Prognostic Value of Bone Marrow Micrometastasis in Patients with Operable Esophageal Squamous Cell Carcinoma: A Long-Term Follow-Up Study

IntroductionDetection of bone marrow micrometastasis (BMM) has been focused on as a prognostic parameter in various malignant neoplasms recently. This study was designed to evaluate the prognostic significance of BMM detection in patients with operable esophageal squamous cell carcinoma (ESCC) after long-term follow-up.MethodsIn 61 consecutive patients with ESCC who had undergone radical surgical resection, BMM was detected through reverse transcriptase-polymerase chain reaction (RT-PCR). Correlation between BMM detection and prognosis of the 61 patients was analyzed.ResultsBMM was found in 13 patients (21.3%). No significant correlation between BMM detection and tumor, node, metastasis (TNM) stage was found. The median survival time, 5-year overall survival rate, 5-year disease-free survival rate, and 5-year distant disease-free survival rate for cases with positive BMM were 13.0 months, 15.4%, 7.7%, and 34.2%, respectively, compared with that of 66.0 months, 59.7%, 49.1%, and 60.6% for cases with negative BMM (p < 0.05). In multivariate analysis, BMM were found to be an independent factor in the prediction of overall survival (odds ratio [OR] 3.928, p = 0.001), disease-free survival (OR 4.285, p < 0.001), and distant disease-free survival (OR 3.270, p = 0.013).ConclusionsBMM is an independent prognostic factor in the prediction of the subsequent development of metastatic disease and disease outcome for operable ESCC patients, and may be a useful adjunct to conventional tumor staging. Further studies are required to evaluate the value of neoadjuvant or adjuvant systemic therapy in ESCC patients with BMM.