Lung cancer and thyroid hormones: Primary hypothyroidism is prognostically significant for survival.
Cleveland Clinic Foundation, Cleveland, OH, United States
AIM: Anecdotal reports and recent data suggest that decreased thyroid function may be associated with improved outcomes in lung and other solid tumors. In a recent large population based study of patients treated for hyperthyroidism by radio-iodine ablation of the thyroid, long term follow up showed a signicantly lower prevalence and risk of dying from lung cancer. There is evidence that tri-iodothyronine [T3] is a significant tumor mitogen and modulates the IGF-1 and EGFR growth factor systems. .his multicenter study was aimed at determining the prognostic value of primary hypothyroidism on survival in lung cancer. METHODS: A hospital-based retrospective case-control study was conducted on 1979 patients with AJCC stages 1-4 non-small cell and small cell lung cancer treated between January 1996 and July 2002. Patients with a clinical diagnosis of hypothyroidism based on documentation of thyroid hormone supplementation were individually matched to controls based on cancer histology, stage of disease, age, race, and gender. Kaplan-Meier survival curves were generated for each group. Age of cancer diagnosis for the 85 hypothyroid patients and the 1372 euthyroid patients before matching was compared. RESULTS: Overall, 85 hypothyroid cases[4.2%] and 85 matched controls were identified of which 70 were non-small cell and 15 small cell types The female: male ratio was 3.35:1. Primary tumor stage was Stage 1 :- 19 patients, Stage 2 :- 19 patients, Stage 3 :- 86 patients, and Stage 4 :- 46 patients.For AJCC stages 1-4 median survival [M.S.] was 14.5 months in the hypothyroid group and 11.1 months in the euthyroid group( p = .014) . For stage 4, M.S. was 11 vs.5 months(p= .0018). . Median age at diagnosis was 73 for hypothyroid vs. 64 years for euthyroid patients (p = .0006). CONCLUSION:This retrospective case control study suggests that primary hypothyroidism is prognostically significant and associated with a more indolent course in lung cancer.
Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in oral session 993 (Molecular pathology - Part II).