China's first "CSCO Guidelines for the Diagnosis and Treatment of Medullary Thyroid Cancer" was released, opening a new journey of standardized diagnosis and treatment of medullary thyroid cancer

Pathology

Professor Liu Zhiyan

The Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine

The Guidelines emphasize the importance of
pathology in the diagnosis and treatment of MTC from various aspects, such as detection methods.
Based on the differences between pathology departments in different hospitals, the Guidelines recommend different combinations of pathological tests for the diagnosis of MTC, such as FNA cytology supplemented by cell wax blocks and immunocytochemical methods or crude needle aspiration supplemented with immunohistochemical staining
.

With the deepening of the understanding of thyroid cancer, RET gene changes have received more and more clinical attention
.
At present, FISH and PCR are often used in clinical practice for RET gene fusion.
For RET point mutations, ARMS and generation sequencing are often recommended for the detection
of known targets.
The Guidelines combine the advantages and shortcomings of different detection methods and the characteristics of MTC, and give corresponding genetic detection sites and method recommendations
for different types of MTC patients.

Since different types of RET mutations are associated with MTC risk stratification in MEN2A and MEN2B, and also with the risk of pheochromocytoma and hyperparathyroidism in MEN2A, the Guidelines stratified
the risk of recurrence for different RET gene point mutations.

Surgery

Professor Wang Zhuoying

Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine

The incidence of MTC in China is relatively low, resulting in insufficient understanding and diagnosis and treatment experience of some clinicians
.
In addition, the lack of full popularization of Ctn testing and genetic testing for familial MTC has led to shortcomings in clinical diagnosis and treatment, and the lack of previous therapeutic drugs has also affected the treatment concept
of clinicians.
The development of the Guidelines is of great significance, and its surgical chapters cover the surgical treatment of primary lesions, the surgical management of initial regional lymph nodes, and surgical efficacy assessment and recurrence risk assessment, providing guidance to surgeons, especially primary physicians
.

In the surgical chapter of the Guideline, it highlights the prospects
for locally advanced MTC-targeted neoadjuvant therapy.
With the abundance of MTC system therapy (such as RET inhibitor platenib, etc.
), surgeons can use targeted therapy to achieve conversion therapy, so that inoperable patients can regain the opportunity
for surgery.
However, clinical experience is still insufficient
for the timing of drug use.
It is hoped that future studies will be carried out to determine the best population to treat and when
to treat it.

Nuclear Medicine

Professor Gao Zairong

Union Hospital, Huazhong University of Science and Technology

Because MTC originates from parafollicular thyroid cells and lacks iodine uptake capacity, the Guidelines do not recommend postoperative ¹³¹I adjuvant therapy
for MTC patients.
It is worth noting that nuclear medicine treatment still has its unique value
in the diagnosis and treatment of MTC.

Peptide receptor-mediated radionuclide therapy (PRRT) and ¹³¹I-MIBG are two types of nuclear medicine treatments for MTC, which can not only effectively control the disease, especially for metastatic MTC, but also detect the MTC primary lesion and the uptake ability of metastases before treatment, which has the characteristics and advantages
of integrated diagnosis and treatment and individualization 。 Although nuclear therapy can achieve remission in about 60% of MTC patients and achieve a disease stabilization rate of about 30%, MTC is prone to distant metastasis, and clinicians should further strengthen multidisciplinary collaboration in the future to improve the survival prognosis of MTC patients and improve the quality of life of
patients.

Endocrine therapy

Professor Xu Shuhang

Hospital of Integrated Traditional Chinese and Western Medicine Affiliated to Nanjing University of Chinese Medicine

Because MTC is derived from parafollicular thyroid cells, which do not express thyrotropin receptors, the goal of MTC endocrine therapy is usually to normalize thyroid-stimulating hormone (TSH) without TSH suppression
.
It should be noted that the target range of TSH varies among people of different ages or states, such as TSH recommendations for pregnant MTC patients below 2.
5 mIU/L
.

Due to the generally high risk of MTC, its surgical resection range is large, which is easy to lead to hypoparathyroidism
.
Therefore, changes in serum calcium and parathyroid hormone (PTH) levels should be monitored regularly and early after thyroid surgery, drug therapy should be judged based on blood calcium levels, and parathyroid function
should be reviewed regularly after treatment.

For children with MEN2A/2B treated with preventive surgery, because they are still in the growth and development stage and are sensitive to thyroid hormone levels, clinicians must emphasize the importance of regular observation and follow-up after surgery, which is not only to prevent tumorigenesis, but also to adjust the thyroid function of the child and ensure the healthy growth
of the child.

Systematic Therapy

Professor Guo Ye

Dongfang Hospital Affiliated to Shanghai Tongji University

Because the surgical treatment of MTC is relatively less effective than that of DTC and the sensitivity to traditional chemotherapy is relatively low, once patients have recurrent metastasis, there is a lack of effective standard treatment
.
In addition, although there are small molecule multi-target inhibitors such as anlotinib for MTC treatment in China, their side effects are relatively large, and if the patient develops drug resistance, the disease progresses very rapidly
.
Therefore, there is a huge unmet clinical need, and there is an urgent need for high-efficiency and low-toxicity MTC system treatment regimen
.

RET gene is the driver gene of multiple tumor types, whether in hereditary MTC or sporadic MTC, some patients carry RET gene mutations
.
Platinib is a RET inhibitor with high anti-tumor response rate and acceptable toxicity and side effects, which has been approved by the National Medical Products Administration of China for RET mutant thyroid cancer, which is expected to meet the unmet treatment needs of more than half of MTC patients, and may enable them to obtain long-term disease-free survival, which is of positive significance
for changing the status quo of clinical diagnosis and treatment of MTC in China.
However, it should be noted that the optimal therapeutic sequence of multi-target inhibitors and specific target inhibitors and the mechanism
of resistance mutations of RET inhibitors still need to be further explored in the future.

Radiotherapy

Professor Hou Xiaorong

Peking Union Medical College Hospital

Radiotherapy is a non-dominant treatment for MTC, which is mainly used for local lesions, well-defined residual lesions, or recurrent metastatic lesions
with a high risk of recurrence.

As an important part of the comprehensive treatment of MTC, radiotherapy can give a higher radical dose of local tumor or metastatic lesions with the development of technology, and at the same time ensure the safety of normal tissues and organs, so as to achieve the efficacy of radioablation or similar to surgical resection, which plays an important auxiliary role
in the control of patients' condition.

The guidelines give detailed treatment suggestions for radiotherapy technology, scope and dose according to the patient's condition and lesion location, which has important reference and guiding significance
for clinicians.

On the basis of existing radiotherapy, clinicians should further explore the prospect of new radiotherapy technology in MTC, and explore the treatment mode
of combination radiotherapy and systemic therapy.