Prognostic factors in clinical T1N0M0 thoracic esophageal squamous cell carcinoma invading the muscularis mucosa or submucosa

Background: Multimodality treatment is widely performed for clinical T1N0M0 (UICC-TNM classification, 7th edition) thoracic esophageal squamous cell carcinoma (ESCC), but available articles regarding treatment results are limited. This study assessed the outcomes of clinical T1N0M0 thoracic ESCC invading the muscularis mucosa (MM) or submucosa (SM) treated with radiotherapy (RT) or chemoradiotherapy (CRT). Methods: We retrospectively reviewed the medical charts of 90 patients with clinical T1N0M0 thoracic ESCC treated with RT or CRT in our hospital in 2004-2011. Of these 90 patients, we analyzed the cases of 71 patients who met our inclusion criteria. All 71 patients had MM or SM cancer. In the 47 patients treated with CRT, the chemotherapy regimen of 5-fluorouracil (5-FU) plus cisplatin (CDDP) was used for 46 patients and 5-FU and nedaplatin was used for one patient. Forty-five patients underwent endoscopic resection (ER) followed by RT or CRT as an additional treatment. Elective nodal irradiation (ENI) was used in 39 patients. For all analyses, statistical significance was defined as 0.05, and the Bonferroni correction was used for the multivariate analysis. Results: The median age was 70 years (range 47-84). With a median follow-up of 43.6 months (range 1.5-124.2), the 5-year overall survival (OS), disease-specific survival (DSS) and disease-free survival (DFS) rates were 64.0, 72.8 and 50. 0 %, respectively. The multivariate analysis showed that performance status (PS) was an independent prognostic factors for DSS and DFS (DSS, p < 0.001; DFS, p < 0.001). Chemotherapy in addition to RT showed a trend for better DSS (p = 0.032) but was not significant following Bonferroni correction. ER and ENI were not significant predictive factors for DSS and DFS. Conclusions: PS was an independent prognostic factor for DSS and DFS. ER and ENI had no significant relationship with DSS or DFS. The present results may be helpful in treatment decisions for clinical T1N0M0 thoracic ESCC.