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J Peto

Publications and source records attributed to J Peto.

At least 19 recordsLinked to original sources
PubMed1992

Cancer mortality in the first degree relatives of young breast cancer patients.

In a retrospective cohort study, the mothers and sisters of 740 breast cancer patients aged under 36 at diagnosis have been studied for mortality and cancer incidence. Significantly increased breast cancer mortality was observed below age 60 (30 deaths; SMR = 3.4), but not at older ages (four deaths; SMR = 0.9). The cumulative breast cancer incidence in the relatives was 3.6% by age 50, 7.6% by age 60 and 11.6% by age 70. They also suffered excess mortality below age 60 for cancers of reproductive sites (cervix, ovary and endometrium; 15 deaths; SMR = 2.6) and lung (11 deaths; SMR = 3.2), but not for other sites (12 deaths; SMR = 0.9). This large population-based cohort study provides further confirmation of genetic susceptibility to breast cancer at young ages.

Adult↗
PubMed1991

Floating absolute risk: an alternative to relative risk in survival and case-control analysis avoiding an arbitrary reference group.

We discuss the problem of describing multiple group comparisons in survival analysis using the Cox model, and in matched case-control studies. The standard method of comparing the risk in each group with a baseline group is unsatisfactory because the standard errors and confidence limits relate to correlated parameters, all dependent on precision within the baseline group. We describe the construction of standard errors for the parameters of all groups, without the need to select a baseline group. These standard errors can be regarded as relating to roughly independent parameters, so that groups can be compared efficiently without knowledge of the covariances. The method should assist in graphical presentation of relative risks, and in the combination of results from published studies. Two examples are presented.

Adult↗
PubMed1991

Potential markers of the atherosclerotic process in high-risk children.

Children whose parents had early coronary heart disease were investigated. In order to assess high-risk parameters serum total cholesterol (TC), total triglyceride (TT), high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol (LDLC), lipid peroxide (LP), prostacyclin (PGI2), thromboxane (TX) levels, and the distribution of the complement 3 (C3), protein phenotypes were measured. Compared to a group of control children, the offspring of high-risk subjects had increased LDLC, LP, TC, and TX levels, a higher incidence of fast-slow heterozygotes, and decreased HDLC and PGI2 levels. The measurement of serum PGI2, TX levels and the distribution of C3 protein phenotypes may give further information about the true risk of atherosclerosis.

Adolescent↗
PubMed1991

Results of Medical Research Council Childhood Leukaemia Trial UKALL VIII (report to the Medical Research Council on behalf of the Working Party on Leukaemia in Childhood).

During the 1970s, despite apparently similar treatment, the prognosis for children with lymphoblastic leukaemia (ALL) improved more in some countries, notably the United States and West Germany, than in others. To find out why, the first phase of the United Kingdom (UK) Medical Research Council (MRC) childhood ALL trial, UKALL VIII, was designed to see whether similar results to the United States Children's Cancer Study Group (CCSG) could be obtained in the U.K. using an identical protocol (CCG 162). Protocol 162 was one of a series of regimens devised by the American Children's Cancer Study Group in the 1970s and was used specifically for their average risk patients (all children with ALL with an initial white cell count up to 50 x 10(9)/l except those aged 3-6 years with white cell counts under 10 x 10(9)/l). One arm (1A) of their study was adopted by the MRC for all children in the U.K. aged 0-14 years with confirmed ALL. Eight hundred and twenty-nine consecutive patients were entered between 1980 and 1984. The first 199 patients formed a single arm study as per the original protocol 162 (arm 1A), but the subsequent 630 children were randomized to receive or not two doses of daunorubicin on the first 2 d of induction. This randomization was an attempt to answer the important question as to whether event-free survival was influenced by the use of four rather than three induction agents. A second randomization between 2 and 3 years continuing therapy was also introduced at this stage as it had been by the CCSG in their protocol. With a minimum follow up period of more than 5 years, disease-free survival for the whole group is 55%, a considerable improvement on all previous UKALL trials. Results for patients directly comparable with those in CCSG 162 ('average risk' patients) and their American counterparts were similar. Daunorubicin was associated with more early deaths but improved disease-free survival for those achieving remission. More children relapsed who stopped treatment after 2 years than those who continued for 3, but this was balanced by increased treatment mortality in the third year. The fact that for UKALL VIII the results were similar to those of the CCSG suggests that previous MRC protocols were not sufficiently sustained and intensive, particularly during the maintenance phase of treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1990

An overview of prognostic factors in small cell lung cancer. A report from the Subcommittee for the Management of Lung Cancer of the United Kingdom Coordinating Committee on Cancer Research.

Several studies of small cell lung cancer (SCLC) treatments have been performed in the United Kingdom. In some, prognostic factor analyses were carried out but the results were not entirely consistent. The Lung Cancer Subcommittee of the United Kingdom Coordinating Committee on Cancer Research (UKCCCR) consequently initiated an overview of these studies with the aim of identifying the important prognostic factors using a large number of patients. Information on almost 4,000 patients was available, but it was necessary to perform analyses on smaller subsets because the variables recorded in individual studies were inconsistent. A number of variables contributed significantly to the prediction of likely survival over the 6 months after starting treatment, but performance status (PS), alkaline phosphatase (AlkP) and disease stage were shown to be the most important; aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) may also be useful. A prognostic index was devised for this initial period and validated using independent data. For patients who survived the first 6 months, the pre-treatment variables important for prognosis in the 6-24 month period were stage, PS and plasma sodium (Na). The Subcommittee recommends that performance status, disease stage, AlkP, Na, AST and LDH should be measured in all future SCLC studies to assist comparisons between studies and possibly the selection of patients for different treatment strategies. The additional recording of five other variables would allow a more definitive overview to be performed at some future date.

Adult↗
PubMed1990

An update of cancer mortality among chrysotile asbestos miners in Balangero, northern Italy.

The mortality experience of a cohort of chrysotile miners employed since 1946 in Balangero, northern Italy was updated to the end of 1987 giving a total of 427 deaths out of 27,010 man-years at risk. A substantial excess mortality for all causes (standardised mortality ratio (SMR) = 149) was found, mainly because of high rates for some alcohol related deaths (hepatic cirrhosis, accidents). For mortality from cancer, however, the number of observed deaths (82) was close to that expected (76.2). The SMR was raised for oral cancer (SMR 231 based on six deaths), cancer of the larynx (SMR 267 based on eight deaths), and pleura (SMR 667 based on two deaths), although the excess only reached statistical significance for cancer of the larynx. Rates were not increased for lung, stomach, or any other type of cancer. No consistent association was seen with duration or cumulative dust exposure (fibre-years) for oral cancer, but the greatest risks for laryngeal and pleural cancer were in the highest category of duration and degree of exposure to fibres. Although part of the excess mortality from laryngeal cancer is probably attributable to high alcohol consumption in this group of workers, the data suggest that exposure to chrysotile asbestos (or to the fibre balangeroite that accounts for 0.2-0.5% of total mass in the mine) is associated with some, however moderate, excess risk of laryngeal cancer and pleural mesothelioma. The absence of excess mortality from lung cancer in this cohort is difficult to interpret.

Alcohol Drinking↗
PubMed1990

The contribution of inherited predisposition to cancer incidence.

Only a small proportion of cancers, arising in inherited syndromes such as polyposis coli, have an unequivocally inherited basis. Nevertheless, most common cancers show familial clustering, much of which may be due to inherited predisposition. If so, there may be wide variation in genetic susceptibility to common cancers. The precise models of susceptibility are unclear, but for ovarian cancer and breast cancer there is some evidence that a small proportion of cases result from highly penetrant dominant genes. This has been confirmed recently for breast cancer by genetic linkage studies. Clear evidence for genetic susceptibility has been obtained for Hodgkin's disease and nasopharyngeal carcinoma, where the existence of susceptibility genes at the HLA locus has been demonstrated by linkage analysis. These genes could account for the majority of cases of these cancers. Identification of other cancer susceptibility genes should be possible, either directly using linkage analysis, or through identification of constitutional phenotypes related to cancer risk.

Disease Susceptibility↗
PubMed1989

Cancer treatment trials--past failures, current progress and future prospects.

Randomized trials are usually too small to provide decisive evidence on the effectiveness of cancer therapy, and most therapeutic developments have been based on studies of tumour response. This approach, together with survival comparisons using historical controls, has led to the development of effective chemotherapy for a few very responsive tumours, but not for most common cancers, where the impact of treatment on survival is quite small. It is difficult to distinguish effective and ineffective innovations in the treatment of such cancers, and consistent progress, in which the more effective treatments are developed and the less effective ones discarded, cannot be achieved without comparisons based on large numbers of randomized patients. The combined evidence on adjuvant therapy for breast cancer and colorectal cancer is reviewed, and a new meta-analysis of published chemotherapy trials in advanced ovarian cancer is presented. The evidence that certain adjuvant regimens can prolong survival is conclusive for breast cancer and quite strong for colorectal cancer, and there is suggestive evidence that cis-platinum prolongs survival in advanced ovarian cancer. Such results illustrate the importance of large randomized trials in evaluating and improving the treatment of common cancers. The major difficulty in achieving large patient entry to randomized studies is the reluctance of many oncologists to participate in collaborative clinical research. The reasons underlying this reluctance, and the way in which such collaboration should be organized to meet these objections, are also discussed.

Clinical Trials as Topic↗
PubMed1988

Cancers of the respiratory tract in mustard gas workers.

In a study of a cohort of 2498 men and 1032 women employed in the manufacture of mustard gas in Cheshire during the second world war 3354 (95%) individuals were successfully traced for mortality to the end of 1984. Large and highly significant excesses were observed as compared with national death rates for deaths from cancer of the larynx (11 deaths observed, 4.04 expected, p = 0.003), pharynx (15 observed, 2.73 expected, p less than 0.001), and all other buccal cavity and upper respiratory sites combined (lip, tongue, salivary gland, mouth, nose) (12 observed, 4.29 expected, p = 0.002). For lung cancer, a highly significant but more moderate excess was observed (200 observed, 138.39 expected, p less than 0.001). Significant excesses were also observed for deaths from acute and chronic non-malignant respiratory disease (131 observed, 91.87 expected and 185 observed, 116.31 expected, respectively). The risks for cancers of the pharynx and lung were significantly related to duration of employment. None of these results is substantially altered when expected numbers are calculated from Cheshire urban areas rather than national rates, although the relative risks for lung cancer and non-malignant respiratory disease are substantially reduced if rates for Merseyside, the nearest large conurbation, are used. The results provide strong evidence that exposure to mustard gas can cause cancers of the upper respiratory tract and some evidence that it can cause lung cancer and non-malignant respiratory disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Cohort Studies↗
PubMed1987

Medical Research Council Childhood Leukaemia Trial VIII compared with trials II-VII: lessons for future management.

This improvement in medium disease-free survival is probably a result of sustained early cell kill, and UKALL VIII has enabled us to define risk categories requiring even further continuous intensification, as now introduced in MRC UKALL X. Thanks to the greater availability of blood products, for example, the rational use of antibiotics and the development of expertise amongst nurses and doctors, such sustained therapy can now be delivered on a multi-centre basis, but only in experienced centres. The monitoring and removal of morbidity are essential if the advantages of this more sustained chemotherapy are to be realised. All elements of therapy require controlling and patients, parents and, above all, doctors must comply with protocol requirements in order to build further upon these initial promising results.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

AIDS and promiscuity.

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Acquired Immunodeficiency Syndrome↗