Photodynamic therapy for hilar bile duct cancer: clinical evidence for improved tumoricidal tissue penetration by temoporfin.

Photodynamic therapy (PDT) has been established for palliation of non-resectable hilar bile duct cancer (hBDC). Ablation of hBDC using porfimer (P-PDT) improves cholestasis and survival. However, the tumoricidal effect is confined to the inner 4 mm of the tumor wall. Here, we have studied whether temoporfin PDT (T-PDT) shows an efficient local response and an increased tumoricidal penetration depth. In the first stage of a phase-II trial (NCT01016002), eleven patients with hBDC (Bismuth III-IV) were treated with T-PDT plus stenting and 10 could be analyzed for local tumor response. T-PDT resulted in complete local response in n = 1 of 10 patients, partial response in n = 8 and no response in one patient (occluded right hepatic duct re-opened but positive for residual tumor cells) - indicating a tumoricidal efficacy of 90%. Four patients showed a tumoricidal depth of ≥7.5 mm. Cholestasis and palliation improved in 8 patients with an overall median survival of 18 (4.4-32.0) months after the first T-PDT. Adverse events were phototoxic skin reaction (n = 4), cholangitis (n = 3), and liver abscess (n = 3). T-PDT doubles the depth of the local tumor-ablative effect of P-PDT, is highly tumoricidal and is associated with similar rates of infectious complications and grade I and II skin phototoxicity.