Pathologic Assessment of Tumor Regression After Preoperative Chemoradiotherapy of Esophageal Carcinoma. Clinicopathologic Correlations

Background: The benefits of preoperative chemotherapy and radiation for esophageal carcinoma are under investigation. A pilot study was undertaken to determine if pathologic assessment of tumor regression correlated with disease free survival.

Methods: Ninety-three resected specimens from patients treated with cis-dichloro-diamino cisplatin and irradiation before surgery were examined on semiserial sections. Patients selected for surgery were all Status 1 according to the World Health Organization (WHO) classification. Histologic typing was based on the WHO classification. Tumor regression grade (TRG) was quantitated in five grades: TRG 1 (complete regression) showed absence of residual cancer and fibrosis extending through the different layers of the esophageal wall; TRG 2 was characterized by the presence of rare residual cancer cells scattered through the fibrosis; TRG 3 was characterized by an increase in the number of residual cancer cells, but fibrosis still predominated; TRG 4 showed residual cancer outgrowing fibrosis; and TRG 5 was characterized by absence of regressive changes. Survival curves were estimated according to the Kaplan-Meier method. A quantification of the relationship between treatment failure and confounding variables (age, tumor location, tumor size, esophageal wall involvement by residual cancer and/or regressive changes, histology, treatment, adequacy of surgery, pathologic lymph node status, and tumor regression grade) was done using Cox's proportional hazards model.

Results: Forty-two percent of specimens were TGR 1-2; 20%, TGR 3; and 33%, TGR 4-5. Univariate analysis found that tumor size, pathologic lymph node status, tumor regression grade, and esophageal wall involvement were highly correlated with disease free survival (P < 0.05). After multivariate analysis, only tumor regression (i.e., TRG 1-3 versus TRG 4-5) remained a significant (P < 0.001) predictor of disease free survival.

Conclusions: This study highlights the importance of tumor regression in the survival of patients with esophageal carcinoma treated with preoperative chemoradiotherapy. These findings suggest that tumor regression grade should be considered when evaluating therapeutic results.