have to take it? How much is the best amount to take? Some of these questions are topics that may be of concern to thyroid cancer patients both before and after treatment. For thyroid cancer patients, especially after surgical treatment, we hear many different suggestions about taking thyroxine: thyroxine must be taken for a long period of time, TSH must be lowered to 0.00 or so, or the lower the pressure, the better, otherwise the tumor is prone to recurrence…. Many patients have long been entangled in too fine a dosage adjustment, worrying carefully about the amount of thyroxine every day, taking too much causes many discomforts, and worrying about long-term side effects; taking too little and worrying about recurrence, and individually also forming a strong or stubborn psychological burden. Our hospital has the most complete and longest follow-up information in China. According to the observation and analysis of more than 60 years of oncology treatment experience in our hospital, combined with my nearly 40 years of experience in thyroid cancer treatment, we can provide our personal experience and suggestions to share with our friends: First of all, in addition to the thyroid gland after total resection, it is necessary to take thyroxine for the whole life, and those who have part of thyroid gland, or those who have relatively low function of thyroid gland may have relatively long period of treatment according to the individual different circumstances. The situation may require exogenous thyroxine supplementation for a relatively long period of time, depending on the individual. As for the amount of thyroxine to be supplemented, there are simply two points to be grasped: 1. T3T4 is maintained at or near the upper limit of the normal value, and TSH is maintained at or near the lower limit of the normal value, or slightly lower than the normal value; and 2. There is no cardiovascular disease or uncomfortable symptoms as long as they do not appear. If accompanied by cardiovascular disease (coronary heart disease, arrhythmia, etc.), this article takes precedence! Including those who obviously feel discomfort such as fast heart rate and palpitations after taking thyroxine. Thyroid Stimulating Hormone (TSH) is an endocrine hormone secreted by the pituitary gland that promotes the proliferation of thyroid follicular epithelial cells and the synthesis and release of thyroid hormones. When the thyroid gland is underfunctioning or low, it stimulates the proliferation of the thyroid follicles, and it may also cause the formation of what is often referred to as a nodular goiter. “Nodular goiter. The previous “suggestion” can also be analyzed and explained from the following angles: (1) Theoretically, after partial resection of the thyroid gland, in the gland where there is no tumor remaining, new “nodules” may also be formed under the effect of high TSH, and these benign nodules will not become malignant. These benign nodules will not become malignant; if there are still hidden “cancer foci” in the remaining gland or other parts, thyroxine cannot inhibit or reverse the foci that are already cancerous. (2) From the point of view of carcinogenesis, the role of TSH in the formation, occurrence and development of thyroid cancer is not clear, and it only stays in the conclusion of “possible”. Even if the TSH is suppressed at a low level, it is impossible to change the tumor cells that have already mutated, which does not make sense from the point of view of the mechanism. Meanwhile, many basic and clinical researches have also concluded that “nail cancer” is not transformed from “nail nodule”. (3) From the clinical point of view, for the same stage of differentiated thyroid cancer, the recurrence rate of the cancer is not significantly higher in patients with thyroxine supplementation and T3T4/TSH in the normal physiological range than in patients with TSH suppression below the normal value. Moreover, the high recurrence rate appeared about 5 years after the initial treatment, which seemed to be less related to whether TSH was suppressed for a long time or not, and clinically confirmed to be more related to whether the first surgery was thorough or not. (4) There are many scholars who believe that poor TSH suppression is not necessarily the cause of tumor recurrence, but may also be the result of changes in endocrine substances after tumor recurrence. Personally, I am more of the opinion that the main role of postoperative application of thyroxine may only lie in the substitution effect, while the therapeutic role of excessive TSH suppression on tumor recurrence is highly suspected. According to the experience of long-term treatment in the Cancer Hospital of the Academy of Medical Sciences, thyrotropin concentration maintained in the normal near-low range has no obvious relationship with tumor recurrence. Many doctors’ recommendations on TSH inhibition therapy are mostly based on foreign guidelines, and the “guidelines” are also based on many clinical conclusions that “TSH inhibition effectively reduces tumor recurrence”, so are there any mistakes in so many experts’ opinions? Regarding some academic questions in clinical medicine, there may not always be a standardized answer with a unanimous understanding. Some foreign associations related to thyroid disease (mostly composed of endocrinologists and experts) have issued multiple versions of the guidelines, and there is still little relevant research in China, so they have issued their own guidelines by referring to foreign literature and combining with domestic conditions. It is undeniable that the guidelines have positive significance for the treatment of thyroid cancer in China. At the same time, it should also be recognized that guidelines are not standards or principles, but actually can be regarded as an in-depth structured “literature review”, which is the guidance of some experts and scholars. Any “guideline” will be influenced by their professional background, subjective will, literature adoption preferences and other factors, and some recommendations may not necessarily be reasonable, are “experts”, or even have completely opposite views. There are some guidelines based on large-scale retrospective studies of TSH suppression therapy, and many experts and scholars in the United States, including many of them, have disagreed and questioned some of their views. In particular, their inconsistent criteria for surgical procedures, the misuse of postoperative radioactive iodine, the non-standardized use of thyroxine preparations, the sensitivity of TSH suppression assays and the different sources of statistical data have affected the quality of the results of these documents. The quality of these results is affected by the different sources of statistical data. It is therefore important to “build on the strengths and discard the weaknesses” of these guidelines and to practice them thoughtfully. When applying thyroxine therapy, we should take into account the fact that in recent years, many patients have a young age of onset of disease, and that prolonged use of thyroxine or TSH suppression to a state of mild hyperthyroidism may lead to long-term cardiovascular and skeletal consequences, especially increased ventricular burden, atrial fibrillation, and concomitant osteoporosis, as well as other potentially detrimental effects of medically induced subclinical hyperthyroidism. Many studies have shown that excessively low serum TSH concentrations increase cardiovascular mortality in patients and also increase the risk of fractures in postmenopausal women. Therefore, thyroxine therapy should also be applied on an individual basis to balance the potential adverse effects. The above discussion, some of the terminology is more very professional, looks more withered and difficult to understand, would like to vernacularize a little, scientific and popular, after all, it is difficult to have it both ways, the inadequacy of please bear with me. Some of the ideas may be contrary to some of the “mainstream” advice or information that patients have been exposed to. Please use your own knowledge and judgment in deciding to accept what you believe to be relatively correct information.