Photodynamic Therapy with m-THPC as Adjuvant Treatment for Resected Malignant Mesothelioma
P. Baas, F.A. Zoetmulder, L. Murrer, F.A. Stewart, H. Schouwing, HB Ris*, N. van Zandwijk and E.J.Th.Rutgers. The Netherlands Cancer Inst., Amsterdam, The Netherlands. *Bern, Switzerland.
Malignant Mesothelioma (MM) is a disease which is difficult to treat. In some cases surgical resection is performed but microscopical tumor is often left behind. We therefore investigated the additional role and toxicity of preoperative PDT in 9 patients. Intra-cavitary PDT with laser light of 652 nm (6W diode laser AOC) 4 days after intra-venous 0.1 mg/kg (group 2).
Dosimetry: the light dose was measured in situ by isotropic light detectors laced in the thoracic cavity with a total energy of 11-15 J/cm2. The combined procedure in group 1 was judged to be feasible with manageable complications, some were directly attributable to the surgery (no 30 day postoperative mortality, 1 diaphragmatic rupture, 1 hematopericardium, 1 skin phototoxicity). The additional operation time was 40 minutes, mean hospital stay 21 days (18-40), f-up > 10 months. One patient died of recurrent tumor after 5 months. In group 2 one patient with preexisting cardiovascular disease died of myocardial infarction complicated by an aa spinalis anterior syndrome which slowly improved. Both patients had large tumors and complicated operations with pericardial resection. All had grade 2-3 sunburn effects of the skin around the incision.
PDT as adjunctive treatment appears feasible and offers possibilities for local control. It is unclear whether the additional toxicity in group 2 was due to the higher dose of m-THPC or surgical complications associated with the higher tumor load.