Factors predicting 'time to distant metastasis' in radically treated head and neck cancer

Context: Various studies have shown the important risk factors for distant metastasis in head and neck cancer (HNC) which are present in most of the patients in developing countries. Identification of factors on the basis of time to distant metastasis (TDM) can help in future trials targeting smaller subgroups. Aims and Objectives: To identify the factors that predict TDM in radically treated HNC patients. Settings and Design: Retrospective audit. Materials and Methods: Retrospective audit of the prospectively maintained electronic database of a single HNC radiotherapy clinic from 1990 to 2010 was done to identify radically treated patients of HNC who developed distant metastasis. Univariate and multivariate analysis were done to identify baseline (demographic, clinical, pathological, and treatment) factors which could predict TDM, early time to metastasis (ETM; <12 months), intermediate time to metastasis (ITM; 12-24 months), and late time to metastasis (LTM; >2 years) using Kaplan Meier and Cox regression analysis, respectively. Results: One hundred patients with distant metastasis were identified with a median TDM of 7.4 months; 66 had ETM, 17 had ITM, and 17 had LTM. On multivariate analysis, the nodal stage 2-3 (N2/3) was the only baseline factor independently predicting TDM, ETM, and ITM, whereas none of the baseline factors predicted LTM. Conclusions: Higher nodal burden (N2/3) is associated with both ETM and ITM, and calls for aggressive screening, systemic therapy options, and surveillance. It is difficult to predict patients who are at a risk of developing LTM with baseline factors alone and evaluation of biological data is needed.