Tumour multifocality offers no risk prognostic value in PTC outcomes
It appears that tumour multifocality does not predict clinical outcomes of papillary thyroid cancer (PTC), suggests a recent study.
“Multifocality is often treated as a risk factor for PTC, prompting aggressive treatments,” according to researchers.
To determine the prognostic value of tumour multifocality in clinical outcomes of PTC, the investigators recruited 2,638 patients (median age 46 years; 2,015 women) and followed them for a median 58 months at 11 medical centres in six countries. The Surveillance, Epidemiology and End Results (SEER) data was used for validation.
Disease recurrence was 198 of 1,000 (19.8 percent) in multifocal and 221 of 1,624 (13.6 percent) in unifocal PTC (hazard ratio [HR], 1.55; 95 percent CI, 1.28 to 1.88; p<0.001). This became insignificant after multivariate adjustment (HR, 1.13; 0.93 to 1.37).
The results were comparable in PTC variants, including conventional PTC, follicular-variant PTC, tall-cell PTC and papillary thyroid microcarcinoma. No association existed between multifocality and mortality in any of these PTC settings. However, classic risk factors strongly predicted cancer recurrence or mortality, and this association remained significant after multivariate adjustment.
In patients with intrathyroidal PTC (n=1,423), disease recurrence was 20 of 455 (4.4 percent) and 41 of 967 (4.2 percent; p=0.892) and mortality was zero of 455 (0.0 percent) and three of 967 (0.3 percent; p=0.556) in multifocal and unifocal PTC, respectively.
“The results were reproduced in 89,680 patients with PTC in the SEER database,” according to researchers.
The indiscriminate use of tumour multifocality as an independent risk factor, prompting overtreatment of patients, should be avoided, they added.