Mental disorders and mortality in cancer survivors: Key unaddressed factors

Abstract

We were very interested in reading the study by Mai et al.,¹ which provides important data on the association between mental disorders and mortality in cancer survivors. However, there are some potential flaws in the study that have not been fully explored and are worth further analysis and improvement.

First, the data for this study were collected from patients who had cancer between 2009 and 2015 and included a follow-up period of 5 years to assess the incidence of mental disorders and their association with mortality outcomes in 2021. We noted that the mortality data collection in 2021 occurred during the coronavirus disease 2019 pandemic, but the study did not consider the possible impact of the pandemic on the mental health of cancer survivors. During the pandemic, health care resources were reallocated globally, and patients may have faced delays in treatment, increased psychological stress, and a decline in quality of life, all of which had a profound impact on mental health.² The cancer survivors mentioned in the study were more likely to experience mental health symptoms, such as stress, anxiety, depression, loneliness, and hopelessness, especially young adults, adults without a high school diploma, women, and survivors with limited social support.³ Therefore, the failure to consider the impact of coronavirus disease 2019 may introduce bias into the study, particularly regarding the relationship between mental disorders and mortality during the pandemic. Future research should take into account these specific factors during the pandemic and assess their potential effects on the mental health and mortality of cancer survivors, especially the long-term exacerbation of mental disorders.

Second, data from Mai Tran et al.¹ indicate that the incidence of mental disorders is significantly higher in female cancer survivors compared with males. The rates of depression and anxiety in women are 12% and 15%, respectively, whereas the corresponding rates for men are 8% and 10%, respectively. However, although the data indicate higher rates of mental disorders in women, the study does not thoroughly explore the underlying causes of this sex difference. Sex differences in mental health are multifaceted and may be closely related to physiologic factors, psychological stress, social roles, and sex-specific differences in cancer treatment. Women may face more psychological challenges related to body image, gender roles, and hormonal fluctuations during cancer treatment,⁴ but these differences are not adequately addressed in the study. In addition, female patients may face greater social support and economic pressures after cancer treatment, factors that can worsen mental health issues. Future research should delve deeper into the causes of these differences and explore the biologic and sociologic mechanisms behind mental disorder development in female cancer survivors, ultimately leading to personalized psychological interventions.

Moreover, the study focuses on the association between a single type of mental disorder and mortality but does not examine the impact of comorbid mental disorders on mortality. In reality, cancer survivors may have multiple mental disorders simultaneously,⁵ and literature and clinical evidence suggest that comorbid mental disorders increase the pathologic burden, lower treatment adherence, and elevate the risk of suicide.⁵ The physical and psychological burden on patients with comorbid conditions is more complex, and the impact on mortality is not simply the additive effect of individual disorders. The failure to investigate this aspect may result in an incomplete assessment of how mental disorders affect mortality. We recommend that the authors conduct subgroup analyses to compare patients who have comorbidities with those who have a single mental disorder, assess the additional risks of comorbidity, or introduce multivariable models to explore how interactions between different mental disorders affect mortality in cancer survivors.

By strengthening the exploration of these aspects in future research, we can provide a more comprehensive evidence base for managing the mental health of cancer survivors and offer more precise guidance for public health policies and personalized treatment strategies.

The authors declared no conflicts of interest.