Elsevier

Clinical Colorectal Cancer

Volume 15, Issue 4, December 2016, Pages e221-e227
Clinical Colorectal Cancer

Original Study
Metastatic Colorectal Cancer in Hispanics: Treatment Outcomes in a Treated Population

Presented in part at American Society of Clinical Oncology GI 2013 abstract 373.
https://doi.org/10.1016/j.clcc.2016.03.001Get rights and content

Abstract

Background

In United States Hispanics have disparities in the presentation and outcome of colorectal cancer (CRC) largely attributed to their late presentation and lower socioeconomic status. Impact of treatment, especially in the metastatic setting, in the observed outcome is an unexplored area. We explored the role of treatment in the outcome of metastatic CRC we performed a retrospective analysis to assess the contribution of demographics, tumor characteristics, and health care setting on survival differences.

Patients and Methods

We conducted a retrospective study of patients who were treated with metastatic CRC at Los Angeles County Hospital–University of Southern California (LAC-USC, a public hospital) and Norris Comprehensive Cancer Center (NCCC, private hospital) between 2002 and 2012. Both these institutions are staffed by the same providers and therefore treatment algorithms and access to drugs were similar. We identified metastatic CRC patients who received chemotherapy from administrative records. Demographics, tumor, and treatment related factors were collected. The primary end point was time to progression (TTP: time from the first day of chemotherapy to the date of progression). Overall survival (OS) was measured from the first day of chemotherapy to death or last follow-up. Descriptive statistics were used to describe the population and chi-square, Wilcoxon, and log-rank tests were used for comparison between the groups.

Results

A total of 242 patients, 44% Hispanic, 26% non-Hispanic whites (NHWs), 21% Asian and 9% black were included. Median TTP was 9.2 months (95% confidence interval [CI], 7.6-11.6) in Hispanics, and 20.7 months (95% CI, 9.6-27.5; P < .05) in NHWs. Median OS in Hispanics was 16.3 months (95% CI, 13.3-18.5), and in NHWs was 33.5 months (95% CI, 22.1-63.6; P < .001). Hispanics who were treated at LAC-USC had longer TTP in comparison to Hispanics at NCCC (P = .04).

Conclusion

Hispanics with metastatic CRC have shorter TTP and OS on first line therapy when adjusted for health care setting, demographics, disease characteristics, and treatment factors.

Introduction

Colorectal cancer (CRC) is the third most common cancer in terms of incidence and mortality in the United States. In 2014, it was estimated that there would be 136,830 new cases of CRC and 50,310 deaths attributable to CRC, accounting for 8% of all cancer deaths in the United States.1 There exists a significant ethnic disparity in CRC incidence and survival in the US. African Americans have the highest incidence and mortality rates of CRC, followed by non-Hispanic whites (NHW), Hispanics, and Asians.2, 3

The past decade has seen a decline in the CRC mortality rate, attributable to declining incidence rates due to advances in screening and detection of precancerous lesions, and improvements in treatment.4 While Hispanics have a better survival from CRC compared to other major ethnic groups, the magnitude of improvement in their mortality has been less than NHWs over the last decade (Figure 1).4 For example, from 2000 to 2009 in the United States, deaths from CRC have decreased by 3.2% per year among white men, whereas this decrease was only 1.4% per year among Hispanic men. A similar trend can also be seen in Hispanic women.4 Reasons for this ethnic disparity in outcome are unclear, but may include differences in risk factors such as diabetes and obesity, diet, screening practices, socioeconomic status, access to timely medical care, treatment with new agents, posttreatment surveillance, tumor stage, and tumor biology.5, 6, 7, 8, 9, 10, 11, 12

Hispanics account for 16.7% of the United States population and are expected to make up one third of the population by 2050.13 Multiple published reports in the literature have assessed the degree and reasons for outcome disparity in Hispanic patients with CRC; however, survival data are often based on information from cancer registries, which are not reliably resources to identify treatment regimens, especially for those with metastatic disease.

The current landscape of metastatic disease treatment involves 5-fluorouracil (5-FU) and leucovorin (or capecitabine) in combination with either irinotecan or oxaliplatin.14 Addition of biologic therapies to chemotherapy results in improved efficacy. Bevacizumab is a vascular endothelial growth factor (VEGF) antibody, which inhibits angiogenesis and prevents tumor growth.15, 16, 17 Likewise, epidermal growth factor receptor (EGFR) antibodies have shown to add to the benefit of chemotherapy.18, 19

To explore the prognosis and the role of treatment in the outcome of metastatic CRC we performed a retrospective study in a diverse population with metastatic CRC to determine the degree of racial disparity in survival, adjusted for treatment regimens. We explored the contribution of demographic factors, tumor characteristics, and health care setting (diagnosis and receipt of cancer treatment in a private cancer hospital vs. a public/safety net hospital) to the observed survival differences.

Section snippets

Patient Selection

Using administrative records, we identified patients with metastatic CRC who received their first line chemotherapy at Los Angeles County–University of Southern California (LAC-USC) hospital, a safety net hospital, and Norris Comprehensive Cancer Center (NCCC), a private cancer hospital, between 2002 and 2012. Patients' demographics, tumor characteristics (tumor location, tumor stage, histology, and molecular markers), and treatment-related information were collected for all participants.

Results

A total of 242 patients met our inclusion criteria and were included for analysis. Patient demographics, tumor characteristics, and health care setting are summarized in Table 1. The median age of the cohort was 56 years (range, 23-84 years), and 55% of patients were men. Among the entire cohort, 44% of patients were Hispanics, 26% white, 21% Asian and 9% black with 71% of the patients in our study treated at LAC-USC and 29% at NCCC. There was no statistically significant difference in age, and

Discussion

In the era of targeted therapies the differences in responses in different individuals have become increasingly important. Our findings highlight that in metastatic CRC patients who received treatment, the benefit of treatment as measured by TTP as well as OS is worse in Hispanics than NHWs. The difference in TTP on the first line therapy translates to the difference in OS in these patients. Receipt of second line therapy is an important determinant of OS. In our study, 47% of patients who were

Disclosure

The authors have stated that they have no conflict of interest.

Acknowledgments

Supported in part by award P30CA014089 from the National Cancer Institute. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health.

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