Photodynamic therapy (PDT) is used for the treatment of centrally-located early lung cancers (CLELCs) and is recommended for tumors ≤ 1.0 cm in diameter. We previously reported that PDT using talaporfin sodium, second-generation photosensitizer, for tumors > 1.0 cm but ≤ 2.0 cm in diameter was able to achieve a therapeutic outcome comparable to that of tumors with a diameter of ≤ 1.0 cm. However, the effectiveness of PDT using talaporfin sodium for tumors > 2.0 cm in diameter remains unclear. We conducted a retrospective analysis of cases in which PDT was performed for flat-type CLELCs with tumor diameters of > 2.0 cm.

We retrospectively analyzed seven cases (eight lesions) with tumor diameters > 2.0 cm and no evidence of extracartilaginous invasion or lymph node metastasis.

All the patients underwent multiple PDT sessions. The PDT treatment results over the study period were partial response in one case (14.3%), stable disease (SD) in three cases (42.9%), and progressive disease (PD) in three cases (42.9%). At the time of writing this report, five of seven cases (71.4%) are still undergoing treatment. The duration of SD—the time from the start of treatment until the criteria for PD were met (SD or better maintained)—ranged from 7–52 months (mean, 25.3 months).

“Maintenance PDT” for CLELCs > 2.0 cm in diameter has the potential to inhibit tumor progression in the long term while maintaining quality of life, rather than simply aiming only for a quick radical cure.