Volume 5 • Issue 4 • 1000238 J Cytol Histol ISSN: 2157-7099 JCH, an open access journal Research Article Open Access Diaz-Cano, J Cytol Histol 2014, 5:4 DOI: 10.4172/2157-7099.1000238 Short Communication Open Access Multicentric Papillary Thyroid Carcinoma: Stratification for Treatment Salvador J. Diaz-Cano* Department of Histopathology, King’s College Hospital and King’s Health Partners, London, United Kingdom *Corresponding author: Salvador J. Diaz-Cano, King’s College Hospital, Dept of Histopathology, Denmark Hill, London, Greater London, SE5 9RS, United Kingdom, Tel: +44 20 3299-3041 Fax: +44 20 3299-3670; E-mail: sdiaz-cano@nhs.net Received December 18, 2013; Accepted March 29, 2014; Published March 31, 2014 Citation: Diaz-Cano SJ (2014) Multicentric Papillary Thyroid Carcinoma: Stratifcation for Treatment. J Cytol Histol 5: 238. doi:10.4172/2157- 7099.1000238 Copyright: © 2014 Diaz-Cano SJ. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Tumor stage is the main prognosticator of differentiated thyroid carcinomas, but it needs further stratifcation for multicentric neoplasms (most frequently papillary thyroid carcinomas, PTC), which frequently present as foci smaller than 1cm and are considered by default as high-risk tumors. Not all cases of multicentric PTC should be considered of high risk and they should be stratifed to avoid unnecessary radioiodine ablation in selected cases. Currently, there are known variables for this stratifcation: size and number of tumor foci, clonal patterns, and specifc markers of aggressive behaviour (infltrative growth, BRAF mutation). In a near future, the identifcation of a gene expression pattern associated with a higher risk of recurrence would allow us to focus more aggressive treatment appropriately. Keywords: Tyroid; Papillary carcinoma; Multicentric; Treatment stratifcation Abbreviations: miRNA: Micro RNA; PTC: Papillary Tyroid Carcinoma Short Commentary on Early Multicentric PTC Te treatment of papillary thyroid carcinoma (PTC) has signifcantly changed recently and it is mainly based on surgery and radioiodine ablation, the latter for high-risk patients only [1-4]. However, this treatment is currently subjected to extensive review especially for low risk carcinomas. Two main factors have contributed to this review: the increased incidence of secondary neoplasms afer radioiodine treatment and the efciency demonstrated by low dose treatment [4,5]. Cancer treatment selection depends on patient stratifcation according to risk for a given tumor, but it is particularly challenging for patients with low-risk thyroid cancers because of the slow growth of such tumors. Tumor stage is the main prognosticator of diferentiated thyroid carcinomas, but it needs further stratifcation for multicentric neoplasms (most frequently PTC), which frequently present as foci smaller than 1cm and are considered by default as high- risk tumors. Microscopic PTCs (<1.0 cm) are considered a subset of PTCs that behave more benign. Tey follow an indolent course and carry an excellent prognosis. Distant metastases and mortality rates were reported to be less than 0.5% [6]. However, some authors suggest that there exists a subgroup of microscopic PTCs that can be aggressive, requiring therapeutic management similar to larger tumors [7]. Unfortunately, within this set of patients, prognostic factors have not been well defned. However, in recent years some specifc markers for aggressiveness were identifed, including sizes larger than 5 mm, multifocality, tumor extension beyond the parenchyma, lymph node involvement, tumor non-incidentally discovered, and the extent of primary surgery [7-10]. Currently, both biologic and pathologic variables provide a reliable basis for risk stratifcation of early stage thyroid cancer. Intratumor heterogeneity is at the foundation of tumor progression and it correlates with the tumor volume and multicentricity [11]: the potential to metastasize increase directly with primary size (the main element for T staging), and multicentric neoplasms (expressed by (m) in the T classifcation). Tese two key elements are the main general prognosticators used to plan any adjuvant radioiodine treatment. Although multicentric PTCs are not stratifed further considering that the presence of multicentricity provides a risk for all patients, no statistical diference in cancer mortality has been observed between the ablated and nonablated groups of patients with multicentric PTC [12], most likely refecting the lack of selection criteria. Multicentricity is considered an expression of tumor heterogeneity, the main driver of tumor progression by increasing the number of diferent clones and therefore the probability of sub-clone development with additional acquired capabilities [11]. Multicentric PTC is more frequently detected due to improved diagnostic methods. More than 70% of microscopic PTCs are diagnosed incidentally (in specimens of the thyroid removed for benign thyroid disease) and it is responsible for the 2.4x increase in incidence of diferentiated thyroid carcinoma [13]. Multiple foci have been reported in approximately 7-56% of microscopic PTCs [6,14]. A number of clinical studies showed that patients with ≥ two foci had higher recurrence rate and cancer mortality than those with unifocal PTMCs [6,12]. Moreover, multifocality is an independent risk factor for metastases [15]. It was demonstrated that cases with positive lymph nodes had a higher risk of recurrence [13]. Hence, multifocal PTMCs have been considered to have a poor prognosis requiring radioiodine ablation and close surveillance within the frst year. Patients with multicentric microscopic PTC need to be treated as highrisk patients, which partially explain the increase in the proportion of patients receiving radioactive iodine [5,16]. Te recurrence rate increases signifcantly in cases with ≥ 5 foci, which frequently undergo 131 I ablation [12]. As all foci are governed by the volume growth criteria expressed below, the clinical signifcance given to each focus must be linked to its size and a demonstrable evidence of diferent cellular progenitor. Terefore, the stratifcation of patients with multicentric tumors would require considering both the size of each focus, the number of foci, and a sensible application of clonality tests (such as X-chromosome inactivation and fractional allelic loss assays) [17]. An appropriate use of these markers serves to Journal of Cytology & Histology J o u r n a l o f C y t o l o g y & H i s t o l o g y ISSN: 2157-7099