1. Introduction
kin cancer is the most common type of cancer in the world. Pattern of skin cancer is different in various geographical regions, depending on the genetic and environmental factors [1]. Basal Cell Carcinoma (BCC) is the most common type of skin cancer mainly caused by sun exposure [2, 1]. Squamous Cell Carcinoma (SCC) and malignant melanoma types are less common but are fatal skin cancers that may not be related to exposure to ultraviolet. Trauma, immunosuppressive therapy, human papilloma viruses and chronic ulcers may have a role in skin cancers. Unfortunately the incidence of malignant melanoma and SCC has been increased in recent years compared to BCC [2, 3]. This study aims to determine the incidence of skin cancers in Guilan province with a mild and humid climate located in north of Iran, and evaluate the changes in its occurrence.
2. Materials and Methods
In this descriptive cross-sectional study, the data related to all cases of skin cancer that had been registered for Guilan province in the National Cancer Registry reports during 2010-2014 were used. The age-sex incidence of skin cancer was standardized using the standard population of the World Health Organization. The age-standardized incidence rate of skin cancers including BCC, SCC and melanoma in Guilan Province was calculated, and its trends were then evaluated.
3. Results
A total of 1664 cases with skin cancer, 1014 men and 650 women, were reported in the province between 2010 and 2014. Incidence of skin cancer was higher in men. BCC was the most common skin cancer (66%). The most common sites of BCC was the face and scalp. For SCC, it was the lip, and melanoma most frequently occurred on the acral regions. The incidence of skin cancer in Guilan province had a rising trend and had raised in all age groups (Figure 1). 4. Discussion and Conclusion
The results of this study showed an increasing trend of skin cancer in Guilan Province of Iran. Therefore, planning for detection, prevention and control of its risk factors is necessary. The increasing trend may be partially explained by more accurate diagnostic methods, earlier detection and registration of new cases in recent years. The most common sites of cutaneous malignancies reported in previous reports [5, 4] are similar to our results. Radiation therapy for treatment of tinea capitis in past decades, immunosuppressive therapy in organ-transplanted patients, and occupational exposures to carcinogens can increase the incidence of skin cancers in middle-aged patients [2, 3]. Therefore, paying attention to these risk factors and regular skin examination should be considered in high-risk patients.

Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Ethics Committee of Guilan University of Medical Sciences (Code: IR.GUMS.REC.1396.200).

Funding
This project was supported by the Vice-Chancellor of Research and Technology of Guilan University of Medical Sciences.

Authors' contributions
Conceptualization, investigation, writing – review & editing, resources: All authors; Methodology: Rana Rafiei, Seyyedeh Sareh Shafaei; Data collection: Fatemeh Shamsa; Writing – original draft: Rana Rafiei, Abbas Darjani, Fatemeh Shamsa; Cooperation in funding acquisition: Abbas Darjani; Supervision: Abbas Darjani, Rana Rafiei.

Conflicts of interest
The authors declare no conflict of interest 

Acknowledgements
The authors would like to thank the cooperation of the Vice-Chancellor of Research and Technology, Guilan University of Medical Sciences, and Ms. Elahe Rafiei.


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