Clinical Implications of Conversion Surgery After Induction Therapy for T4b Thoracic Esophageal Squamous Cell Carcinoma

Definitive chemoradiation therapy or chemotherapy alone is generally recommended for patients with unresectable cT4b esophageal cancer. However, conversion surgery has emerged as a therapeutic option when downstaging is achieved by induction therapy.

We studied 169 patients with cT4 esophageal cancer who underwent induction therapy. Survival and prognostic factors were examined.

Of 169 patients, 25 who achieved a clinical complete response (cCR) underwent surveillance, 72 patients underwent conversion surgery, while another 72 patients whose tumors were regarded as unresectable after induction therapy did not undergo surgery. Among 169 patients, the 3- and 5-year survival rates were 31.0% and 25.9%, respectively. Sixty-four patients who underwent curative resection showed better survival comparable with survival of 25 patients who achieved cCR (3- and 5-year survival; 56.8% and 48.6% versus 64.0% and 52.0%, respectively). However, the survival of eight patients who underwent noncurative resection was as dismal as that of patients who did not undergo conversion surgery. Multivariate analysis in 169 patients identified female sex and achieving cCR or R0 resection as independent prognostic factors. Multivariate analysis in 72 patients who underwent conversion surgery identified sex, lymph node status, and R0 resection as independent prognostic factors in patients with cT4b esophageal cancer.

The present study showed that conversion surgery after induction therapy can be a potentially curative treatment option for select patients with cT4b esophageal cancer. An important issue for further research is to establish a method for more accurately diagnosing tumor resectability after induction therapy for cT4b esophageal cancer.