No evidence to support the impact of migration background on treatment response rates and cancer survival: a retrospective matched-pair analysis in Germany

Abstract

Background: Immigration has taken the central stage in world politics, especially in the developed countries like Germany, where the continuous flow of immigrants has been well documented since 1960s. Strikingly, emerging data suggest that migrant patients have a poorer response to the treatment and lower survival rates in their new host country, raising concerns about health disparities. Herein, we present our investigation on the treatment response rate and cancer survival in German patients with and without an immigrant background that were treated at our comprehensive cancer center in Germany.

Methods: Initially, we considered 8162 cancer patients treated at the Center for Integrated Oncology (CIO), University Hospital Bonn, Germany (April 2002-December 2015) for matched-pair analysis. Subsequently, the German patients with a migration background and those from the native German population were manually identified and catalogued using a highly specific name-based algorithm. The clinical parameters such as demographic characteristics, tumor characteristics, defined staging criteria, and primary therapy were further adjusted. Using these stringent criteria, a total of 422 patients (n = 211, Germans with migration background; n = 211, native German population) were screened to compare for the treatment response and survival rates (i.e., 5-year overall survival, progression-free survival, and time to progression).

Results: Compared to the cohort with migration background, the cohort without migration background was slightly older (54.9 vs. 57.9 years) while having the same sex distribution (54.5% vs. 55.0% female) and longer follow-up time (36.9 vs. 42.6 months). We did not find significant differences in cancer survival (5-year overall survival, P = 0.771) and the response rates (Overall Remission Rate; McNemar's test, P = 0.346) between both collectives.

Conclusion: Contrary to prior reports, we found no significant differences in cancer survival between German patients with immigrant background and native German patients. Nevertheless, the advanced treatment protocols implemented at our comprehensive cancer center may possibly account for the low variance in outcome. To conduct similar studies with a broader perspective, we propose that certain risk factors (country-of-origin-specific infections, dietary habits, epigenetics for chronic diseases etc.) should be considered, specially in the future studies that will recruit new arrivals from the 2015 German refugee crisis.

Keywords: Cancer; Comprehensive cancer center; Germany; Matched-pair analysis; Migration background; Response rate; Socioeconomic status; Survival.

Fig. 1

Kaplan-Meier curves including all entities. a 5-year overall survival (5-y OS) of all patients with and without migration background (n = 422). The mean OS was 34.8 months for the native German cohort (n = 211) and 30.8 months for the migration cohort (n = 211) (conditional logistic regression model; HR 0.951, 95% CI [0.670;1.349]; p = 0.771). b Progression-free survival (PFS) of all patients with and without a migration background (n = 422). The mean PFS was 23.5 months for the native German cohort (n = 211) and 22.5 months for the patients with migration cohort (n = 211) (HR 0.957, 95% CI [0.719;1.275]; p = 0.766). c Time to progression (TTP) of all patients with and without a migration background (n = 422). The mean TTP was 24.1 months for the native German cohort (n = 211) and 22.8 months for the migration cohort (n = 211) (conditional logistic regression model; HR 0.947, 95% CI [0.709;1.236]; p = 0.709)