Evaluation of the efficacy and safety of salvage photodynamic therapy with talaporfin sodium for lesions beyond those indicated for investigator-initiated clinical trials

Objectives: Since the efficacy of salvage photodynamic therapy (PDT) for locally recurrent esophageal cancer after definitive chemoradiotherapy (CRT) was proven for the first time in an investigator-initiated clinical trial, various reports have supported the clinical utility of PDT for these lesions. However, the clinical trial had limited indications, including a luminal circumference of ≤1/2, maximum longitudinal lesion length of 3 cm, and no invasion into the cervical esophagus, and there have been few reports of treatment outcomes for lesions exceeding the indications used in the investigator-initiated clinical trial. Therefore, this study was performed to assess the outcomes of treating lesions exceeding the above indications. Methods: We retrospectively enrolled 34 consecutive esophageal cancer patients with 38 lesions who underwent PDT with talaporfin sodium. Lesions were classified as meeting (within-indications group; 23 patients, 25 lesions) or exceeding (beyond-indications group; 11 patients, 13 lesions) the indications in the investigator-initiated clinical trial. The local complete response rate (L-CR), overall survival (OS), progression-free survival (PFS), and incidence of PDT-related adverse events were compared between the groups. Results: The L-CR rate was 88.0 and 92.3% in the within- and beyond-indications groups, respectively. The 2-year OS rate was 69.5% and 90.0% and the 2-year PFS rate was 43.3 and 56.6% in the within- and beyond-indications groups, respectively. In terms of adverse events, there were no serious adverse events in either group. Conclusion: Salvage PDT might be effective for local recurrence after CRT for lesions exceeding the indications in the investigator-initiated clinical trial.