Differentiated thyroid carcinoma: multifocality and associated factors

The purpose of research is to evaluate risk factors of multifocal differentiated thyroid cancer. Work tasks.1. To determine the frequency of multifocal well-differentiated thyroid cancer. 2. To evaluate the influence of patients' clinical features and tumor morphology on the manifestation of multifocal well-differentiated thyroid cancer. 3. To assess the relationship between well-differentiated multifocal thyroid cancer and cancer risk predictors leading to a bad cancer prognosis. 4. To determine the effect of multifocal thyroid cancer total tumor diameter (TTD) on the change of disease stage. 5. To assess thyroid cancer TTD interactions with thyroid cancer risk factors which lead to poor prognosis. Methodology. A retrospective research of medical records of patients diagnosed and operated on for thyroid cancer (ICD-10-AM: C73) was caried out from 2012.01.01 to 2016.12.31 in LUHS Hospital department of Surgery. The study included 548 patients. During the research were analyzed the affect of the risk factors of differentiated thyroid cancer was anlyzed on the occurance of multifocality. Statistical analysis was performed using SPSS statystical program. Results. Multifocality rate was 23.5% (n=129) of differentiated thyroid cancer cases. Multifocality was characterized by papillary thyroid carcinoma. Multiple tumor foci were commonly found in both thyroid lobes. Multifocal papillary thyroid carcinoma (MPTC) was significantly associated with an older patient age (p=0,012): in ≥ 45 age group detected for - 26,7 % of patients. Multifocality manifestation was associated with classic papillary carcinoma variant - 29,0 %, (p=0,026). MPTC was related to the more advanced stage of cancer (p=0,021) – T3. Papillary thyroid multifocality was significantly correlated with extrathyroidal extension (p=0,009), lymphovascular invasion (p=0,014), lymph node metastasis (p=0,008). According to the total tumor diameter (TTD) for multifocal carcinoma, higher rate of tumors was found in category T2 and significantly higher rate of regional cervical lymph nodes metastasis set in T2 category (p=0,019). Conclusions. Multifocal well-differentiated thyroid cancer is detected in 23.5% of cases and is exclusively characteristic of papillary thyroid carcinoma. A higher than 45 years of age is significantly (p=0,012) associated with multiple papillary carcinoma. Multifocality was significantly (p=0,026) more common in the case of the histological variant of the classical thyroid cancers – 29,0%. An advanced stage of thyroid cancer is associated with multiple papillary carcinoma. Multifactority is significantly related to the risk factors for poor prognosis: the prevalence of lymphovascular invasion (p=0,014), extrathyroidal extension (p=0,009), and lymph node metastasis (p=0,008). The total tumor diameter significantly changes the evaluation of the thyroid cancer stage and is an important factor in the evaluation of thyroid multiple tumors