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A M Benhamiche

Publications and source records attributed to A M Benhamiche.

32 records · Page 2Linked to original sources
PubMed1999

[Prognostic factors of recurrence and/or death in colorectal cancer: multistate modeling].

Analysis of survival of patients with cancer sets particular epidemiological and statistical problems, especially when one wants to take into account metastasis or local recurrences. Cox's model does not allow modeling multiple events. Wei et al. have proposed an extension of Cox's model, by formulating the marginal distributions of multivariate failure times, which allows testing covariates effects on different events. We applied these methods to data from the Registry of Digestive Tumors of Burgundy, France. Prognostic factors of recurrence are rectal location of tumor and advanced stage at diagnosis. Prognostic factors of death are male gender, age greater than 75, rectal location and advanced stages. However, relative risk of recurrence for advanced stages is significantly greater than relative risk of death (p=4.10(-3)), while tumor location has the same influence on the two events.

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PubMed1999

Are there several colorectal cancers? Epidemiological data.

The knowledge of descriptive epidemiology of colorectal cancer is a prerequisite essential to a better understanding of the aetiology of the disease and the development of prevention strategies. This work provides an update of descriptive epidemiological data on colorectal cancer incidence in the world. In 1988-1992, incidence rates of colorectal cancer varied from 15- to 25-fold according to the geographical area. The highest rates were observed in Western countries, especially in North America, Australasia and, to a lesser extent, in northern and western Europe. The geographical distribution of colorectal cancer was similar in men and women. An examination of incidence data by subsites showed that the magnitude of geographical variations was more important for colon cancer than for rectal cancer. Contrasting with the male predominance for rectal cancer and, to a lesser degree, for left colon cancer, cancers of the right colon were found to be as frequent in women as in men. Examination of time trends during the last decades reveals a sharp increase in incidence of colorectal cancer in Japan and in eastern and southern Europe. On the other hand, incidence rates show some stagnation in North America and western Europe in recent years. In fact, there are some suggestions for differential time trends according to the anatomical subsite, with a recent proximal shift in the distribution of cancers of the large bowel in Western countries. In conclusion, descriptive epidemiological data support the notion that distinct pathogenic mechanisms may be involved in the carcinogenesis of the proximal and distal bowel.

Adult↗
PubMed1998

Time trends and age-period-cohort effects on the incidence of primary liver cancer in a well-defined French population: 1976-1995.

BACKGROUND/AIMS: There is growing interest worldwide in primary liver cancer. The aim of this study was to describe the incidence of this cancer over a 20-year period in a well-defined French population. METHODS: Time trends by 4-year period were studied by sex, age group, place of residence, histological type and associated cirrhosis. Trends were also analysed using the age-period-cohort model. RESULTS: Primary liver cancer incidence in men increased from 7.5/100000 for the period 1976-79 to 10.2/100000 for the period 1992-95. The mean annual variation was +2.2%, (p<0.05). The increase in incidence was seen mainly in the 55-64 and 65-74 age groups and concerned hepatocellular carcinomas. In men, the increase in incidence rates with time was observed mainly in rural areas, whereas incidence rates in urban areas remained stable. The rise in incidence was due mostly to an increase in primary liver cancer with cirrhosis, in relation to a progressive increase in post-hepatitic cirrhosis and a recent increase in alcoholic cirrhosis. The estimated cumulative risk for the life span 30-74 years increased from 0.8% for the 1904-1908 cohort to 2.1% for the 1934-1938 cohort. There was no significant trend in female rates. CONCLUSIONS: In France, incidence rates for primary liver cancer are increasing in men, whilst they are remaining stable in women. Our data confirm the primary importance of alcohol in the aetiology of this cancer. Further studies are necessary to unravel the respective roles of alcohol and hepatitis C virus in the increasing incidence of primary liver cancer.

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PubMed1998

How to ensure data security of an epidemiological follow-up: quality assessment of an anonymous record linkage procedure.

A computerised record hash coding and linkage procedure is proposed to allow the chaining of medical information within the framework of epidemiological follow-up. Before their extraction, files are rendered anonymous using a one-way hash coding based on the standard hash algorithm (SHA) function, in order to respect the legislation on data privacy and security. To avoid dictionary attacks. two keys have been added to SHA coding. Once rendered anonymous, the linkage of patient information can be accomplished by means of a statistical model, taking into account several identification variables. Quality assessment of this anonymous record linkage procedure shows a specificity of 100% and a sensitivity of 95%.

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PubMed1998

[Superficial cancer of the stomach: evolution of their characteristics over a 20 year period in one population].

OBJECTIVES: The aim of this study was to analyse the incidence, treatment and prognosis of early gastric cancer in a population-based series and to draw a picture of time trends. METHODS: Over a 20-year period (1976-1995), 80 early gastric cancers were diagnosed in the Côte-d'Or area (493,000 residents). Incidence rates were calculated by sex, age groups and 5-year periods. Prognostic factors were determined using the Kaplan-Meier method and the Cox model. RESULTS: Age-standardized incidence rates were 0.8/100,000 in men and 0.3/100,000 in women. Incidence increased slightly over time (NS) and their proportion among gastric cancers increased from 3.4% (1976-1980) to 7.9% (1991-1995) (P < 0.01). Among these cancers, 25 were intramucosal (31.3%), 55 were submucosal (68.8%) and 8 had lymph node metastases (10.0%). Overall 21 patients (24.1%) had already been treated for a peptic ulcer. The 5-year crude survival rate was 63.1% and the corresponding net survival rate was 86.3%. Lymph node metastases, location, sex and cancer extension and age were independent prognostic factors. CONCLUSIONS: Though it is on the increase, the proportion of early gastric cancers remains low among gastric cancers. This study confirms the importance of performing a gastroscopy with biopsy upon each bout of ulcer and that the prognosis is lower than suggested by hospital based series.

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PubMed1998

Automatic record hash coding and linkage for epidemiological follow-up data confidentiality.

A protocol is proposed to allow linkage of anonymous medical information within the framework of epidemiological follow-up studies. The protocol is composed of two steps; the first concerns the irreversible transformation of identification data, using a one-way hash function which is used after spelling processing. To avoid dictionary attacks, two large random files of keys, called pads, are introduced. The second step consists in the linkage of files rendered anonymous. The weight given to each linkage field is estimated by a mixture model, the likelihood of which being maximized with the Expectation and Maximization (EM) algorithm. The performance of this method has been assessed by comparing record linkage, based on exclusive use of the automatic procedure, with a manual linkage, obtained by the Burgundy Registry of Digestive Cancers. The result of the linkage of a file of 2,847 cancers with a file of 388,614 hospitalization stays in the Dijon university hospital showed a sensitivity of 97% and a specificity of 93%.

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PubMed1998

[Informative value of Hemoccult test according to the number of positive slides in mass screening of colorectal cancer].

Our aim was to study the relationship between the level of positivity of the Hemoccult colorectal cancer screening test and the positive predictive value on one hand, and the characteristics of the screened neoplasms on the other. This study focuses on four successive colorectal cancer screening campaigns in a population of 45,642 subjects born between 1914 and 1943. There were 1 or 2 positive slides in 50.1% of cases, 3 or 4 in 30.7% of cases and 5 or 6 in 19.2% of cases. The positive predictive value was 11.1% for cancer, 17.4% for adenoma > or = at 1 cm and 10.1% for adenoma < 1 cm. For a cancer or adenoma > or = at 1 cm, the positive predictive value varied between 18.6% when there were 1 or 2 positive slides, and 52.5% when there were 5 or 6 positive slides. Dukes A cancers are less likely to have 5 or 6 positive slides than more advanced cancers. On the contrary, neither cancer localisation nor characteristics of adenomas > or = at 1 cm (localisation, size, degree of dysplasia) influenced the number of positive slides. Owing to intermittent colorectal cancer bleeding, it seems necessary to take several successive samples. Two samples per stool over three successive stools seem like a good compromise. The informative value of the test increases with the number of positive slides.

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PubMed1997

[Epidemiology and etiology of malignant gastric tumors].

Stomach cancer remains a common type of cancer, though its incidence has been halved in the last forty years. It is unevenly distributed throughout the world. In France, it holds fifth place among cancers and there are 8700 new cases each year. Helicobacter pylori infection, a high salt intake as well as an inadequate diet take part in the first stages of carcinogenesis. Later on, nitrates and nitrites, polycyclic hydrocarbons, alcohol, tobacco and bilc acids are incriminated. The protective role of vegetables and fruit has been well established. The protective role of vitamin C and beta-carotene is currently undergoing evaluation in subjects suffering from precancerous conditions such as dysplasia and incomplete intestinal metaplasia. The development of a vaccine against Helicobacter pylori induced infection also represents an important goal.

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PubMed1997

Time trends in diagnostic strategy, treatment, and prognosis of gastric cancer in the elderly: a population based study.

The impact of changes in diagnostic strategies for gastric cancer and attitudes towards surgery in elderly patients is not known. A population-based series of 842 gastric cancers diagnosed between 1976 and 1993 in patients aged 70 and older in Côte-dOr, France, was used to establish trends in diagnostic strategy, treatment, and prognosis. The use of endoscopy alone increased from 3% (1976-78) to 81% (1991-93). This trend was initially associated with a decrease in the use of x-ray alone, then with a decrease in the use of both x-ray and endoscopy. The proportion of resection for cure increased from 26% during 1976-78 to 43% during 1991-93 (P < 0.001). The proportion of cancers not extending beyond the gastric wall increased from 12% to 24% (P < 0.05). Operative mortality decreased from 38.7% (1976-78) to 13.3% (1991-93) and the corresponding 3-year crude survival rate rose from 7% to 18%. Improvements in the care of gastric cancer in elderly patients have been achieved, but further progress is warranted.

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PubMed1997

Population-based study of diagnosis, treatment and prognosis of gastric cancer.

BACKGROUND: Gastric cancer remains a common cancer with a poor prognosis. Improving trends seen in Japan have not yet been observed in Western countries. METHODS: A population-based series of 1329 patients with gastric cancer diagnosed over an 18-year period in Côte d'Or, France, was used to establish time trends in diagnostic strategy, treatment and prognosis. RESULTS: The use of endoscopy alone increased from 2.7 per cent in 1976-1978 to 76.6 per cent in 1991-1993 (P < 0.0001). This trend was associated at first with a significant decrease in the use of radiography alone, then by a significant decrease in the use of both radiography and endoscopy. The proportion of resections for cure increased from 37.9 per cent in 1976-1978 to 50.0 per cent in 1991-1993 (mean 3-year variation + 5.8 per cent, P < 0.01). The proportion of cases confined to the gastric wall increased from 6.1 to 11.7 per cent (mean 3-year variation + 13.1 per cent, P < 0.01), while the proportion of other stages remained stable. The operative mortality rate decreased dramatically from 25.6 per cent in 1976-1978 to 13.6 per cent in 1991-1993 (P < 0.001) and the 5-year relative survival rate rose from 12.8 per cent in 1976-1978 to 26.4 per cent in 1988-1990 (P < 0.001). CONCLUSION: This study has demonstrated that improvements in the care of patients with gastric cancer have been achieved, but that further progress may be made.

Adult↗
PubMed1996

[Mass screening of colorectal cancer: where are we up to?].

Considering the present state of knowledge on the question, only the strategy of screening for intestinal tumours at the asymptomatic stage would seem capable of reducing such a problem as colorectal cancer. Detection of occult blood in stool is currently being evaluated through a mass screening test. Methods used to obtain a high participation rate are now well-defined. In France, to achieve this goal, the test must be proposed by GPs and then mailed to those who do not consult GPs. Four case-control studies and one randomized study conducted among volunteers suggest the efficacy of screening with faecal occult blood testing to reduce mortality from colorectal cancer but they do not indicate effectiveness within a population. Four population-based studies have been set up in Europe (Denmark, England, Sweden and France). Results will be available within one to three years. They should lead to a national screening strategy.

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PubMedDate not supplied

[Long-term prognosis of gastric cancer in the population of Côte-d'Or].

AIMS: The aim of this study was to determine long term prognostic factors of gastric cancer in a population-based series. METHODS: Out of 1 462 gastric cancers diagnosed in the Côte-d'Or area (494 000 residents) over a 20-year period (1976-1995), 649 (44.4 %) were resected for cure. Prognostic factors were determined using the actuarial method and relative survival and a multidimensional relative survival model. RESULTS: The 10-year crude survival rate was 8.7 % and the corresponding relative survival rate was 14.9 %. Age, stage and period of diagnosis were independent prognostic factors. After surgery for cure, operative mortality decreased from 18.3 % (1976-1979) to 6.6 % (1988-1991) and 10-year relative survival increased from 30.8 % to 37.2 % (NS). After resection for cure (postoperative mortality excluded), the 10-year survival rate remained stable over time. Stage at diagnosis was the main prognostic factor: the relative risk of death was more than 10 times higher at stages IIIB and IV than at stage I. Age, site and macroscopic type of growth were prognostic factors independently of stage. Prognosis did not improve over time after resection for cure. CONCLUSION: Although improving, the overall prognosis of gastric cancer remains poor. Improvement in prognosis was mainly due to decrease in operative mortality. Earlier diagnosis and effective adjuvant treatment represent two ways to improve prognosis.

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