C olon cancer is a major health problem. It is one of the

60 COLORECTAL CANCER Colon cancer in France: evidence for improvement in management and survival C Faivre-Finn, A-M Bouvier-Benhamiche, J M Phelip, ...
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COLORECTAL CANCER

Colon cancer in France: evidence for improvement in management and survival C Faivre-Finn, A-M Bouvier-Benhamiche, J M Phelip, S Manfredi, V Dancourt, J Faivre .............................................................................................................................

Gut 2002;51:60–64

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....................... Correspondence to: C Faivre-Finn, Registre Bourguignon des Cancers Digestifs (INSERM EPI 106), Faculte de Medecine, 7 Boulevard Jeanne d’Arc, 21079 BP 87900, Dijon, France; [email protected] Accepted for publication 23 October 2001

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Background: Cancer registries recording all cases diagnosed in a well defined population represent the only way to assess real changes in the management of colon cancer at the population level. Aims: To determine trends over a 23 year period in treatment, stage at diagnosis, and prognosis of colon cancer in the Côte-d’Or region, France. Patients: A total of 3389 patients with colon cancer diagnosed between 1976 and 1998. Methods: Time trends in clinical presentation, surgical treatment, chemotherapy treatment, stage at diagnosis, postoperative mortality, and survival were studied. A non-conditional logistic regression was performed to obtain an odds ratio for each period adjusted for the other variables. To estimate the independent effect of the period on prognosis, a relative survival analysis was performed. Results: Between 1976 and 1991, the resection rate increased from 69.3% to 91.9% and then remained stable. This increase was particularly marked in the older age group (56.4% to 90.5%). The proportion of stage III patients treated with adjuvant chemotherapy rose from 4.1% for the 1989–1990 period to 45.7% for the 1997–1998 period. Over the 23 years of the study the proportion of stage I and II patients increased from 39.6% to 56.6%, associated with a corresponding decrease in the proportion of patients with advanced stages. Postoperative mortality decreased from 19.5% to 7.3%. This led to an improvement in five year relative survival (from 33.0% for the 1976–1979 period to 55.3% for the 1992–1995 period). Conclusions: Advances in the management of colon cancer have resulted in improving the prognosis of this disease. However, progress is still possible, particularly in the older age group.

C

olon cancer is a major health problem. It is one of the most frequent cancers in both sexes in France, affecting 21 500 new patients a year and representing almost 10% of all newly diagnosed cancers.1 Recent studies have demonstrated an increase in the incidence of colon cancer and this trend will continue, at least because of the increasing life expectancy.2 However, the mortality rate has remained stable over the last 20 years, suggesting an improvement in prognosis.1 Possible explanations are that both early detection and treatment of this cancer have improved. Adjuvant therapy developed in the last decade may also have had a role to play in this improvement. Data on the management and prognosis of colon cancer have mostly been provided by specialised hospital units and as such cannot be used as reference because of unavoidable selection bias. Population based studies recording all cases diagnosed in a well defined population represent the only way to assess improvement in the management of colon cancer. Some cancer registries collect detailed data on therapeutic approaches allowing clinicians to access information about changes in the management of cancer at a population level. This interest is recent and therefore there is a paucity in the literature of reports of this type. The objective of this study was to determine trends over a 23 year period in treatment, stage at diagnosis, and prognosis in a well defined French population.

POPULATION AND METHODS Population A population based cancer registry has, since 1976, recorded all digestive tract cancers occurring in the Côte-d’Or, Burgundy, France. This area has a population of 493 000 according to the 1990 census. Information is regularly obtained from pathologists, hospitals (university hospitals, including the cancer centre, general hospital, and private physicians; gastroenterologists, surgeons, oncologists, and radio-

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therapists), and general practitioners as well as from public administration (death certificates). No cases were registered through death certificates alone but they were used to identify missing cases. Because of the involvement of the entire medical profession, we assumed that nearly all newly diagnosed cases were recorded. Cancers were classified according to the International Classification of Diseases, 10th revision.3 A total of 3419 incident cases of colon cancer (ICD-10C18) were recorded between 1976 and 1998. Histological types including lymphomas (n=22), sarcomas (n=2), and carcinoids (n=6) were excluded as their natural history and management are quite different to other carcinomas. A total of 3389 patients were considered for this study. Studied variables Available variables included sex, age at diagnosis, place of residence, date at diagnosis, histological type, location of the tumour, clinical presentation, stage at diagnosis, and surgical and chemotherapy treatment modalities. Two categories were assigned by age: those aged 75 years (n=1520). Place of residence was recorded as university hospital town (Dijon, n=1462), other urban area (that is, towns of more than 2000 inhabitants, n=678), and rural areas (n=1249). The period of diagnosis was divided into five groups of four years and one group of three years for the last study period. As chemotherapy was an anecdotal treatment before 1989, this variable was studied using two time periods between 1989 and 1998. Location of the tumour was divided into right colon (caecum, ascending, hepatic flexure, transverse, n=1472), left colon (splenic flexure, descending, sigmoid, n=1896), and unknown location (n=21). Surgical procedures were divided into curative resection (n=2452), palliative resection (n=447), and palliative surgery with no

Colon cancer in France

Time trends in emergency management of colon cancer between 1976 and 1998

1976–1979 1980–1983 1984–1987 1988–1991 1992–1995 1996–1998

Colostomy followed by Colostomy alone resection (n (%)) (n (%))

Surgical resection with stoma (n (%))

5 12 11 5 4 7

9 10 12 6 13 21

(7.3) (14.8) (15.9) (6.7) (5.1) (7.6)

13 13 5 4 6 2

(18.8) (16.0) (7.3) (5.3) (7.7) (2.2)

(13.1) (12.4) (17.4) (8.0) (16.7) (22.8)

tumour resection (that is, colostomies or explorative laparotomies, n=208). Resection was considered curative when the surgeon deemed the tumour completely removed and the distal margins were free from tumour, with no evidence of distant metastasis. Cancer extension at the time of diagnosis was classified, for resected cancers, according to the TNM classification, 1997 revision4: 566 patients were classified as stage I, 138 stage II, 814 stage III, and 725 stage IV. Those who underwent resection but were not staged were classified as unknown (n=11). Those in whom the cancer was not resected (bypass, exploratory laparotomy, no laparotomy) and with no evidence of visceral metastasis were classified as advanced stage (n=135). This group of patients was analysed together with TNM stage IV. Adjuvant chemotherapy (n=165) was defined as chemotherapy given after resection with curative intent for stage I, II, or III tumours. Palliative chemotherapy (n=115) was defined as chemotherapy given to patients who did not undergo surgery and/or to patients with metastatic disease. Postoperative mortality was defined as death within 30 days of surgery. Complete follow up to January 2000 was obtained for 98.2% of patients. Statistical analysis Associations between categorial data were analysed using χ2 tests for heterogeneity. A non-conditional logistic regression was used to obtain odds ratios associated with the probability of tumour resection and with the probability of performance of adjuvant chemotherapy for each period adjusted for the other variables. Computations were performed using the BMDP software package.5 Relative survival rates were computed using the Relsurv 1.0 program for relative survival (Guy Hedelin, Strasbourg, France). Survival rate is defined as the ratio of the observed survival rate to the expected survival rate in that area according to sex and age group. Multivariate analysis was performed using a relative survival model with proportional hazard applied to the net mortality by interval. This model makes it possible to calculate relative risks in comparison with a baseline which is the cumulative net hazard calculated from a priori defined intervals.6 The last study period (1996–1998) has not been considered in the survival analysis because the five year follow up is not yet available for all patients.

RESULTS Clinical presentation Overall, 77.9% of patients presented with symptoms and 13.7% presented as an emergency (obstruction and/or perforation of the colon). The remaining 5.8% were patients diagnosed after a routine examination or faecal occult blood testing. In 2.6% of cases the type of presentation was unknown. Presentation as an emergency was influenced by age (12.6% in the younger age group compared with 16.5% in those aged 80 years and older; p=0.003), by location of the tumour (15.0% for left colon compared with 12.1% for right colon; p=0.014), and by stage at diagnosis (2.1% for stage I, 16.3% for stage II, 18.1% for stage III, and 13.7% for advanced

Surgical resection without stoma (n (%)) 35 41 41 59 52 60

(50.7) (50.7) (59.4) (78.7) (66.6) (65.2)

Exploratory No surgery laparotomy (n (%)) (n (%)) 3 (4.3) 4 (4.9) 0 0 2 (2.6) 0

4 (5.8) 1 (1.2) 0 1 (1.3) 1 (1.3) 2 (2.2)

100 90 80 70

Per cent

Table 1

61

60

Resection age 75

40

Palliative surgery

30

No surgery

20 10 0 1976 –

1980 –

1984 –

1988 –

1992 –

1996 –

1979

1983

1987

1991

1995

1998

Time (years)

Figure 1

Time trends in surgical treatment.

stages; p

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