PDT combined with Intravesical BCG instillation would form an autovaccine for bladder cancer?

Abstract

Bladder cancer is the second most common urologic malignancy after prostate cancer. Intravesical BCG as a treatment of superficial bladder cancer (SBC) has been used by urologists for over 30 years. Recently, photodynamic therapy (PDT), which uses a red laser and a photosensitive drug to destroy cancer cells, has been showed encouraging results in SBC treatment. However, BCG and PDT are applied to treatment of SBC alone. Currently, cancer vaccines are made in vitro. Several studies confirmed that tumour cells treated in vitro by PDT can be used for generating potent cancer vaccines, which were more effective than other modes of creating whole tumor vaccines, i.e., UV or ionizing irradiation [Gollnick SO, Vaughan L, Henderson BW. Generation of effective antitumor vaccines using photodynamic therapy. Cancer Res 2002;62:1604-8]. Moreover, BCG is a pleiotropic immune stimulator oriented to cellular immunity. We thought that: after PDT destroyed targeted tumor cells on a large scale, Intravesical BCG could elicit and amplify the immune responses, which would directly form an in situ autovaccine in vivo against the primary tumor and metastases at distant sites. In this paper, we propose that the combination of Intravesical BCG and PDT would be a promising new modality for bladder cancer.