Alessandro Franchi - Pathology of Sinonasal Tumors and Tumor-Like Lesions

Sinonasal cancers (SNCs) represent less than the 0.2% of all malignant cancers yearly diagnosed in the world []. Despite this low frequency, a great variety of histological types may be found, and the most frequent are keratinising squamous cell carcinoma (SCC) , adenocarcinomas (AD) , cylindrical cell ( non-keratinising ) carcinoma , undifferentiated carcinoma , lymphoma , melanoma and olfactory neuroblastoma .

SNCs may be classified as rare cancer , but the low absolute risk in the general population effectively contrasts with the high relative risks for specific chemical exposures and occupational settings. SNCs are indeed considered rare cancers with high occupational attributable fraction (AF: 2043%) []. In this chapter, we review the current knowledge on epidemiological aspects of SNC.

SNCs represent less than the 0.2% of all malignant cancers yearly diagnosed in the world. The incidence rates are around 1/100,000 inhabitants, as reported in the publication Cancer Incidence in Five Continents-Volume XI, a report published approximately every 5 years by the International Agency for Research on Cancer and the International Association of Cancer Registries, which provides comparable high-quality statistics on the incidence of cancer from cancer registries around the world []; in volume XI, the period 20082012 is analysed.

The annual number of new cases is available where population-based cancer registries exist, with some approximation, because current statistics are by site and the three-digit ICD-O-3 codes C30C31 (cancers of the nasal cavity , middle ear and paranasal sinuses) encompass middle ear cancers too []. The percentage distribution of cancers across subsites of the sinonasal region is different in different geographic areas. Generally, the subsite middle ear is the less represented (e.g. in males it accounts for less than 3% of cases in the USA). Nevertheless, when descriptive epidemiology of cancers of the SNC are presented, current statistics must be interpreted considering that the ICD-O-3 codes for SNC take into account also middle ear.

SNCs may be classified as rare cancer: according to the European Parliament and Council of the European communities, rare diseases are defined as those with a prevalence of <50 per 100,000 [] and proposed a new definition of rarity for cancers and a list of rare cancers in Europe.

The low frequencies of rare cancers, and the consequent limited medical expertise on the matter, create specific problems in clinical decision making, clinical research and healthcare organisation. In addition, patients and their families are confronted with a wide range of difficulties arising directly from the rarity of the pathologies. Such difficulties may include wrong diagnosis leading to inaccurate treatments, delays in the period between the onset of the first symptoms and the diagnosis, insufficient scientific knowledge and lack of appropriate quality healthcare.

In North America, crude incidence rates are about 1.1/100,000 inhabitant among men and 0.6/100,000 among women, with similar values in Asia (about 1.0/100,000 men and 0.6/100,000 women). Rates are slightly higher in Europe (about 1.2/100,000 men and 0.7/100,000 women) and Oceania (about 1.1/100,000 men and 0.6/100,000 women) and lower in Central/South America (about 0.5/100,000 men and 0.3/100,000 women) and Africa (about 0.4/100,000 men and 0.3/100,000 [].