HPV appears to play an etiologic role in many cancers of the oropharynx and possibly a small subgroup of cancers of the oral cavity. The most common HPV type in genital cancers (HPV16) was also the most common in these tumors. The mechanism of transmission of HPV to the oral cavity warrants further investigation.

Background: The magnitude of risk conferred by the interaction between tobacco and alcohol use on the risk of head and neck cancers is not clear because studies have used various methods to quantify the excess head and neck cancer burden. Methods: We analyzed individual-level pooled data from 17 European and American case-control studies (11,221 cases and 16,168 controls) participating in the International Head and Neck Cancer Epidemiology consortium. We estimated the multiplicative interaction parameter (y) and population attributable risks (PAR). Results: A greater than multiplicative joint effect between ever tobacco and alcohol use was observed for head and neck cancer risk (y = 2.15; 95% confidence interval, 1.53-3.04). The PAR for tobacco or alcohol was 72% (95% confidence interval, 61-79%) for head and

Poor oral health has been reported as a risk factor in the etiology of head and neck cancer. Data on oral health were ascertained as part of two multicenter case-control studies comprising 924 cases and 928 controls in central Europe and 2,286 cases and 1,824 controls in Latin America. Incident cases of squamous cell carcinoma of the head and neck (oral cavity, pharynx, larynx) and esophagus, as well as age (in quinquennia)- and sex frequency-matched controls, were enrolled from 1998 to 2003. Poor condition of the mouth (central Europe: odds ratio (OR) = 2.89, 95% confidence interval (CI): 1.74, 4.81; Latin America: OR = 1.89, 95% CI: 1.47, 2.42), lack of toothbrush use (Latin America: OR = 2.36, 95% CI: 1.28, 4.36), and daily mouthwash use (Latin America: OR = 3.40, 95% CI: 1.96, 5.89) emerged as risk factors for head and neck cancer, independent of tobacco use and alcohol consumption. Missing between six and 15 teeth was an independent risk factor for esophageal cancer (central Europe: OR = 2.84, 95% CI: 1.26, 6.41; Latin America: OR = 2.18, 95% CI: 1.04, 4.59). These results indicate that periodontal disease (as indicated by poor condition of the mouth and missing teeth) and daily mouthwash use may be independent causes of cancers of the head, neck, and esophagus.

A variety of statistics are used to quantify the burden (occurrence and outcome) of cancer generally and of breast cancer specifically. When undertaking any cancer control program, understanding these statistics, their source, and their quality is important for assessing the current situation, allocating resources to different control strategies, and evaluating progress. Two core statistics are the cancer incidence rate and the cancer mortality rate, which provide estimates of the average risk of acquiring and of dying from the disease, respectively. About 16% of the world's population is covered by registration systems that produce cancer incidence statistics, while mortality data are available for about 29%. Breast cancer incidence and mortality vary considerably by world region. In general, the incidence is high (greater than 80 per 100,000) in developed regions of the world and low (less than 30 per 100,000), though increasing, in developing regions; the range of mortality rates is much less (approximately 6-23 per 100,000) because of the more favorable survival of breast cancer in (high-incidence) developed regions. The incidence of breast cancer is increasing almost everywhere. This unfavorable trend is due in part to increases in risk factors (decreased childbearing and breast-feeding, increased exogenous hormone exposure, and detrimental dietary and lifestyle changes, including obesity and less physical activity). On the other hand, mortality is now decreasing in many high-risk countries due to a combination of intensified early detection efforts and the introduction of mammographic screening, resulting in the diagnosis of more small, early stage tumors, and advances in treatment.

Sexual behaviours are associated with cancer risk at the head and neck cancer subsites that have previously been associated with HPV infection.