Pain during topical photodynamic therapy: uncomfortable and unpredictable

Background The major drawback of the widely used photodynamic therapy (PDT) is treatment-related pain. Objective Gain insight into the intensity of and predictive factors for painful burning sensation associated with PDT. Methods A prospective cohort study was performed at the department of Dermatology in the Maastricht University Medical Centre in Maastricht, a reference centre for dermatological oncology in The Netherlands. A total of 141 lesions in 108 patients were included, treated from November 2008 until June 2009 with PDT for superficial basal cell carcinoma, Bowen's disease (BD) or actinic keratosis (AK). Painful burning sensation was scored based on an 11-point pain intensity numeric rating scale (PI-NRS) (0 = no pain; 10 = worst possible pain). Results The percentage of patients with a PI-NRS score over six was 32.6% and 37.9% during the primary and follow-up PDT session respectively. A total of 76.6% (95/124) of the patients was consistent in pain intensity score reporting. Factors associated with higher PI-NRS scores were treatment of AK or BD, tumour localization in the head/neck region, patient's age over 70, Fitzpatrick skitype I/II, photosensitizer 5-aminolevulinic acid and use of oral analgesics. After mutual adjustment of these factors, Fitzpatrick skintype remained the only independent predictor of PI-NRS scores during PDT. Conclusion It remains difficult to decide which patients should be considered for pain relieving measures. The solution remains to support all patients treated with PDT with pain relieving techniques or to let the support of pain relieving measures depend on the reported pain score for the primary session.