RISK STRATIFICATION FOR PATIENTS WITH PAPILLARY THYROID MICROCARCINOMA - A RETROSPECTIVE COHORT STUDY
Friday, May 8, 2020
11:15 AM – 11:30 AM
Participants should be aware of the following financial/non-financial relationships: Jessita Singh Natasha Albert Messiah Dhas, MD: Disclosure information not submitted.
Objective : Papillary thyroid microcarcinoma (PTMC) is defined as papillary thyroid cancer with tumor size ≤10 mm. Although, majority of PTMC are considered low risk cancers, some can have aggressive behavior. This study analyzes the clinical, laboratory and histopathological characteristics of PTMC patients, and aims to identify parameters that help risk stratification for better clinical management and outcome.
Methods: A retrospective medical chart review was conducted to identify patients with a pathological diagnosis of PTMC from thyroidectomy specimens obtained during 1/1/2002 to 12/31/2012 at our hospital. Only those who had follow up till 12/2018 were included in our study. Cases with positive lymph nodes at the time of surgery were excluded. During the follow-up period, cases with evidence of metastatic disease (either positive thyroglobulin level or/and positive imaging) were designated as high-risk group (HRG); the others were classified under low-risk group (LRG, no disease). Information regarding their demographics and tumor cytopathology was reviewed. Student t-test or Chi-square was used to determine statistical significance.
Results: A total of 255 PTMC patients during the 6-16 years follow up were identified. Out of which, 19 (7.45%) were in the HRG and 236 (92.55%) were in the LRG. The demographic analysis revealed no differences in age or sex (female to male ratio) between the LRG and HRG (49 years versus (vs) 46.6 years; 5.56 vs 2.8; p > 0.05). Among the histomorphological parameters, PTMC multifocality was identified more commonly in HRG than in LRG (78.9 % vs 42.9 %, P =0.003). Follicular patterned PTMC were identified more commonly in LRG than in HRG (41.5 % vs 10.5 % p=0.008). Hashimoto’s thyroiditis was identified in 58.9% of LRG vs 21.1% of HRG (P=0.001). There were no statistically significant differences between the two groups with respect to the tumor size, lymph-vascular invasion or surgical margin positivity.
Discussion/Conclusion: Our data reveals that 7.45% of PTMC patients developed the metastatic disease during the 6-16 years of follow up. PTMC multifocality was associated with developing the metastatic disease during follow up, while the follicular patterned PTMC and Hashimoto’s thyroiditis were associated with patients who remain disease-free during follow up. PTMC patients with multifocal involvement are more likely to need aggressive follow up to detect metastasis than those with associated follicular pattern and Hashimoto’s thyroiditis. Additional studies are needed to determine the workup required and the frequency of follow up.