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Globally, 39% of the world's adult population is overweight or obese and 23% is insufficiently active. These percentages are even larger in high-income countries with 58% overweight/obese and 33% insufficiently active. Fourteen cancer types have been declared by the World Cancer Research Fund to be causally associated with being overweight or obese: oesophageal adenocarcinoma, stomach cardia, colon, rectum, liver, gallbladder, pancreas, breast, endometrium, ovary, advanced/fatal prostate, kidney, thyroid and multiple myeloma. Colon, postmenopausal breast and endometrial cancers have also been judged causally associated with physical inactivity. We aimed to quantify the proportion of cancer cases that would be potentially avoidable in Australia if the prevalence of overweight/obesity and physical inactivity in the population could be reduced. We used the simulation modelling software PREVENT 3.01 to calculate the proportion of avoidable cancers over a 25-year period under different theoretical intervention scenarios that change the prevalence of overweight/obesity and physical inactivity in the population. Between 2013 and 2037, 10-13% of overweight/obesity-related cancers in men and 7-11% in women could be avoided if overweight and obesity were eliminated in the Australian population. If everyone in the population met the Australian physical activity guidelines for cancer prevention (i.e. engaged in at least 300 min of moderate-intensity physical activity per week), an estimated 2-3% of physical inactivity-related cancers could be prevented in men (colon cancer) and 1-2% in women (colon, breast and endometrial cancers). This would translate to the prevention of up to 190,500 overweight/obesity-related cancers and 19,200 inactivity-related cancers over 25 years.

Cancer is a leading cause of disease burden in Australia, particularly fatal burden, accounting for an estimated thirty percent of deaths. Many cancers develop because of exposure to lifestyle and environmental factors that are potentially modifiable. We aimed to quantify the proportions and numbers of cancer deaths and cases in Australia in 2013 attributable to 20 modifiable factors in eight broad groupings that are established causes of cancer, namely: tobacco smoke (smoking and second-hand), dietary factors (low intake of fruit, non-starchy vegetables and dietary fibre; and high intake of red and processed meat), overweight/obesity, alcohol, physical inactivity, solar ultraviolet radiation, infections (seven agents), and reproductive factors (lack of breastfeeding, menopausal hormone therapy use, combined oral contraceptive use). We estimated population attributable fractions (PAF) using standard formulae incorporating exposure prevalence and relative risk data. Of all cancer deaths in Australia in 2013, approximately 38% overall (males 41%, females 34%) could be attributed to the factors assessed; the corresponding PAF for cancer cases was 33% (males 34%, females 32%). Tobacco smoke was the leading cause of cancer deaths and cases, with PAFs of 23 and 13%, respectively, followed by dietary factors (5% deaths/5% cases), overweight/obesity (5%/4%) and infections (5%/3%). Cancer sites with the highest numbers of potentially preventable deaths/cases were lung (n = 6,776/9,272), colorectum (n = 1,974/7,380) and cutaneous melanoma (n = 1,390/7,918). We estimate that about 16,700 cancer deaths and 41,200 cancer cases could be prevented in Australia each year if people's exposures to 20 causal factors were aligned with levels recommended to minimise cancer risk.

The incidence of human papillomavirus (HPV)-associated tonsil cancer is increasing but the prevalence of HPV, and of premalignant precursors, in tonsil tissue is unknown. We aimed to assess prevalence of HPV infection in nonmalignant tonsillar crypt epithelia and to histopathologically characterise positive samples. Formalin-fixed paraffin-embedded (FFPE) tonsil tissue specimens were obtained from an age- and sex-stratified random sample of patients aged 0-69 years whose paired tonsils were archived following elective tonsillectomy at hospitals throughout England and Southern Scotland from 2004 to 2008. Homogenised fresh-frozen tonsil tissue was also obtained from archive for two random subsets of males aged 25-34 and over 44. HPV status was assessed in all samples for 20 mucosal HPV types by GP5+/6+ polymerase chain reaction (PCR) enzyme immunoassay and by HPV16 type-specific PCR targeting the E6 gene. In the homogenised material, HPV status was also assessed for 44 HPV types by SPF10-PCR enzyme immunoassay. Of 4,095 randomly sampled FFPE specimens, amplifiable DNA was extracted from 3,377 (82.5%) and from 511 of 524 (97.5%) homogenised tonsils. HPV DNA was identified in 0 of 3,377 (0%, 95% CI 0-0.089%) fixed samples and 0 of 511 (0%, 95% CI 0-0.58%) homogenised samples. This suggests HPV infection may be rare in tonsil reticulated crypt epithelia. Furthermore, we found no evidence of HPV-associated premalignant neoplasia. These data suggest that if HPV-associated premalignant lesions do occur, they are likely to be rare and may have a high risk of progression to carcinoma.

Human papillomavirus (HPV) infection is common worldwide and, in immunodeficient populations, may contribute to the pathogenesis of keratinocyte cancers, particularly squamous cell carcinomas (SCC). However, their role in SCC in the general population is less clear. We conducted a comprehensive analysis to investigate the independent effects of seropositivity for cutaneous alpha, beta and gamma HPV types on risk of SCC, and a meta-analysis of the available literature. In a population-based case-control study from New Hampshire, USA (n = 1,408), histologically confirmed SCC cases and controls were tested for L1 antibodies to alpha, beta and gamma cutaneous HPV types 2-5, 7-10, 15, 17, 20, 23, 24, 27b, 36, 38, 48-50, 57, 65, 75-77, 88, 92, 95, 96, 101, 103 and 107 using multiplex serology. An increasing risk of SCC with number of beta HPVs to which an individual tested positive was observed even among those seronegative for gamma types (p for trend = 0.016) with an odds ratio of 1.95 (95% confidence interval (CI) = 1.07-3.56) for four or more beta types positive. In a meta-analysis of six case-control studies, increased SCC risks in relation to beta HPV seropositivity were found across studies (meta odds ratio = 1.45, CI = 1.27-1.66). While the prevalence of gamma HPVs assayed was somewhat higher among SCC cases than controls, the association was only weakly evident among those seronegative for beta HPVs. Overall, the association between cutaneous HPVs and skin cancers appears to be specific to SCC and to genus beta HPVs in a general US population.

The outcome of patients with palpable melanoma metastases in lymph nodes in the presence (metastatic melanoma of known primary site, MKP) or absence (metastatic melanoma of unknown primary site, MUP) of an identifiable primary tumour remains controversial. Some of the previous studies contained large case series that included historical patients. We aimed to compare outcomes of those with MUPs versus MKPs with palpable lymph node invasion, after staging with modern imaging technology. Aprospective study of patients from a single tertiary institution who were undergoing lymph node dissection for palpable metastatic melanoma between 2000 and 2011 was conducted. All patients were ascertained by computerised tomography scanning and most diagnosed after 2004 had positron emission tomography scanning also. Clinicopathological details about the primary melanoma and lymph node dissections were gathered. Factors associated with recurrence and melanoma-specific mortality in those with MKP and with MUP were assessed using univariate and multivariate analyses. Out of 485 patients studied, 82 had MUP and 403 had MKP. Patients were followed up for a median of 17.4 and 19.0 months, for MKP and MUP, respectively. Five-year adjusted melanoma-specific survival was 58% for MUPs versus 49% for MKPs and was not significantly different between the two groups (adjusted Cox proportional Hazard ratio = 0.88 95% confidence interval [0.58, 1.33] p = 0.54). Previously established prognostic factors such as number of positive nodes and extracapsular extension were confirmed in both sets of patients. We conclude that among melanoma patients presenting with clinically detectable nodes, when accurately staged, those without an identifiable primary lesion have similar outcomes to patients with MKP.