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Article: Carmen F. A. Eustatia-Rutten, Eleonora P.M. Corssmit, Nienke R. Biermasz, Alberto M. Pereira, Johannes A. Romijn, and Johannes W. Smit Survival and Death Causes in Differentiated Thyroid Carcinoma J Clin Endocrinol Metab 2005; 0: jc.2005-1322v1 [Abstract]

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Re: Age is not a prognostic factor in differentiated thyroid carcinoma

Johannes W Smit   (9 January 2006)

Age is not a prognostic factor in differentiated thyroid carcinoma

Thera P Links, Piet L. Jager, Adriënne C.M. Persoon, John T.M. Plukker, Wim J. Sluiter   (4 January 2006)

Re: Age is not a prognostic factor in differentiated thyroid carcinoma 9 January 2006
Johannes W Smit, internist-endocrinologist Leiden University Medical Center Send letter to journal: Re: Re: Age is not a prognostic factor in differentiated thyroid carcinoma jwasmit{at}lumc.nl Johannes W Smit	We thank Dr. Links and colleagues for their comments, and we appreciate their work. The interrelationships of prognostic factors for survival in differentiated thyroid carcinoma was the reason we performed multivariate Cox-regression analysis, including stage and age as covariates. We found that age, as a continuous factor, was an independent prognostic indicator, irrespective of T stage. Therefore, this supports our original conclusion. The calculation of standardized mortality rates for age groups below and above 55 years was simply meant to illustrate this outcome. We agree that subdivision of age groups according to TNM stage affects its predictive power.
Age is not a prognostic factor in differentiated thyroid carcinoma 4 January 2006
Thera P Links, Endocrinologist University Medical Center Groningen, University of Groningen, Piet L. Jager, Adriënne C.M. Persoon, John T.M. Plukker, Wim J. Sluiter Send letter to journal: Re: Age is not a prognostic factor in differentiated thyroid carcinoma t.p.links{at}int.umcg.nl Thera P Links, et al.	In general, patients with differentiated thyroid carcinoma (DTC) have a good overall survival, but a subgroup exists with high risks of recurrence and death. It is difficult to identify this specific group of patients. Many staging and scoring systems have been developed to overcome this problem (1). The TNM scoring (2) has been stated to be the most general, but, among other factors, it still underestimates the contribution of histologically poor variants to the survival. Eustatia- Rutten et al (3) described the survival and specific death causes in a group of 366 patients with DTC. They also reveal the limitations of the TNM system. Ten patients with T1-3M0 thyroid carcinoma died from DTC. T4 stage, distant metastases, and advanced age were associated with an increased relative risk for DTC related death. We question the generally identified risk factor of age, which has been advocated as a risk factor by others (4), but not found to be one in our population (5). One of the limitations of age is that T4 stage and distant metastases at presentation are overrepresented in older age groups. Age is, therefore, not independent of these other parameters. This was also an issue in the report of Eustatia-Rutten et al (3). They used age 55 years as cut-off point and concluded that patients older than 55 years are at increased risk of death from DTC. However, we calculated the disease specific hazard ratios (HR) of death in the subgroups of patients above and below 55 years from table 3 (3) and found for T1-3M0 1.48 (CI 0.44;5.00), p=0.52; for T4M0 1.41 (0.34;5.92), p=0.64; and for M1 0.35 (0.09;1.36), p=0.13. Total HR 1.47(0.71;3.04) p=0.30 as the ratio of their standardized mortality rates. Therefore, one can conclude from their data that age is not an independent risk factor for excess mortality either in the whole group or in subgroups based on a certain cut-off point. Furthermore, the limited number of deaths in the younger age groups yields insufficient statistical power to show that the standardized mortality rate in this group is increased as well. References 1. Schlumberger M, and Pacini FM 1999 in: Thyroid tumors, Éditions Nucléon, Paris. Pp 94-100 2 Brierley JD, Panzarella T, Tsang RW, Gospodarowitz MK and O’Sullivan B 1997 A comparison of different staging systems predictability of patient outcome : thyroid carcinoma as example. Cancer 79:2414-2423. 3. Eustatia-Rutten CF, Corssmit EP, Biermasz NR, Pereira AM, Romijn JA and Smit JWA 2005 Survival and Death Causes in Differentiated Thyroid Carcinoma. J Clin Endocrinol Metab Nov 1 (Epub ahead of print) 4. Tubiana M, Schlumberger M, Rougier P, Laplanche A, Benhamou E, Gardet P, Caillou B, Travagli JP, Parmentier P 1985 Long-term results and prognostic factors in patients with differentiated thyroid carcinoma. Cancer 55:794-804 5. Links TP, van Tol KM, Jager PL, Plukker JT, Piers DA, Boezen HM, Dullaart RP, de Vries EG, Sluiter WJ 2005 Life expectancy in differentiated thyroid cancer: a novel approach to survival Endocr Relat Cancer 12:273-280