The patients were evaluated at seven days after treatment and at two-monthly follow-up consultations. The bilirubin level fell by over 70% within one week in all patients, and the Karnofsky index also improved (Fig. 1). At two months, all of the patients were assessed endoscopically and the stents were replaced. Because of persisting cancer, five patients were re-treated a second time with PDT. In three of these five patients, after the second treatment no intraluminal cancer was identified, and indeed in two of them no further endoprosthesis was required. One patient was treated three times.
The treatments were all carried out on an in-patient basis, with a median hospital stay of seven days for the PDT treatment (range 1-25 days). Compared to patients undergoing stenting reported in the literature (not treated with PDT), with a 30-day mortality of between 32% and 75% and a median survival of between 62 and 70 days in patients with Bismuth III and IV, the achievement of median survival of
439 days (Fig. 2) and a reduction in the 300-day mortality to 0 is progress indeed. Although this is a small group, the patients were of the most advanced and difficult type to treat.
What about side effects? Sunlight sensitivity, the most common side effect, may last three to six weeks. This is inconvenient, but not serious. No other serious effects were noted. The study also demonstrates that PDT can be used repeatedly without loss of effect, in contrast to radiotherapy. Thus, PDT seems to be a useful modality for the treatment of unresectable cholangiocarcino-ma, reducing jaundice and improving several measurable quality of life parameters.
What of the future? It will be necessary to confirm these data at other centers, and to consider a larger randomized multicenter study. The era of PDT acceptability is now at hand. Obviously, some fine tuning will need to be done. Intraluminal staging with ultrasound high-frequency catheters will improve patient selection and measurement of the response (Duda et al. Cardiovase Intervent Radid 1997; 20:133). I predict that PDT will be a potential challenge to traditional resection when treating tumor localized to the mucos'a. Diode devices will mean that the laser equipment takes up less space in already crowded endoscopy units. The difference will be between the current refrigerator-sized devices and the newer diode laser sources (the size of a transportable small suitcase), which do not require special electrical or water attachments. Newer sensitizers, with different activating wavelengths that allow deeper destruction, are fast approaching. However, they may result in more frequent complications related to excessive necrosis, such as hemorrhage or perforation. The use of PDT in combination with other modalities such as intralesional injection chemotherapy and/or hyperthermia, remains to be explored. Although many of these patients are unwell and require prolonged hospitalization, the procedure is also well suited to an ambulatory, outpatient setting, with the consequent improvements in cost-effectiveness. Hopefully, more light will reach us at the end of the endoscopic tunnel.
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