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Biomedical subjects

A Kricker

Publications and source records attributed to A Kricker.

At least 37 records · Page 2Linked to original sources
PubMed1998

Should women take part in clinical trials in breast cancer? Issues and some solutions.

PURPOSE: The purpose of this review is to consider the issues for women related to participation in clinical trials that evaluate the management of breast cancer and provide some recommendations for future initiatives to address the identified areas of concern. METHODS: The National Health and Medical Research Council (NHMRC) National Breast Cancer Centre hosted an international workshop to address the question "Clinical Trials in Breast Cancer: Should Women Take Part?" We also reviewed the literature on informed participation in clinical trials that was identified in a broadly based search that covered Medline, PsycLIT, and HealthPlan from 1986 to 1996. RESULTS AND CONCLUSION: When women are asked to participate in a clinical trial, they are faced with a number of questions and dilemmas. These include issues related to the conduct and ethical considerations of the trial; the effect of participation or nonparticipation on treatment; the roles of the doctor as clinician and as researcher; the process of informed consent; the timing of the request for participation; and the benefits and costs of participation. A number of steps are identified that could help women decide whether to participate in clinical trials. These include provision of community information about clinical trials; establishment of independent brokers and registers for clinical trials; consumer review of information and protocols and involvement in trials; review of the role of ethics committees; collection of data about the proportion of women currently recruited to clinical trials, their reasons for participating or declining, and their views about the process of recruitment and participation; models for optimal practice in recruiting women to clinical trials and encouraging ongoing participation in trials; evidence-based communication skills training for clinicians to teach skills to inform women adequately of clinical trial participation; and auspicing and promotion of trials by an independent agency.

Breast Neoplasms↗
PubMed1998

Reproducibility of reported measurements of sun exposure in a case-control study.

We examined the reproducibility of the measurement of sun exposure in a cohort study of nonmelanocytic skin cancer in Geraldton, Western Australia. Two analyses were undertaken: a comparison of cutaneous sun damage with sun exposure reported at interview, and an analysis of test-retest reproducibility of reported exposure. Skin cancers and cutaneous indicators of sun damage (cutaneous microtopography and solar elastosis of the neck) were recorded at a survey in 1987. A case-control study was conducted in 1988 in which subjects were interviewed about their lifetime sun exposure. All subjects had European ancestry. A subset of these subjects was reinterviewed using the same interview schedule in 1993. The comparison of reported exposure with skin damage was restricted to 201 cases of basal cell carcinoma and 700 controls, all of whom were born in Australia and had no southern European ancestors. The analysis of test-retest reproducibility included 62 cases with basal cell carcinoma and 162 controls. After adjustment for the skin's sensitivity to sunlight, cutaneous microtopography explained 7% and solar elastosis of the back of the neck explained 13% of the variance in the reported time spent outdoors. The intraclass correlation between time spent outdoors reported in the two interviews was 0.77 [95% confidence interval (CI), 0.71-0.83], whereas for exposure to a specific anatomical site, it was 0.65 (95% CI, 0.55-0.73). The reported site-specific exposure was lower on the second occasion in controls but higher in cases. The hours of exposure on vacations and the proportion of exposure that occurred on nonworking days had poor reproducibility. Furthermore, cases reported a more intermittent pattern of weekly exposure on the first occasion than on the second, whereas the controls showed little difference in their pattern on the two occasions. The weighted kappa statistic for lifetime painful sunburns was 0.53 (95% CI, 0.41-0.66), and for lifetime number of blistering sunburns, it was 0.54 (95% CI, 0.44-0.65). Thus, the reported sun exposure showed only moderate agreement with biological markers of sun damage. Total sun exposure and, to a lesser extent, site-specific exposure showed good agreement on the two occasions. However, indicators of intermittent sun exposure had poor agreement, and sunburn had only fair agreement.

Adult↗
PubMed1997

Incidence of non-melanocytic skin cancer in Geraldton, Western Australia.

To measure the rate at which non-melanocytic skin cancers develop, we conducted a population-based, longitudinal study in Geraldton, Western Australia. Subjects were residents of Geraldton, Western Australia, who were between 40 and 64 years of age and registered on the electoral roll in 1987. In 1987 and again in 1992, dermatologists examined participants for skin cancers. They examined all skin areas, apart from those covered by underwear or hair. Subjects were asked about skin cancers that they had had treated between the 2 surveys. When all skin cancers were counted, the incidence rates of basal cell carcinoma were 3,379 per 100,000 person-years in women and 7,067 per 100,000 in men; those of squamous cell carcinoma were 501 per 100,000 in women and 775 per 100,000 in men. Sixteen percent of men and 14% of women developed at least one basal cell carcinoma; 2.8% of men and 2.2% of women had at least one squamous cell carcinoma. Most incident skin cancers were diagnosed at the second examination. More than half of the subjects who had a skin cancer at the first examination developed another. Squamous cell carcinomas occurred almost exclusively on parts of the body that are usually exposed. Basal cell carcinomas were common on the head, neck and trunk but not on the forearms and backs of hands. A quarter of people with a skin cancer on an exposed site also had one on the trunk. Our results show that skin cancer is extremely common in this population and frequently undiagnosed. Multiple skin cancers occur commonly, and skin cancers on exposed sites often are associated with skin cancers on less exposed sites.

Adult↗
PubMed1997

Sunlight and cancer.

Epidemiologic evidence on the relation between sunlight and cancer is reviewed. Strong evidence implicates sunlight as a cause of skin cancer, although, for melanoma and basal cell carcinoma, the relationship is complex. Both types of cancer are associated more strongly with nonoccupational exposure than with occupational exposure, and the pattern and amount of exposure each appear to be important. Squamous cell carcinoma appears to be related more strongly to total (i.e., both occupational and nonoccupational) exposure to the sun. The evidence that sunlight causes melanoma of the eye is weak. It shows no latitude gradient and the results of case-control studies are conflicting. There is inadequate evidence to suggest that sunlight does or does not cause any other type of cancer.

Australia↗
PubMed1997

Sun exposure and skin cancer.

By 1927 for basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), and by 1955 for melanoma, the broad grounds for relating sun exposure to skin cancer had been established: that these are more frequent in residents of areas of high ambient solar irradiance, are more frequent in sun-sensitive people, occur mainly on sun-exposed body sites, are more frequent in people with high sun exposure, and are more frequent in people with benign sun-related skin conditions. The past 40 years have added both quantity and quality to the epidemiological evidence and, most recently, provided direct evidence that sun exposure is the cause of mutations in critical tumour suppressor genes in BCC, SCC and melanoma. Complete or more convincing answers are still needed to many questions of detail. They include whether the pattern of sun exposure is really important in, and acts independently of amount of sun exposure in, affecting the risk of melanoma and BCC; what the shape of the relationship between the amount of sun exposure and risk of BCC and melanoma is when the pattern of exposure is held constant; whether there really is a plateau in risk of BCC and melanoma beyond some level of the amount of exposure; whether this exposure-response relationship depends on cutaneous sensitivity to the sun and in what way; whether sunburn makes a specific contribution to the risk of skin cancer independent of the amount of sun exposure; whether sun exposure close to the time of diagnosis of skin cancer contributes anything to the development of the cancer; what the solar radiation action spectrum is for each kind of skin cancer; and whether sunscreens are effective in protecting against skin cancer.

Australia↗
PubMed1995

Breast cancer in NSW women: a shift in tumour size.

OBJECTIVE: To determine whether there has been an increase in the proportion of small (< 1 cm in size) and localised breast cancers in women aged 50-69 (the group actively recruited to mammographic screening) compared with women aged 40-49. DESIGN: Cases of invasive breast cancer in women aged 40-69 notified to the NSW Central Cancer Registry in 1986, 1989 and 1992 were included. Tumour sizes were determined from histopathology reports. RESULTS: A higher percentage of breast cancers were under 1 cm in size in 1992 (10%) than in 1986 and 1989 (7%). The increase in the percentage of small breast cancers was statistically significant in women aged 50-69 (chi 2 for linear trend, 7.9; P = 0.005) but not in those aged 40-49 (chi 2 for linear trend, 2.5; P = 0.12). Slightly more than half the breast cancers (53%) in 1992 were localised to the breast, representing an increase from 49% in both 1986 and 1989. This increase was also statistically significant in women aged 50-69 (chi 2 for linear trend, 3.9; P = 0.05) but not in those aged 40-49 (chi 2 for linear trend, 1.4; P = 0.24). CONCLUSIONS: Breast cancers in 1986, 1989 and 1992 showed a moderately strong shift to smaller tumours and localised disease in women aged 50-69. As women of this age group were targeted by mammographic screening, the widespread availability of mammography may explain this shift.

Adult↗
PubMed1995

A dose-response curve for sun exposure and basal cell carcinoma.

A population-based case-control study of sun exposure and basal cell carcinoma (BCC) was conducted in Western Australia in 1988. Its aim was to examine the relationship between risk of BCC and the amount and pattern of sun exposure. This report deals with amount of exposure. The odds ratios (ORs) for BCC on the head and neck and limbs decreased with increasing total exposure, whereas the opposite was observed for BCC on the less heavily exposed trunk, with the highest OR in those with the greatest exposure. In an analysis of all body sites together in which the total hours of exposure to the specific site was treated as a continuous variable, an initial rise in risk of BCC was seen with a peak OR of 1.4 at about 35,000 hr of exposure, followed by a fall. In contrast to these site-specific patterns, lifetime accumulated sun exposure of the whole body showed no appreciable association with BCC either in total or for working days only. Risk of BCC was positively associated with lifetime exposure on non-working days, however, with an OR for higher than baseline categories of around 1.7. There was a significant interaction between ability to tan and total and occupational sun exposure. Risk increased with increasing exposure in those who tanned well but not in those who tanned poorly. This pattern is consistent with other observations which indicate that beyond a certain level of sun exposure risk of BCC does not increase further.

Adult↗
PubMed1995

Does intermittent sun exposure cause basal cell carcinoma? a case-control study in Western Australia.

Our report deals with the relationship of pattern and timing of sun exposure to basal cell carcinoma (BCC) in a population-based case-control study conducted in Western Australia in 1988. The main measure of intermittent exposure was based on the amount of exposure on non-working days relative to that over the whole week. Outdoor recreational activities, holidays and sunburn were also considered to be markers of intermittent exposure. We observed a statistically significant increase in risk of BCC with increasing proportion of weekly sun exposure obtained at the weekend, especially in late teenage (OR = 3.9, 95% CI 1.9-7.8 for maximum intermittency of exposure), exposure of the site of skin cancer during holidays (OR = 1.9, 95% CI 1.1-3.1 for the highest exposure quarter) and sunburn to the site (ORs of 1.8 for 3-10 and 1.5 for 11+ sunburns in a lifetime). Risk of BCC increased substantially with increasing intermittency in poor tanners but not at all in good tanners. Our data suggest that a particular amount of sun exposure delivered in infrequent, probably intense increments will increase risk of BCC more than a similar dose delivered more continuously over the same total period of time.

Adult↗
PubMed1995

Skin cancer.

It is estimated that 92,000 new cases of melanoma and 2,750,000 cases of nonmelanocytic skin cancer occur worldwide each year. Incidence of these cancers varies more than 100-fold from low rates in Asian populations to very high rates in the white population of Australia. Incidence of melanoma has been increasing in white populations by some 3% to 7% per year over the past 30 years; recent very sharp increases in some populations are probably due to early and increasing detection of cancers that were already there. Incidence of nonmelanocytic skin cancers probably is also increasing. Sun exposure is the main cause of skin cancer, accounting for at least 65% of melanomas worldwide and a much higher proportion in white populations. Pattern as well as amount of sun exposure is important in determining the risk of melanoma and probably also of basal cell carcinoma, with an intermittent pattern being associated with the greatest risk. There is increasing evidence that nonsolar sources of ultraviolet radiation, in particular sunlamps and sunbeds, increase the risk of melanoma, and PUVA therapy and exposure to ionizing radiation are established causes of nonmelanocytic skin cancer.

Female↗
PubMed1994

Sun exposure and non-melanocytic skin cancer.

Non-melanocytic skin cancer has long been regarded as one of the harmful effects of solar ultraviolet (UV) radiation on human health. In this review, we examine epidemiologic evidence linking sun exposure and skin cancer coming from both descriptive studies in populations and analytical studies involving estimates of exposure in individuals. Particular attention is given to the quality of the published data. The epidemiologic evidence that sun exposure causes skin cancer is mainly indirect. Incidence or mortality is inversely related to latitude in populations of mainly European origin (e.g., the United States, Australia), and is higher in people born in Australia (high ambient solar radiation) than in migrants to Australia from the United Kingdom (lower ambient radiation). Skin cancer occurs mainly at sun-exposed body sites and in people who are sensitive to the sun; a reduced capacity to repair UV-induced DNA damage appears to increase the risk. The direct evidence linking sun exposure and skin cancer is weaker with few well-conducted studies of sun exposure in individuals. Mostly, studies of total sun exposure have not found statistically significant positive associations; those that did, had not adjusted for potential confounding by age and gender and thus their interpretation is limited. Studies of occupational sun exposure had relative risks not greater than 2.0; recreational exposure has been little studied. Other measurements, less direct but potentially less prone to measurement error, are sunburn (not evidently associated with skin cancer risk) and indicators of benign cutaneous sun-damage (strongly associated but lacking empirical evidence that sun exposure is their main cause). Many questions remain about the relationship between sun exposure and skin cancer.

Adult↗
PubMed1994

Cutaneous melanoma.

Between the early 1960s and the late 1980s, the incidence of melanoma increased at a rate of 3-7% per year in populations of mainly European origin. Corresponding trends were observed in mortality. Higher rates of increase in incidence were observed in a few populations (eg 8.9% per year in Hawaii whites). With the exception of Japan and possibly Puerto Rico, incidence rates of melanoma have remained stable in the few populations of mainly non-European origin for which reliable incidence data were available. A comparison of age specific trends in incidence and mortality in populations of mainly European origin showed two general patterns: a continuous increase in incidence in all age groups but with moderation or cessation of the previous rising trend in mortality in younger people in more recent time periods (eg Canada, continental USA, Denmark and the UK) and recent moderation or cessation of both incidence and mortality trends in younger people (eg New Zealand and, possibly, Hawaii whites). The first of these two patterns appeared to be the most common. Studies of site specific trends in incidence in 13 populations indicate that the highest rates of increase have generally been for melanomas on the trunk and the lowest for those on the head and neck. There is weak evidence to suggest that the rate of increase on the lower limbs has been greater in women than in men. Studies of incidence trends in the 1980s by thickness of melanoma in seven populations show that relative and absolute incidence has increased most for the thinnest melanomas and least for the thickest lesions. Increasing detection, earlier diagnosis and a real rise may together explain the increase in incidence of melanoma. The increases in mortality suggest that incidence has really increased, and the recent moderation in mortality trends may be explained by improved survival from melanoma due, most likely, to increasingly early diagnosis. In some populations, it may also indicate that the incidence increases are coming to an end. The disproportionately increasing incidence of thin melanoma, the divergence between incidence and mortality trends and the recent sharp increases in incidence in some populations suggest that earlier diagnosis or greater detection of less aggressive melanomas may have contributed to the incidence trends. A progressive change from predominantly occupational to predominantly recreational patterns of sun exposure is the most likely cause of increasing real incidence of melanoma in populations of mainly European origin.

Adolescent↗
PubMed1993

How much melanoma is caused by sun exposure?

Estimates have been made of the proportion of cutaneous malignant melanomas caused by sun exposure by comparing the observed incidence of melanoma with estimates of the incidence in the absence of sun exposure. The estimated proportions varied from 0.97 in males and 0.96 in females in Queensland, Australia, when the incidence on the whole body was compared with that on unexposed sites, to 0.68 when incidence in people born in Australia was compared with that in migrants to Australia from areas of lower sun exposure. A comparison of US Whites and US Blacks, in which the incidence in Blacks was taken as the incidence in unexposed Whites, gave estimates of 0.96 in males and 0.92 in females. It was estimated that some 59,000 (65%) of about 92,000 melanomas that occurred worldwide in 1985 were caused by sun exposure. This is probably a minimum estimate. That 20% of the world's melanomas are estimated to occur in Black African and Asian populations and are of unknown cause would justify studies of the causes of melanoma in these populations.

Algorithms↗
PubMed1991

Pigmentary and cutaneous risk factors for non-melanocytic skin cancer--a case-control study.

The roles of ethnic origin, pigmentary traits, sun sensitivity and other cutaneous characteristics as risk factors for basal-cell carcinoma (BCC) and squamous-cell carcinoma (SCC) were examined in a case-control study of prevalent and incident cases of histopathologically confirmed skin cancers. Two hundred and twenty six confirmed cases of BCC, 45 of SCC and 1,015 controls with no lesions were identified in a population-based survey of skin cancer in 1987 in Geraldton, Western Australia. The risk of both cancers was higher in native-born Australians than in migrants. The risk of BCC decreased with increasing age at arrival in Australia. Southern European ancestry was strongly protective against BCC (for any southern European grandparents) and SCC (no case of SCC had any grandparents of southern European origin). Inability to tan was the strongest pigmentary risk factor for both BCC and SCC. Among factors that incorporated a measure of sun exposure as well as sun sensitivity, freckling on the arm in childhood was important for both cancers, the number of moles on the back was important for BCC, and forearm skin colour and having a permanent colour difference between the neck and adjacent protected areas were important for SCC. Among measures of sun damage to the skin, solar elastosis of the neck was a strong risk factor for both BCC and SCC, loss of fine texture of the skin of the back of the hands (as measured by cutaneous microtopography) was important for BCC and telangiectasia of the face for SCC. When all important variables for each cancer were examined together in a single model with age, sex, migrant status or age at arrival in Australia, and ethnicity, in ability to tan, solar elastosis of the neck, and the number of moles on the back were independently significant risk factors for BCC and solar elastosis of the neck and having a permanent colour difference between the neck and adjacent protected areas were independently significant risk factors for SCC. The effects of age at arrival or migrant status and ethnic origin remained important in the models incorporating these factors. A history of ever having acne and a history of warts were protective for BCC and a history of acne was protective for SCC.

Adult↗
PubMed1990

Skin cancer in Geraldton, Western Australia: a survey of incidence and prevalence.

A survey of the incidence and prevalence of non-melanocytic skin cancer in Geraldton, Western Australia, was undertaken in November 1987. All residents aged 40 to 64 years whose names were on the electoral roll on August 1, 1987 were invited to undergo a whole-body skin examination by a dermatologist. When a skin cancer was suspected, participants were referred for treatment to their usual medical practitioner. Subjects were asked to recall incident skin cancers over the preceding two years, and medical records were searched for confirmatory evidence. Histological confirmation of all lesions, both prevalent and incident, was sought and sections were obtained for a standardized review. The prevalence of confirmed non-melanocytic skin cancer in those aged 40 to 64 years was 7.0% in men and 4.7% in women. The prevalence of basal-cell carcinoma (BCC) was 6.5% in men and 4.5% in women while the prevalence of squamous-cell carcinoma (SCC) was 1.2% in men and 0.3% in women. The estimated incidence rate of non-melanocytic skin cancer in this age group was 1560 per 100,000 person-years. The estimated incidence rate of BCC in men was 1335 per 100,000 person-years, and in women 817 per 100,000, while in men the estimated incidence rate of SCC was 890 per 100,000 person-years, and in women it was 289 per 100,000 person-years.

Adult↗