Importance of the patient's clinical questionnaire for the diagnosis of skin cancer through teledermatology in remote areas of Brazil

Introduction: Skin cancer is the most common cancer worldwide and in Brazil represents 25% of cases of cancer. Brazil is a developing country with a large territorial dimension and not many people have access to information and healthcare providers. Teledermatology is already being used in programs for cancer prevention in a mobile unit at Barretos Cancer Hospital. The aim of this study was to assess the incremental value of the use of a clinical questionnaire added to digital photography to improve the screening of skin cancer. Methods: A total of 623 patients were included. In the first phase of the study, 436 patients were screened for skin malignancy from February 2010 to July 2011. In the second phase, 186 patients were screened between June and July 2012. All patients had their skin lesions photographed. In the second phase of the study, information on medical and family history, physical characteristics of the lesion and risk factors was collected. Photographs and clinical information from the second phase only were sent to the Barretos Cancer Hospital for diagnosis by medical specialists. Sensitivity, specificity, positive and negative predictive values and accuracy of observers were analysed, using the pathology diagnosis as the gold standard. Results: The majority of lesions in the first and second phases (68.3% and 64%, respectively), were classified as basocellular carcinoma, and melanoma represented 1.4% and 2.2%, respectively, of skin cancers. The specificity and positive predictive values in the first and second phases of the study regarding observers 1 and 2 changed significantly with the addition of a clinical questionnaire (observer 1: p=0.003; observer 2: p=0.002). Moreover, there was a significant increase in receiver operating characteristic curve for the observers, comparing the two phases when the clinical questionnaire for diagnosis is implemented. Conclusions: The clinical questionnaire combined with digital photography has increased the performance of observers for skin cancer diagnosis in an opportunistic screening scenario.