Thyroid cancer risk classification and prognosis assessment
In the clinical management of thyroid cancer, patients and colleagues often ask questions about the staging, severity and prognostic criteria of thyroid cancer.
The most commonly used systems for thyroid cancer risk grading and prognosis assessment include the AGES system, AMES system and MACIS system.
1.AGES system
Score = 0.05 × Age (≥40 years)
+ 1 (stage 2)
+ 3 (stage 3, 4)
+ 1 (extraperitoneal invasion)
+ 3 (distant metastasis)
+ 0.2 × tumor size (cm, maximal diameter line)
20-year survival rate:
≤3.99 = 99%
4-4.99 = 80%
5-5.99 = 67%
≥6 = 13%
2. AMES system (for papillary and follicular thyroid cancer)
Low risk: young (male ≤40 years, female ≤50 years): no distant metastases
Older (male >40 years, female >50 years).
Intraglandular papillary carcinoma;
Microinfiltrating follicular carcinoma of the envelope;
Primary tumor diameter <125px< p="">
High risk/distant metastases (regardless of age)
Older (male >40 years, female >50 years).
Extrathyroidal infiltrative papillary carcinoma;
Extensive infiltrative follicular carcinoma of the envelope;
Primary tumor diameter 5>cm
20-year survival rate:
Low risk = 99%
High risk = 61%
3.MACIS system (for papillary thyroid cancer)
Score = 3.1 (age <40 years) or 0.08 × age (age ≥40 years)
+ 0.3 × tumor size (cm, maximal diameter)
+ 1 (tumor not completely resected)
+ 1 (local invasion)
+ 3 (distant metastasis)
20-year survival rate:
<6 = 99%
6-6.99 = 89%
7-7.99 = 56%
≥8 = 24%
Throughout the three staging systems described above, age and the presence of distant metastases (e.g., lung metastases, bone metastases, etc.) are the two most important factors affecting the prognosis of patients with differentiated thyroid cancer. Even with local lymph node involvement, incomplete tumor resection, or even tumor invasion of blood vessels and envelope, it is very rare for young patients to die from thyroid cancer. At the same time, each of these three approaches has its own characteristics and each thyroid cancer clinic has a preference in the choice of clinical application. For example, the MACIS system avoids the subjectivity in physicians’ understanding of pathological grading, and only evaluates prognosis in five aspects: distant metastasis (M), age (A), completeness of resection (C), presence of local invasion (I) and tumor size (S), which is a relatively simple method with high feasibility. However, it is mainly suitable for patients with papillary thyroid cancer. This evaluation system comes from close observation of a large sample of patients and is probably the most credible and accurate assessment method available.
In addition, as long as the tumor is completely removed, how much of the thyroid gland itself is removed has no impact on prognosis. Unlike other tumors (e.g., breast, colorectal, lung, etc.), patients with papillary thyroid cancer do not have an impact on survival even if they develop cervical lymph node metastases. As far as patients are concerned, the actual condition and treatment of each thyroid cancer patient still varies considerably. Fortunately, the majority of patients with thyroid cancer are evaluated in the low-grade category (MAICS score below 6.0) and have a very good prognosis after treatment with the classical model “surgery + iodine-131 + thyroxine”.
It is important to note that the above risk classification and prognosis assessment system is only applicable to differentiated thyroid cancer (papillary and follicular). As medullary and undifferentiated carcinomas are difficult to quantify, there is no reliable grading method for clinical reference.