Endocrine-Related Cancer December 2006 [antikvár]

COMMENTARY Endocrine-Related Cancer (2006) 13 971-977 The role of external beam radiotherapy in the treatment of papillary thyroid cancer Nancy Lee^ and Michael Tuttle^ 'Radiation Oncology and ^Endocrine Service, Memóriái Sioan-Kettering Cancer Center, New York, NY, USA Abstract The role of external beam radiotherapy (EBRT) in treating thyroid cancer has brought forth controversy. Due to various histologic presentations and different natural histories, there Is no uniform approach/recommendation among centers and/or authorities regarding the role of EBRT for thyroid cancer. This is particularly true for papillary thyroid carcinoma (PTC) where the clinical course can range from a disease that Is cured with simple surgery to an aggressive form of poorly differentiated thyroid cancer with high rates of recurrence/death from disease. In addition, because the majority of the patients with PTC undergo postoperative radioactive iodine (RAI) treatment, the question remains as to what is the exact role of EBRT for PTC in the setting of RAI treatment? In this issue of Endocrine-Related Cancer, Chow and colleagues identified indications for EBRT and RAI therapy for PTC based on a retrospective review of 1300 patients. The authors concluded that postoperative RAI treatment is indicated in patients with pT2-pT4, pNO-pNIb while postoperative EBRT is recommended for patients with gross residual, positive margin, pT4, pN1 b, and lymph nodes > 2 cm disease. Other centers have also published their experience on the value of EBRT for PTC but with different indications. The reasons for the variations from different centers are complex. However, when all published results are taken together, the findings confirm the added value of EBRT to the present management of PTC in a select group of patients, particularly those with high risk features. In this commentary, these issues will be discussed and recommendations regarding the role of EBRT will be given. Endocrine-Related Cancer (2006) 13 971-977 Overview External beam radiotherapy (EBRT) for papillary thyroid cancer (PTC) has been a controversial topic in the field of endocrinology, head and neck surgery, as well as radiation oncology. There is no consensus on who is a candidate for EBRT as each center has its own philosophy in terms of the role of EBRT for PTC. For example, one center reports the importance of prophylactic EBRT in differentiated thyroid cancer even among patients with no microscopic residual disease based on improvement in the locoregional relapse-free and cause-specific survival in patients who underwent adjuvant EBRT after complete surgical resection (Esik et al. 1994). In contrast, investigators from other centers do not rourinely recommend EBRT for PTC as no improvement in overall survival was observed (Benker et al. 1990, Lin et al. 1997). In fact, there was a higher survival rate among those who did not receive EBRT in one study (Lin et al. 1997). In addition, Mazzaferri et al. showed the routine use of EBRT to have an adverse effect on outcome, but this observation was likely to be secondary to the marked selection bias of very high risk patients selected for EBRT in this series (Mazzaferri & Young 1981). The age of the patient also has been factored into the decision making for EBRT in many centers. For example, it is generally accepted that no postoperative EBRT is necessary for a young patient with limited gross residual disease where there is good demonstration of RAI uptake (O'Connell et al. 1994, Tsang et al. 1998, Brieriey et al. 2005). Others, however, failed to find any correlation of outcome with age (Benker et al. 1990). Due to these opposing views from different groups, confusion arises for both the patient as well as the physician, as EBRT might be strongly recommended in one center but not recommended at all at another center. The discrepancies in findings between centers are largely due to the retrospective nature of the studies with variation in patient selection. Endocrme-Relaled Cancer (2006) 13 971-977 1351-0088/06/013-971 © 2006 Society for Endocrinoiogy Printed In Great Britain DOi:10.1677/ERC-06-0039 Online version via http://www.endocrinology-journais.org