The modified PCOQ showed evidence of construct validity in patients with advanced prostate cancer. The correlations between this measure and related theoretical constructs were mostly aligned with the Dodd Symptom Management Model [20]. On average, patients experiencing symptoms considered a minor reduction in symptom severity acceptable. Acceptable symptom levels were significantly higher for sexual dysfunction than most other symptoms. Patient priorities for symptom treatment varied widely and were correlated with certain symptom levels and other clinical characteristics.
Preliminary construct validity of the PCOQ showed results that were largely consistent with our hypotheses. The severity of all symptoms on the PCOQ was strongly correlated with standard measures of the same symptoms. For the majority of symptoms, greater severity was correlated with worse functional status and quality of life. Among the symptoms, only lack of appetite, prevalent in many clinical conditions [32–34], showed a significant correlation with the number of medical comorbidities. Additionally, moderate, positive correlations were found between symptom severity and importance for all symptoms except for sexual dysfunction and lack of appetite. Findings suggest that symptom severity and importance are related yet distinct concepts. Previous research in chronic pain and cancer has found similar associations between symptom severity and patient subgroups based on symptom importance [2, 5, 11, 13, 14, 35].
Potential explanations for the moderate correlation between symptom severity and importance have rarely been assessed. In one qualitative study, patients with advanced lung cancer provided varied reasons for symptom importance ratings that extended beyond symptom severity [13]. For example, some patients reported that their ratings of symptom importance reflected their ability to tolerate the symptom or the extent to which the symptom interfered with daily activities. Others stated that their low symptom importance ratings were due to prioritizing survival over symptom management.
Patients generally preferred low symptom severity levels across all symptoms and considered minor reductions in symptom severity acceptable, although acceptability varied across symptoms. The acceptable severity levels in the current sample align with success criteria for symptom improvement in patients with chronic pain and metastatic breast and lung cancer [2, 10, 13, 14, 35]. The lowest acceptable severity ratings were found for diarrhea and nausea, emphasizing their importance as intervention targets. A previous study of patients with prostate cancer identified diarrhea as a more troubling side effect than urinary symptoms, underscoring its significance [36]. However, in this study, patients, on average, had very mild diarrhea and nausea. Conversely, sexual dysfunction, a prevalent side effect of prostate cancer therapies, had a significantly higher acceptable severity level than most symptoms. This side effect is often addressed in patient education [37], which may help facilitate adaptive coping strategies. Additionally, reduced sexual desire, a frequent side effect of treatment [38, 39], may lead to greater tolerance of sexual dysfunction. The severity and importance of sexual dysfunction were not significantly correlated in this study, consistent with its higher acceptable severity level. Fatigue severity was the most distant from its acceptable level, aligning with research that identifies fatigue as the most troublesome symptom for patients with advanced prostate cancer [40]. However, in this study, fatigue did not require substantial reduction to be considered manageable.
Three distinct subgroups of patients were identified based on the importance of seeing symptom improvement: those who rated all symptoms as low, moderate, or high in importance. This classification illustrates the variability in patient attitudes towards symptom management. Studies in advanced breast and lung cancer also identified one patient subgroup that rated all symptoms as highly important [13, 14]. Differences in the remaining patient subgroups across studies likely reflect variations in the examined symptoms and sample characteristics.
In the current study, patients who rated all symptoms as moderately or highly important were more likely to have greater physical symptoms (e.g., pain, fatigue), a history of pain treatment, and worse functional status than patients who rated all symptoms as low in importance. In addition, patients who rated all symptoms as highly important showed higher levels of emotional distress than patients who rated all symptoms as low in importance. Our findings align with the Dodd Symptom Management Model, which posits correlations between health-related characteristics and symptom experiences [20]. Other findings in advanced breast and lung cancer and chronic pain were largely inconsistent with this model; few demographic and clinical correlates of patient subgroups based on symptom importance were found [2, 10, 13, 14, 35]. Findings suggest that for patients with advanced prostate cancer, symptom importance ratings may more closely parallel other aspects of their functioning and clinical care as compared to patients with other advanced solid tumors or chronic pain.
Limitations of the current study should be noted. This study was conducted at a single academic medical center in the midwestern United States and primarily enrolled non-Hispanic white participants. The relatively small sample size may have reduced statistical power for detecting significant associations. Finally, the cross-sectional design did not allow for the evaluation of test-retest reliability and longitudinal changes.
Our findings highlight the need for personalized symptom management for patients with advanced prostate cancer. This approach would incorporate patient criteria for symptom treatment success and treatment priorities into the shared decision-making process. Specifically, patients in our study often required low symptom severity to view treatment as satisfactory, underscoring the need for tailored patient-provider discussions about expected treatment outcomes. Additionally, given the varied priorities among patients for symptom improvement, understanding individual treatment goals would inform patient-centered care. For example, providers may consider asking patients which symptom is most important to address first. Finally, it is important for providers to consider the interconnectedness of symptoms and discuss potential side effects of treatments to align with patients’ symptom management priorities. For example, previous studies indicate that treating co-occurring symptoms such as urinary problems and pain can also mitigate fatigue [41]. However, single-symptom treatments like steroids or stimulants for fatigue might worsen other symptoms, such as anxiety and sleep problems [42].
There are several important directions for future research. The psychometric properties of our modified PCOQ should be examined in larger advanced prostate cancer samples that are fully representative of the population. In addition, researchers could modify and validate the PCOQ for other advanced cancer populations. Longitudinal studies could assess changes in acceptable symptom levels and priorities for symptom improvement over the cancer trajectory. Finally, pragmatic intervention trials targeting symptom clusters could assess patient priorities for symptom improvement to guide the next steps in their care. This research will lead to patient-centered approaches to enhancing quality of life and functioning in advanced cancer.