Social inequalities in cancer survival: A population-based study using the Costa Rican Cancer Registry

Health inequalities in a middle-income country: a systematic review of the Costa Rican case

Objective

This study systematically reviews evidence of socioeconomic health disparities in Costa Rica, a middle-income country, to elucidate the relationship between socioeconomic status and health outcomes.

Methods

Published studies were identified through a systematic review of PubMed (English) and Scielo (Spanish) databases from December 2023 to January 2024, following PRISMA guidelines. Search terms included socioeconomic status, social determinants, social gradient in health, and health inequalities.

Results

Of 236 identified references, 55 met the inclusion criteria. Findings were categorized into health inequalities in mortality (among the general population, infants, and older adults), life expectancy, cause-specific mortality, and health determinants or risk factors mediating the association between the social environment and health. The studies indicate higher mortality among the most disadvantaged groups, including deaths from respiratory diseases, violence, and infections. Higher socioeconomic status was associated with lower mortality rates in the 1990s, indicating a positive social gradient in health (RII = 1.3, CI [1.1-1.5]). Disparities were less pronounced among older adults. Urban areas exhibited concentrated wealth and increased risky behaviors, while rural areas, despite greater socioeconomic deprivation, showed a lower prevalence of risky behaviors. Regarding smoking, people living in rural areas smoked significantly less than those in urban areas (7% vs. 10%). Despite the relatively equitable distribution of public primary healthcare, disparities persisted in the timely diagnosis and treatment of chronic diseases. Cancer survival rates post-diagnosis were positively correlated with the wealth of districts (1.23 [1.12-1.35] for all cancers combined).

Conclusion

The study highlights the existence of social health inequalities in Costa Rica. However, despite being one of the most unequal OECD countries, Costa Rica shows relatively modest social gradients in health compared to other middle and high-income nations. This phenomenon can be attributed to distinctive social patterns in health behaviors and the equalizing influence of the universal healthcare system.

Social gradient and rural-urban disparities in cancer mortality in Costa Rica

INTRODUCTION

Data on social inequalities in cancer mortality are sparse, especially in low- and middle-income countries. We aimed to analyze the socioeconomic inequalities in cancer mortality in Costa Rica between 2010 and 2018.

METHODS

We linked 9-years of data from the National Electoral Rolls, National Birth Index and National Death Index to classify deaths due to cancer and socioeconomic characteristics of the district of residence, as measured by levels of urbanicity and wealth. We analyzed the fifteen most frequent cancer sites in Costa Rica among the 2.7 million inhabitants aged 20 years and older. We used a parametric survival model based on a Gompertz distribution.

RESULTS

Compared to urban areas, mixed and rural area residents had lower mortality from pancreas, lung, breast, prostate, kidney, and bladder cancers, and higher mortality from stomach cancer. Mortality from stomach, lung and cervical cancer was higher, and mortality from colorectal cancer, non-Hodgkin lymphoma and leukemia was lower in the most disadvantaged districts, compared to the wealthiest ones.

CONCLUSION

We observed marked disparities in cancer mortality in Costa Rica in particular from infection- and lifestyle- related cancers. There are important opportunities to reduce disparities in cancer mortality by targeting cancer prevention, early detection and opportune treatment, mainly in urban and disadvantaged districts.

Health inequalities in the geographic distribution of dental practitioners in Costa Rica: An ecological study

OBJECTIVE

The uneven distribution of dental health services in a territory can cause an imbalance in accessibility, increasing health inequalities. This study aimed to describe the geographical distribution of dental health practitioners according to urbanicity and area-level socio-economic status in Costa Rica.

METHODS

A National Dentist Survey was developed to identify employment status, number of working hours, address and list of the working clinics. Data was completed using information from the national College of Surgeons, including all Costa Rican dentists. The Minimal Geographic Units (MGU) allowed for aggregating the population's individual level socio-economic position. Local Potential Accessibility (LPA) calculated the density of full-time hour's equivalents around each MGU using floating sectors. Clinics were geocoded using Geographic Information Systems, creating 2853 clinical points. Distance between each MGU and the nearest accessible clinics considering full-time working hours equivalents was estimated. MGU were divided into six categories: 'No accessibility', 'Very low accessibility', 'Low accessibility', 'Good accessibility' 'High accessibility' and 'Very high accessibility'.

RESULTS

Mean national LPA was 6.5 full-time equivalents per 10 000 inhabitants, 3.4% of the Costa Rican population had no access to dentist; 12.9% had very low accessibility, 22.7% had low accessibility, 35.0% had good accessibility, 16.2% had high accessibility, and 9.8% had very high accessibility. Overall, 39% of the population has a rather low accessibility. LPA was higher in urban districts compared to rural districts and in wealthiest districts compared to most disadvantaged districts. Within districts, after adjustment for district's characteristics, LPA was higher in urban MGU compared to rural MGU and in wealthiest MGU compared to most disadvantaged MGU.

CONCLUSIONS

This study found that despite having a high number of dentists, their numbers are small in many areas, increasing inequalities in access to health care. The dentist's free establishment, where they can decide to provide private services within a community, creates zones with very high densities, in particular in the wealthiest urban areas, and others with very low densities, in particular the poorest rural areas. The lack of territorial planning has been one of the reasons that has encouraged an imbalance in the availability of dental human resources. To achieve effective universal health coverage, public institutions should focus their efforts on improving access to dental services in underserved areas.

Worldwide sources of data in haematology: Importance of clinician-biostatistician collaboration

The field of haematology has benefitted greatly from registry-based observational research. Medical and technical advances, changes in regulations and events such as the global pandemic is changing the landscape for registries. This review describes features of high-quality registries, statistical approaches and study design needed, an overview of worldwide hematologic registries, and how registries are evolving and expanding. The importance of collaborations between biostatisticians and haematologists in designing and conducting registry-related research is highlighted.

Is Season of Diagnosis a Predictor of Cancer Survival? Results from the Zurich Cancer Registry

In Switzerland, there is a large seasonal variation in sunlight, and vitamin D deficiency is relatively common during winter. The season of diagnosis may be linked to cancer survival via vitamin D status. Using data from the Cancer Registry of Zurich, Zug, Schaffhausen, and Schwyz with more than 171,000 cancer cases registered since 1980, we examined the association of the season of diagnosis with survival for cancers including prostate (ICD10 code C61; International Categorization of Diseases, version 10), breast (C50), colorectal (C18-21), lung (C34), melanoma (C43), and all sites combined. Cox proportional hazards regression models were used to assess the differences in the all-cause mortality by the season of the diagnosis. Winter was used as the reference season. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for all the cancers combined (excluding nonmelanoma skin cancer) and for prostate (in men), breast (in women), colorectal, lung cancer, and melanomas, separately. A diagnosis in summer and/or autumn was associated with improved survival in all the sites combined for both sexes (men: HR 0.97 [95% CI 0.96-0.99]; women: HR 0.97 [95% CI 0.94-0.99]) and in colorectal (HR 0.91 [95% CI 0.84-0.99]), melanoma (HR 0.81 [95% CI 0.65-1.00]), and breast cancer (HR 0.91 [95% CI 0.94-0.99]) in women. Our study results suggest that a cancer diagnosis in summer and/or autumn is associated with a better prognosis. The improved seasonal survival coincides with the seasonal variation of sun-induced vitamin D, and vitamin D may play a protective and beneficial role in cancer survival.

To what extent do age, stage and treatment influence survival after invasive cervical cancer: a French population-based study

PURPOSE

In an attempt to understand why cervical cancer (CC) survival is decreasing with diagnosis period among older women in France, this study aimed to estimate the effects of main prognostic factors on net survival in CC according to age.

METHODS

French cancer registries databases were used to retrospectively analyze women diagnosed with CC in 2011-2012. Net survival was estimated with the Pohar-Perme method and prognostic factors (socio-demographic, clinical variables, stage at diagnosis, therapeutic management) were analyzed with Lambert and Royston's flexible parametric model.

RESULTS

One thousand one hundred fifty three women with CC were identified. 30.4% were < 45, 41.4% 45-64, and 28.3% ≥ 65 years. Older women were diagnosed at a more advanced stage than younger women: 54.8% regional (FIGO IB2-IVA), 33.0% distant (IVB) in women ≥ 65 years vs 33.7% and 8.0%, respectively in women < 45 years. Half of women with regional stage of CC received recommended treatment; this rate decreased with increasing age (< 45: 66.1%, 45-64: 62.7%, ≥ 65: 29.2%). Older age was significantly associated with increased risk of death: hazard ratio 1.89 for age ≥ 65, as were regional stage (2.81), distant stage (15.99), and not receiving recommended treatment (2.26).

CONCLUSION

Older women with CC diagnosed at advanced stage who do not receive standard of care are at markedly increased risk of death. Special attention to the management of older women is warranted in France, not only to diagnose cancer at an earlier stage (via gynecological follow-up in these menopaused women who remain at risk of CC), but also to ensure they receive standard of care, taking into account their overall state of health.

Social inequality in incidence and mortality of malignant neoplasms of lip, oral cavity and pharynx: Is Costa Rica an international paradox?

OBJECTIVES

Low socioeconomic position (SEP) has been associated with higher incidences and mortality of lip, oral cavity and pharynx (LOP) cancers in the vast majority of countries with available data. The origins of health inequalities in cancer are socioeconomic, although they vary by time and country. Evidence from Low-and Middle-income Countries (LMICs) remains scarce. This study aims to identify and describe socioeconomic inequalities in LOP cancers incidence and mortality in Costa Rica. The hypothesis tested is that people leaving in low-SEP districts in Costa Rica have greater incidence and mortality rates of lip, oral cavity and pharynx cancers.

METHODS

The 10th revision of the International Classification of Diseases (ICD-10) was used to define cancer sites. Data come from a national population-based Cancer Registry with 100% completeness to study incidence. Incidence rate included all new cases of LOP cancer diagnosed from January 1, 2011, and December 31, 2015, for a total of 2 798 517 individuals, 13 832 524 years of follow-up and 601 LOP cases. Mortality rate was extracted from the National Death Index, including 2 739 733 individuals, 23 950 240 person-years of follow-up and 586 LOP cancer deaths, from January 1, 2010, to December 31, 2018. The 2011 Census (with 94% of Costa Rican inhabitants) was used to characterize the urbanicity and wealth of 477 districts. Survival models were performed for both incidence and mortality, allowing to consider existing competitive risks. Cox models were used for incidence, and parametric survival models based on a Gompertz distribution for mortality.

RESULTS

The study found that people who lived in the most socioeconomically disadvantaged areas had lower probabilities of developing LOP cancers than people in the richest districts. The same pattern for mortality, however, was not significant.

CONCLUSIONS

The hypothesis that incidence and mortality of LOP cancers will show a positive social gradient was not confirmed in this study, contradicting the existing literature. This could be explained by the social distribution of risky health behaviours, more frequent in socially advantaged populations.

"Registries are not only a tool for data collection, they are for action": Cancer registration and gaps in data for health equity in six population-based registries in India

In India, population-based cancer registries (PBCRs) cover less than 15% of the urban and 1% of the rural population. Our study examines practices of registration in PBCRs in India to understand efforts to include rural populations in registries and efforts to measure social inequalities in cancer incidence. We selected a purposive sample of six PBCRs in Maharashtra, Kerala, Punjab and Mizoram and conducted semistructured interviews with staff to understand approaches and challenges to cancer registration, and the sociodemographic information collected by PBCRs. We also conducted a review of peer-reviewed literature utilizing data from PBCRs in India. Findings show that in a context of poor access to cancer diagnosis and treatment and weak death registration, PBCRs have developed additional approaches to cancer registration, including conducting village and home visits to interview cancer patients in rural areas. Challenges included PBCR funding and staff retention, abstraction of data in medical records, address verification and responding to cancer stigma and patient migration. Most PBCRs published estimates of cancer outcomes disaggregated by age, sex and geography. Data on education, marital status, mother tongue and religion were collected, but rarely reported. Two PBCRs collected information on income and occupation and none collected information on caste. Most peer-reviewed studies using PBCR data did not publish estimates of social inequalities in cancer outcomes. Results indicate that collecting and reporting sociodemographic data collected by PBCRs is feasible. Improved PBCR coverage and data will enable India's cancer prevention and control programs to be guided by data on cancer inequities.