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Biomedical subjects

Bruce K Armstrong

Publications and source records attributed to Bruce K Armstrong.

At least 37 records · Page 2Linked to original sources
PubMed2005

Stage at diagnosis and cancer survival for Indigenous Australians in the Northern Territory.

OBJECTIVE: To investigate whether Indigenous Australians with cancer have more advanced disease at diagnosis than other Australians, and whether late diagnosis explains lower Indigenous cancer survival rates. DESIGN: Retrospective cohort study. SETTING AND PARTICIPANTS: Indigenous and non-Indigenous people diagnosed with cancers of the colon and rectum, lung, breast or cervix and non-Hodgkin lymphoma in the Northern Territory of Australia in 1991-2000. MAIN OUTCOME MEASURES: SEER summary stage of cancer at diagnosis (local, regional or distant spread), cause-specific cancer survival rates and relative risk of cancer death. RESULTS: Diagnosis with advanced disease (regional or distant spread) was more common for Indigenous people (70%; 95% CI, 62%-78%) than for non-Indigenous people (51%; 95% CI, 53%-59%) with cancers of the colon and rectum, breast, cervix and non-Hodgkin lymphoma, but for lung cancer the opposite was found (Indigenous, 56% [95% CI, 46%-65%] v non-Indigenous, 69% [95% CI, 64%-75%]). Stage-adjusted survival rates were lower for Indigenous people for each cancer site. With few exceptions, the relative risk of cancer death was higher for Indigenous people for each category of stage at diagnosis for each cancer site. CONCLUSIONS: Health services apparently could, and should, be performing better for Indigenous people with cancer in the Northern Territory, and probably elsewhere in Australia. This study has demonstrated that data from cancer registers, enhanced with data on stage at diagnosis, can be used to monitor health service performance for Indigenous Australians in the Northern Territory; similar data is available in other States, and could be used to monitor health service performance for Indigenous people throughout Australia.

Breast Neoplasms↗
PubMed2005

Sun exposure and mortality from melanoma.

BACKGROUND: Melanoma incidence and survival are positively associated, both geographically and temporally. Solar elastosis, a histologic indicator of cutaneous sun damage, has also been positively associated with melanoma survival. Although these observations raise the possibility that sun exposure increases melanoma survival, they could be explained by an association between incidence and early detection of melanoma. We therefore evaluated the association between measures of skin screening and death from cutaneous melanoma. METHODS: Case subjects (n = 528) from a population-based study of cutaneous melanoma were followed for an average of more than 5 years. Data, including measures of intermittent sun exposure, perceived awareness of the skin, skin self-screening, and physician screening, were collected during in-person interviews and review of histopathology and histologic parameters (i.e., solar elastosis, Breslow thickness, and mitoses) for all of the lesions. Competing risk models were used to compute risk of death (hazard ratios [HRs], with 95% confidence intervals [CIs]) from melanoma. All statistical tests were two-sided. RESULTS: Sunburn, high intermittent sun exposure, skin awareness histories, and solar elastosis were statistically significantly inversely associated with death from melanoma. Melanoma thickness, mitoses, ulceration, and anatomic location on the head and neck were statistically significantly positively associated with melanoma death. In a multivariable competing risk analysis, skin awareness (with versus without, HR = 0.5, 95% CI = 0.3 to 0.9, P = .022) and solar elastosis (present versus absent, HR = 0.4, 95% CI = 0.2 to 0.8, P = .009) were strongly and independently associated with melanoma death after adjusting for Breslow thickness, mitotic index, and head and neck location, which were also independently associated with death. CONCLUSIONS: Sun exposure is associated with increased survival from melanoma.

Adult↗
PubMed2005

Risk of non-Hodgkin lymphoma associated with occupational exposure to solvents, metals, organic dusts and PCBs (Australia).

OBJECTIVE: Several studies have suggested that there is an occupational component to the causation of non-Hodgkin lymphoma (NHL). We aimed to use accurate means to assess occupational exposures to solvents, metals, organic dusts and polychlorinated biphenyls (PCBs) in a case-control study. METHODS: Cases were incident NHLs during 2000 and 2001 in two regions of Australia. Controls were randomly selected from the electoral roll and frequency matched to cases by age, sex and region. A detailed occupational history was taken from each subject. For jobs with likely exposure to the chemicals of interest, additional questions were asked by telephone interview using modified job specific modules. An expert allocated exposures using the information in the job histories and the interviews. Odds ratios were calculated for each exposure adjusting for age, sex, region and ethnic origin. RESULTS: 694 cases and 694 controls (70 and 45 respectively of those potentially eligible) participated. The risk of NHL was increased by about 30 for exposure to any solvent with a dose response relationship, subgroup analysis showed the finding was restricted to solvents other than benzene. Exposure to wood dust also increased the risk of NHL slightly. Exposures to other organic dusts, metals, and PCBs were not strongly related to NHL. CONCLUSIONS: The risk of NHL appears to be increased by exposure to solvents other than benzene and possibly to wood dust.

Adult↗
PubMed2005

An exploratory study of cancer patients' views on doctor-provided and independent written prognostic information.

This is the first study to systematically compare cancer patients' views on prognostic information provided by their doctor and written prognostic information obtained from a major cancer organisation (The Cancer Council New South Wales). Twenty-six adult patients who were recruited from a cancer clinic and an oncologist's private rooms completed a questionnaire and an interview. Participants varied in their views about the relative accuracy of doctor-provided and independent written information and responses to contradictory information. Participants' need for certainty, trust in their doctor and concerns about the effect of undermining that trust, appear to influence whether they would discuss independent information with their doctor, and how they would deal with conflicting information. Although preliminary, this study has identified a number of issues that may need to be taken into account both by people developing written prognostic information and by doctors, who may need to address patient concerns about trust to assist patients to deal with conflicting information.

Adaptation, Psychological↗
PubMed2005

Relationship of treatment delay with surgical defect size from keratinocyte carcinoma (basal cell carcinoma and squamous cell carcinoma of the skin).

Larger keratinocyte carcinoma (KC) lesions are associated with higher morbidity. This study examined the association of potentially modifiable characteristics, including treatment delay, with KC defect size after Mohs micrographic surgery (MMS). A stratified random sample of patients treated for KC with MMS were selected for telephone interview. Two hundred and nineteen interviews were completed (refusal rate 24%). Regression models were used to examine the predictors to defect size and delay. Anatomic site, age, histology, and gender predicted defect size (R(2) = 0.39) and were used as control variables. Self-reported delay between initial physician examination and MMS predicted defect size (p = 0.0004), with greater than 1 y delay being associated with a doubling of defect size (adjusted odds ratio (OR) 2.0; 95% confidence interval (CI) 1.3-3.1). Delays of this duration were associated with initial examination by a primary provider (unadjusted OR 3.9; 95% CI 1.7-8.8), misdiagnosis (unadjusted OR 6.8; 95% CI 2.5-18.7), being treated without biopsy (unadjusted OR 23.3; 95% CI 6.5-83.7), and multiple surgical removals (unadjusted OR 6.2; 95% CI 2.5-15.5). All but provider specialty were independent predictors of delay. Attention to processes of care delivery for KC may have a greater impact on morbidity than efforts are earlier detection by the public.

Adult↗
PubMed2005

Cancer incidence and survival for indigenous Australians in the Northern Territory.

OBJECTIVE: To compare cancer incidence and survival for the Northern Territory (NT) Indigenous population with that of other Australians, and to assess NT Indigenous incidence time trends. METHODS: Cancer registry data were used to calculate cancer incidence rate ratios (NT Indigenous to total Australian), the average annual change in NT Indigenous cancer incidence and the relative risk of cancer death after diagnosis of cancer (NT Indigenous to combined Western Australian and Tasmanian cases) for 1991-2001. RESULTS: For NT Indigenous people, incidence rates were high for cancers of the liver, gallbladder, cervix, vulva and thyroid and, in younger people only, for cancers of the oropharynx, oesophagus, pancreas and lung, but low for cancers of the colon and rectum, breast, ovary, prostate, bladder, kidney, melanoma and lymphoma. Incidence rate ratios ranged from 0.1 for melanoma to 7.4 for liver cancer. Incidence increased for breast and pancreatic cancers. Survival was low for almost all specific cancers examined, and for all cancers combined (relative risk of death 1.9, 95% CI 1.7-2.1). CONCLUSIONS: Compared with other Australians, NT Indigenous people have higher, and increasing, incidence for some cancers (particularly smoking-related cancers) and lower survival for most. IMPLICATIONS: Cancer has a greater impact on NT Indigenous people than other Australians. Well-established cancer risk factors should be more effectively tackled in Indigenous people and known effective screening programs more effectively implemented. Research is urgently required into the reasons why survival from cancer in NT Indigenous people is so much lower than in other Australians.

Adolescent↗
PubMed2005

Etiologic and other factors predicting nevus-associated cutaneous malignant melanoma.

Cutaneous malignant melanomas with histologic evidence of an associated nevus (N+) may have a different risk factor profile from that of melanomas without it (N-). To address this question, a case-only analysis of 932 people with cutaneous malignant melanoma was done to identify etiologic and other factors associated with N+ melanoma. Evidence of an associated nevus was found in 36% of melanomas. N+ melanomas were thinner (Ptrend=0.0009) and more likely to be of the superficial spreading type than other types of melanoma. Subjects with N+ melanomas were younger (Ptrend<0.0001) and reported a higher nevus density on their skin than subjects with N- melanomas [odds ratio (OR), 3.1; 95% confidence interval (CI), 1.6-6.0, for high nevus density versus no nevi]. Indicators of high accumulated sun exposure were less prevalent among subjects with N+ melanomas (OR, 0.3; 95% CI, 0.2-0.4, for melanoma location on the head and neck versus location on trunk; OR, 0.2; 95% CI, 0.1-0.4, for severe solar elastosis adjacent to the melanoma versus no elastosis; OR, 0.2; 95% CI, 0.1-0.4, for lentigo maligna melanoma subtype versus superficial spreading subtype). With the exception of solar elastosis and age, all of the aforementioned variables remained significantly associated with N+ melanomas in multivariate analyses. No associations with self-reported measures of sun exposure, sunburn, or pigmentation phenotype were apparent. Our findings provide some support for the hypothesis of etiologically separate pathways for melanoma, with N+ melanomas appearing less likely to develop in the presence of characteristics suggesting high accumulated sun exposure than N- melanomas. However, it is possible that high UV exposure causes involution of nevi, thus reducing the density of nevi in exposed skin and thereby the probability of N+ melanoma.

Adult↗
PubMed2005

Reliability and validity of a telephone questionnaire for estimating lifetime personal sun exposure in epidemiologic studies.

Our Australia-wide case-control study of ocular melanoma diagnosed in 1996 to 1997 needed a short telephone interview on sun exposure. We constructed one by examining data from 700 controls ages 40 to 64 years in the Geraldton Skin Cancer Survey in 1988; they had answered a "whole-of-life" questionnaire in a face-to-face interview. Sun exposure in their first 4 decade years of age best predicted their lifetime annual average sun exposure, so the shortened questionnaire asked about sun exposure in these 4 decade years only. Retesting 60 participants 1 year later with the whole-of-life questionnaire gave an intraclass correlation coefficient of 0.65 (95% confidence interval, 0.48-0.78) for ranked total sun exposure between the two interviews; the intraclass correlation coefficient was higher in men (0.73) than in women (0.54). Correlations were also high between parallel measurements of sun exposure on working days in the decade years and in outdoor occupations throughout life in the telephone interview of the ocular melanoma study (Spearman's R = 0.75) and in another study of non-Hodgkin's lymphoma (R = 0.71). Agreement between simultaneous parallel measures of total exposure (nonworking + working day and recreational + occupational exposure) was slightly weaker and of nonworking day and recreational exposure much weaker. Occupational exposure in women was much less strongly correlated with total exposure than it was in men possibly because of their frequently combined work and family roles, which the questionnaires did not try to separate. Research is needed into how this might be done to improve sun exposure measurement in women.

Adult↗
PubMed2004

Sun exposure may protect against non-Hodgkin lymphoma: a case-control study.

Ultraviolet radiation is a hypothesised risk factor for non-Hodgkin lymphoma (NHL) but no epidemiological study has examined this association using direct measures of sun exposure in individuals. Adults aged 20-74 years living in NSW and ACT, Australia, were the study population. Cases (704 of 829 invited to take part, 85%) were diagnosed January 2000 to August 2001. Controls (694 of 1,136 invited to take part, 61%) were randomly selected from state electoral rolls and frequency-matched to cases by age, sex and state of residence. A self-administered questionnaire and telephone interview measured outdoor hours on working and nonworking days and vacations at 10, 20, 30, 40, 50 and 60 years of age. Logistic regression models of NHL and sun exposure contained the 3 matching variables, ethnicity and sun sensitivity measures as covariates. Contrary to expectations, risk of NHL fell with increasing reported sun exposure hours. Relative to 1.0 for the lowest quarter of total sun exposure hours, the odds ratios (ORs) for successively higher quarters were 0.72 (95% CI 0.53-0.98), 0.66 (0.48-0.91) and 0.65 (0.46-0.91) (p(trend)=0.01). The association of sun exposure on nonworking days with NHL was stronger; OR for highest quarter 0.47 (0.34-0.66) (p(trend)=0.0001). Risk also fell with sun exposure on vacations; OR for highest quarter 0.60 (0.43-0.85) (p(trend)=0.003). These associations appeared strongest in women and in childhood. There was little evident trend in risk with exposure on working day. Our results provide strong statistical evidence for an inverse association between sun exposure and NHL. Increasing evidence that vitamin D may protect against cancer makes UV-mediated synthesis of vitamin D a plausible mechanism whereby sun exposure might protect against NHL.

Adolescent↗
PubMed2004

Artificial ultraviolet radiation and ocular melanoma in Australia.

We examined risk of ocular melanoma with exposure to artificial sources of exposure to ultraviolet radiation (UVR) in a population-based epidemiologic study of 290 cases of ocular melanoma and 893 controls aged 18-79 years in Australia in 1996-1998. Cases were identified through a prospective survey of all ophthalmologists and cancer registries in Australia; 91.8% participated. Controls were sourced from electoral rolls; 67.4% of those who were eligible and contactable participated, while 27.3% could not be contacted. Exposure to welding and use of sunlamps, including sunbeds and tanning booths, was measured by telephone interview. Analyses used unconditional logistic regression and included age, sex, region of birth, eye color, ocular and cutaneous sun sensitivity and personal sun exposure as covariates. Risk of choroid and ciliary body melanoma in 246 cases increased significantly with longer duration of use of sunlamps, first use before 21 years of age and first use after 1980. These effects were independent of personal sun exposure. Risk of these melanomas also increased with increasing duration of welding exposure, although the trend was not significant overall. There was no evidence that these exposures increased the risk of iris (n = 25) or conjunctival (n = 19) melanomas. Personal exposure to sunlamps and welding predicts risk of choroid and ciliary body melanoma in Australia.

Adolescent↗
PubMed2004

Remoteness of residence and survival from cancer in New South Wales.

OBJECTIVE: To analyse cancer survival in New South Wales by geographic remoteness. DESIGN, SETTING AND PARTICIPANTS: A survival analysis of all patients with cancers diagnosed in NSW between 1 January 1992 and 31 December 1996. Survival was determined to 31 December 1999. MAIN OUTCOME MEASURES: The relative excess risk (RER) of death over 5 years was estimated for each geographic remoteness category relative to the highly accessible category for 20 cancer types adjusted for age, sex, years since diagnosis and, subsequently, stage of cancer at diagnosis. RESULTS: There were statistically significant differences in the RER of death across remoteness categories (P < 0.001) for cancers of the cervix and prostate and for all cancers. The RERs for the most remote categories (compared with the highly accessible category) before and after adjustment for stage were cervix, 3.22 (95% CI, 1.54-6.75) and 2.25 (95% CI, 1.06-4.77); prostate, 3.38 (95% CI, 2.21-5.16) and 2.53 (95% CI, 1.60-4.01); all cancers, 1.35 (95% CI, 1.20-1.51) and 1.25 (95% CI, 1.11-1.41). In addition, there were significant variations in RER of death by remoteness for head and neck, lung and colon cancers and cutaneous melanoma. CONCLUSION: Cancer survival varies by remoteness of residence in NSW for all cancers together and some cancers individually. Access to screening or early diagnosis probably contributes to this variation, but persistence after adjustment for stage suggests that treatment variation is also important.

Humans↗
PubMed2004

Pigmentary characteristics, sun sensitivity and non-Hodgkin lymphoma.

We report on pigmentary characteristics, sun sensitivity and some other possible risk factors for non-Hodgkin lymphoma (NHL) in people 20-74 years of age. A statewide case-control study was conducted in New South Wales, Australia, with population-based sampling of cases (n = 704) and controls (n = 694). Risk of NHL was increased in subjects with hazel eyes (OR = 1.48; 95% CI = 1.07-2.04), very fair skin (OR = 1.44; 95% CI = 1.01-2.07) and poor ability to tan (OR = 1.70; 95% CI = 1.06-2.71). Risk with mild facial freckling as a child (OR = 0.77; 95% CI = 0.59-0.99) was reduced relative to that with no or moderate to severe freckling. Smokers were not at increased risk of NHL. A past history of treatment for skin cancer was associated with a slight nonsignificant increase in risk. Previous radiotherapy and chemotherapy were associated with 1.5- to 2-fold increases in risk but with wide confidence intervals. These results provide weak support for the possibility that sun sensitivity or perhaps sun exposure increases risk of NHL.

Adult↗
PubMed2004

Long-term trends in cancer mortality for Indigenous Australians in the Northern Territory.

OBJECTIVE: To examine long-term trends in cancer mortality in the Indigenous people of the Northern Territory (NT) of Australia. DESIGN: Comparison of cancer mortality rates of the NT Indigenous population with those of the total Australian population for 1991-2000, and examination of time trends in cancer mortality rates in the NT Indigenous population, 1977-2000. PARTICIPANTS: NT Indigenous and total Australian populations, 1977-2000. MAIN OUTCOME MEASURES: Cancer mortality rate ratios and percentage change in annual mortality rates. RESULTS: The NT Indigenous cancer mortality rate was higher than the total Australian rate for cancers of the liver, lungs, uterus, cervix and thyroid, and, in younger people only, for cancers of the oropharynx, oesophagus and pancreas. NT Indigenous mortality rates were lower than the total Australian rates for renal cancers and melanoma and, in older people only, for cancers of the prostate and bowel. Differences between Indigenous and total Australian cancer mortality rates were more pronounced among those aged under 64 years for most cancers. NT Indigenous cancer mortality rates increased over the 24-year period for cancers of the oropharynx, pancreas and lung, all of which are smoking-related cancers. CONCLUSIONS: Cancer is an important and increasing health problem for Indigenous Australians. Cancers that affect Indigenous Australians to a greater extent than other Australians are largely preventable (eg, through smoking cessation, Pap smear programs and hepatitis B vaccination).

Adolescent↗
PubMed2004

Familial aggregation of melanoma risks in a large population-based sample of melanoma cases.

OBJECTIVE: Melanoma has been shown in numerous studies to be associated with sun exposure, and with host phenotypic factors of genetic origin. In this study we use information from a large series of incident cases of melanoma from an international population-based study to examine the patterns of incidence of melanoma in the first-degree relatives of these cases. METHODS: A total of 2508 incident cases of melanoma provided information on basic demographic data and pigmentary characteristics, in addition to detailed information on family history of melanoma. These data were used to examine the incidence rates ratios of melanoma in the relatives of cases in relation to population rates, and also with respect to phenotypic characteristics of the probands that have been shown to be associated with melanoma: mole counts, hair color, eye color, and skin sensitivity to the sun. RESULTS: The incidence rates reflect the underlying patterns of incidence in the source populations, with generally higher rates in the Australian sample, low rates in Italy, and intermediate rates in the USA and Canada. Also, rates are higher in men than in women, except at very young ages. Phenotypic characteristics of the probands were only weakly associated with the observed rates in the relatives although there is a strong inverse association with age at diagnosis. Cumulative risk of melanoma rises to 6.9% (6.1%) at age 80 in male (female) first-degree relatives of cases, and to 10.8% (9.5%) in relatives of cases diagnosed before age 50. CONCLUSIONS: Relatives of cases diagnosed with melanoma are at considerable lifetime risk of the disease, especially if the case is diagnosed at a young age.

Adult↗
PubMed2004

Estimating regional variation in cancer survival: a tool for improving cancer care.

OBJECTIVE: To improve estimation of regional variation in cancer survival and identify cancers to which priority might be given to increase survival. METHODS: Survival measures were calculated for 25 major cancer types diagnosed in each of 17 health service regions in New South Wales, Australia, from 1991 to 1998. Region-specific risks of excess death due to cancer were estimated adjusting for age, sex, and extent of disease at, and years since, diagnosis. Empirical Bayes (EB) methods were used to shrink the estimates. The additional numbers of patients who would survive beyond five years were estimated by shifting the State average risk to the 20th centile. RESULTS: Statistically significant regional variation in the shrunken estimates of risk of excess death was found for nine of the 25 cancer types. The lives of 2903 people (6.4%) out of the 45,047 whose deaths within 5 years were attributable to cancer could be extended with the highest number being for lung cancer (791). CONCLUSIONS: The EB approach gives more precise estimates of region-specific risk of excess death and is preferable to standard methods for identifying cancer sites where gains in survival might be made. The estimated number of lives that could be extended can assist health authorities in prioritising investigation of and attention to causes of regional variation in survival.

Adolescent↗
PubMed2003

Chromosomal gains and losses in ocular melanoma detected by comparative genomic hybridization in an Australian population-based study.

To define the location of potential oncogenes and tumor suppressor genes in ocular melanoma we carried out comparative genomic hybridization (CGH) analysis on a population-based series of 25 formalin-fixed, paraffin-embedded primary tumors comprising 17 choroidal, 2 ciliary body, 4 iris, and 2 conjunctival melanomas. Twelve (48%) of the 25 melanomas showed no chromosomal changes and 13 (52%) had at least one chromosomal gain or loss. The mean number of CGH changes in all tumors was 3.3, with similar mean numbers of chromosomal gains (1.5) and losses (1.8). The highest number of chromosomal changes (i.e., nine) occurred in a conjunctival melanoma and included four changes not observed in tumors at any other ocular site (gains in 22q and 11p and losses in 6p and 17p). The most frequent gains in all primary ocular melanomas were on chromosome arm 8q (69%), 6p (31%) and 8p (23%) and the most frequent losses were on 6q (38%), 10q (23%), and 16q (23%). The most common pairing was gain in 8p and gain in 8q, implying a whole chromosome copy number increase; gains in 8p occurred only in conjunction with gains in 8q. The smallest regions of copy number alteration were mapped to gain of 8q21 and loss of 6q21, 10q21, and 16q22. Sublocalization of these chromosomal changes to single-band resolution should accelerate the identification of genes involved in the genesis of ocular melanoma.

Adolescent↗
PubMed2003

Incidence of ocular melanoma in Australia from 1990 to 1998.

Routinely collected incidence data have often lacked specific identification of ocular melanoma in the past and with increasing diagnosis and management of this disease by noninvasive techniques may now underestimate the true incidence. We attempted to accurately measure the incidence of ocular melanoma in Australia from 1990 to 1998 using 2 population-based sources, cancer registries and ophthalmologists. We examined the distribution across the continent, by latitude and in subpopulations, and evaluated the extent of nonnotification to cancer registries. One-half (51%) of the incident cases from 1996 to 1998 were diagnosed clinically and had no tissue diagnosis. An estimated 20% of melanomas, mainly those lacking a tissue diagnosis, were not notified to Australian cancer registries, but only 1.3% were not notified by ophthalmologists. Expert reviewers agreed that a high proportion (95%) of clinically diagnosed lesions were probable or possible melanomas. Incidence was significantly higher in men than in women, especially at older ages, relatively uniform across the Australian states with only weak evidence of a latitude gradient, and higher in rural than in urban areas. The incidence of ocular melanoma in people born in Southern Europe was half and in those born in Asia only 20% of the rate in people born in Australia and New Zealand. We concluded that it was possible to identify a high proportion of cases by surveying relevant sources additional to cancer registries and to be reasonably confident of the accuracy of the clinical diagnoses. The higher incidence in older men, who probably have higher sun exposure, than in older women and in residents of rural areas, where outdoor work is more prevalent, than in urban areas; the low incidence in dark-eyed populations, who may have a lower sensitivity to or less transmission of solar radiation to the choroid; and the preferential location of ocular melanomas in ocular sites known to receive the highest exposure to solar radiation all support a role for solar radiation in the aetiology of ocular melanoma. The absence of a strong latitude gradient in incidence does not argue against such a role because exposure of the eye to solar UV is probably determined most by the horizon sky, where ambient solar UV is less affected by latitude.

Adult↗