We studied the association between cancer-specific beliefs and mortality prospectively in a population-based cohort of African-American and White men and women with newly diagnosed non-metastatic CRC. Our multivariate Cox regression model adjusting for relevant socio-demographic and biomedical variables showed that patients who believed that most cancers cannot
be cured had a 59% increased risk of mortality in the 15-year period following diagnosis. Furthermore, this finding was specific with respect to the four beliefs examined, with the other three beliefs showing no association with mortality. Thus, we have identified a potential specific, clinically relevant psychosocial marker for individuals at risk for poor outcomes. Importantly, we found the same specific association between the belief that most cancers cannot be cured and mortality among breast cancer, 7
indicating the robustness of this finding across major cancer types.
In terms of outcome disparities across race, our multivariate results suggested that African-American and White participants had similar survival outcomes regarding all-cause mortality, but African-Americans had a higher risk of CRC-specific death than Whites. These findings are consistent with previous results, 2, 3, 40–42
except in populations where both groups received similar treatment and care, in which case disparities almost disappeared.43, 44
A recent meta-analysis concludes that racial differences in survival are greatly reduced when accurate measures of treatment quality and socioeconomic factors are taken into consideration.45
With respect to a prognostic relationship between gender and CRC, we found that men diagnosed with CRC were at higher risk than women for all-cause mortality and CRC-specific mortality, as previously observed by others, 40, 42, 46
although the literature remains inconclusive. 40
Regarding prevalence of cancer-specific beliefs by race and gender, we found African-Americans were more likely than Whites to believe that regular checkups would not detect cancer unless a person already had one of the seven warning signals. This belief is likely to influence early cancer detection.47, 48
Evidence of race as an independent predictor of CRC screening remains inconclusive whereas race disparities in CRC stage at diagnosis have been observed consistently in the recent literature.49
In our sample, women were also more likely than men to doubt the efficacy of regular checkups regarding cancer detection which supports the existing evidence that women are less likely to adhere to CRC screening guidelines. 48
Taking into account the number of factors relevant to a cancer prognosis, a significant association between a psychosocial characteristic measured shortly after diagnosis and the relative risk of dying during a 15-year follow-up period is noteworthy and a potentially useful tool for quickly identifying individuals at risk for unfavorable outcomes. The underlying mechanisms for associations between psychosocial factors and survival are likely to include health protective behaviors,26, 50–52
adherence to recommended medical protocols and monitoring of disease recurrence, 42, 53
as well as neuroimmunological, neuroendocrine, and other physiological pathways.13–15
A recent review12
and a meta-analysis15
concluded that, although current evidence regarding the role of psychosocial influences on prognosis is mixed, there is support for the effect of hopelessness, minimization of the impact of the cancer, emotional distress (especially depression) and stress-related psychosocial factors among individuals diagnosed with cancer. A recent prospective randomized clinical trial with an 11-year follow-up of breast cancer survivors concluded that an intervention designed to reduce cancer-specific distress was successful at significantly improving survival outcomes. 13
Although these factors were not measured explicitly as part of our study, the belief that most cancers cannot be cured among individuals recently diagnosed with cancer may reflect fear of recurrence or of a second primary tumor, which is likely to contribute to hopelessness and anxiety/distress.26
Fatalistic views on cancer prevention and prognosis have been associated with poorer health promotion behaviors among cancer survivors. 54
Further, cancer survivors who believe that their cancer was caused by potentially controllable factors (stress, lifestyle, environmental exposures),55
that positive health behaviors may prevent recurrence, 51, 55
or who reported greater intrusive thoughts 26
were more likely to adopt healthier behaviors. These findings are relevant since incidence and/or mortality of CRC have been associated with smoking, 56–61
physical activity,64, 66
and alcohol consumption. 67
Although we did not include BMI or smoking in the final model in the interest of parsimony, we did find that the associations of these variables with all-cause mortality and CRC-specific mortality approached statistical significance. However, neither variable confounded the association between perceived incurability and survival. Our measure of alcohol consumption did not show any association with survival and, due to data limitations, we were unable to examine the role of physical activity.
Unfortunately, despite their increased susceptibility to a recurrence, a second primary tumor, or secondary effects from treatment, cancer survivors tend to have health behavior profiles similar to those of the general population 68
and few meet current lifestyle recommendations. 69
However, some recent findings suggest that although cancer survivors may be receptive to improving their health behaviors 70, 71
their level of readiness to make lifestyle changes varies as much as that of healthy individuals.72
Fatalistic perceptions and/or sense of hopelessness regarding cancer curability may also impact adherence to medical protocols such as treatment 73
and post-treatment surveillance for recurrences and for missed synchronous lesions at initial diagnosis.42
Unfortunately, studies of prevalence of post-treatment surveillance (e.g., colonoscopy) in population-based cohorts of CRC survivors are scarce and limited by their retrospective design.42
To the authors’ knowledge, there are no prospective studies examining psychosocial predictors of post-treatment surveillance among CRC patients.
In sum, perceived incurability of the disease may be a psychosocial marker for survivors at higher risk of harmful psychological factors (e.g., hopelessness) with physiological consequences, such as stress, and/or behavioral factors such as lack of adherence to lifestyle and medical surveillance recommendations.
Our study contributes to the almost non-existent research addressing psychosocial and cultural variables that may influence survival in a racially diverse cohort of cancer patients. 74
Our results are consistent with previous work on survivors of other cancers.7, 13, 73, 75, 76
However, a recent meta-analysis 15
supported the effect of psychosocial factors such as emotional distress/depression on cancer survival for other cancers but not for CRC.
These findings should be interpreted in the context of the study’s limitations. The sample size (n=286), though fairly large for a population-based cancer survival study, may not have provided enough power to detect significant interactions between cancer-specific beliefs and participants’ characteristics. Also, only one wave of psychosocial, socioeconomic, and health behavior information was collected shortly after diagnosis. While not an uncommon limitation, 6, 75
it does preclude the examination of how potential changes in beliefs across time and disease events (e.g., recurrence) may impact disease course and survival outcomes and, vice versa, how the disease course may impact beliefs. Similarly, though participants were asked about their communication with their physician, the data lack detailed information regarding what the patient was told by the physician at time of diagnosis regarding his or her prognosis which may have influenced the patient’s perception about cancer curability. However, given the set of biomedical prognostic variables included in the analysis, we believe we have accounted for a large portion of post-baseline variability in disease course. Likewise, this adjustment accounted for the disease characteristics most likely to have informed physicians’ prognosis and, presumably, their message to their patients regarding their prognosis.
Major strengths of this study include a population-based design, a large representation of African-American cancer patients (40% of the sample), a 15-year follow-up period, in-depth personal interviews, three individual-level measures of socioeconomic status, medical records abstraction, collection of registry survival and treatment data (supplemented with physician surveys at follow-up), standardized staging of cases, and statistical adjustment for socio-demographic, biomedical and health behavior prognostic factors.
In conclusion, in a population-based cohort of racially diverse men and women diagnosed with non-metastatic CRC, perceived curability of cancer was independently associated with long-term survival after adjusting for relevant prognostic factors and potential confounders. Longitudinal research is needed to confirm these findings and determine what combination of mediators in the bio-behavioral pathway explains the association between perceived curability and survival. The identification of specific psychosocial prognostic factors at time of diagnosis may be valuable in the identification of cancer patients at risk for unfavorable outcomes, and who may benefit the most from psycho-behavioral and cognitive interventions. Finally, ascertaining the mechanisms through which these factors affect survival and whether they vary by individual characteristics (e.g., gender, race, age) would facilitate the design of effective interventions targeting CRC survivors.