PubMed Health⌕ Search

Biomedical subjects

P Bethwaite

Publications and source records attributed to P Bethwaite.

18 recordsLinked to original sources
PubMed2006

Pathways to diagnosis of cervical cancer: screening history, delay in follow up, and smear reading.

BACKGROUND: The aim of this study was to determine the most important ways to reduce incidence of and mortality from cervical cancer by a nationally co-ordinated screening programme. DESIGN: Descriptive study. SETTING: The New Zealand National Cervical Screening Programme: a nationally organised and co-ordinated programme. SAMPLE: Women aged younger than 80 years with histologically proven primary invasive cervical cancer, including microinvasive disease, diagnosed between 1 January 2000 and 30 September 2002. Consent for access to medical records was gained for 371 of 445 eligible women (83%). A total of 359 (81%) of eligible women or their next of kin consented to interview. METHODS: Data on events prior to diagnosis were obtained from routine sources, interview, medical record review and slide reread. MAIN OUTCOME MEASURES: Frequency of screening in the 7 years prior to diagnosis, time from abnormal smear or symptoms to appropriate diagnostic confirmation, proportion of negative smears upgraded to high grade on reread. RESULTS: Half of the 371 participants (83% of 445 eligible women) had not had a screening smear in the 3 years prior to diagnosis, and 80% were defined as inadequately screened. A maximum of 17% of women overall or within any defined subgroup experienced delays in follow up of abnormal smears or bleeding. Only 11% of women overall had had a high-grade smear, which was originally read as negative. CONCLUSIONS: The most important factor in women's pathways to a diagnosis of cervical cancer was inadequate screening. While delays in diagnosis could be reduced and laboratory performance improved, priority must be given to improving uptake and frequency of screening.

Adult↗
PubMed2001

Adult-onset acute leukemia and employment in the meat industry: a New Zealand case-control study.

OBJECTIVES: To assess the risks for adult-onset acute leukemia associated with employment in the New Zealand meat industry. METHODS: A total of 110 incident leukemia cases identified from referrals to one of six treatment centers between 1989 and 1991 were compared with 199 general population controls. Detailed occupational exposure histories were obtained by interview. RESULTS: There was an elevated risk associated with ever having worked in an abattoir (OR = 2.3, 95% CI 1.0-5.2), which appeared confined to those with over 2 years exposure (OR = 4.9, 95% CI 1.5-15.6). The excess risk was confined to abattoir workers having direct contact with animals or animal products (OR = 5.2 95% CI 1.2-22.2). Ever having worked as a butcher was associated with elevated risk (OR = 2.9, 95% CI 1.1-7.2), confined to those individuals who worked as a butcher in an abattoir (OR = 4.8) or who butchered livestock on farms (OR = 8.2). No increased risk was found for work as a retail/wholesale butcher or meatpacker (OR = 1.2). CONCLUSIONS: This study found increased leukemia risks associated with employment in the meat industry. These were confined to abattoir workers with over 2 years employment in the industry, and to persons whose jobs involved contact with animals or animal tissue, implying that biological exposures may be responsible.

Adult↗
PubMed2001

Acute leukemia in electrical workers: a New Zealand case-control study.

OBJECTIVES: To assess the risks for adult-onset acute leukemia associated with electrical employment in New Zealand. METHODS: The occupational and environmental exposures histories of 110 incident leukemia cases and 199 general population controls were compared. The cases were recruited through referrals to treatment centers in New Zealand between 1989 and 1991. For subjects classified as having worked in one or more of the "electrical occupations," the degree of exposures to extremely low frequency electromagnetic fields (ELF-EMFs) was assessed in detail using a job-exposure matrix. RESULTS: An odds ratio of 1.9 (95% Cl 1.0-3.8) was found for subjects who had ever worked in an electrical occupation. Significantly increased risks for leukemia are seen amongst welders/flame cutters (OR = 2.8 (95% CI 1.2-6.8)) and telephone line workers (OR = 5.81 (95% CI 1.2-27.8)). The excess leukemia risk appeared to be confined to acute non-lymphocytic leukemia (OR=2.31 (95% CI 1.2-4.6)), in comparison to acute lymphoblastic leukemia (OR = 0.9 (95% CI 0.3-2.9)) but for the latter category the numbers were very small. A dose-response effect was also found, with acute leukemia risk rising with increasing occupational magnetic field exposure, based on both current and historical occupational field exposure estimates. CONCLUSIONS: The findings of the current study indicate a significantly elevated risk of acute leukemia for electrical workers overall, and for the specific occupational categories of welders/flame cutters and telephone line workers. A dose-response effect was also found, indicating that acute leukemia risk was related to historical and current magnetic field exposures in an occupational context.

Adult↗
PubMed1998

Reproducibility of new classification schemes for the pathology of ductal carcinoma in situ of the breast.

AIM: To compare the interobserver variation in the pathological classification of ductal carcinoma in situ of the breast using two recently proposed classification schemes. METHODS: 11 pathologists classified a set of 25 cases of ductal carcinoma in situ chosen to reflect a range of lesions, using the traditional architectural classification together with the modified cytonuclear grading scheme of Holland et al and the Van Nuys classification scheme. Participating pathologists received a standard tutorial, written information, and illustrative photomicrographs before their assessment of the cases. RESULTS: Interobserver agreement was poorest when using the architectural scheme (kappa = 0.44), largely owing to variations in classifying lesions with a mixed component of patterns (kappa = 0.13). Agreement was better using the modified cytonuclear grading scheme (kappa = 0.57), with most consistency achieved using the Van Nuys scheme (kappa = 0.66). Most discordant results using the later scheme were due to inconsistency in assessing the presence or absence of luminal necrosis. CONCLUSIONS: Both the new classification schemes assessed in this study were an improvement over the traditional architectural classification system for ductal carcinoma in situ, and resulted in more reproducible pathological assignment of cases. The Van Nuys classification scheme is easy to apply, even to small areas of carcinoma, resulting in acceptable interobserver agreement between reporting pathologists. Additional work will be required to arrive at a consensus definition of necrosis for cases in the non-high-grade group.

Breast Neoplasms↗
PubMed1997

Social class and male cancer mortality in New Zealand, 1984-7.

Social class differences in cancer mortality among New Zealand men aged 15-64 years are examined for the period 1984-7. Age-standardised rates are presented for all cancer deaths, and for 23 specific cancer sites. The strongest social class mortality gradients were found for cancers of the larynx, liver, buccal cavity/pharynx, oesophagus, lung and for soft tissue sarcoma. On the other hand, rectal cancer, malignant melanoma, colon cancer, brain/nervous system cancers, and multiple myeloma showed higher death rates for the more advantaged socioeconomic groups. Lung cancer accounted for 54.1% of the overall social class gradient, and the major smoking related cancers (these include buccal/pharynx, oesophagus, larynx, lung and bladder, although it should be stressed that not all cases of these cancers are caused by smoking) accounted for 77.6% of the overall gradient.

Adolescent↗
PubMed1994

Renal cell carcinoma in New Zealand: a national survival study.

OBJECTIVE: To determine clinical and pathologic prognostic factors for renal cell carcinoma (RCC) using cases reported to a population-based cancer registry. METHODS: All cases of RCC reported to the New Zealand Cancer Registry between 1976 and 1986 were retrieved and data analyzed to determine parameters of prognostic importance. RESULTS: In eleven years, 1,308 cases of RCC (66.7% males and 33.3% females) were reported to the New Zealand Cancer Registry. The age-standardized incidence rate was 3.78 per 10(5) person-years and showed no significant trend over the period of the study. There was a significant difference in the age at presentation between the largest racial groups (Maori 52.2 years; non-Maori 63.2 years), which is accounted for by increased predisposing risk factors among Maori. The five-year actuarial survival rate was 42.4 percent with 63 percent of patients reported dead in follow-up to December 1990. In the series, patient gender (female > male), tumor laterality (right > left), stage (intrarenal > localized > disseminated), grade (1 > 2 > 3 > 4), and treatment modality (surgery > nonsurgery) were found to be significant prognostic factors, although only tumor stage and treatment modality were of independent significance. Tumor laterality was of prognostic significance for Stage II (localized) surgically treated tumors only. CONCLUSIONS: The results of the study emphasize the paramount importance of tumor stage as a prognostic parameter for RCC. The prognostic significance of laterality for localized, surgically treated tumors suggests that radical nephrectomy is less likely to result in tumor clearance for left-sided RCC than for tumors on the right side.

Actuarial Analysis↗
PubMed1992

Increasing incidence of non-Hodgkin's lymphoma: occupational and environmental factors.

The incidence of non-Hodgkin's lymphoma (NHL) has been increasing steadily for the last 30 years, and attention is being focused on the possible causes of this increase. Possible explanations have included the exposure to viruses, radiation, nutrition, and pesticides, and these issues are addressed by other presentations in this workshop. The interest in a possible role of pesticides stems from the observation that farmers have an increased risk of NHL. However, farmers may also be exposed to oncogenic viruses carried by farm animals, and studies of abattoir workers and meat inspectors have found increased risks of NHL; although these findings are unlikely to be directly relevant to the general population, they do complement other suggestions that exposure to oncogenic viruses may be a factor in the general increase in NHL. Farmers may also be exposed to chronic antigenic stimulation which may increase the risk of NHL. This latter observation is consistent with the observation that NHL is associated with several autoimmune diseases which involve chronic antigenic stimulation. NHL has also been associated with a number of occupational exposures but these are generally rare and the findings are inconsistent, although a number of studies have found an increased risk of NHL in work involving exposure to wood, solvents, or related chemicals. Perhaps the strongest evidence of an association with an environmental exposure comes from two studies showing that use of hair dyes increases the risk of NHL. This exposure is relatively common in women, and hair dye use may account for approximately 20% of all NHL cases in women.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1992

The prognosis of adenosquamous carcinomas of the uterine cervix.

OBJECTIVES: Firstly, to identify a cohort of women with invasive adenosquamous carcinomas of the uterine cervix, including mucin-producing squamous cell carcinomas. Secondly, to compare the biological characteristics and behaviour of a cohort of adenosquamous carcinomas with a cohort of non-mucin-producing squamous cell carcinomas. DESIGN: Histological review, retrospective survival analysis. SETTING: Regional multidisciplinary gynaecological oncology service. SUBJECTS: 161 cases of stage 1B and above invasive cervical carcinoma presenting between 1 January 1980 and 31 July 1987. Thirty nine women with adenosquamous carcinomas were compared with 103 women with non-mucin-producing squamous cell tumours. RESULTS: Inclusion of routine stains for mucin in the assessment of histological material resulted in the reclassification of 38 (24%) of the cases, including the identification of 31 mucin-producing squamous cell carcinomas. The survival with adenosquamous tumours was significantly worse than with squamous cell cancers (P = 0.006), 5-year survival rates being 52% and 75% respectively. Multivariate analysis showed that this effect was explained by differences in clinical stage, pelvic lymph node metastasis and vascular invasion by tumour. CONCLUSIONS: The application of routine mucin stains to cervical tumours identifies a group of previously unrecognized adenosquamous cancers. Tumours so identified are likely to pursue a more aggressive clinical course associated with a poorer survival when compared to non-mucin-producing squamous carcinomas.

Adenocarcinoma↗
PubMed1990

Follow up of New Zealand participants in British atmospheric nuclear weapons tests in the Pacific.

OBJECTIVE: To study the health of Royal New Zealand Navy personnel who participated in atmospheric nuclear weapons tests conducted by the United Kingdom at Malden Island and Christmas Island in 1957 and 1958. DESIGN: Blinded, controlled follow up of up to 30 years. SETTING: New Zealand. SUBJECTS: 528 Men known to have participated in the tests and a control group of 1504 men who were in the Royal New Zealand Navy during the same period but did not participate in the tests. MAIN OUTCOME MEASURES: Mortality and incidence of cancer. RESULTS: Follow up for the period 1957-87 was 94% complete in test participants and 91% complete in the controls. There were 70 deaths among test participants and 179 deaths among controls, yielding a relative risk of 1.08 (90% confidence interval 0.85 to 1.38, p = 0.29). The relative risk of death from causes other than cancer was 0.96 (0.71 to 1.29, p = 0.59) whereas the relative risk of death from cancer was 1.38 (0.90 to 2.10, p = 0.09) and of the incidence of cancer was 1.12 (0.78 to 1.60, p = 0.29). For cancers other than haematological malignancies the relative risk was 1.14 (0.69 to 1.83, p = 0.31) for mortality and 1.01 (0.67 to 1.50, p = 0.48) for incidence. There were seven deaths from haematological cancers among test participants (relative risk 3.25, 90% confidence interval 1.12 to 9.64, p = 0.02), including four leukaemias (5.58, 1.04 to 41.6, p = 0.03). The relative risk for incidence of haematological cancers was 1.94 (0.74 to 4.84, p = 0.10) and that for leukaemia was 5.51 (1.03 to 41.1, p = 0.03). There were no cases of multiple myeloma in the test participants during the follow up period, but the expected number was only 0.3. CONCLUSIONS: Although the numbers are small, the findings for leukaemia are similar to those for British participants in the nuclear weapons test programme. Some leukaemias, and possibly some other haematological cancers, may have resulted from participation in this programme. There is little evidence of an increased risk for non-haematological cancers, and there is no evidence of an increased risk for causes of death other than cancer.

Cause of Death↗
PubMed1986

Economic aspects of screening for cervical cancer in New Zealand.

The allocation of scarce health resources to cervical screening indicates that an implicit valuation is being placed on the lives that will be saved. From a model which compares the lives saved with the costs of various screening policies, the valuation of life implied by these policies has been calculated. Screening every three years implies a valuation of life of between $86,000 and $191,000 (1984 prices), which is of a similar order of magnitude to valuations placed on life for other policy purposes. Annual screening would only be appropriate if the valuation of life is $420,000 or over. If screening is to take place at all then it should be done at least every five years. Very infrequent screening cannot be justified because the costs of screening still have to be borne, yet the frequency of detection allows a considerable development of invasive lesions between screenings.

Costs and Cost Analysis↗