Changing Epidemiology and Improved Survival In Patients With Waldenstrom Macroglobulinemia: Review Of Surveillance, Epidemiology, and End Results (SEER) Data

Waldenstrom Macroglobulinemia (WM) is a hematological malignancy that affects 1500 people each year in the United States. Due to lack of literature on era comparative population-based analysis, we have analyzed Surveillance Epidemiology and End Results (SEER) data to evaluate the changes in incidence and survival patterns in the new millennium where modern therapeutic agents such as rituximab, immunomodulatory drugs and proteasome inhibitors were offered to WM patients; in contrast to the earlier period when they were non-existent.

The SEER 18 registry which includes data from 1973-2010 from 18 geographic areas including 28% of US representative population was used in analysis. ICD-O-3 code 9761 was used for identifying patients for this analysis. SEER* Stat 8.0.4 is used to calculate age-adjusted incidence and mortality rates based on race, gender, and age for patients. Age adjusted rates were used in this anlaysis to avoid confounding variables when comparing rates over time.

We have included 4304 patients in the analysis (1244 patients diagnosed before 2000 and 3060 patients after 2000). The incidence rate of WM increased with age. The 10 year cumulative incidence rate per 100,000 by age stratification (<50 yrs, 50-59 yrs, 60-69 yrs, 70-79 yrs and >80) are 0.02%, 0.40%, 1.01%, 2.14% and 2.98% respectively. Over the last decade the trend of incidence rate in WM has been steadily decreasing across all age groups (Figure 1). Median survival for all WM patients is 74 months (m) (70.2-77.8). Significant survival improvement was seen in the current era (median survival ≥2000 vs. <2000: 84 m (79.8-92.2) vs. 64 m (57-67); p=0.000) Survival difference ≥2000 vs. <2000 was seen across most groups (male: 83 m vs. 58 m, p=0.000; female: 87 m vs. 70 m, p=0.004; white: 85 m vs. 62 m, p=0.000; age 50-59: 122 vs NR; p=0.002; age 60-69: 123 vs. 81 m; p=0.000; age 70-79: 69 vs. 53 m; p=0.001; age >80: 36 vs. 31 m; p=0.05). Younger patients <50 (NR vs. 204 m, p=0.53) and African American patients (75 m vs. 62 m, p=0.72) did not see survival benefit.

Figure 1

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Figure 1

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The incidence rates of Waldenstrom's macroglobulinemia are trending down over the last decade for reasons unclear. The survival rates have significantly improved across most stratifications of age, sex, gender in the new millennium. These results could be secondary to the favorable impact of new drugs used in treating patients with Waldenstrom's macroglobulinemia. Also should be taken into consideration, that the current classification for WM took place in the new millennium which is a limitation for interpretation of this survival benefit observed.

Boise: Onyx Pharmaceuticals: Consultancy. Kaufman:Onyx: Consultancy; Celgene: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Janssen: Consultancy; Millenium: Consultancy; Merck: Research Funding. Heffner:Genentech: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Biotest: Honoraria, Research Funding; Onyx: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding. Lonial:Millennium: Consultancy; Celgene: Consultancy; Novartis: Consultancy; BMS: Consultancy; Sanofi: Consultancy; Onyx: Consultancy.