Evaluation of the 8th Edition TNM Classification for Anaplastic Thyroid Carcinoma

• Main Authors: Naoyoshi Onoda, Iwao Sugitani, Ken-ichi Ito, Akifumi Suzuki, Takuya Higashiyama, Tatsuya Fukumori, Nobuyasu Suganuma, Katsuhiko Masudo, Hirotaka Nakayama, Atsuhiko Uno, Katsunari Yane, Seiichi Yoshimoto, Aya Ebina, Yukari Kawasaki, Shigeto Maeda, Manabu Iwadate, Shinichi Suzuki
• Format: Article
• Language: English
• Published: MDPI AG 2020-02-01
• Series: Cancers
• Subjects: anaplastic thyroid cancer; prognosis; disease stage; tnm classification; prognostic index
• Online Access: https://www.mdpi.com/2072-6694/12/3/552

Background: The tumor&#8722;node&#8722;metastasis (TNM) classification system to categorized anaplastic thyroid cancer (ATC) was revised. Methods: The revised system was evaluated using a large database of ATC patients. Results: A total of 757 patients were analyzed. The proportion and median overall survival values (OS: months) for each T category were T1 (<i>n</i><i> </i>= 8, 1.1%, 12.5), T2 (<i>n</i> = 43, 5.7%, 10.9), T3a (<i>n</i> = 117, 15.5%, 5.7), T3b (<i>n</i> = 438, 57.9%, 3.9), and T4 (<i>n</i> = 151, 19.9%, 5.0). The OS of the N0 and N1 patients were 5.9 and 4.3, respectively (log-rank <i>p</i> &lt; 0.01). Sixty-three (58.3%) patients migrated from stage IV&#8201;A to IV&#8201;B by revision based on the existence of nodal involvement and 422 patients (55.7%) were stratified into stage IV&#8201;B, without a worsening of their OS (6.1), leaving 45 patients (5.9%) in stage IV A with fair OS (15.8). The hazard ratios for the survival of the patients of stage IV&#8201;B compared to stage IV&#8201;A increased from 1.1 to 2.1 by the revision. No change was made for stage IV C (<i>n</i> = 290, 38.8%, 2.8). Conclusion: The revised TNM system clearly indicated the prognoses of ATC patients by extracting rare patients with fair prognoses as having stage IV&#8201;A disease and categorized many heterogeneous patients in stage IV&#8201;B.