Our findings provide a snapshot of HRQOL for survivors of aggressive NHL 2–5 years post-diagnosis. While NHL survivors reported MCS scores similar to those of the U.S. general population, their PCS scores were significantly lower, suggesting that many in this survivor population report deficits in physical functioning. Similar findings have been reported in another recent study of NHL survivors that examined all NHL types across a much larger window of time since diagnosis (mean 11 years).14,33
These findings suggest that persistent disease or treatment-related adverse outcomes related to physical function may be present for aggressive NHL survivors during this time period.
This study also provides further details on NHL survivors’ HRQOL by reporting rates of depression, anxiety, and fatigue. While the anxiety and depression scores suggest that, on average, these are healthy survivors who report normal mental health, approximately 1 in 5 survivors reported scores above the clinical threshold for depression or an anxiety disorder. The overall rates of anxiety and depression in this NHL survivor cohort were slightly higher than those reported by the general U.S. population,34
and were consistent with the rates previously reported among lymphoma survivors.35–37
One recent study found a higher rate of anxiety (37%) than we did among aggressive NHL survivors in a clinical setting.38
Fatigue levels were higher than the scores reported (using the same scale we used) for both the general population26
and for cancer survivors more than one year post-treatment.25
This suggests that fatigue is higher among survivors of aggressive NHL than among other cancer survivors, but further research is necessary to determine the clinical relevance of this difference.
Specific patient-level characteristics were found to be associated with HRQOL. Younger survivors, those with limited access to healthcare, those without a partner, and those with greater illness burden reported poorer HRQOL. Subgroup differences often exceeded 0.5SD, suggesting that these HRQOL deficits are likely to be clinically meaningful. Some patient characteristics were found to be specific to physical and mental health domains (PCS and MCS): younger age was associated with lower mental health, and disease recurrence or progression was associated with lower physical health. Other characteristics, such as having a partner, private insurance, or having a greater comorbidity burden, were associated with both lower physical and mental health domains. This supports previous findings reported in survivors of NHL14,39
and other cancers,40,41
as well as the general U.S. population.42
This study did not replicate some other relationships identified in previous studies. While older age has been shown to be associated with poorer physical health in cancer survivors and the general population, no age difference was found in this study for physical health. Instead, PCS scores reported here were significantly lower across all age subgroups of NHL survivors (8–10 points, 0.8SD–1.0SD) than the U.S. general population mean, suggesting a strong physical health burden across this entire survivor population. Additionally, sociodemographic characteristics (education, race/ethnicity) and clinical variables (NHL grade and treatment history) showed no association with any HRQOL domains. Lack of significant differences may be due to this study’s smaller survivorship window of 2–5 years and our focus on aggressive NHL. Although further research is needed to investigate these differences, our findings nonetheless provide important information about specific subgroups of NHL survivors who might be at greater risk for decrements in physical and mental health during the period of 2–5 years post-diagnosis.
Perceptions of greater health competence and personal control were consistently associated with higher HRQOL. Moreover, differences among survivors with low levels of competence and control and those with high levels of competence and control exceeded thresholds for clinical significance. The one exception was that physical health was positively associated with perceived health competence but not with personal control. This finding illustrates the subtle, distinct impact that these two cognitive factors may have on NHL survivors’ perception of physical and mental aspects of their HRQOL. Additionally, the cognitive appraisal variables explained more variance in MCS, anxiety, depression, and fatigue outcomes than the sociodemographic and clinical factors, thereby showing the distinctive associations that static patient characteristics and more mutable cognitive factors may have with respect to HRQOL for this population. Overall, our findings suggest that different aspects of survivors’ cognitive health appraisal may be associated not only with their perceptions of overall physical or mental health but also with specific long-term symptoms, such as anxiety, depression, and fatigue.
Existing studies report that facilitation of cancer survivors’ information-seeking efforts and facilitation of shared decision-making between clinicians and survivors during follow-up care visits may improve cancer survivors’ perceptions of health competence and control.19,28,43
Our findings suggest that such efforts directed at improving survivors’ cognitive health appraisal may also facilitate better adjustment among survivors of aggressive NHL. However, given the cross-sectional nature of our study, we encourage future longitudinal studies to replicate our finding of positive association of perceived health competence and personal control with HRQOL.
Our findings should be interpreted in light of three potential limitations. First, our response rate was modest at 55% and respondents may have systematically differed from non-responders. As has been published elsewhere,20
we compared study responders and non-responders on a limited number of indicators available from the SEER registry (age, gender, race/ethnicity, NHL grade, and time since diagnosis). Among NHL survivors who we were able to contact, we did not find any significant differences among those who participated in the study and those who refused. Also, as noted earlier, we found little bias in our respondent sample between those who completed the abbreviated telephone interview and those who filled out the mailed questionnaire. Second, this cohort was diagnosed between 1998 and 2001, and medical treatments for aggressive NHL have changed over the past 10 years, especially with the introduction of Rituximab. However, treatment for this type of NHL remains aggressive with potential for similar impact on HRQOL, limiting the possibility of any major differences than what has been reported here. Nevertheless, we encourage additional studies with more recent cohorts of NHL survivors be conducted to replicate our findings and further research examining specific treatment protocols. Finally, NHL survivors from Los Angeles County may not be representative of all U.S. survivors and our findings may not generalize to the experiences of longer term survivors, thereby limiting generalizability of our findings. Despite these limitations, this study adds to the very limited literature on the HRQOL of NHL survivors providing a more comprehensive assessment of HRQOL outcomes in this population than has been previously reported. Recruitment of survivors from a population-based SEER registry, rather than a clinically recruited sample, further adds to the strength and validity of our findings.