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J Mark Elwood

Publications and source records attributed to J Mark Elwood.

13 recordsLinked to original sources
PubMed2006

The relationship between melanoma thickness and time to diagnosis in a large population-based study.

OBJECTIVE: To examine the relationship between melanoma thickness and reported time from first recognition and from first physician contact to the diagnosis of invasive melanoma. DESIGN: Telephone survey of patients recently diagnosed as having melanoma, combined with relevant pathological data (including melanoma thickness and morphologic structure) from the population-based Queensland Cancer Registry. A test-retest study (n = 176) was also conducted. SETTING: Population-based study in Queensland. PARTICIPANTS: Residents of Queensland (n = 3772) who had been diagnosed as having invasive melanoma between January 1, 2000, and December 31, 2003. MAIN OUTCOME MEASURES: Prepresentation time (time between first noticing a suspicious spot and the first physician visit), postpresentation time (time between the first physician visit and diagnosis), and total time to diagnosis (time from initial detection of the melanoma to diagnosis). RESULTS: With 1 exception, we found no significant association between melanoma thickness and reported time to diagnosis for all melanomas combined, superficial spreading melanomas, or nodular melanomas. The exception was a positive association between melanoma thickness and postpresentation delay of physician-detected nodular melanomas. The reliability study gave intraclass correlation coefficients of 0.85 to 0.90 for the measures of intervals. CONCLUSIONS: This large study demonstrates no clear relationship between the melanoma thickness when diagnosed and the time from first recognition of changes or from first physician examination to diagnosis. This may be because of varying biological characteristics of melanomas, as well as methodological limitations of retrospective studies when trying to measure this complex association.

Adult↗
PubMed2006

Childhood leukemia and residential magnetic fields: are pooled analyses more valid than the original studies?

The association seen in epidemiological studies between childhood leukemia and magnetic field strength in the child's home has been very important in influencing reviews of international groups and standard setting organizations. This association is usually based on the results of two published pooled analyses, which use definitions of exposure that differ from those of some the original studies. However, the results and conclusions of the pooled analyses differ from those of the three largest recent studies, which have the most sophisticated methodology and together account for the majority of the exposed cases at high exposure levels in the pooled analyses. These recent studies, using the exposure methods and the cut-off levels set a priori, each concluded that there was little evidence of any association. The pooled analyses, using different exposure measures and different cut-offs, conclude that an association exists at high exposure levels. It is not clear if the results of the pooled analysis are more valid than those of the recent major studies, although this has been often assumed in influential reviews.

Bias↗
PubMed2006

Pregnancy history and incidence of melanoma in women: a pooled analysis.

There is evidence that pregnancy history including age at first birth and parity may play a role in risk of cutaneous melanoma in women, although, epidemiological findings are inconsistent. We conducted a collaborative analysis of these factors using the original data from ten completed case-control studies (2391 cases and 3199 controls), and assessed the potential confounding effects of socioeconomic, pigmentary, and sun exposure-related factors. We found no overall association with ever having a live birth (pooled odds ratio (pOR) 0.95, 95% confidence interval (CI) 0.67-1.35). However, we detected a reduced risk of melanoma among women with higher parity (> or = 5 versus no live births pOR 0.76, 95% CI 0.49-1.18, each live birth pOR 0.95, 95% CI 0.91-0.99, p trend = 0.05). Women with both earlier age at first birth (e.g., <20 years) and higher parity (e.g., > or = 5 live births) had a particularly lower risk than women with later age at first birth (e.g., > or = 25 years) and lower parity (e.g., <5 live births) (pOR 0.33, 95% CI 0.14-0.75). The results are compatible with an effect of reproductive history-related factors on melanoma risk, but also could reflect differences in other factors, such as sun exposure history.

Adult↗
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↗
PubMed2003

Epidemiological studies of radio frequency exposures and human cancer.

Epidemiological studies of radio frequency (RF) exposures and human cancers include studies of military and civilian occupational groups, people who live near television and radio transmitters, and users of mobile phones. Many types of cancer have been assessed, with particular attention given to leukemia and brain tumors. The epidemiological results fall short of the strength and consistency of evidence that is required to come to a conclusion that RF emissions are a cause of human cancer. Although the epidemiological evidence in total suggests no increased risk of cancer, the results cannot be unequivocally interpreted in terms of cause and effect. The results are inconsistent, and most studies are limited by lack of detail on actual exposures, short follow-up periods, and the limited ability to deal with other relevant factors. In some studies, there may be substantial biases in the data used. For these same reasons, the studies are unable to confidently exclude any possibility of an increased risk of cancer. Further research to clarify the situation is justified. Priorities include further studies of leukemia in both adults and children, and of cranial tumors in relationship to mobile phone use.

Brain Neoplasms↗
PubMed2002

Developing areas in cancer in New Zealand.

New Zealand has a cancer profile similar to those of Western developed countries, with a high rate of melanoma, similar to Australia. Statistics separating the Maori from the non-Maori population, although open to difficulties in interpretation, show higher rates in Maori of liver, stomach, lung and cervix uterine cancer and lower rates of colorectal cancer and of melanoma. Screening and prevention programmes are limited by resource constraints; there is population screening for cervical cancer and breast cancer screening is being developed. Screening for hepatitis B and liver cancer is proposed, despite conflicting scientific opinions, while screening for colorectal cancer is not planned, despite randomized trial evidence of benefit. There is no clear national cancer control programme at present. Investigation of stomach cancer in Maori families had identified a new gene.

Breast Neoplasms↗
PubMed1978

Incidence rates and risk factors of benign breast neoplasms.

A case-control study of benign breast disease was conducted in Greater Boston in 1968-1969. Cases were nearly all women living in the reference population who were initially diagnosed as having fibrocystic disease, fibroadenoma or a "mixed" lesion during the study period. Controls were a random sample of the entire reference population. A mail questionnaire was completed for 678 cases and for 1807 controls. For fibrocystic disease the age-standardized incidence rate was 89.4 per 100,000 woman-years; for fibroadenoma it was 32.8. Fibrocystic disease rises in incidence to age 45 and then declines sharply. The incidence rate of fibroadenoma peaks during the 20's, while that of mixed tumors has a mode at 30 to 34. Among young women, the highest rates occur in married nulliparae, but this is not so at higher ages. Neither for fibroadenoma nor fibrocystic disease was there a consistent relationship of risk with parity or with age at first birth. Fibrocystic disease risk was strongly and directly related to age at natural menopause, directly but not strongly related to an index of socioeconomic status, and was increased among women who gave a history of arthritis. Both fibrocystic disease and fibroadenoma were much less frequent in more obese women. Neither fibrocystic disease nor fibroadenoma has an epidemiologic pattern which corresponds closely to that of breast cancer. Therefore, it seems reasonable to suggest that the apparent increased risk of breast cancer among women with benign breast disease is concentrated within a subset of these women.

Adenofibroma↗