Esophageal cancer is a malignant tumor that ranks as the sixth leading cause of cancer death globally.
1 Esophagectomy, often in combination with chemotherapy or chemoradiotherapy, is the main treatment approach with curative intent. Patients with esophagectomy for cancer usually suffer from substantially decreased health-related quality of life (HRQL), especially within 6 months post-surgery.
2,
3 From 1 year post-surgery, HRQL is reported to have recovered to a large extent.
2,
3 Previous studies have demonstrated that histology type, tumor stage, tumor location, operation approach, postoperative complications, and comorbidity are predictors of poor postoperative HRQL.
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7 However, patients with similar characteristics in these aspects still report varied HRQL, indicating that other factors, such as personality traits, might also have an influence.
Dispositional optimism is a relatively stable personality trait, which refers to the global expectation that more desirable than bad things will happen in the future.
8 No previous study has assessed the association between dispositional optimism and HRQL among patients with esophageal cancer. Studies conducted among patients with other subtypes of cancer have shown that higher dispositional optimism is associated with better HRQL in several aspects, such as global quality of life, emotional function, social function, pain, and body image.
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15 However, its associations with other aspects including physical function, role function, and cognitive function were ambiguous, as some studies reported significant associations while others reported nonsignificant associations.
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14,
16 In addition, one study found that the association between dispositional optimism and HRQL tends to attenuate when near death.
17 Given that more than 50% of surgically treated patients with esophageal cancer die within 5 years post-surgery,
18 it remains uncertain whether higher dispositional optimism could predict better HRQL in this population. Clarifying this predictive effect may help identify vulnerable patients who are at higher risk of suffering from poor HRQL after surgery, thus providing early and personalized interventions to patients in need. Moreover, as dispositional optimism can be increased via psychological interventions,
19 if this predictive effect exists, it may also imply a potential intervention target to improve postoperative HRQL.
In this study, we aimed to use Swedish nationwide population-based longitudinal data to assess whether higher dispositional optimism predicts better HRQL after esophageal cancer surgery.
Discussion
This study showed that, compared with patients with lower dispositional optimism, patients with higher dispositional optimism reported better HRQL at 1, 1.5, and 2 years after esophageal cancer surgery, in the aspects of global quality of life, emotional function, social function, anxiety, pain, and body image, which is in line with previous studies conducted among patients with other subtypes of cancer.
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15 However, this study further found that dispositional optimism predicted fewer self-reported problems in dyspnea, diarrhea, dry mouth, trouble with taste, and worry about weight loss after esophageal cancer surgery.
The potential mechanisms for these observed associations might be related to coping, goal adjustment, and social support.
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40 Previous studies have shown that patients with higher dispositional optimism tend to adopt more effective coping and goal adjustment strategies.
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39 When the challenge is controllable, people with higher dispositional optimism tend to make every possible effort to overcome it, but if the challenge is uncontrollable, they also tend to disengage from the unattainable goals and adapt to unfavorable situations more quickly via using emotional acceptance and positive reinterpretation.
37,
38 Therefore, patients with higher dispositional optimism may be more persistent in pursing beneficial lifestyle,
41 such as obeying the special postoperative dietary instructions, quitting smoking, and undertaking more physical exercise,
41 which might help them reduce the symptoms of diarrhea and eating difficulty,
42 and relieve their worry about weight loss. In addition, after esophageal cancer diagnosis and surgery, some life goals may become unattainable for patients. Timely disengagements from unrealistic goals and reengagement in new achievable goals can help patients avoid accumulating negative experience and reduce rumination,
39 which might lead to better emotional function as well as less anxiety and pain.
38,
39 Given that psychological distress is a potential cause of dyspnea,
43 better emotional function might further help optimistic patients reduce dyspnea symptom. Additionally, more optimistic people are more likely to have higher perceptions of available social support as well as actually receive higher supportiveness from significant others,
40 thus leading to better social function and less self-doubt about body image. The combined beneficial effects of high dispositional optimism on the above HRQL aspects might further contribute to better global quality of life.
The observed predictive effect of dispositional optimism on HRQL among patients with esophagectomy for cancer has both clinical and research implications. It may help identify patients at higher risk of suffering from persistently impaired HRQL after esophageal cancer surgery, thus providing tailored follow-up and timely interventions to improve their postoperative HRQL. Moreover, although dispositional optimism is relatively stable, it can be increased via psychological interventions such as cognitive behavior therapy and the Best Possible Self exercise.
19 The findings of this study suggest that increasing dispositional optimism might be a potential intervention target to improve postoperative HRQL. In addition, given that poor HRQL recovery is associated with higher mortality,
44 the predictive value of dispositional optimism on HRQL may also imply its potential predictive effect on survival, and future studies on this topic are warranted.
To the best of the authors’ knowledge, this is the first study examining the predictive effect of dispositional optimism on HRQL after esophageal cancer surgery. The study reduced confounding bias through adjusting for several potential confounders. HRQL was measured comprehensively using both a cancer general questionnaire (EORTC QLQ-C30) and a disease-specific module (EORTC QLQ-OG25). Moreover, the clinical relevance of adjusted MSD was evaluated according to the evidence-based guidelines, and its statistical significance was tested only if it had clinical significance, which not only decreased the risk of chance findings but also ensured the clinical relevance of the results. Additionally, the nationwide population-based longitudinal study design facilitated the generalizability of the findings.
This study also has some limitations. First, because the OSCAR study focuses on patients who have survived for at least 1 year after esophagectomy, we measured dispositional optimism at 1 year post-surgery and not at time of cancer diagnosis or surgery. The observed predictive effect of dispositional optimism on HRQL should be interpreted in light of the assessment time point, even though dispositional optimism remains relatively stable over time and across stressful situations including receiving cancer diagnosis and surgery,
45,
46 and surgical factors were not associated with dispositional optimism based on our data. Second, we categorized patients into four subgroups according to the quartile of LOT-R sum score. Misclassification might happen due to the measurement error in the LOT-R, which can cause potential bias in either direction.
47 Third, patients with lower dispositional optimism and poor HRQL might be more likely to decline to participate in the study and not answer the follow-up questionnaires, which could make the observed associations underestimated. Last but not least, prediction does not equal causation. The observed association might be due to the effect of unmeasured confounders such as genetic factors,
48,
49 and whether increasing dispositional optimism could improve HRQL needs to be examined by future interventional studies.
In conclusion, this study showed that higher dispositional optimism predicted better HRQL at 1, 1.5, and 2 years post-surgery in several aspects among patients with esophagectomy for cancer. The predictive value of dispositional optimism may help identify high-risk patients with poor HRQL recovery after esophageal cancer surgery, leading to timely and tailored interventions to patients in need, and therefore contribute to the improvement of postoperative HRQL and probably even survival.
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