Contributions
Abstract: EP640
Type: E-Poster Presentation
Session title: Chronic lymphocytic leukemia and related disorders - Clinical
Background
Therapeutic advances in chronic lymphocytic leukemia (CLL) across various therapy lines over the past decades significantly improved the outcomes of CLL patients at the population level. The greater longevity of CLL patients requires measures that capture the prognosis for long-term CLL survivors because survival estimates measured from diagnosis are no longer relevant. Conditional survival is an appropriate measure in this respect because it considers the survival likelihood of patients who have already survived several years post-diagnosis. At present, studies on conditional relative survival (CRS) in CLL have hitherto been lacking.
Aims
This nationwide, population-based study examined up-to-date estimates of 5-year relative survival (RS) at diagnosis and for each additional year survived up to 15 years post-diagnosis among CLL patients in the Netherlands.
Methods
We selected all CLL patients diagnosed in the Netherlands between 1989 and 2018—with survival follow-up through 2019—from the Netherlands Cancer Registry. We used RS to approximate the disease-specific survival. RS was calculated as the ratio of the observed patients’ overall survival over the expected survival of an age-, sex- and period-matched group from the general population. We estimated RS using the hybrid approach to provide up-to-date survival estimates for patients diagnosed between 1989 and 2018 who were alive during the follow-up interval of 2008-2019. The survival estimates produced herein can be interpreted as the predicted survival probabilities of patients during 2008-2019. Five-year RS was stratified by sex and age at diagnosis (18-65, 66-75, and >75 years) and calculated up to fifteen years post-diagnosis. Differences in survival estimates were considered significant when the 95% confidence intervals (CIs) did not overlap
Results
A total of 22,840 CLL patients (61% males; median age, 69 years) were diagnosed in the Netherlands during 1989-2018, of whom 16,439 (72%) were at risk under the hybrid approach. Overall, 5-year RS was 87% (95% CI, 86%>88%) at diagnosis and gradually decreased over time, reaching 81% (95% CI, 77%>84%) at 15 years post-diagnosis (Figure 1A). This pattern was observed irrespective of sex, with no obvious sex differential in survival over time (Figure 1B). There was, however, an apparent age differential in 5-year RS at diagnosis, with corresponding estimates (95% CI) of 93% (92%>94%), 88% (87%>90%), and 75% (73%>79%) for patients across the three age groups, respectively (Figure 1C). Five-year RS decreased with each additional year survival post-diagnosis irrespective of age. As a result, the prognostic effect of age mainly persisted during the follow-up period.
Conclusion
CLL patients continue to experience considerable excess mortality in contemporary clinical practice—as compared to equivalent groups from the general population—despite surviving up to 15 years post-diagnosis. This finding might be explained by the indolent and largely incurable nature of CLL. As such, further progress is warranted to decrease excess mortality in CLL. Furthermore, our data underscore that excess mortality is more significant in elderly patients, especially among over 75-year-olds. Therefore, age above 75 might be considered in prognostic models such as the CLL-IPI to enhance prognostication. Collectively, CRS statistics may offer CLL patients and their physicians information to engage in dialogue about personal health-related planning and surveillance activities.
Keyword(s): Chronic lymphocytic leukemia, Population, Survival
Abstract: EP640
Type: E-Poster Presentation
Session title: Chronic lymphocytic leukemia and related disorders - Clinical
Background
Therapeutic advances in chronic lymphocytic leukemia (CLL) across various therapy lines over the past decades significantly improved the outcomes of CLL patients at the population level. The greater longevity of CLL patients requires measures that capture the prognosis for long-term CLL survivors because survival estimates measured from diagnosis are no longer relevant. Conditional survival is an appropriate measure in this respect because it considers the survival likelihood of patients who have already survived several years post-diagnosis. At present, studies on conditional relative survival (CRS) in CLL have hitherto been lacking.
Aims
This nationwide, population-based study examined up-to-date estimates of 5-year relative survival (RS) at diagnosis and for each additional year survived up to 15 years post-diagnosis among CLL patients in the Netherlands.
Methods
We selected all CLL patients diagnosed in the Netherlands between 1989 and 2018—with survival follow-up through 2019—from the Netherlands Cancer Registry. We used RS to approximate the disease-specific survival. RS was calculated as the ratio of the observed patients’ overall survival over the expected survival of an age-, sex- and period-matched group from the general population. We estimated RS using the hybrid approach to provide up-to-date survival estimates for patients diagnosed between 1989 and 2018 who were alive during the follow-up interval of 2008-2019. The survival estimates produced herein can be interpreted as the predicted survival probabilities of patients during 2008-2019. Five-year RS was stratified by sex and age at diagnosis (18-65, 66-75, and >75 years) and calculated up to fifteen years post-diagnosis. Differences in survival estimates were considered significant when the 95% confidence intervals (CIs) did not overlap
Results
A total of 22,840 CLL patients (61% males; median age, 69 years) were diagnosed in the Netherlands during 1989-2018, of whom 16,439 (72%) were at risk under the hybrid approach. Overall, 5-year RS was 87% (95% CI, 86%>88%) at diagnosis and gradually decreased over time, reaching 81% (95% CI, 77%>84%) at 15 years post-diagnosis (Figure 1A). This pattern was observed irrespective of sex, with no obvious sex differential in survival over time (Figure 1B). There was, however, an apparent age differential in 5-year RS at diagnosis, with corresponding estimates (95% CI) of 93% (92%>94%), 88% (87%>90%), and 75% (73%>79%) for patients across the three age groups, respectively (Figure 1C). Five-year RS decreased with each additional year survival post-diagnosis irrespective of age. As a result, the prognostic effect of age mainly persisted during the follow-up period.
Conclusion
CLL patients continue to experience considerable excess mortality in contemporary clinical practice—as compared to equivalent groups from the general population—despite surviving up to 15 years post-diagnosis. This finding might be explained by the indolent and largely incurable nature of CLL. As such, further progress is warranted to decrease excess mortality in CLL. Furthermore, our data underscore that excess mortality is more significant in elderly patients, especially among over 75-year-olds. Therefore, age above 75 might be considered in prognostic models such as the CLL-IPI to enhance prognostication. Collectively, CRS statistics may offer CLL patients and their physicians information to engage in dialogue about personal health-related planning and surveillance activities.
Keyword(s): Chronic lymphocytic leukemia, Population, Survival