Outdoor work as a risk factor for high-grade cutaneous squamous cell carcinoma of the head and neck

Introduction
While it is clear that individuals with outdoor occupations are at a significantly greater risk of developing cutaneous squamous cell carcinoma (cSCC), no previous studies have investigated the potential association between the tumour grade and occupation in this patient population.

Aim
To assess occupation as a risk factor for the development of high-grade cSCC. Secondarily, to determine the association between the tumour grade and other clinical characteristics.

Material and methods
Retrospective analysis of 256 patients treated for head and neck cSCC at our institution in 2007–2016. The following patient characteristics and variables were assessed: age; sex; tumour location and grade; profession; and education level. A univariate analysis was performed to assess the association between each study variable and grade 3 tumour differentiation.

Results
The following variables were significantly associated (p < 0.05) with grade 3 (G3) cSCC tumours: outdoor work vs. indoor work; primary school vs. high school education; and age. Additionally, patients with low-grade (G1) tumours were significantly younger (mean age: 72) than patients with high-grade (G3) tumours (mean age: 79) (p = 0.046).

Conclusions
To our knowledge, this is the first study to assess the variables associated with the tumour grade among outdoor workers. These findings suggest that outdoor workers who develop cSCC are at a greater risk of developing more aggressive cancers. These findings provide additional support for classifying cSCC as an occupational disease. Early education about the dangers of sun exposure during the first years of school is essential to minimize the risks of developing high-grade skin cancer.