Elsevier

The Lancet Oncology

Volume 9, Issue 3, March 2008, Pages 222-231
The Lancet Oncology

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Association of insurance status and ethnicity with cancer stage at diagnosis for 12 cancer sites: a retrospective analysis

https://doi.org/10.1016/S1470-2045(08)70032-9Get rights and content

Summary

Background

Individuals in the USA without private medical insurance are less likely to have access to medical care or participate in cancer screening programmes than those with private medical insurance. Smaller regional studies in the USA suggest that uninsured and Medicaid-insured individuals are more likely to present with advanced-stage cancer than privately insured patients; however, this finding has not been assessed using contemporary, national-level data. Furthermore, patients with cancer from ethnic minorities are more likely to be uninsured or Medicaid-insured than non-Hispanic white people. Separating the effects on stage of cancer at diagnosis associated with these two types of patient characteristics can be difficult.

Methods

Patients with cancer in the USA, diagnosed between 1998 and 2004, were identified using the US National Cancer Database—a hospital-based registry that contains patient information from about 1430 facilities. Odds ratios and 95% CIs for the effect of insurance status (Medicaid, Medicare (65–99 years), Medicare (18–64 years), private, or uninsured) and ethnicity (white, Hispanic, black, or other) on disease stage at diagnosis for 12 cancer sites (breast [female], colorectal, kidney, lung, melanoma, non-Hodgkin lymphoma, ovary, pancreas, prostate, urinary bladder, uterus, and thyroid) were estimated, while controlling for patient characteristics.

Findings

3 742 407 patients were included in the analysis; patient characteristics were similar to those of the corresponding US population not included in the analysis. Uninsured and Medicaid-insured patients were significantly more likely to present with advanced-stage cancer compared with privately insured patients. This finding was most prominent for patients who had cancers that can potentially be detected early by screening or symptom assessment (eg, breast, colorectal, and lung cancer, as well as melanoma). For example, the odds ratios for advanced-stage disease (stage III or IV) at diagnosis for uninsured or Medicaid-insured patients with colorectal cancer were 2·0 (95% CI 1·9–2·1) and 1·6 (95% CI 1·5–1·7), respectively, compared with privately-insured patients. For advanced-stage melanoma, the odds ratios were 2·3 (2·1–2·5) for uninsured patients and 3·3 (3·0–3·6) for Medicaid-insured patients compared with privately insured patients. Black and Hispanic patients were noted to have an increased risk of advanced-stage disease (stage III or IV) at diagnosis, irrespective of insurance status, compared with White patients.

Interpretation

In this US-based analysis, uninsured and Medicaid-insured patients, and those from ethnic minorities, had substantially increased risks of presenting with advanced-stage cancers at diagnosis. Although many factors other than insurance status also affect the quality of care received, adequate insurance is a crucial factor for receiving appropriate cancer screening and timely access to medical care.

Introduction

Cancer is a common disease in the USA, with 1 444 920 newly diagnosed individuals and 559 650 deaths expected in 2007.1 For most types of cancer, early detection is associated with a better outcome. For example, in patients with colon cancer, diagnosis at stage I is associated with a 5-year disease-specific survival of 93·2%; however, this value decreases to 44·3% for patients diagnosed at stage IIIC and 8·1% for patients diagnosed at stage IV.2

Several factors have been reported to be associated with the presentation of advanced-stage cancer at diagnosis including: residence in a nursing home;3 distance to nearest hospital;4 residence in rural areas;5 and residence in areas of low socioeconomic status (SES).6, 7 Two further factors are ethnicity and insurance status. Several studies have suggested that people from ethnic minorities are more likely to be diagnosed with advanced-stage cancer than non-Hispanic white people.6, 8, 9, 10 Previous studies have also reported that health-insurance status is an important factor in determining receipt of cancer prevention and screening services, as well as access to timely diagnostic care and treatment for cancer. Individuals without insurance or with Medicaid insurance (a US government programme for low-income or medically-needy individuals) tend to use screening less frequently11, 12, 13 and have more advanced cancer at diagnosis compared with patients who are privately insured.10, 14, 15 Even in higher-income individuals, an absence of health insurance is associated with a decreased use of cancer screening tests.16

Ethnicity and insurance status are not independent factors. Members of ethnic minority groups are more likely to be uninsured or have Medicaid insurance than non-Hispanic white people, both in the overall US population17, 18 and in the population of individuals diagnosed with cancer.19 In general, studies that have assessed associations between disease stage at diagnosis and insurance status have predominantly involved small patient groups or patient groups from specific geographical regions (eg, a single US state). Simultaneous assessment of the association of stage of cancer at diagnosis with insurance status and ethnicity has not been possible in many studies due to small sample sizes. Furthermore, many of these studies provide information from patients diagnosed with cancer in the early-1990s to mid-1990s. In order to provide general and contemporary information on the associations of both insurance status and ethnicity with cancer stage at diagnosis, we assessed these relations for 12 common types of cancer using a US hospital cancer registry database. The 12 cancer sites included in this study were selected on the basis of their high prevalence or mortality in the USA. Some can be detected early by routine screening or symptom assessment, whereas others are generally not detectable at early stages.

Section snippets

Patients

Data for this study were obtained from the US National Cancer Data Base (NCDB). The NCDB, jointly sponsored by the American College of Surgeons and the American Cancer Society, is a hospital-based cancer registry. The NCDB includes about 75% of individuals diagnosed with cancer in the USA and collects data from more than 1400 hospitals, which have cancer-treatment programmes approved by the US Commission on Cancer (CoC).20 In general, although the likelihood of having a CoC-approved programme

Results

Before exclusion of individuals with missing or out-of-range characteristics, the NCDB population included about 73% (5 050 213 of 6 918 100)) of the estimated total US population of patients with cancer of these sites, diagnosed between 1998 and 2004 (data not shown). The percentage of the estimated total US population of patients with cancer recorded by the NCDB ranged from 53% (208 502 of 393 400) for non-Hodgkin lymphoma to 108% (145 152 of 134 400) for pancreatic cancer (ie, previous US

Discussion

The main finding of our study, which uses recent data from a large US population of patients with cancer, is that patients who are uninsured or have Medicaid insurance have a substantially increased risk of being diagnosed with more advanced disease than privately insured patients. This finding was noted across all the cancer types assessed, and was statistically significant (except for cancers of the ovary and pancreas), while controlling for other available patient sociodemographic

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