A combination of preoperative or intraoperative MB-PDT and surgery in the treatment of giant cutaneous squamous cell carcinoma with infection.

BACKGROUND Giant cutaneous squamous cell carcinoma (cSCC) with infection is a major clinical issue, as the infection not only promotes the progress of tumor, but also effects the success of surgery. Traditional antibiotic treatment is not always sufficient to clear the infection, especially for cSCC infected with multidrug-resistant bacteria. Photodynamic therapy (PDT) has broad-spectral antibacterial activity and non-selective pressure, which makes it difficult to induce antibiotic resistance. Here, we aim to evaluate the safety and efficacy of PDT, along with photosensitizers MB (Methylene blue) - in the treatment of cSCC infected with multidrug-resistant bacteria. METHODS In our study, 6 patients with giant csCC accompanied infection were diagnosed by pathological examination and the depth of tumor tissues was examined by X-Ray or MRI. All patients' tumor wounds were firstly irradiated with MB-PDT (635 nm, 120 J/cm2, 100 mW/cm2) using the red LED to control the infection. After the control of infection was confirmed by the culture of secretion, tumor underwent expanded resection. Multi-point pathological monitoring was performed during the operation to assure that there was no residual tumor tissue on the wound, and the primary or secondary repair was performed according to the condition of the wound. If the wound requires the tissue flaps transplation in secondary stage, the wound was irradiated again with intraoperative MB-PDT to remove the possible residual tumor cells, as well as to prevent wound infection. All patients were followed up for 0.8-3 years after flap transplation. RESULTS In 6 patients, the cSCC infection was completely controlled by MB-PDT, and the flap survival was 100%. There was no recurrence of cSCC in the follow-up of 1.6 years (range, 0.8-3 years) after the comminated treatment with MB-PDT and surgery. CONCLUSIONS Multi-drug resistant bacteria could efficiently be killed by MB-PDT, and the combination of surgery with MB-PDT is a safe and effective approach for treating giant cSCC with infection.