(ChemotherapyAdvisor) – Positive results on mutation panel testing and lymph node metastasis at presentation were the only two predictors of recurrence of papillary thyroid cancer in a long-term follow-up study reported during the 82nd Annual Meeting of the American Thyroid Association (ATA) in Québec City, Québec, Canada, September 20.

“To optimize surveillance strategies, the routine use of molecular testing to identify patients with papillary thyroid cancer at risk for recurrence should be strongly considered,” stated Gina Howell, MD, of the University of Pittsburgh, Pittsburgh, PA, and colleagues.

The investigators reviewed clinicopathologic characteristics in a series of 80 patients with initial operations between June 1999 and December 2001 who had archived tissue available for molecular testing and >1 year clinical-follow-up.

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“Retrospective molecular testing was performed for BRAFV600E, NRAS61, HRAS61, and KRAS12/13 mutations, and RET/PTC1 and RET/PTC3 rearrangements. Recurrence was diagnosed if 1) there was pathologic or cytologic confirmation of disease after reoperation, or 2) radiographic imaging demonstrated local or distant metastasis,” Dr. Howell reported.

Mean age was 46 years (range 13-78) and mean follow-up, 102 months (range 12-149). A total of 15 patients (19%) had disease recurrence, and mean time to recurrence was 55 months (range 1-133).

“All 15 recurrences were mutation positive (12 BRAFV600E, 1 HRAS61, and 2 RET/PTC1),” they found. No recurrences occurred in the 25 of 80 patients who were mutation negative. Incidence of mutation-positive papillary thyroid cancer detected by the panel was 69%, or 55 of 80 patients. In predicting recurrence, the panel had a 27% positive predictive value and 100% negative predictive value.

Recurrence was found to be associated with extrathyroidal extension (P=0.03), lymph node metastasis (P=0.001), and TNM stage III/IV (P=0.008) at presentation; of these, on multivariable analysis, only lymph node metastasis predicted recurrence (P=0.013). Age >45 years (P=0.06), male gender (P=0.55), and tumor size >2 cm (P=0.05) were not associated with disease recurrence.

Abstract [Click on Full Text PDF and search using author name Howell]