Investigations and referral for suspected cancer in primary care in New Zealand-A survey linked to the International Cancer Benchmarking Partnership.

A national internet-based survey of New Zealand (NZ) primary care physicians (n = 192) used the survey instrument developed by the International Cancer Benchmarking Partnership (ICBP). Practitioners were recruited by a range of methods assisted by NZ general practice networks and contacts. Compared to 11 other ICBP jurisdictions, direct access to diagnostic tests was more limited and took more time than in most other areas; the average wait for a test to be done and reported was 3.0 weeks for X-rays and 8.0 for ultrasound, compared to ICBP averages of 1.6 and 4.7 weeks respectively. Forty-five per cent of respondents could get specialist advice within 48 hr. Sixty-six per cent were aware of NZ guidelines for cancer in primary care, and of those 44% consulted them sometimes or often. Access to tests was greater, and time required much less, in the private than the public care system. NZ respondents each answered two of five clinical vignettes, with results similar to other ICBP areas. The survey also included general practice trainees (N = 42); their results were similar to the main group. The results suggest that improvements in prompt access to diagnostic tests and referrals for suspected cancer need to be given priority in NZ.

Risk factors associated with mortality from breast cancer in Waikato, New Zealand: a case-control study.

OBJECTIVES: The aim of this study is to identify key characteristics associated with mortality from breast cancer among women with newly diagnosed breast cancer in New Zealand (NZ). STUDY DESIGN: Case-control study. METHODS: All primary breast cancers diagnosed between 01/01/2002 and 31/12/2010 in Waikato, NZ, were identified from the Waikato Breast Cancer Register. A total of 258 breast cancer deaths were identified from 1767 invasive cancers diagnosed over this period. RESULTS: Breast cancer deaths (n = 246) were compared with an age and year of diagnosis matched control group (n = 652) who were alive at the time of the death of the corresponding case and subsequently did not die from breast cancer. Diagnosis through symptomatic presentation, advanced stage, higher grade, absent hormone receptors (i.e. oestrogen and progesterone) and HER-2 amplification were associated with significantly higher risks of breast cancer mortality in bivariate analysis. Tumour stage, grade and hormone receptor status remained significant in the multivariable model, while mode of detection and HER-2 status were non-significant. In the bivariate analysis, Maori women had a higher risk of breast cancer mortality compared to NZ European women (OR 1.34) which was statistically non-significant. However in the adjusted model, risk of mortality was lower for Maori compared to NZ European women, although this was not significant statistically (OR 0.85). CONCLUSIONS: Mortality pattern from breast cancer in this study were associated with established risk factors. Ethnic inequity in breast cancer mortality in NZ appears to be largely attributable to delay in diagnosis and tumour related factors. Further research in a larger cohort is needed to identify the full impact of these factors on ethnic inequity in breast cancer mortality.

Effect of obesity on aromatase inhibitor efficacy in postmenopausal, hormone receptor-positive breast cancer: a systematic review.

Aromatase inhibitors (AIs) decrease the production of oestrogen, decreasing stimulation of hormone receptor-positive breast cancer. Theoretically, AIs may be less effective in obese women, due to the greater quantity of aromatase in peripheral fatty tissue. We performed a systematic review to assess the effect of obesity on AI efficacy in breast cancer treatment. The review followed PRISMA guidelines. Studies included were interventional or observational studies with comparison groups, of postmenopausal women with hormone receptor-positive breast cancer on treatment with an AI, alone or in combination with other drugs, in which body mass index or another measure of obesity was recorded. Studies in all languages were included; if published as an abstract only, authors were contacted for further information. Outcome measures included overall survival, disease-free survival or time to progressive disease, survival from the start of therapy, mortality measures, local or distant recurrence of primary cancer and time to recurrence. Of 2,344 citations identified from five databases, eight studies met the criteria for inclusion; three randomised controlled trials and five retrospective cohort studies. Due to variability in study factors, it was not possible to perform a quantitative meta-analysis. However, the systematic review showed a trend towards a negative effect of obesity on AI efficacy. There is evidence of a negative effect of obesity on AI efficacy in postmenopausal hormone receptor-positive breast cancer, but the size of the effect cannot be assessed. More information is needed before clinical recommendations are made.

Impact of dermoscopy and short-term sequential digital dermoscopy imaging for the management of pigmented lesions in primary care: a sequential intervention trial.

BACKGROUND: Studies have shown the benign to malignant ratio of excised pigmented skin lesions is suboptimal in primary care. OBJECTIVES: To assess the impact of dermoscopy and short-term sequential digital dermoscopy imaging (SDDI) on the management of suspicious pigmented skin lesions by primary care physicians. METHODS: A total of 63 primary care physicians were trained in the use of dermoscopy and SDDI (interventions) and then recruited pigmented lesions requiring biopsy or referral in routine care by naked eye examination. They were then given a dermatoscope and the option of a SDDI instrument, and change of diagnosis and management was assessed. RESULTS: Following the use of the interventions on 374 lesions a total of 163 lesions (43.6%) were excised or referred, representing a reduction of 56.4%. Of the 323 lesions confirmed to be benign, 118 (36.5%) were excised or referred, leading to a reduction of 63.5% (P < 0.0005) in those requiring excision or referral. The baseline naked eye examination benign to melanoma ratio was 9.5 : 1 which decreased to 3.5 : 1 after the diagnostic interventions (P < 0.0005). Of the 42 malignant lesions included in the study (34 melanoma, six pigmented basal cell carcinoma and two Bowen disease) only one in situ melanoma was incorrectly managed (patient to return if changes occur) resulting in the correct management of 97.6% and 97.1% of malignant pigmented lesions and melanoma, respectively. CONCLUSIONS: In a primary care setting the combination of dermoscopy and short-term SDDI reduces the excision or referral of benign pigmented lesions by more than half while nearly doubling the sensitivity for the diagnosis of melanoma.

A pooled analysis of 10 case-control studies of melanoma and oral contraceptive use.

Data regarding the effects of oral contraceptive use on women's risk of melanoma have been difficult to resolve. We undertook a pooled analysis of all case-control studies of melanoma in women completed as of July 1994 for which electronic data were available on oral contraceptive use along with other melanoma risk factors such as hair colour, sun sensitivity, family history of melanoma and sun exposure. Using the original data from each investigation (a total of 2391 cases and 3199 controls), we combined the study-specific odds ratios and standard errors to obtain a pooled estimate that incorporates inter-study heterogeneity. Overall, we observed no excess risk associated with oral contraceptive use for 1 year or longer compared to never use or use for less than 1 year (pooled odds ratio (pOR)=0.86; 95% CI=0.74-1.01), and there was no evidence of heterogeneity between studies. We found no relation between melanoma incidence and duration of oral contraceptive use, age began, year of use, years since first use or last use, or specifically current oral contraceptive use. In aggregate, our findings do not suggest a major role of oral contraceptive use on women's risk of melanoma.

A randomised trial of population screening for melanoma.

OBJECTIVES: Melanoma is a significant cause of morbidity and mortality worldwide and incidence is increasing. Survival after treatment is inversely related to the thickness of the tumour at diagnosis. Population screening has the potential to reduce mortality but there is no conclusive evidence of benefit. Such evidence can come best from a randomised trial. Here we describe the design of a community based randomised trial of a population screening programme for melanoma in Queensland, Australia and early results of the first phase of the trial. METHODS: A total of 44 communities (aggregate population 560 000 adults aged 30 years or more) will be randomised to receive either a community based screening programme for 3 years or normal practice. The screening programme promotes thorough skin self examination and whole body skin examination by a doctor and provides open access skin cancer screening clinics. In its first phase, the trial is underway in nine intervention and nine control communities. The primary outcome measure is mortality from melanoma during 15 years of follow up. RESULTS: The first phase of the trial has shown the feasibility of implementing a population skin screening programme including regular skin cancer screening clinics, and has shown the strong support of communities and doctors for the programme. There has been a significant 2.5-fold increase in participation in screening in the intervention communities in this first phase after the first 12 months of the trial and no significant increase in participation in screening in control communities during this period. CONCLUSIONS: The design of a community based randomised trial of screening for melanoma has been successfully peer reviewed and the intervention has been shown to be feasible in practice. This randomised trial may be one of the last opportunities to develop the evidence required for public health recommendations for population screening for melanoma.

Historical cohort study of a New Zealand foundry and heavy engineering plant.

OBJECTIVES: To investigate the mortality of workers who had been exposed to asbestos, machining fluids and foundry work in a foundry and heavy engineering plant in the railway rolling stock manufacturing industry in New Zealand. METHODS: Historical cohort study design. RESULTS: For the total workforce of 3522 men employed between 1945 and 1991, follow up was 90% of person-years to 31 December 1991. Significantly increased standardised mortality ratios (SMRs) were found for all causes of death combined (SMR 1.07; 95% confidence interval (95% CI) 1.01 to 1.14), all malignancies (SMR 1.15; 95% CI 1.01 to 1.31), circulatory (SMR 1.16; 95% CI 1.07 to 1.27) and musculoskeletal diseases (SMR 3.06; 95% CI 1.39 to 5.84), all digestive cancers (SMR 1.29; 95% CI 1.04 to 1.59), all respiratory cancers (SMR 1.34; 95% CI 1.08 to 1.65), cancer of the oesophagus (SMR 1.97; 95% CI 1.01 to 3.45), and mesothelioma of the pleura (SMR 6.58; 95% CI 1.24 to 19.49). Three deaths from pleural mesothelioma were recorded, with latency times of 51, 53, and 57 years. There were no dose-response relations between exposure to asbestos, machining fluids or foundry work, or by duration of employment in the plant, and any cause of death. CONCLUSIONS: This study found small increases in risk for several causes of death among foundry and heavy engineering workers; however, these increases were small and the possible effects of smoking and other lifestyle factors could not be excluded. There was evidence of asbestos related disease in those involved in engineering work in the past.

Infections, vaccinations, and the risk of childhood leukaemia.

A nationwide case-control study was conducted in New Zealand, to test hypotheses about the role of infections in the aetiology of childhood leukaemia. Children aged 0-14 years with leukaemia were matched on age and sex to controls selected from birth records. Case ascertainment was virtually complete and 121 (92%) of 131 eligible case families took part. The participation rate among the 303 first-choice eligible controls was 69%. Home interviews and serological tests were conducted. Adjusted relative risks were estimated by logistic regression. There was an increased risk of leukaemia in relation to reported influenza infection of the child during the first year of life (adjusted odds ratio 6.8, 95% confidence interval 1.8-25.7). This could be a chance finding due to multiple comparisons, and it should be tested elsewhere. Some key variables relevant to Greaves' hypothesis were not associated with B-cell precursor acute lymphoblastic leukaemia (numbers of infections and vaccinations, firstborn status, attendance at preschool groups), although a small effect could not be ruled out with a study of this size. Leukaemia risk was higher among children in poorer social circumstances, and this was true for all eligible children as well as for the participants.

Public health aspects of breast cancer gene testing in Canada. Part 1: risks and interventions.

The risks (penetrance) of breast and ovarian cancer in carriers of the BRCA1 or BRCA2 genes are high, but it is likely that estimates based on selected large multicase families are inflated by selection bias. Estimates based on a population survey of Ashkenazi Jews are lower, but other population-based estimates are still not available. The proportion of breast or ovarian cancers related to the genes is similarly lower in population-based samples than in referred selected families, and, even for subjects with cancer onset at young ages or with a family history, it is quite small. Other genes with lower prevalence are also important, and there is evidence of some gene environmental interactions. The management of female BRCA gene carriers includes intensive surveillance, prophylactic surgery and the use of tamoxifen. Apart from screening justified by randomized trials in the general community, such as mammography, recommendations for surveillance and prophylactic surgery are based only on expert opinion, and there has been little consideration of risk-benefit or cost-benefit comparisons. Tamoxifen reduced breast cancer incidence in one trial of high-risk women, but not in two other smaller trials, and the effect on mortality has not been determined. The limitations of genetic testing, and particularly of intervention strategies, deserve close scrutiny.

Public health aspects of breast cancer gene testing in Canada. Part 2: selection for and effects of testing.

Criteria set by clinical services for referral for counselling and genetic testing are variable and often arbitrary. Empirical data and computer models are available to estimate the probability of being a mutation carrier, based on family and personal history. Surveys show that high proportions of women at risk of cancer and of women in the general population are interested in being tested, but this may be based on inflated perceptions of personal risk and limitations in understanding of the tests used and their implications. A high proportion of women with a positive family history have a greatly overestimated perception of their own risk, and even expert counselling has little impact on this. This risk perception may produce psychological distress and may reduce participation in screening programs. Counselling, while improving understanding, may also have little impact on prior interest in being tested. Interest in being tested relates to a wish to assess the risk for children, and hazards include potential health insurance discrimination. Testing may result in a reduction of psychological disturbance in those shown to be non-carriers, with little change in those shown to be carriers, but unwillingness to be tested may be related to psychological distress. The impact of publicity concerning genetic testing on perceptions of risk and on psychological disturbance, and the subsequent impact of counselling and intervention, require further assessment.

Public health aspects of breast cancer gene testing in Canada. Part 3: A model of potential need and demand.

Centres offering expert counselling and genetic testing are already experiencing high levels of demand, and yet the potential demand is much greater. There have been few attempts to estimate the potential demand created by particular guidelines for referral or testing. A model of need and demand for genetic services is presented, and research questions are identified that should assist in better prediction of future requirements for genetic counselling and testing. The value of integrated routine data on referral criteria, demand and clinical service load is considerable. Attention needs to be paid to referral at primary care and general specialist levels as well as to expert centres.

A critical review of epidemiologic studies of radiofrequency exposure and human cancers.

This paper reviews studies that have assessed associations between likely exposure to radiofrequency (RF) transmissions and various types of human cancer. These studies include three cluster investigations and five studies relating to general populations; all of these studies consider place of residence at the time of cancer diagnosis in regard to proximity to radio or television transmitters. There are also five relevant occupational cohort studies and several case-control studies of particular types of cancer. These studies assessed a large number of possible associations. Several positive associations suggesting an increased risk of some types of cancer in those who may have had greater exposure to RF emissions have been reported. However, the results are inconsistent: there is no type of cancer that has been consistently associated with RF exposures. The epidemiologic evidence falls short of the strength and consistency of evidence that is required to come to a reasonable conclusion that RF emissions are a likely cause of one or more types of human cancer. The evidence is weak in regard to its inconsistency, the design of the studies, the lack of detail on actual exposures, and the limitations of the studies in their ability to deal with other likely relevant factors. In some studies there may be biases in the data used

Electromagnetic field exposures and childhood leukaemia in New Zealand.

A nationwide case-control study of childhood leukaemia in New Zealand included measurements of electric and magnetic fields in children's homes. There was no significant association between leukaemia and the time-weighted average of the 50 Hz magnetic or electric fields in the bedroom and living (or daytime) room combined.

Clinical outcomes of the Otago-Southland Breast Cancer Screening Programme 1991-1996.

AIM: To document the clinical outcome of the Otago-Southland Breast Cancer Screening Programme through its first two rounds of screening, from 1991-1996. METHODS: Review and analysis of clinical and pathological records. RESULTS: In the first round of screening, 13,876 women were screened, giving 75% uptake; 12.2% were referred for assessment and 126 cancers detected, 9.1 per thousand women screened. For the 9946 incidence screens in the second round, 3.9% of women screened were referred to assessment and 50 cancers detected, 5.0 per thousand women screened. The uptake and cancer detection rates exceed the targets and exceed other published results; the size distribution of the cancers detected was comparable to the Swedish two-counties study, showing that the results should produce an ultimate mortality reduction. The referral rate to assessment was higher than expected in the first round of screening, but within the targeted range in the second round. The benign to malignant ratio for all biopsies was 1.4:1 for the prevalence screen of the first round and 1.2:1 for the incidence screens in the second round, both exceeding the targets set. CONCLUSIONS: The results show that the uptake and clinical results of the programme exceed expectations and that a large number of small invasive tumours have been successfully detected. These results are comparable to the best of overseas studies, and give confidence that mortality reductions will ultimately occur.

Body site distribution of cutaneous malignant melanoma in relationship to patterns of sun exposure.

A study of all newly incident melanoma patients in British Columbia in 1991-1992 was undertaken to test the hypothesis raised by an earlier study, which showed that in younger patients the incidence rate of melanoma per unit area of skin was higher on intermittently exposed skin areas than on continuously exposed areas. Using 1,033 patients and a more detailed body site categorisation than was previously possible, our results confirmed that in both men and women under age 50 the highest melanoma density was on the back. At ages over 50, the greatest density occurred on fully exposed sites, such as the face, though the dorsum of the hand and forearm, likely also to have high exposure, show very low melanoma densities. Differences between males and females correlate well with differences in likely exposure patterns. These results were seen for all invasive cutaneous melanomas combined; the patterns were similar for subtypes and for both invasive and in situ melanoma, with the exception of lentigo maligna melanoma (LMM), which occurs almost exclusively on the face, even at younger ages. Comparison with the earlier study (1976-1979) shows that the age-standardised rates for melanoma excluding LMM have increased by 60%, with the greatest proportional increase being at younger ages; in the recent data, the age-standardised rate for intermittently exposed sites exceeds that for usually exposed sites. Our results confirm that intermittent sun exposure has a greater potential for producing melanoma than continuous exposure at ages below about 50, though at older ages melanoma is more common on body sites with continuous sun exposure.

Electromagnetic field exposures and childhood cancers in New Zealand.

OBJECTIVES: To assess childhood cancer risks for electromagnetic field (EMF) exposures. METHODS: A case-control study was conducted in New Zealand. Cases (aged from zero to 14 years) were ascertained from national databases including the New Zealand Cancer Registry; 303 took part (participation rate, 88 percent). The 303 age- and gender-matched controls were selected randomly from birth records (participation, 69 percent). Mothers were interviewed about appliance exposures (all cases and controls), and 24-hour residential measurements of EMFs were made (leukemia cases and matched controls). RESULTS: For the various appliance exposures, there were some odds ratios (OR) above 1.0 and others below 1.0. For electric blanket use by the child before diagnosis, the adjusted ORs were: leukemia, 2.2 (95 percent confidence interval [CI] = 0.7-6.4); central nervous system cancers, ORs = 1.6 (CI = 0.4-7.1); and other solid cancers, OR = 2.4 (CI = 1.0-6.1). Leukemia risk was increased for the highest category of the mean measured bedroom magnetic field (> or = 0.2microT cf < 0.1 microT), with an adjusted OR of 15.5 (CI = 1.1-224). A gradient in OR with exposure was not shown (middle category: OR 1.4, CI = 0.3-7.6), and there was no association with exposure categorized into thirds based on controls' exposure. The adjusted OR for leukemia in relation to the measured daytime room magnetic field (> or = 0.2 microT cf < 0.1 microT) was 5.2 (CI = 0.9-30.8). CONCLUSIONS: This was a small study and multiple comparisons were made. The positive findings thus should be interpreted cautiously.

Melanoma and sun exposure: an overview of published studies.

To assess the association between the incidence of cutaneous melanoma; intermittent, occupational and total sun exposure; and history of sunburn at different ages, we conducted a systematic review using results of all published case-control studies which have assessed incident melanoma, sun exposure and sunburn. Twenty-nine studies contributed data on sun exposure and 21 on sunburn. Overall, there was a significant positive association (odds ratio [OR] = 1.71) for intermittent exposure, a significantly reduced risk for heavy occupational exposure (OR = 0.86) and a small, marginally significant excess risk for total exposure (OR = 1.18). There was a significantly increased risk with sunburn at all ages or in adult life (OR = 1.91) and similarly elevated relative risks for sunburn in adolescence (OR = 1.73) and in childhood (OR = 1.95). There was significant heterogeneity with all of these estimates except that of all ages or adult sunburn. These results show the specificity of the positive association between melanoma risk and intermittent sun exposure, in contrast to a reduced risk with high levels of occupational exposure. The association with sunburn also is likely to reflect intermittent exposure; the results do not suggest any strong relationship to age at sunburn. These associations are similar to those reported for basal cell skin cancer but different from those reported for squamous cell cancer. The mechanisms by which intermittent exposure increases risk, while other patterns of exposure do not, remain to be elucidated.

Breast cancer screening in younger women: evidence and decision making.

Contrasting conclusions on the efficacy of routine breast cancer screening in younger women, under age 50, have been produced by expert and influential groups, particularly in the United States. In an international workshop in 1993, and again at a consensus development conference in 1997, the National Institutes of Health and the National Cancer Institute concluded that evidence for efficacy was uncertain, and routine screening could not be recommended. The 1997 conference concluded that the individual decision had to be made by each woman and her health care provider. In contrast, the American Cancer Society has advocated routine screening, despite accepting that the randomized trial evidence does not clearly support it. The decision of the 1997 NCI consensus conference has been rejected by the director of the NCI, and a similar controversy occurred in 1993. On two occasions, US Senate subcommittees have affirmed support for screening and criticized the conclusions of expert groups. In this paper, the arguments raised in these discussions, and the differing ways in which scientific evidence has been assessed, are discussed.

Comparison of the site distribution of melanoma in New Zealand and Canada.

A comparison of the site distribution of cutaneous malignant melanoma in New Zealand and Canada was performed. This series deals with 41,331 incident cases registered between 1968 and 1990 and is the largest to date to evaluate the influence of age and gender on the site distribution of melanoma. Site-specific, age-standardized rates per unit surface area and relative tumour density were assessed by gender and country and differences compared with statistical techniques adapted to this context. The age-standardized rates for all sites were higher in New Zealand than in Canada, the ratio being 3.2 for men and 3.8 for women. Occurrence of melanoma was denser for chronically than intermittently exposed sites in both New Zealand and Canada. The highest incidence rate per unit area was for the ears in men which was more than 5 times the rate for the entire body in each country. For each gender, melanomas were relatively commoner on the trunk and the face in Canada, and on the lower limbs in New Zealand. The variations in the site distribution were similar in each country and consistent with the effect of differential patterns of sun exposure between genders. Our results show that the levels of risk of melanoma between phenotypically comparable populations exposed to different amount of UV radiation vary in a site-specific manner, especially for intermittently exposed sites. This suggests that both environmental conditions and lifestyle factors influence the site distribution of melanoma in these two populations.