Recurrence Patterns Of Locally Advanced Head And Neck Squamous Cell Carcinoma Patients After 3d Conformal Radiotherapy With Or Without Chemotherapy

To establish recurrence patterns among locally advanced head and neck non-nasopharyngeal squamous cell carcinoma (HNSCC) patients treated with radical radiotherapy or chemoradiotherapy (chemoXRT) and to correlate the sites of locoregional recurrence with radiotherapy volumes. One hundred and fifty one locally advanced HNSCC patients were treated between January 2004 and December 2005 using three-dimensional (3D) conformal CT-planned external beam radiotherapy. The median age was 59 years (range,34–89 years). Thirty-five (23.2%) patients had Stage III disease, 116 patients had Stage IV A/B. One hundred and fifteen patients were treated with chemoXRT and 36 (23.8%) patients were treated with radical radiotherapy alone. All patient images were reviewed to identify the precise site of locoregional recurrence. Local and regional recurrences were compared to previous radiotherapy doses and target volumes with the aid of radiologist and dosimetrist. The recurrences were classified as 1) "in-field," in which 95% or more of the recurrence volume (V(recur)) was within the 95% isodose; 2) "marginal," in which 20% to 95% of V(recur) was within the 95% isodose; or 3) "outside," in which less than 20% of V(recur) was within the 95% isodose. Univariate and multivariate analyses were performed according to covariates properties. The median follow-up all patients was 38 months (range,3–62 months). One hundred twenty five of 151 (82.8%) patients achieved complete response after their radical treatment. Among the patients who had achieved a complete response 20 patients recurred locally and/or regionally and 16 patients developed distant metastasis. The 3-year local and regional control rates were 86.8%, 89.5%, respectively in complete responders. For the entire cohort of 151 patients, the 3-year cause specific survival rate was 66.8%. Of the 14 local recurrences 12 were in-field recurrences. Of the 11 regional failures 6 were in field recurrences. On univariate analysis age, tumor subsite and T-Stage were significant prognostic factors for progression-free and cause specific survival. On multivariate analysis T-Stage was found as a significant prognostic factor affecting both progression-free and cause specific survival. Most of the local-regional recurrences are within the PTV suggesting that local regional failure is not related to geographical miss but might relate to intrinsic radio-resistance or associated factors (e.g., hypoxia). By improving loco-regional control, the pattern of recurrences is changing compared with historical series, with metastatic relapse a more common occurrence. As translational research may aid outcome prediction we plan to explore this further.