Different prognostic significance of negative conversion of tumor biopsy after preoperative therapy for esophageal cancer according to the local extent of primary tumor

Abstract

Introduction: The major response to the preoperative therapy (POT) is known as a significant prognostic predictor in esophageal cancer patients. However, prognostic implication of the negative conversion of tumor biopsy after the POT has not been fully investigated. The aim of the study was to determine whether the biopsy status after the POT has a significant prognostic impact in esophageal cancer patients. Methods: This retrospective study included 86 patients who underwent POT including chemotherapy (n = 63) and chemoradiotherapy (n = 19) for T1b or deeper esophageal tumor. All patients had cStage II or more advanced disease. Two courses-chemotherapy consisting of 5FU, doxorubicin, and nedaplatin was used as the POT during 2002 and 2012. Three courses-chemotherapy consisting of docetaxel, cisplatin, and S-1 was used during 2013 and 2017. Chemoradiotherapy consisting of 40-66 Gy radiotherapy with nedaplatin/5FU or docetaxel was used as the POT during 2006 and 2013. Biopsy was done at the primary tumor site before and after the POT in all patients. Results: Negative conversion of tumor biopsy after the POT was observed in 48 (56%) of the 86 patients. Although the negative conversion rate was significantly higher (p = 0.035) in the chemoradiotherapy group (79%) than the chemotherapy group (49%), it was not significantly different between cT1/T2 patients (n = 16) and cT3/T4 patients (n = 70): 44% vs 59%. The 5-year survival rate was significantly better (p = 0.044) in the patients having negatively converted biopsy (70%) than in the patients having persistently positive biopsy (42%). However, the biopsy status had no survival impact in patients having cT1/T2 tumor: the 5-year survival rate for the negative conversion group (n = 7) and the persistently positive group (n = 9) was 100% and 88%, respectively. Contrary, the 5-year survival rate for the negative conversion group (n = 41) was significantly better (p = 0.027) than the persistently positive group (n = 29) in cases of cT3/T4 tumor: 65% vs 31%. The survival was extremely dismal in patients having persistently positive biopsy (n = 13) compared with patients having negatively converted biopsy (n = 31) in cases of cT4 tumor: the 5-year survival rate was 11% in the former patients whereas it was 59% in the latter patients (p = 0.009). Of the 48 patients having negatively converted biopsy, 45 (94%) had the major response (CR + PR) to the POT, whereas 21 (55%) of the 38 patients having persistently positive biopsy had the major response to the POT (p < 0.001). Conclusion: The negative conversion of tumor biopsy after the POT is a significant prognostic predictor only in cases of cT3/T4 esophageal cancer. The survival is extremely poor in patients with cT4 tumor if the negative conversion of tumor biopsy was not observed after the POT. Although the biopsy status after the POT is closely related to the response status to the POT, the biopsy status after the POT is a useful and convenient prognostic predictor in patients with cT3/T4 esophageal cancer.