Radioiodine ablation can be avoided in intrathyroidal papillary thyroid cancers ≤2 cm (pT1N0M0)
M. Perrino, C. Colombo, S. De Leo, L. Vicentini, P. Beck-Peccoz & L. Fugazzola
The need for thyroid residue ablation in papillary thyroid cancer (PTC), classified with the TNM staging (AJCC, 2002) as pT1, with a maximum diameter comprised between 1 and 2 cm (pT1/1-2) and/or multifocal, is still debated. Aim of this study was to compare the outcome of pT1N0M0 patients submitted or not to postsurgical radioiodine ablation. Consecutive patients followed-up at this Institution from 1996 to 2010 were enrolled. All pT1/1-2N0M0 cases were radioiodine ablated before June 2002 and not ablated after that date. Patients with local or distant metastases at post-therapeutic whole body scan were excluded. The patients enrolled were 257 (214 F, mean age 47.3 yrs), the median follow-up was 88 months and the persistence/recurrence was evaluated according to the most recent European guidelines. Patients were submitted to total thyroidectomy, associated in 63 cases to central neck dissection. Tumors were classified as pT1/<1 (n=169, Group A) and pT1/1-2 (n=88, Group B). Multifocality was found in 35.5% of Group A and in 38.6% of Group B patients. Central neck dissection was performed in 18.3% (Group A) and 36.3% (Group B) of cases. Radioiodine ablation was performed in 26% of Group A (mean 131 dose: 74 mCi) and in 49% of Group B patients (mean 131 dose: 75 mCi). At the end of follow-up, persistent patients were 2/169 in Group A (both ablated) and 3/88 in Group B (all ablated). At a logistic regression analysis either age, gender, nodule diameter, central neck dissection, multifocality, or radioiodine ablation have been found not to influence the outcome. To our knowledge these are the first data showing that, in the pT1N0M0 category of PTCs, the outcome is not associated neither with the tumor size, nor with the therapeutic intervention, suggesting that radioiodine ablation can be avoided also in pT1/1-2 cases.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector