Analysis of Prognostic Factors of Chemoradiation Therapy for Advanced Hypopharyngeal Cancer – Does Tumor Volume Correlate with Central Necrosis and Tumor Pathology?

Objectives: Not all patients with hypopharyngeal cancer who undergo concurrent chemoradiation therapy have a good prognosis. We hope to find the significant prognostic factors that could help us in patient selection for concurrent chemoradiation therapy. Study Design: We used a retrospective analysis on several prognostic factors which may affect the treatment outcome and prognosis. Methods: We studied 51 patients with stage III–IV hypopharyngeal cancer who underwent chemoradiation therapy as the first treatment method. Possible significant prognostic factors (i.e. tumor volume, central necrosis, pathology, age) were collected to determine whether they correlate with local disease control and survival. Results: Primary tumor volume correlated with local disease control and survival. The greatest risk for local failure was found among patients with primary tumor volumes >19.0 ml (p = 0.001). Other relatively significant prognostic factors were pathology and central necrosis. The survival rate among patients with primary tumor volumes >19.0 ml was only 39.3% compared with 78.3% for patients with volumes <19.0 ml (p = 0.036). A proportional hazard model indicated that significant parameters associated with overall survival were primary tumor volume (p = 0.036) and central necrosis (p = 0.008). According to the cancer cell differentiation, the hazard risk in the well-differentiated group was 5.62 folds higher than in the poorly differentiated group (p = 0.05). Patients with an initial complete response had a primary tumor volume <19 ml (p = 0.001, 0.016), poorly differentiated pathology (p = 0.001, 0.016), and no central necrosis (p = 0.001, 0.016). Other relatively poor significant factors were T stage above III (p = 0.047), cervical lymphadenopathy beyond level II (p = 0.046), and a nodal volume >10.0 ml (p = 0.029). N stage, age and gender were not significant prognostic factors. Conclusion: Tumor volume is the most important prognostic factor of treatment outcome for patients with hypopharyngeal cancer and should always be taken into consideration in treatment planning. Other possible prognostic factors which affect the initial complete response rate and survival rate including central necrosis, pathology, nodal number and nodal volume, T stage above III, and cervical lymphadenopathy beyond level II have a relatively low correlation with treatment outcome. In our study, there was a correlation between tumor volume and central necrosis, but no significant correlation between pathological differentiation and tumor volume, although both affect treatment outcome.