Eero Pukkala

Human papillomavirus infection as a risk factor for squamous-cell carcinoma of the head and neck

BACKGROUNDnOncogenic human papillomaviruses (HPVs), especially HPV type 16 (HPV-16), cause anogenital epithelial cancers and are suspected of causing epithelial cancers of the head and neck.nnnMETHODSnTo examine the relation between head and neck cancers and HPVs, we performed a nested case-control study within a joint Nordic cohort in which serum samples were collected from almost 900,000 subjects. Samples collected at enrollment from 292 persons in whom squamous-cell carcinoma of the head and neck developed, on average, 9.4 years after enrollment and from 1568 matched controls were analyzed for antibodies against HPV-16, HPV-18, HPV-33, and HPV-73 and for cotinine levels as a marker of smoking habits. Polymerase-chain-reaction (PCR) analyses for HPV DNA were performed in tumor tissue from 160 of the study patients with cancer.nnnRESULTSnAfter adjustment for cotinine levels, the odds ratio for squamous-cell carcinoma of the head and neck in subjects who were seropositive for HPV-16 was 2.2 (95 percent confidence interval, 1.4 to 3.4). No increased risk was observed for other HPV types. Fifty percent of oropharyngeal and 14 percent of tongue cancers contained HPV-16 DNA, according to PCR analysis.nnnCONCLUSIONSnHPV-16 infection may be a risk factor for squamous-cell carcinoma of the head and neck.

Human papillomavirus infection as a risk factor for anal and perianal skin cancer in a prospective study

Human papillomavirus has emerged as the leading infectious cause of cervical and other anogenital cancers. We have studied the relation between human papillomavirus infection and the subsequent risk of anal and perianal skin cancer. A case–cohort study within two large Nordic serum banks to which about 760 000 individuals had donated serum samples was performed. Subjects who developed anal and perianal skin cancer during follow up (median time of 10 years) were identified by registry linkage with the nationwide cancer registries in Finland and Norway. Twenty-eight cases and 1500 controls were analysed for the presence of IgG antibodies to HPV 16, 18, 33 or 73, and odds ratios of developing anal and perianal skin cancer were calculated. There was an increased risk of developing anal and perianal skin cancer among subjects seropositive for HPV 16 (OR=3.0; 95%CI=1.1–8.2) and HPV 18 (OR=4.4; 95%CI=1.1–17). The highest risks were seen for HPV 16 seropositive patients above the age of 45 years at serum sampling and for patients with a lag time of less than 10 years. This study provides prospective epidemiological evidence of an association between infection with HPV 16 and 18 and anal and perianal skin cancer.Human papillomavirus has emerged as the leading infectious cause of cervical and other anogenital cancers. We have studied the relation between human papillomavirus infection and the subsequent risk of anal and perianal skin cancer. A case–cohort study within two large Nordic serum banks to which about 760 000 individuals had donated serum samples was performed. Subjects who developed anal and perianal skin cancer during follow up (median time of 10 years) were identified by registry linkage with the nationwide cancer registries in Finland and Norway. Twenty-eight cases and 1500 controls were analysed for the presence of IgG antibodies to HPV 16, 18, 33 or 73, and odds ratios of developing anal and perianal skin cancer were calculated. There was an increased risk of developing anal and perianal skin cancer among subjects seropositive for HPV 16 (OR=3.0; 95%CI=1.1–8.2) and HPV 18 (OR=4.4; 95%CI=1.1–17). The highest risks were seen for HPV 16 seropositive patients above the age of 45 years at serum sampling and for patients with a lag time of less than 10 years. This study provides prospective epidemiological evidence of an association between infection with HPV 16 and 18 and anal and perianal skin cancer.

Cancers of affluence: Positive social class gradient and rising incidence trend in some cancer forms

This study shows that, unlike most diseases, some cancer forms are more common in upper social classes. All cancer cases diagnosed in Finland in 1971-75 aged 30-69 and recorded in the Finnish Cancer Registry (n = 36,500) were linked to the file of the 1970 Population Census of Finland with data on socio-economic status and education. Cancers related to both high socio-economic status and high level of education in men were colon, prostate, testis, kidney and melanoma of the skin, and in women colon, breast, and corpus uteri. Since 1953, the incidence of all these cancers had been rising, although that of the testicular cancer had levelled off in the seventies.

Strategies for the introduction of human papillomavirus vaccination: modelling the optimum age- and sex-specific pattern of vaccination in Finland

Phase III trials have demonstrated the efficacy of human papillomavirus (HPV) vaccines in preventing transient and persistent high-risk (hr) HPV infection and precancerous lesions. A mathematical model of HPV type 16 infection and progression to cervical cancer, parameterised to represent the infection in Finland, was used to explore the optimal age at vaccination and pattern of vaccine introduction. In the long term, the annual proportion of cervical cancer cases prevented is much higher when early adolescents are targeted. Vaccinating against hr HPV generates greater long-term benefits if vaccine is delivered before the age at first sexual intercourse. However, vaccinating 12 year olds delays the predicted decrease in cervical cancer, compared to vaccinating older adolescents or young adults. Vaccinating males as well as females has more impact on the proportion of cases prevented when vaccinating at younger ages. Implementing catch-up vaccination at the start of a vaccination programme would increase the speed with which a decrease in HPV and cervical cancer incidence is observed.

Increased incidence of cancer in patients with cartilage-hair hypoplasia

OBJECTIVEnPrevious reports have suggested an increased risk of cancer among patients with cartilage-hair hypoplasia (CHH). This study was carried out to further evaluate this risk among patients with CHH and their first-degree relatives.nnnSTUDY DESIGNnOne hundred twenty-two patients with CHH were identified through 2 countrywide epidemiologic surveys in 1974 and in 1986. Their parents and nonaffected siblings were identified through the Population Register Center. This cohort underwent follow-up for cancer incidence through the Finnish Cancer Registry to the end of 1995.nnnRESULTSnA statistically significant excess risk of cancer was seen among the patients with CHH (standardized incidence ratio 6.9, 95% confidence interval 2.3 to 16), which was mainly attributable to non-Hodgkins lymphoma (standardized incidence ratio 90, 95% confidence interval 18 to 264). In addition, a significant excess risk of basal cell carcinoma was seen (standardized incidence ratio 35, 95% confidence interval 7.2 to 102). The cancer incidence among the siblings or the parents did not differ from the average cancer incidence in the Finnish population.nnnCONCLUSIONSnThis study confirms an increased risk of cancer, especially non-Hodgkins lymphoma, probably attributable to defective immunity, among patients with CHH.

Smoking and risk of colorectal cancer

Tobacco smoking was studied in relation to colorectal cancer in 56 973 Finnish men and women initially free from cancer. Smoking status was determined by a health questionnaire. During a follow-up period of 28 years, from the baseline in 1966-72 to the end of 1994, 457 cases of colorectal cancer occurred. There was no significant association between baseline smoking status and colorectal cancer risk over the total follow-up period. The sex- and age-adjusted relative risk of colorectal cancer between smokers and non-smokers was 1.06 (95% confidence interval 0.84-1.33). For follow-up periods of 11-20 years, however, the relative risk was 1.57 (95% confidence interval 1.09-2.24). In a subgroup in which smoking habits were assessed twice, the relative risk of colorectal cancer among persistent smokers was 1.71 (95% confidence interval 1.09-2.68) compared with others. The results of the present prospective study are consistent with the possibility that smoking increases the risk of colorectal cancer after a relatively long induction period. To clarify the role of smoking in colorectal cancer development, further cohort studies are needed with long follow-up periods and allowing for control of dietary and other potential confounding factors.

A population-based study on the risk of cervical cancer and cervical intraepithelial neoplasia among grand multiparous women in Finland

Previous studies suggest that high parity increases the risk of cervical cancer. We studied the risk of cervical cancer (CC) and cervical intraepithelial neoplasia (CIN3) in a Finnish cohort of grand multiparous (GM) women (at least five children) with low prevalence of sexually transmitted infections (STI). The Finnish Cancer Registry data revealed 220 CC and 178 CIN3 cases among 86u2009978 GM women. Standardised incidence ratios (SIR) were calculated from the numbers of observed and expected cases. Interval analyses by parity, age at first birth and average birth interval were done using multivariate Poisson regression. Seroprevalence of human papillomavirus (HPV) 16 and Chlamydia trachomatis was tested among 561 GM women and 5703 women with 2–4 pregnancies. The incidence among GM women was slightly above the national average for squamous cell carcinoma of cervix uteri (SIR 1.21, 95% CI 1.05–1.40) and CIN3 (1.37, 95% CI 1.17–1.58), but lower for adenocarcinoma (SIR 0.77, 95% CI 0.52–1.10). The seroprevalence of HPV16 and Chlamydia trachomatis among GM women was lower than in the reference population, except among those women who had their child under age 19. Age under 20 years at first birth increased the risk of CC and CIN3 especially in premenopausal GM women, while increasing parity had no effect. The small relative risks of CC and CIN3 among GM women in our study as compared to studies from other countries can be explained by the exceptionally low prevalence of STIs in Finnish GM women. The observed SIRs between 1.2 and 1.4 should be interpreted to represent increased risk attributable to grand multiparity. The increased incidence of CC and CIN3 among young GM women suggests causal association to HPV 16 and Chlamydia trachomatis infections.

Increased mortality in cartilage-hair hypoplasia

BACKGROUND Cartilage–hair hypoplasia (CHH) is an autosomal recessive chondrodysplasia with severe growth failure and impaired immunity. Impaired immunity may result in increased mortality. AIMS To follow a cohort of 120 CHH patients for mortality from 1971 to 1995. METHODS The overall and cause specific disease mortality rates in patients with CHH, and the disease mortality rate in 194 parents and 158 non-affected sibs were compared with the national rates. RESULTS During follow up seven disease related deaths were observed versus 0.8 expected (standardised mortality ratio 9.3, 95% confidence interval 3.7 to 19). In most cases, the deaths were confined to the younger age groups and associated with defective immunity. The mortality of the parents and the non-affected sibs was similar to that in the general population. CONCLUSION The study confirms increased mortality in patients with CHH attributable to defective immunity, especially in children.

Attack rates of human papillomavirus type 16 and cervical neoplasia in primiparous women and field trial designs for HPV16 vaccination

Background: Identification of human papillomavirus type 16 (HPV16) as the major risk factor for cervical neoplasia, and mass production of DNA free HPV capsids have paved the way to preventive vaccination trials. Design of such trials requires reliable attack rate data. Objective: Determination of (1) HPV16 and (2) cervical neoplasia attack rates in primiparous women. Estimation of actuarial sample sizes for HPV16 vaccination phase IV trials. Design: A longitudinal cohort study. Methods: Population based Finnish Maternity Cohort (FMC) and Finnish Cancer Registry (FCR) were linked for the identification of two cohorts of primiparous women: (1) a random subsample of the FMC: 1656 women with two pregnancies between 1983–9 or 1990–6 and living in the Helsinki metropolitan area, and (2) all 72 791 primiparous women living in the same area during 1983–94. Attack rate for persistent HPV16 infection (1) was estimated in 1279 seronegative women by proportion of seroconversions between the first and the second pregnancy. Comparable 10 year cumulative incidence rate (CR) of cervical intraepithelial neoplasia grade III and cervical cancer (CIN III+) (2) was estimated based on cases registered at the FCR during 1991–4. Results: The HPV16 attack rates were 13.8% (<18 years), 7.0% (18–19 years), 2.3% (21 years), 2.4% (23 years), and 4.5% (<25 years). Number of vaccinees required for a 5 year efficacy trial with persistent HPV16 infection as the end point ranged between 1000 and 3900, assuming 80% power, 90%–70% vaccine efficacy (VE), and misclassification. The CRs of CIN III+ were 0.33% (<18 years), 0.44% (18–19 years), 0.21% (20–24 years), and 0.28% (<25 years). Number of vaccinees required for a 10 year efficacy trial with HPV16 positive CIN III+ as the end point was 15 000 assuming 80% power, 90% VE, and 75% aetiological fraction of CIN III+ for HPV16. Conclusions: The attack rates of HPV16 and CIN III+ identify primiparous women under 25 years of age among target populations for postnatal HPV vaccination at phase II/III trials.

The cost-effectiveness of nationwide breast carcinoma screening in Finland, 1987–1992

The aim of this study was to evaluate the cost‐effectiveness, from a societal perspective, of the Finnish nationwide breast carcinoma screening program.