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Biomedical subjects

C Chilvers

Publications and source records attributed to C Chilvers.

At least 37 records · Page 2Linked to original sources
PubMed1989

Further results from a census based mortality study of fertiliser manufacturers.

The results of a further follow up of two cohorts of men identified as manufacturers of fertilisers in the 1961 and 1971 censuses of England and Wales are reported. Both cohorts have now been followed up until 1985 through the National Health Service Central Register. In the 1961 cohort the previous findings are replicated--low mortality from all causes, all cancers, and all circulatory diseases, and no evidence of dose response relation nor excess mortality from cancer at any site. In the 1971 cohort there remain more deaths from cancer than expected but none of the observed deaths from individual cancers differs significantly from expectation by comparison with national mortality rates or rates for other employed men. Evidence of an association between cancer mortality and frequency of exposure to nitrate containing dust is strengthened in the reanalysis of the 1971 cohort after longer follow up, but a negative trend, significant for digestive organ cancers, is observed in the analysis by product type in which manufacturers of straight nitrogen and compound fertilisers might have been expected to be most at risk. Failure to find specifically any excess mortality from gastric cancer and the contradictory dose response relations, weigh against the notion that the nonsignificant excesses of cancers in the 1971 cohort are related to nitrate exposure.

Air Pollutants, Occupational↗
PubMed1989

Anthraquinone laxatives and human cancer: an association in one case.

An 18 year old girl presented with a leiomyosarcoma of the small bowel with widespread dissemination. Despite short term remissions after chemotherapy and surgery she died of the disease 10 months later. A history of prolonged exposure to danthron (an anthraquinone laxative) in childhood was obtained. Anthraquinones are known to be mutagenic and may be carcinogenic in experimental systems but danthron is not a proven carcinogen in man. The association of danthron and a rare bowel cancer in one case cannot prove a causative link. However, collection of further data seems advisable.

Adolescent↗
PubMed1987

Adjuvant aminoglutethimide therapy for postmenopausal patients with primary breast cancer.

Three hundred and twenty-two postmenopausal patients with primary breast cancer and ipsilateral axillary node involvement were randomized to receive aminoglutethimide and hydrocortisone or placebo for 2 years in a double blind randomized trial between April 1980 and March 1985. Two hundred and eighty-six patients were eligible for the study of whom 145 received active drug and 141 received placebo. At the present time significantly fewer patients have relapsed or died without previous relapse in the treatment arm (P = 0.002); 43 of 145 (30%) patients receiving aminoglutethimide have relapsed or died compared with 63 of 141 (40%) of those receiving placebo. Local recurrence is also significantly reduced (P = 0.002) since only 6 patients receiving active treatment developed local recurrence compared to 21 receiving placebo. Side effects were severe enough to necessitate complete withdrawal or reduction of therapy in 27 of 145 (19%) in the treatment arm of the study compared with 21 of 141 (15%) in the placebo arm. A single treatment-related death occurred, due to agranulocytosis. Aminoglutethimide and hydrocortisone therefore delay relapse after surgery for primary breast cancer in postmenopausal women. It is too early to assess any effect on overall survival.

Aged↗
PubMed1986

Effect of age at orchidopexy on risk of testicular cancer.

69 (9.5%) of 724 patients with testicular cancer first seen at the Royal Marsden Hospital over the 10-year period 1975 to 1984 had a history of cryptorchidism. 11 patients had an uncorrected undescended testis when their testicular cancer was diagnosed, and 58 had had an orchidopexy or an orchidectomy for undescended testis. There are no general population data with which to compare the 15.9% (11/69) of testicular cancer patients with uncorrected cryptorchidism. However, the distribution of age at orchidopexy (or orchidectomy) of the 58 patients treated for undescended testis was almost identical to that expected on the basis of national rates. The age at treatment of undescended testis appears to have no effect on the risk of testicular cancer.

Adolescent↗
PubMed1986

Undescended testis: the effect of treatment on subsequent risk of subfertility and malignancy.

The literature was reviewed for information on the long-term effects of cryptorchidism on fertility and cancer incidence. In unilateral cryptorchidism, treatment policies of orchidopexy alone, or of human chorionic gonadotrophin (hCG) therapy followed, if necessary, by orchidopexy, have resulted in similar levels of reduced fertility (15% azoospermia, and an additional 30% oligospermia, ie, sperm count less than 20 X 10(6)/mL). Very similar results were observed in unilateral cryptorchid men who had had no treatment (and were still cryptorchid at semen examination). In contrast, no untreated bilaterally cryptorchid men have normal fertility (sperm count greater than 20 X 10(6)/mL), whereas of those treated, a quarter have normal fertility. In some series, as many as half of the bilateral cryptorchid testes descended following hormonal treatment; a finding that could be attributed, at least in part, to the frequent difficulty in deciding on clinical examination, whether these testes are truly cryptorchid. There is little evidence that operation early rather than late within the age range of 4 to 14 years has any effect on subsequent fertility. Histologic studies suggest that orchidopexy should be carried out before age 2, but there are almost no follow-up data with which to evaluate the results of early operation. Since there is evidence that orchidopexy may result in testicular atrophy in a small proportion of cases, a trial of luteinizing hormone-releasing hormone (LHRH) may be advisable. There is little information available concerning the effect of age at orchidopexy on the subsequent risk of testicular cancer. Testes that cannot be brought into the scrotum should be excised.

Age Factors↗
PubMed1986

Month of birth of men with malignant germ cell tumours of the testis.

A recent paper has suggested that there is a temporal cycle in birth rates of men with testis cancer with a peak in April/May. We have investigated the suggestion using data from the South Thames and Los Angeles cancer registries. There is some slight evidence of a peak in August, which is confined to teratomas. The effects demonstrated are, however, too small and inconsistent to provide any real clue to the aetiology of testis cancer.

California↗
PubMed1986

A double blind randomised clinical trial of adjuvant aminoglutethimide versus placebo given to post menopausal patients with histologically confirmed stage II breast cancer.

A multicentre double blind trial is underway to evaluate aminoglutethimide (AG) (Orimeten, Ciba) 1.000 mg/day with hydrocortisone (HC) 20-40 mg/day versus placebo for adjuvant treatment of post menopausal patients with histologically confirmed stage II breast cancer. An interim analysis in February 1985 indicates that of 338 patients randomised 165 received AG + HC and 173 received placebo. At this time 143 AG + HC patients and 141 placebo patients were eligible and assessible for analysis. Of those who received AG + HC 41 have developed metastases and 27 died compared to placebo patients, 53 of whom have developed metastases (p = 0.04) and 34 have died (p = 0.21). These results are similar to the reported advantages for adjuvant tamoxifen given for stage II breast cancer.

Aged↗
PubMed1985

Cancer mortality in England in relation to levels of naturally occurring fluoride in water supplies.

Sixty-seven small areas in England have been classified into four groups according to the level of naturally occurring fluoride in their water supplies. Small area mortality statistics for 1969-73 have been used to look for differences in cancer mortality in relation to fluoride levels. Deaths from all cancers and from cancer at 12 specific body sites have been examined; no consistent trends in mortality are apparent. These results provide no evidence of a harmful effect of naturally occurring fluoride in water supplies.

England↗
PubMed1984

Apparent doubling of frequency of undescended testis in England and Wales in 1962-81.

Examination of Hospital Inpatient Enquiry data for England and Wales for the years 1962-81 shows that the annual number of discharges with a diagnosis of undescended testicle has risen by a factor of 2.3. Cohort analysis suggests that the cumulative rate to age 15 of discharge for undescended testis has risen from 1.4% for the 1952 birth-cohort to 2.9% for the 1977 birth-cohort. Whether this is a reflection of an increase in true cryptorchidism is not known. Changes in known risk factors for cryptorchidism--exogenous oestrogen exposure, being first-born, and low birth-weight--cannot fully account for the apparent increase. With the tendency to carry out orchidopexies on apparently undescended testes at younger ages in order to preserve fertility, it is possible that a considerable number of boys with retractile testes that would have descended naturally at puberty are now being operated upon.

Adolescent↗
PubMed1984

Estimating levels of disturbed behaviour among psychiatric in-patients using a general linear model.

Disturbed behaviour was studied in relation to two contrasting ward environments, one representing the 'medical model' of psychiatry and the other being a modified form of 'therapeutic community'. A mathematical model was used in order to identify the characteristics of disturbed patients. The results suggested that behavioural disturbance of a patient in our sample was related to diagnosis, to the ward of admission and to the length of stay in hospital. Patients in all diagnostic categories tended to be more disturbed in the 'therapeutic community' than in the 'medical model' ward.

Adult↗
PubMed1984

A survey of dietary nitrate in well-water users.

The hypothesis that high nitrate ingestion may increase the risk of stomach cancer has led to concern over rising levels of nitrate in drinking water, but with little consideration as to whether nitrate from water makes a major contribution to total nitrate intake. In order to investigate the relative importance of water and food as sources of nitrate, 404 adult well-water users completed a diet diary over a 48-hour period and provided a 24-hour urine specimen and a sample of their drinking water. Where the waterborne nitrate level is less than 50 mg/I, as recommended by the World Health Organization (WHO), 30% of ingested nitrate is from water. As the well-water nitrate concentration rises the contribution of water to daily intake increases; at levels between 50 and 100 mg/I, on average, nearly 70% of daily intake is from water, and above 100 mg/I over 80% of daily intake is waterborne. Thus it is only at levels above those currently recommended by the WHO that waterborne nitrate appears to be the major contributor to total nitrate intake.

Adult↗
PubMed1983

Cancer mortality and fluoridation of water supplies in 35 US cities.

The possibility of a cancer risk associated with fluoridation of public water supplies is re-examined using mortality data for 35 US cities, 20 with fluoridated water supplies and 15 with non-fluoridated water. Crude cancer death rates, and mortality ratios standardized for age, sex, and ethnic group are examined, using four alternative sets of standard rates and three different combinations of pericensal years' deaths. Changes in cancer mortality before and after fluoridation in the fluoridated cities are compared with changes in the non-fluoridated cities over the same time period. In none of the analyses have differences in mortality trends been found that could not be due to chance alone. Thus, these results do not support the suggestion of an association between fluoridation of water supplies and cancer mortality.

Fluoridation↗