Adjuvant intraoperative photodynamic therapy (AIOPDT) after photosensitization with mTHPC in a CC531 colon carcinoma model in mice

The effectiveness of PDT as an adjuvant alternative therapy method for diverse malignant tumors has been investigated in numerous studies. The therapeutic benefit and extent of side effects is mainly determined by the applied photoactive substance. The second generation photosensitizer (PS) mTHPC is capable of causing selective tumor cell death in colon carcinoma when combined with laser irradiation of a PS specific wavelength. Our study revealed PDT with mTHPC as an efficient adjuvant intraoperative modality after R1/R2 resection of a subcutaneously implanted colon tumor. There was a significant increase of postoperative recurrence-free survival time using PDT compared to a control group in a colon cancer model in nude mice. The accumulation of the PS determined by point spectrometry showed a high tumor-selectivity in the tumor, tumor bed, and overlying skin compared to muscle tissue as reference parameter.