Weather conditions and daylight-mediated photodynamic therapy: protoporphyrin IX-weighted daylight doses measured in six geographical locations.

BACKGROUND: Photodynamic therapy (PDT) is an attractive therapy for nonmelanoma skin cancers and actinic keratoses (AKs). Daylight-mediated methyl aminolaevulinate PDT (daylight-PDT) is a simple and painless treatment procedure for PDT. All daylight-PDT studies have been performed in the Nordic countries. To be able to apply these results in other parts of the world we have to compare the daily protoporphyrin IX (PpIX) light dose in other countries with the PpIX light doses found in Nordic countries. OBJECTIVES: To calculate where and when daylight-PDT of AKs was possible in six different geographical locations using ground stations measuring PpIX-weighted daylight doses. METHODS: PpIX-weighted daylight doses were measured using a dosimeter with a customer-specific photodiode with a detector sensitivity that mimics the PpIX absorption spectrum and measures in 'PpIX doses'. The dosimeters were built into ground stations that were placed in six geographical locations measuring from July to December 2008. Temperature data for each location were obtained from the internet. The maximal ultraviolet (UV) index for Copenhagen was obtained for the measuring period of the dosimeters. RESULTS: If the PpIX light dose should be above 8Jcm(-2) and the maximum temperature of the day at least 10°C, it was possible to treat patients on nearly all days until the middle of September in Reykjavik and Oslo, until the last week of October in Copenhagen and Regensburg, until the middle of November in Turin and all year in Israel. CONCLUSIONS: Where and when to perform daylight-PDT depends on the PpIX light dose and outdoor temperature. The PpIX light dose was influenced by the geographical location (latitude), weather condition and time of year. The UV index was not more suitable than temperature and weather to predict if the intensity of daylight would be sufficient for daylight-PDT.

Human papillomavirus in venous ulcers with and without squamous cell carcinoma.

Malignant transformation of chronic wounds is a well-known, albeit rare, phenomenon. We examined archival paraffin blocks of samples of squamous cell carcinoma (SCC) in chronic venous leg ulcers previously taken from 23 patients and of chronic noncancerous venous leg ulcers from 35 patients for the presence of human papillomavirus (HPV) DNA. The methods used were the polymerase chain reaction (PCR) with GP05+/06+ (mucosal) and nested PCR with CP65/70 and CP66/69 (EV-associated) primers. A subsequent nonradioactive Southern blot hybridization was used to confirm the specificity of the PCR. With PCR three samples were positive on the gel, and with Southern blotting, a further seven samples were positive, to give a total of ten samples. All of the positive samples were from the noncancerous ulcers and with the primers GP05+/06+. HPV infection is probably not the carcinogen responsible for the malignant transformation of venous leg ulcers. The difference in positivity between the ulcers and the SCCs was statistically significant (P = 0.01) and raises the question as to whether HPV-positive cells are eliminated in the interaction between the SCC and the immune system. Further studies on the carcinogenic effects of chronic proliferation and the role of HPV infection therein, are needed.

Squamous cell carcinoma complicating chronic venous leg ulceration: a study of the histopathology, course and survival in 25 patients.

We have studied 25 cases of squamous cell carcinoma in chronic venous leg ulcers. Twenty-three of the patients were dead and two were alive. The mean age at cancer diagnosis was 78.5 years. The median survival was 1 year. Eleven tumours were well-differentiated, 10 moderately and four poorly. All patients with a poorly differentiated tumour died within a year. Metastases were certain in eight cases. The disease was lethal in 10 cases which included all poorly differentiated tumours. The survival of the study group was significantly shortened compared with a control group of patients with lower limb non-melanoma skin cancer (n = 433) from the Swedish Cancer Registry (P = 0.0084). When diagnosed, squamous cell carcinoma in chronic leg ulcers merits a thorough investigation of the degree of differentiation and spread. Assertive treatment is indicated as poorly differentiated tumours and some moderately differentiated tumours may be fatal.