Prognostic factors and follow-up of patients with differentiated thyroid carcinoma with false negative or nondiagnostic FNAC before surgery. Comparison with a control group

Abstract

Since the clinical implementation of fine needle aspiration cytology (FNAC) to diagnose thyroid carcinoma, few patients remain misdiagnosed and little is known about their clinical outcomes. An observational retrospective study was carried out to analyse prognostic factors and follow-up of patients with differentiated thyroid carcinoma (DTC) not disclosed by FNAC before surgery, compared to a control group. From October 2003 to July 2010, 308 patients underwent surgery as treatment for nodular goitre and 53 had DTC. Cases were 12 subjects with DTC and benign (n = 7) or nondiagnostic (n = 5) FNAC. Controls were 39 subjects with DTC and suspicious (n = 19) or malignant (n = 20) FNAC. Prognostic factors, recurrence and survival rates were compared. Cases had longer time from FNAC to surgery than the control group (86.8 ± 74.1 vs. 16.4 ± 23.8 weeks; P < 0.001), higher prevalence of follicular carcinoma (33.3 vs. 2.6%; P = 0.009), and of two-time total thyroidectomy (75 vs. 30.8%; P = 0.016). Average follow-up was 42.7 ± 25.3 months (2-86 months). There were no deaths. Disease-free survival for cases was 66.9 ± 5.8 months, and for controls 78.7 ± 3.9 months (P: ns). In patients with DTC, the result of the FNAC performed before surgery was not an independent predictor of recurrences or mortality in the first 7 years of follow-up. Thus, false negative or nondiagnostic FNAC in a patient with DTC does not seem to be a primary prognostic factor, but it may reveal other adverse prognostic factors such as longer time to therapy and higher prevalence of follicular carcinoma that may influence long-term outcomes.

Is there a relationship between preoperative cytological diagnosis and evolution in patients with differentiated thyroid carcinoma? A retrospective study

“…In this study, which used dynamic risk classification recommended by the latest ATA guidelines (5), no association was found between preoperative cytological diagnosis and patient clinical status at final evaluation, differing from that reported by other authors (11). Also, no association was found between disease-free survival time and cytological diagnosis, corroborating the findings of some studies (9,14), but disagreeing with others (11,13), who reported longer time in patients with a cytology showing lower probability of malignancy. As previously mentioned, the nonstandardization of cytological diagnosis methods and of outcome evaluation could contribute to these divergences.…”

“…In this study, the 7 th edition of AJCC/TNM (19) was considered, once that it was the parameter in force at the time of data collection. No association was seen between cytological diagnosis and risk of death, similar to descriptions by other authors (12,14), but different to the findings of VanderLaan and cols., who found an association between Bethesda cytology Class VI and the more advanced TNM stages (8). AJCC/TNM staging was also not associated to disease status in final evaluation, reinforcing the concept that it does not have prognostic value regarding therapeutic response or disease persistence, restricting itself as just a predictor of mortality from neoplasia (29).…”

“…A worrying finding was that 13% of the cases of DTC had a cytological diagnosis I/II. However, there are studies with similar designs to this one reporting even higher percentages (20.7 to 32.7%) of these cytological classes (12,14). The truth is that the rates of false-negative FNA have been very variable.…”

“…We found an association between suspected or malignant cytological diagnosis (classes V/VI) and earliest surgical intervention, corroborating García-Pascual and cols. (14). In fact, preoperative cytological diagnosis, through FNAB, could impact the speed, and perhaps the aggressiveness of surgical approach.…”

“…In this context, some authors have reported that preoperative cytological diagnosis could be one more factor in DTC prognosis (8)(9)(10)(11)(12)(13). However, despite the relevance of Bethesda classification in thyroid neoplasia diagnosis, its prognostic role is still controversial (14,15). Some of the factors responsible for this lack of consensus could be the lack of adherence to cytological classification standardization, which still persists, and a lack of uniformity in outcome assessment.…”