First experience of using intraoperative photodynamic therapy for primary locally advanced cancer of the oral mucosa

Objective. Cancer of the oral mucosa is frequently detected only at stages III and IV of the disease despite the visual accessibility of the tumor in 37.6% of the total number of cases, resulting in recurrence being the main problem after completion of primary treatment in these patients. The search for interventions to improve the treatment efficacy of locally advanced oral mucosa tumors is ongoing.

Material and methods. Twelve patients with primary locally advanced cancer of the oral mucosa T3-4aN0-2M0 underwent radical tumor excision and intraoperative photodynamic therapy (PDT). The device “Latus-T Fara” with the following parameters: wavelength 662 nm, power density 45 MW, light energy at a dose of 200–300 J/cm2 was used along with Chlorin E6 photosensitizer. PDT was carried out on the postsurgical tumor bed before the surgical wound was closed, and PDT duration depended on the size of the tumor bed.

Results. In 1 (8.3%) out of 12 patients, partial failure of the dermal-fat flap used for plastic surgery of the mouth floor was noted together with the wound dehiscence. In all patients within 3 days after surgery with the use of intraoperative PDT there was a pronounced edema of soft tissues in the area of the floor of the mouth, lips, cheeks. On the third day after surgery, decannulation was performed after the regression of edema and the restoration of sufficient mobility of the tongue: within the time period when patients had increased tongue stump movements and were able to swallow saliva without gagging. On day 9, the sutures were removed, and the nasogastric tube was removed. No late complications were observed. Twelve months after complex or combined treatment with the addition of intraoperative PDT, 100% of patients had no signs of local recurrence and metastasis.

Conclusion. A safe method of intraoperative photodynamic therapy for the treatment of patients with locally advanced cancer of the oral mucosa has been developed, wherein the treatment is applied to the surgical bed before the wound defect closure. The analysis of the short-term outcomes after 12 months suggests the possibility of using intraoperative photodynamic therapy to prevent the development of local recurrences and metastasis in patients with primary locally advanced cancer of the oral mucosa.

Key words: intraoperative photodynamic therapy, locally advanced oral mucosa cancer, Chlorin E6 photosensitizer, Latus-T Fara

Conflicts of interest. The authors have no conflicts of interest to declare.

Financing. The study was carried out within the framework of the state task on the topic: Development of prognostic and predictive algorithms based on the identification of new immunological and molecular genetic characteristics of malignant tumors and their microenvironment.