High risk alpha human papillomaviruses (HPVs) are recognized to be causally related to a subset of head and neck squamous cell carcinoma (HNSCC) arising from the crypt epithelium of the palatine and lingual tonsils. The aim of this study was to explore the trends in the incidence of HNSCC arising from different anatomical sites potentially related and unrelated to HPV infection among Italian women and men to provide clues on possible growing impact of HPV in the epidemiology of HNSCC in Italy.
Epidemiological data were retrieved from 10 long-term Cancer Registries of the Network of Italian Cancer Registries (AIRTUM) covering a population of 7.8 million of inhabitants (13% of the whole country) in the period 1988-2012. Trends were described by means of the estimated annual percent change (APC) with appropriate 95% confidence intervals stratified by age, sex, and birth cohort and compared between HPV-related and HPV-unrelated anatomical sites. Only cases with squamous cell histology or morphologic variants of HNSCC were included in the analysis. Cancers arising from lip, nasopharynx, nasal cavity and sinuses were excluded as they are linked to other etiological factors.
A total of 28,883 HNSCCs were included in the analysis. The age-standardized (on European population) annual incidence trends of all sites showed a significant decrease in males (APC: -1.61, 1988-1998; P<0.0001; APC:-3.18, 1998-2012; P<0.0001) and a significant increased in females (APC: +1.41, 1988-2012; P=0.0002). The incidence of cancers arising from head and neck sites strongly related to HPV infection (tonsil and base of tongue/lingual tonsil) increased significantly over the period 1988-2012 (APC: +1.34%; P<0.0001), particularly in females (APC: +2.59%; P=0.0029). Conversely cancers arising from sites poorly related to HPV infection decreased markedly in males and remained relatively stable in females.
The pattern observed suggest a potential increasing impact of HPV infection on the epidemiology of HNSCC in Italy.