Déterminants socio-géographiques de la prise en charge des cancers en France – Exemple des cancers colorectaux incidents entre 1997 et 2004 dans le département du Calvados

Social inequalities in health: How do they influence the natural history of colorectal cancer?

As regards colorectal cancer (CRC) in France, social inequalities in health (SIH) exist. Underprivileged patients are characterized by reduced incidence of CRC and, conversely, by excess mortality. The explanatory mechanisms of the SIHs influencing survival are complex, multidimensional and variable according to healthcare system. Among the most deprived compared to the least deprived patients, SIHs are reflected by lower participation in screening campaigns, and CRC diagnosis is more frequently given at a later stage in an emergency context. During treatment, disadvantaged patients are more at risk of having to undergo open surgery and of enduring severe postoperative complications and belated chemotherapy (when recommended). Study of SIHs poses unusual challenges, as it is necessary not only to pinpoint social deprivation, but also to locate the different treatment facilities existing in a given territorial expanse. In the absence of individualized socioeconomic information, research in France on the social determinants of health is based on duly constituted cancer registries, in which an ecological index of social deprivation, the European Deprivation Index (EDI), provides an aggregate measure of the socioeconomic environment of a given individual in a given geographical setting at a given point in time. All in all, studies on SIHs are justified as means of identification and comprehension of the mechanisms underlying social deprivation, the objective being to more precisely orient programs and practices aimed at combating SIH.

Cancer Survival and Travel Time to Nearest Reference Care Center for 10 Cancer Sites: An Analysis of 21 French Cancer Registries

BACKGROUND

The impact of several non-clinical factors on cancer survival is poorly understood. The aim of this study was to investigate the influence of travel time to the nearest referral center on survival of patients with cancer.

PATIENTS AND METHODS

The study used data from the French Network of Cancer Registries that combines all the French population-based cancer registries. For this study, we included the 10 most common solid invasive cancer sites in France between 1 January 2013 and 31 December 2015, representing 160,634 cases. Net survival was measured and estimated using flexible parametric survival models. Flexible excess mortality modelling was performed to investigate the association between travel time to the nearest referral center and patient survival. To allow the most flexible effects, restricted cubic splines were used to investigate the influence of travel times to the nearest cancer center on excess hazard ratio.

RESULTS

Among the 1-year and 5-year net survival results, lower survival was observed for patients residing farthest from the referral center for half of the included cancer types. The remoteness gap in survival was estimated to be up to 10% at 5 years for skin melanoma in men and 7% for lung cancer in women. The pattern of the effect of travel time was highly different according to tumor type, being either linear, reverse U-shape, non-significant, or better for more remote patients. For some sites restricted cubic splines of the effect of travel time on excess mortality were observed with a higher excess risk ratio as travel time increased.

CONCLUSIONS

For numerous cancer sites, our results reveal geographical inequalities, with remote patients experiencing a worse prognosis, aside from the notable exception of prostate cancer. Future studies should evaluate the remoteness gap in more detail with more explanatory factors.

Small-area geographic and socioeconomic inequalities in colorectal tumour detection in France

The aim of this study was to assess the impact of area deprivation and primary care facilities on colorectal adenoma detection and on colorectal cancer (CRC) incidence in a French well-defined population before mass screening implementation. The study population included all patients aged 20 years or more living in Côte d'Or (France) with either colorectal adenoma or invasive CRC first diagnosed between 1995 and 2002 and who were identified from the Burgundy Digestive Cancer Registry and the Côte d'Or Polyp Registry. Area deprivation was assessed using the European deprivation index on the basis of the smallest French area available (Ilots Regroupés pour l'Information Statistique). Healthcare access was assessed using medical density of general practitioners (GPs) and road distance to the nearest GP and gastroenterologist. Bayesian regression analyses were used to estimate influential covariates on adenoma detection and CRC incidence rates. The results were expressed as relative risks (RRs) with their 95% credibility interval. In total, 5399 patients were diagnosed with at least one colorectal adenoma and 2125 with invasive incident CRC during the study period. Remoteness from GP [RR=0.71 (0.61-0.83)] and area deprivation [RR=0.98 (0.96-1.00)] independently reduced the probability of adenoma detection. CRC incidence was only slightly affected by GP medical density [RR=1.05 (1.01-1.08)] without any area deprivation effect [RR=0.99 (0.96-1.02)]. Distance to gastroenterologist had no impact on the rates of adenoma detection or CRC incidence. This study highlighted the prominent role of access to GPs in the detection of both colorectal adenomas and overall cancers. Deprivation had an impact only on adenoma detection.