IS DESMOPLASTIC STROMAL REACTION USEFUL TO MODULATE THE EXTENSION OF SURGICAL PROCEDURE IN SPORADIC MEDULLARY THYROID CARCINOMA?

AUTHORS:
P.F. Procopio (Rome, Italy) , F. Pennestrì (Rome, Italy) , N. Voloudakis (Rome, Italy) , S. La Rocca (Rome, Italy) , P. Gallucci (Rome, Italy) , E.D. Rossi (Rome, Italy) , C. De Crea (Rome, Italy) , M. Raffaelli (Rome, Italy)
Background:
The extension of index operation for sporadic medullary thyroid carcinoma (MTC) remains controversial. Among different perioperative parameters, desmoplastic stromal reaction (DSR) emerged as the most reliable predictor of nodal metastases. This study evaluated the role of DSR in the therapeutic algorithm.
Methods:
Among a series of 4216 patients who underwent thyroidectomy for malignancies (2014-2023), 246 MTCs were retrospectively identified from a prospectively maintained Institutional database. One-hundred-thirty-nine sporadic MTCs (56.5%) were considered eligible. In 57 (23.2%) cases a single experienced pathologist (EDR) retrospectively evaluated presence or absence of DSR. The primary and secondary endpoints were evaluating the risk factors for nodal metastases and analyzing the correlations between DSR and nodal metastases, respectively.
Results:
There were 21 males and 36 females with a median age of 59 (52-70) years: 44 (77.2%) pT1, 9 (15.8%) pT2, 3 (5.3%) pT3, 1 (1.7%) pT4 tumors. Nodal metastases were present in 17 (30%) cases (8 pN1a and 9 pN1b). At univariable analysis, bCT>113 pg/mL (p=0.004), DSR+ (p=0.002) and lesion size >2 cm (p=0.042) were significantly associated with nodal metastases. After backward stepwise logistic regression, DSR+ and bCT>113 pg/mL were identified as independent risk factors for nodal metastases. DSR+ showed a specificity 100%, a sensitivity of 82.5%, a PPN of 18.4% and a NPV of 100%.
Conclusions:
In case of minimal disease (DSR- and bCT<100 pg/mL) prophylactic lateral neck dissection (LND) could be avoided. LND should be considered in case of DSR+ and bCT>500 pg/mL. In the "gray zone", surgical treatment should be tailored on patient and lesion characteristics.