Occupation and cutaneous melanoma: a 45-year historical cohort study of 14·9 million people in five Nordic countries.

BACKGROUND: The age-adjusted incidence of cutaneous melanoma (CM) in the Nordic countries has increased during the last 60 years. Few prospective population-based studies have estimated the occupational variation in CM risk over time. OBJECTIVES: To determine occupational variation in CM risk. METHODS: A historical prospective cohort study with a 45-year follow-up from 1961 to 2005 (Nordic Occupational Cancer Study, NOCCA) based on record linkages between census and cancer registry data for Nordic residents aged 30-64 years in Denmark, Finland, Iceland, Norway and Sweden. National occupational codes were converted to 53 occupational categories, and stratified into indoor, outdoor and mixed work, and into socioeconomic status. The standardized incidence ratios (SIRs) were estimated as observed number of CM cases divided by the expected number calculated from stratum-specific person-years and national CM incidence rates. RESULTS: During a follow-up of 385 million person-years, 83 898 incident cases of CM were identified. In all countries combined, men with outdoor work had a low SIR of 0·79 [95% confidence interval (CI) 0·77-0·81] and men with indoor work had a high SIR of 1·09 (95% CI 1·07-1·11). Differences in women pointed in the same direction. High socioeconomic status was associated with an excess risk: SIR 1·34 (95% CI 1·28-1·40) in men and SIR 1·31 (95% CI 1·26-1·36) in women. Technical, transport, military and public safety workers with potential skin exposure to carcinogens had excess risks. CONCLUSIONS: Occupational variation in CM risk may be partly explained by host, socioeconomic and skin exposure factors. Differences in CM risk across socioeconomic groups attenuated slightly over time.

Predictors of oropharyngeal cancer survival in Europe.

OBJECTIVES: HPV16-positive oropharyngeal cancer (OPC) patients experience better outcomes compared to HPV16-negative patients. Currently, strategies for treatment de-escalation are based on HPV status, smoking history and disease stage. However, the appropriate cut-point for smoking and the role of other non-clinical factors in OPC survival remains uncertain. MATERIALS AND METHODS: We examined factors associated with OPC outcome in 321 patients recruited in a large European multi-center study. Seropositivity for HPV16 E6 was used as a marker of HPV16 positive cancer. Hazard ratios (HR) and confidence intervals (CI) were estimated using Cox proportional models adjusted for potential confounders. RESULTS: Overall 5-year survival following OPC diagnosis was 50%. HPV16-positive OPC cases were at significantly lower risk of death (aHR = 0.51, 95% CI: 0.32-0.80). A significant effect on OPC survival was apparent for female sex (aHR 0.50: 95% CI: 0.29-0.85) and being underweight at diagnosis (aHR: 2.41, 95% CI: 1.38-4.21). A 10 pack year smoking history was not associated with overall survival. Higher stage at diagnosis appeared as the only factor significantly associated with OPC recurrence (aHR: 4.88, 95% CI: 2.12-11.21). CONCLUSION: This study confirms that HPV16 status is an independent prognostic factor for OPC survival while female sex lowers risk of death and being underweight at diagnosis increases the risk of death. Smoking was not an independent predictor of OPC survival.

Incidence and occupational variation of ovarian granulosa cell tumours in Finland, Iceland, Norway and Sweden during 1953-2012: a longitudinal cohort study.

OBJECTIVE: To determine the incidence and occupational variation of granulosa cell tumours (GCTs) in Finland, Iceland, Norway and Sweden over a 60-year period, 1953-2012. DESIGN: A longitudinal cohort study. SETTING AND POPULATION: Finland, Iceland, Norway and Sweden and a total of 249 million women over a 60-year period (1953-2012). The NOCCA (Nordic Occupational Cancer Study) included 6.4 million women with 776 incident GCT cases diagnosed until the end of follow up. METHODS: Incidence rates were calculated from the national cancer registries and compared using quasi-Poisson regression models. Occupation-specific standardised incidence ratios (SIRs) were calculated from the Nordic Occupational Cancer (NOCCA) database. MAIN OUTCOME MEASURES: Incidence rates and standardised incidence ratios. RESULTS: The age-adjusted (World Standard) incidence rates remained quite constant: about 0.6-0.8 per 100 000 for most of the study period. The age-specific incidence was highest at 50-64 years of age. There were no occupations with significantly increased risk of GCT. Major changes in the use of oral contraceptives, postmenopausal hormonal therapy, fertility rate and lifestyle in general during the study period and among different occupational categories do not appear to have a marked effect on the incidence of GCT. CONCLUSION: Our findings support the concept of GCT as a primarily sporadic, not exposure-related, cancer. TWEETABLE ABSTRACT: The Nordic incidence rates of GCTs show stability over time and among different occupational categories.

Benzene exposure and risk of lymphohaematopoietic cancers in 25 000 offshore oil industry workers.

BACKGROUND: The aim of this work was to examine the risk of lymphohaematopoietic (LH) cancer according to benzene exposure among offshore workers. METHODS: Cancer registry data were used to identify 112 cancer cases diagnosed during 1999-2011 in a cohort of 24 917 Norwegian men reporting offshore work between 1965 and 1999. Analyses were conducted according to a stratified case-cohort design with a reference subcohort of 1661 workers. Cox regression was used to estimate hazard ratios with 95% confidence intervals, adjusted for other benzene exposure and smoking. RESULTS: Most workers were exposed to benzene for <15 years. The upper range values of average intensity and cumulative exposure were estimated to 0.040 p.p.m. and 0.948 p.p.m.-years, respectively. Risks were consistently elevated among exposed workers for all LH cancers combined and for most subgroups, although case numbers were small and yielded imprecise risk estimates. There was evidence of dose-related risk patterns according to cumulative exposure for acute myeloid leukaemia (AML), multiple myeloma (MM) (P trends 0.052 and 0.024, respectively), and suggestively so for chronic lymphocytic leukaemia (CLL) according to average intensity (P trend 0.094). CONCLUSIONS: Our results support an association between cumulative and intensity metrics of low-level benzene exposure and risk for AML, MM, and suggestively for CLL.

Cancer incidence among 41,000 offshore oil industry workers.

BACKGROUND: Cancer incidence among Norwegian offshore oil industry workers has been studied in two equally sized cohorts of 28000 workers, in a survey-based cohort study followed 1999-2005 and a register-based cohort study followed 1981-2003. AIMS: To determine the overall cancer incidence in both cohorts merged, with an extended follow-up. METHODS: The merged cohort yielded 41,140 individuals followed for cancer diagnoses 1999-2009. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were computed by gender and by period of first employment using cancer registry data. RESULTS: Among female workers, the total number of cancers was slightly higher than expected (SIR 1.17, 95% CI 1.02-1.34), and excesses of acute myeloid leukaemia (AML) (SIR 5.29, 95% CI 1.72-12), malignant melanoma (SIR 2.13, 95% CI 1.41-3.08) and lung cancer (SIR 1.69, 95% CI 1.03-2.61) were observed. Among male workers, the total number of cancer cases was close to that expected (SIR 1.03, 95% CI 0.99-1.08), but cases of pleural cancer (SIR 2.56, 95% CI 1.58-3.91) and bladder cancer (SIR 1.25, 95% CI 1.05-1.49) were higher than expected. Among male workers first employed before 1986, the numbers of observed cancer cases were higher than expected for most sites, while this was not evident among those employed later. CONCLUSIONS: Further studies with exposure data and confounder control are needed to address whether the observed excesses of pleural cancer and AML can be attributed to offshore work.

Role of medical history and medication use in the aetiology of upper aerodigestive tract cancers in Europe: the ARCAGE study.

BACKGROUND: The study aimed to investigate the role of medical history (skin warts, Candida albicans, herpetic lesions, heartburn, regurgitation) and medication use (for heartburn; for regurgitation; aspirin) in the aetiology of upper aerodigestive tract (UADT) cancer. METHODS: A multicentre (10 European countries) case-control study [Alcohol-Related CAncers and GEnetic susceptibility (ARCAGE) project]. RESULTS: There were 1779 cases of UADT cancer and 1993 controls. History of warts or C. albicans infection was associated with a reduced risk [odds ratio (OR) 0.80, 95% confidence interval (CI) 0.68-0.94 and OR 0.73, 95% CI 0.60-0.89, respectively] but there was no association with herpetic lesions, heartburn, regurgitation or medication for related symptoms. Regurgitation was associated with an increased risk for cancer of the oesophagus (OR 1.47, 95% CI 0.98-2.21). Regular aspirin use was not associated with risk of UADT cancer overall but was associated with a reduced risk for cancer of oesophagus (OR 0.51, 95% CI 0.28-0.96), hypopharynx (OR 0.53, 95% CI 0.28-1.02) and larynx (OR 0.74, 95% CI 0.54-1.01). CONCLUSIONS: A history of some infections appears to be a marker for decreased risk of UADT cancer. The role of medical history and medication use varied by UADT subsites with aspirin use associated with a decreased risk of oesophageal cancer and suggestive of a decreased risk of hypopharyngeal and laryngeal cancers.

Occupation and risk of primary fallopian tube carcinoma in Nordic countries.

The aetiology of primary Fallopian tube carcinoma (PFTC) is poorly understood. Occupational exposures may contribute to PFTC risk. We studied incidence of PFTC in occupational categories in the Nordic female population aged 30-64 years during the 1960, 1970, 1980/1981 and/or 1990 censuses in Denmark, Finland, Iceland, Norway and Sweden. Standardized incidence ratios (SIRs) for the years following inclusion in the study up to 2005 were calculated for 53 occupations; the expected numbers of cases were based on PFTC incidence in the national populations. Altogether 2,206 PFTC cases were detected during follow up via data linkages with the Nordic cancer registries. Significantly increased risks of PFTC were observed for smelting workers (SIR 3.99, 95% confidence interval 1.46-8.68, Obs = 6), artistic workers (2.64, 1.44-4.43, Obs = 14), hairdressers (2.18, 1.41-3.22, Obs = 25), packers (1.62, 1.11-2.29, Obs = 32), nurses (1.49, 1.14-1.92, Obs = 60), shop workers (1.25, 1.07-1.46, Obs = 159) and clerical workers (1.20, 1.07-1.35, Obs = 271) and these sustained over times and different Nordic countries. There was a nonsignificant increased risk for PFTC among welders, printers, painters and chemical process workers. The risk was significantly and consistently low for women working in farming (0.68, 0.47-0.95, Obs = 34) and among economically inactive women (0.88, 0.82-0.94, Obs = 833). The possible role of occupational exposures to the PFTC risks found in this study must be further evaluated in studies with a possibility to adjust for possible confounding factors, such as reproductive and life-style factors, which was not possible in our study.

Effects of occupation on risks of avoidable cancers in the Nordic countries.

Knowledge of cancer risk according to occupational affiliation is an essential part of formatting preventive actions aimed at the adult population. Herein, data on 10 major cancer sites amenable by life style exposures from the Nordic Occupational Cancer Study (NOCCA) are presented. All subjects aged 30-64 years participating in one or more national censuses in Denmark, Finland, Iceland, Norway, or Sweden between 1960 and 1990 were included in the cohort and followed up for cancer from inclusion until 2003/2005 via a linkage with the national cancer registries, and standardised incidence ratios (SIRs) were computed. Variation in risk across occupations was generally larger in men than in women. In men, the most consistent cluster with high risk of numerous cancer types included waiters, cooks and stewards, beverage workers, seamen, and chimney sweeps. Two clusters of occupations with generally low cancer risks were seen in both men and women. The first one comprised farmers, gardeners, and forestry workers, the second one included groups with high education, specifically those in health and pedagogical work. Although cancer risk varies by occupation, only a smaller part of the variation can be attributed to occupational exposures in the strict sense. Preventive measures at the work place are important to avoid established and new occupational health hazards. This study also indicates that the work place in addition should be seen as a useful arena for reaching groups of adults with more or less similar habits and attitudes for general health promotion.

Life course social mobility and risk of upper aerodigestive tract cancer in men.

The aim of this study was to explore associations between social mobility and tumours of the upper aero-digestive tract (UADT), focussing on life-course transitions in social prestige (SP) based on occupational history. 1,796 cases diagnosed between 1993 and 2005 in ten European countries were compared with 1585 controls. SP was classified by the Standard International Occupational Prestige Scale (SIOPS) based on job histories. SIOPS was categorised in high (H), medium (M) and low (L). Time weighted average achieved and transitions between SP with nine trajectories: H --> H, H --> M, H --> L, M --> H, M --> M, M --> L, L --> H, L --> M and L --> L were analysed. Odds ratios (ORs) and 95%-confidence intervals [95%-CIs] were estimated with logistic regression models including age, consumption of fruits/vegetables, study centre, smoking and alcohol consumption. The adjusted OR for the lowest versus the highest of three categories (time weighted average of SP) was 1.28 [1.04-1.56]. The distance of SP widened between cases and controls during working life. The downward trajectory H --> L gave an OR of 1.71 [0.75-3.87] as compared to H --> H. Subjects with M --> M and L --> L trajectories ORs were also elevated relative to subjects with H --> H trajectories. The association between SP and UADT is not fully explained by confounding factors. Downward social trajectory during the life course may be an independent risk factor for UADT cancers.

Socioeconomic factors associated with risk of upper aerodigestive tract cancer in Europe.

INTRODUCTION: In the European Union, there are 180,000 new cases of upper aerodigestive tract (UADT) cancer cases per year--more than half of whom will die of the disease. Socioeconomic inequalities in UADT cancer incidence are recognised across Europe. We aimed to assess the components of socioeconomic risk both independently and through their influence on the known behavioural risk factors of smoking, alcohol consumption and diet. PATIENTS AND METHODS: A multicentre case-control study with 2198 cases of UADT cancer and 2141 controls from hospital and population sources was undertaken involving 14 centres from 10 countries. Personal interviews collected information on demographics, lifetime occupation history, smoking, alcohol consumption and diet. Socioeconomic status was measured by education, occupational social class and unemployment. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed using unconditional logistic regression. RESULTS: When controlling for age, sex and centre significantly increased risks for UADT cancer were observed for those with low versus high educational attainment OR=1.98 (95% CI 1.67, 2.36). Similarly, for occupational socioeconomic indicators--comparing the lowest versus highest International Socio-Economic Index (ISEI) quartile for the longest occupation gave OR=1.60 (1.28, 2.00); and for unemployment OR=1.64 (1.24, 2.17). Statistical significance remained for low education when adjusting for smoking, alcohol and diet behaviours OR=1.29 (1.06, 1.57) in the multivariate analysis. Inequalities were observed only among men but not among women and were greater among those in the British Isles and Eastern European countries than in Southern and Central/Northern European countries. Associations were broadly consistent for subsite and source of controls (hospital and community). CONCLUSION: Socioeconomic inequalities for UADT cancers are only observed among men and are not totally explained by smoking, alcohol drinking and diet.

Expression of matrix metalloproteinase-2 in serous borderline ovarian tumors is associated with noninvasive implant formation.

OBJECTIVE: To investigate matrix metalloproteinase (MMP) proteolytic and vascular endothelial growth factor (VEGF) and receptor (VEGFR-1, VEGFR-2) angiogenetic capacity in serous borderline ovarian tumors (S-BOTs) for women with and without noninvasive implants. METHODS: The population was made up of 99 patients with S-BOTs as the primary diagnosis between 1985 and 1995, 44 of whom had noninvasive implants and 55 without implants. MMP-2, MMP-14, the type-2 tissue inhibitor of MMPs (TIMP-2), and VEGF and receptors (VEGFR-1, VEGFR-2) were examined by immunhistochemistry. RESULTS: Strong positive (+++) MMP-2 staining was found more frequently in women with primary S-BOTs and noninvasive implants (76%) than in those without implants (53%; p < 0.05). In contrast, staining for MMP-14 and TIMP-2 was not significantly different in the two groups. Furthermore, expression of MMP-2, MMP-14, and TIMP-2 was similar in primary tumors and in their noninvasive implants. Most tumors in both groups had no VEGF expression (84% in the noninvasive implant group and 82% in the group without implants), while moderate (++) to strong (+++) expression of VEGFR-1 and VEGFR-2 was detected in 79% and 94% of the two tumor groups, with no significant difference between the groups. CONCLUSIONS: Enhanced MMP-2 was seen in primary S-BOT with noninvasive implants. The presence of noninvasive implants was prognostic for disease-free survival.

Eighth international mesothelioma interest group.

The eighth International Mesothelioma Interest Group (IMIG) meeting was held in Chicago, IL, United States, in 19-22 October 2006 to discuss mesothelioma - the cancer often linked to asbestos exposure. It is a very aggressive malignancy with a median survival of less than 1 year from diagnosis. Millions of people have been exposed worldwide to asbestos, especially during the second half of the twentieth century when asbestos use increased significantly. The tons of asbestos utilized in the past remain a health hazard for current and future generations because asbestos is difficult to be disposed off. This makes asbestos and mesothelioma research a public health issue in addition to a medical problem. Moreover, the very high costs of asbestos litigation have a significant impact on the whole economy. In the United States, up until 2001, defendant companies had paid 54 billion dollars in claims and estimated future liabilities ranged from 145 to 210 billion. Therefore, asbestos research is of great interest to a large audience that includes patients, millions of asbestos-exposed individuals, scientists, physicians, public health officials, politicians, unions of asbestos workers, lawyers and the public at large. During the past few years, there has been significant progress in understanding the process of mineral fiber carcinogenesis and mesothelioma pathogenesis. With improved understanding of the pathogenesis of mesothelioma, new diagnostic, preventive and therapeutic options are being developed. A total of 247 papers were presented at the IMIG: the abstracts of these presentations were published in Lung Cancer, Supplement 1, October 2006. Here, experts in different disciplines critically review some of the most exciting presentations of the IMIG meeting. The result is a comprehensive review of the research field of asbestos carcinogenesis and mesothelioma, and of the progress that has been made in recent years in both basic and clinical sciences.

Asbestos fibers in ovarian tissue from Norwegian pulp and paper workers.

An elevated risk of ovarian cancer has been observed in Norwegian pulp and paper workers who were possibly occupationally exposed to asbestos. The present study was initiated to investigate if the increased risk could be associated with asbestos fibers in ovarian tissue from workers in this industry. Normal ovarian tissue specimens from three groups of women were included in the study. The case group included specimens from 46 women diagnosed with ovarian cancer in the period 1953-2000, and who had been working in one or more pulp and paper mills between 1920 and 1993. Normal ovarian tissue specimens from two control groups without occupational history from pulp and paper work were selected from the Cancer Registry database. Tissue blocks were digested and prepared for transmission electron microscopy. Number of fibers per gram wet weight was calculated. Asbestos fibers were found in normal ovarian tissue from two subjects in the case group, while no fibers were found in the control groups. The two asbestos positive cases had been working as paper sorter/packer and chlorine plant worker, respectively. Both were possibly secondary exposed to asbestos from family members working as insulators. We conclude that the findings in this study did not allow drawing any firm conclusion about an association between occupational exposure to asbestos and ovarian cancer in Norwegian pulp and paper workers. Our study confirms that asbestos fibers may reach the ovaries and demonstrates that the applied method is appropriate for identification of the fibers.

Mortality from non-malignant diseases in a cohort of female pulp and paper workers in Norway.

OBJECTIVES: The objective of the present study was to investigate the risk of death from non-malignant diseases in female pulp and paper workers in Norway. METHODS: A total of 3143 women first employed between 1920-93 were included in the study cohort. Information about each cohort member was obtained from personnel record files in the mills in order to identify employment periods and job categories. Data on cause and date of death were added by linkage to the Cause of Death Register using unique personal identification numbers. The follow up period was 1951-2000. Standardised mortality ratios (SMRs) with 95% confidence intervals (95% CIs) were calculated using the national female mortality rates as reference. Poisson regression analysis was used to examine internal relations between the duration of employment in paper departments and the risk of death from selected causes. Relative risks (RRs) and 95% CIs were calculated. RESULTS: The study showed a significantly increased risk for total non-malignant mortality (SMR = 1.14, 95% CI 1.05 to 1.24), mainly due to increased mortality from ischaemic heart disease (SMR = 1.22, 95% CI 1.03 to 1.43) and cerebrovascular diseases (SMR = 1.16, 95% CI 0.94 to 1.42). Analysis by department showed the highest risk of death in paper department workers with short term employment. Internal analyses showed a 5% and 9% increase in risk of dying from ischaemic heart disease and respiratory diseases, respectively, among paper department workers exposed to paper dust. The risk decreased with increasing duration of employment. CONCLUSION: The increased risk of ischaemic heart diseases and respiratory diseases seen among employees of paper departments may be related to exposure to paper dust.

Cross shift changes in lung function among bar and restaurant workers before and after implementation of a smoking ban.

OBJECTIVE: To study possible cross shift effects of environmental tobacco smoke (ETS) on pulmonary function among bar and restaurant employees before and after the implementation of a smoking ban in Norway. METHODS: The study included 93 subjects employed in 13 different establishments in Oslo. They were examined at the beginning and end of a workshift both while ETS exposure was present and when smoking was banned. The mean exposure level of nicotine and total dust before the ban was 28 microg/m3 (range 3-65) and 275 microg/m3 (range 81-506), respectively. Following the smoking ban, the mean level of nicotine and total dust was 0.6 mug/m3 and 77 microg/m3, respectively. Assessment of lung function included dynamic lung volumes and flows. RESULTS: The cross shift reduction in forced vital capacity (FVC) among 69 subjects participating in both examinations changed from 81 ml (SD 136) during exposure to ETS to 52 ml (SD 156) (p = 0.24) following the smoking ban. The reduction in forced expired volume in one second (FEV1) during a workshift, was borderline significantly reduced when comparing the situation before and after the intervention, by 89 ml (SD = 132) compared to 46 ml (SD = 152) (p = 0.09), respectively. The reduction in forced mid-expiratory flow rate (FEF25-75%) changed significantly from 199 ml/s (SD = 372) to 64 ml/s (SD = 307) (p = 0.01). Among 26 non-smokers and 11 asthmatics, the reduction in FEV1 and FEF25-75% was significantly larger during ETS exposure compared to after the smoking ban. There was an association between the dust concentration and decrease in FEF25-75% before the ban among non-smokers (p = 0.048). CONCLUSIONS: This first study of cross shift changes before and after the implementation of a smoking ban in restaurants and bars shows a larger cross shift decrease in lung function before compared with after the implementation of the ban.

Improved short-term survival for advanced ovarian, tubal, and peritoneal cancer patients operated at teaching hospitals.

The aim of this study was to study the impact of hospital level and surgical skill on short-term survival of advanced ovarian, tubal, and peritoneal cancer patients in a prospective population-based study. All 198 women with a diagnosis of advanced epithelial invasive ovarian, tubal, and peritoneal cancer in Norway who underwent surgery during 2002 were included in this study. The data were derived from notifications to the Norwegian Cancer Registry and from medical, surgical, and histopathologic records. The hospitals were grouped into teaching and nonteaching hospitals (NTH), and the operating physicians were classified according to specialty (specialist gynecologist, gynecologist, and surgeon). The follow-up period was from 455 to 820 days. The short-term survival at 450 days was 79% for women operated at teaching hospitals (TH) and 62% at NTH (P= 0.02). After simultaneous adjustment for seven prognostic factors and residual disease, the risk of death within 600 days at NTH was unchanged compared to TH, hazard ratio 1.83. The women operated on by specialist compared to general gynecologists had a 20% increased short-term survival (P < 0.0001). TH and specialist gynecologists achieved better short-term survival of patients operated for advanced ovarian, tubal, and peritoneal cancer. Centralization and specialization of ovarian cancer surgery might improve the outcome for this patient group.

Symptoms and referral of women with epithelial ovarian tumors.

OBJECTIVE: To study referral to hospital units and the clinical characteristics of women with epithelial ovarian tumors in a prospective, population-based study. METHODS: Clinical information on all women diagnosed with epithelial invasive (n=486) and borderline ovarian tumors (n=137) in Norway during 2002 was derived from notifications to the Cancer Registry of Norway and medical, surgical and histopathological records. RESULTS: Sixty-one percent of women with invasive ovarian tumors were initially referred to gynecology units. The 38% of women referred to surgical and medical units were more likely to have symptoms as 'bowel irregularity', 'pain outside the abdominal cavity', 'persisting fatigue' and 'respiratory difficulties'. These women were older, had lower performance status and had a delay in treatment of 20 and 24 days respectively compared to 11 at gynecology units. CONCLUSION: Greater awareness of the symptoms of ovarian cancer might lead to earlier diagnosis and treatment and thus possibly improve survival.

Cancer risk among female nurses: a literature review.

Some studies have demonstrated increased risk of different cancers among female nurses. A review of relevant papers was made to assess whether the increase is caused by occupational exposures or other factors. A computerized literature search on combinations of the keywords 'nurses', 'occupation', 'hazards', 'cancer' and 'mortality' and related articles was performed. A total of 30 reports were identified from 19 independent studies conducted between 1983 and 2001. The majority of the studies were registry studies, with limited data on employment history and confounding factors. In conclusion, knowledge about exposures and observed excesses of cancer risk give reason to suspect an occupational influence on breast cancer and leukaemia. The grouping together of nurses from different workplaces may camouflage real differences in risk. Future studies should collect information at the individual level about work history and personal risk factors.

[Examination, treatment and follow-up of ovarian cancer in Norway]. / Utredning, behandling og etterkontroll av eggstokkreft i Norge.

BACKGROUND: In order to improve our knowledge about the medical examination, treatment and follow of cancer patients, suggestions have been put forward for a system for quality assurance of clinical data on cancer in Norway (Government White Paper 20: 1997). MATERIAL AND METHODS: In spring 2000, a questionnaire was sent to 41 gynaecological departments with focus on ovarian cancer patients. Four of the departments were regional cancer centres. RESULTS: All gynaecological departments answered the questionnaire. Standard gynaecological examination, vaginal ultrasonography and CA-125 determination were included in the diagnostic procedures in all departments. Some differences were detected: Cytological examination of pleural effusions as part of the staging procedure was not performed by all hospitals. In one health region, hospitals used a Risk of Malignancy Index for referring women with suspected malignant pelvic masses to a centralised gynaecologic oncology unit for primary surgery. Sixteen hospitals out of 37 operated on patients with FIGO stage I disease without performing lympadenectomy. When operating on suspected FIGO stage II-IV disease, three out of 22 local hospitals never performed surgery of the intestines in order to achieve optimal tumour reduction. All regional hospitals gave adjuvant chemotherapy to high-risk FIGO stage I patients. Standard treatment in advanced stages was paclitaxel/carboplatinum. Some hospitals participated in randomized trials on chemotherapy. Third-line treatment depended on the patient's condition, earlier toxicity and response. One regional centre preferred not to give any third-line chemotherapy. Only a few hospitals recorded the patient's performance status (WHO or Karnofsky's grading table) during the treatment and follow-up. Most of the gynaecological departments referred the patients to the regional hospital at the time of recurrence. About half of the outpatient departments gave a written report to the regional hospital. INTERPRETATION: There are differences between the hospitals in how they handle ovarian cancer patients. One cannot, however, determine from this inquiry what kind of medical examination, treatment and follow-up is best. An extended registration of ovarian cancer organised by the Cancer Registry of Norway will be started with the aim of providing reliable population-based data (the OVANOR project).