{'fraction_non_alphanumeric': 0.018543821979308997, 'fraction_numerical': 0.010150302557095451, 'mean_word_length': 5.035335689045937, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 3, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Human papillomavirus and head and neck cancers: emerging trends and improving survival

We were interested to read the findings of Adair et al. in relation to oral, pharyngeal and oesophageal cancer mortality rates over time in Australia modelled against trends in tobacco, alcohol and fruit and vegetable consumption. As the authors noted, attribution of changes in mortality to trends in risk factor exposure at the population level is complex, given the different exposure to risk factors by age and sex subgroups, the lag time between exposure and the development of cancer, and possible changes in treatment and survival over time. Further complicating the interpretation of trends in head and neck cancer mortality in Australia, is the changing exposure to an important cause of some oral cavity, oropharyngeal and other head and neck cancers not mentioned by Adair et al: oncogenic human papillomavirus (HPV) infection. HPV has been identified as being strongly associated with some head and neck cancers, most particularly those arising from the oropharynx, including the base of tongue, lingual tonsil and tonsil (including Waldeyer’s ring). The International Agency for Research on Cancer has found that on the basis of epidemiological and laboratory data, there is sufficient evidence to determine that HPV 16 is causally associated with these oropharyngeal cancers. A recent case series in Australia found a rising proportion of HPV positive oropharyngeal cancers over time, from 19% in 1987 to 66% in 2005/06. While much remains to be established about the natural history of oral oncogenic HPV infection, it is clear that sexual history (more partners, earlier age of first sex and male same sex partners) is a risk factor for HPV positive tumours suggesting that genital-oral transmission of HPV is important. In Australia, an increasing proportion of the population is engaging in oral-genital sexual practices over time and at a younger age. We recently analysed incidence trends of head and neck tumours in Australia between 1982 and 2005, stratified into those cancers established to be HPVassociated and those that are not, according to the classification of Ryerson et al. We noted a decline in non HPV-associated cancers in males but a significant increase in HPV-associated cancers over time. This trend has also been noted internationally and suggests that careful monitoring is required as to the relative contribution of population level risk factors for head and neck cancers into the future. Supplementary data in relation to survival may be of relevance in interpreting the changing epidemiology of head and neck cancers over the past decade. We obtained cancer data from the National Cancer Statistics Clearinghouse database, as previously described. Relative survival proportions were calculated by the Cancer and Dunedin. All such toilets were included in the study. A random sample of toilets in food premises were included, using a list of the 658 registered food premises listed on the DCC website. Only food premises where it was acceptable to buy only a cup of coffee were included. Bars and dine-only restaurants were excluded because it was impractical to buy only a coffee in them. If it was unclear whether a toilet for customer use was present, a phone call was made to ascertain this. Toilets were visited and reporting sheets were completed for male, female and unisex toilets. An unannounced audit of handwashing facilities was carried out. For each of the food premises visited, a small purchase was made and a minimum time of 15 minutes was spent, in order to not reveal the main purpose of the visit. In total, 91 toilets in these 60 premises were investigated (24 toilets in 17 public places, 24 toilets in 14 other locations, 43 toilets in 29 food premises). Results are presented in Table 1. Most toilets (76/91, 84%) provided some potential for recontamination, because they required users to either touch bins to deposit paper towels, or to touch the door to exit. This was common in all kinds of toilets surveyed. There were very few differences between male, female and unisex toilets. Most cafes provided good facilities, but the absence of any handwashing facilities in two premises is very concerning. It was unclear whether staff members involved in food-preparation or serving at these premises used the same facilities. Public toilets maintained by the City Council provided poorer quality handwashing facilities, with very few providing warm water and many not providing soaps or hand-drying facilities. In the Dunedin climate, the lack of warm water for hand washing is likely to contribute to reduced frequency of handwashing and more hurried handwashing, particularly in winter, when respiratory infections are more common. Similar deficiencies in handwashing facilities have been found in other studies and future research should investigate which aspects of handwashing facilities affect handwashing behaviour in publicly accessible toilets in the community, and how to ensure that those who own and maintain toilets provide appropriate quality facilities.