Assessment of systemic reaction to inflammation induced by photodynamic therapy in cervical intraepithelial neoplasia.

Photodynamic therapy is a curative treatment of human papillomavirus-associated diseases that provides a selective effect leading to the destruction of pathological cells containing the virus. The retrospective study aimed to determine the role of systemic inflammatory reaction induced by photodynamic stimulation in low- and high-squamous intraepithelial lesion treatment.

Methods: 143 patients with confirmed human papillomavirus-associated cervical intraepithelial neoplasia underwent photodynamic therapy with Photolon and activation in the range of 662 nm. All patients underwent colposcopy, histologic study, HPV DNA analysis, CBC, and immunogram. The chi-square criterion was used to evaluate differences before, 5 days post, and 3 months after PDT; a P value <0.05 was considered significant.

Results: A complete regression in patients with low-squamous intraepithelial lesion (n=117) was achieved 3 months after PDT in 89.7% of cases (105/117) while it persisted in 12 patients. Complete regression in patients with high-squamous intraepithelial lesion (n=26) was achieved in 92.3% (24/26), one patient retained with the lesion, and another one had partial regression in the form of lower grade lesion. On the 5th day post-PDT, the formation of dense fibrin in photodynamic effect was noted on colposcopy, and changes in CBC, accompanied by statistically significant neutrocytosis, increased ESR and other indicators of reactive inflammation were recorded. Patients noted increased body temperature up to 37.8±0.5°C in 88% of cases.

Conclusion: One of the mechanisms of PDT`s antitumor and antiviral action is the development of acute inflammation in response to cytotoxic action on cells and vascular response in the form of pathological area devascularization. Such reactive inflammation activates all parts of the immune system. Changes on day 5 post-PDT in inflammatory parameters in CBC and IL-1, IL-6 and TNF-α markers correlate with the clinical picture of the post-photodynamic effect.