High frequency of level II–V lymph node involvement in RET/PTC positive papillary thyroid carcinoma.

Abstract: Aims: To investigate the frequency and clinical significance of RET rearrangement in Chinese patients with papillary thyroid carcinoma (PTC) and discuss the role of RET rearrangement in therapeutic decision-making after the performance of level VI lymph node dissection and the 2002 AJCC staging system. Methods: RET/PTC-1 and RET/PTC-3 were detected in 126 PTCs using reverse transcription-polymerase chain reaction (RT-PCR) and direct sequencing. Results: RET rearrangement was detected in 18 cases of PTC. The patient group aged <20years had the highest frequency (3/6) of RET rearrangement among the age groups (<20years, 20–40years and ≥40years; P =0.03). RET/PTC-1 positive patients were more likely to suffer from Hashimoto''s thyroiditis simultaneously (P =0.02) while RET/PTC-3 positive patients had a higher frequency of extrathyroidal extension (P <0.01) and advanced T classification (P <0.01). RET rearrangement (OR=8.70, 95% CI 1.69–44.81), male (OR=3.88, 95% CI 1.41–10.69), age (OR=0.96, 95% CI 0.93–0.99), multifocality (OR=3.54, 95% CI 1.33–9.41) and advanced T classification (OR=7.32, 95% CI 2.91–18.40) were all identified as risk factors of level II–V lymph node involvement in the multivariate analysis. Conclusions: The frequency of RET rearrangement in Chinese patients is low and age related. RET/PTC-1 and RET/PTC-3 are associated with different clinical pathological characteristics but not with lymph node involvement. The RET/PTC positive patients should receive more attention to lateral neck in the management of PTC. [Copyright &y& Elsevier]