One of the important contributions of this study is that it examined how the QOL in PCa patients correlated with the QOL of their partners while taking into consideration both partners’ baseline and time-varying demographic, cancer-related, and psychosocial variables. Different from previous studies using measures at one time point to model QOL of patients and partners separately (e.g., Kershaw et al. [8
]), we used a more comprehensive analytical method, i.e., MLM, to examine how QOL of patients and partners measured at four data points correlated. We evaluated both the lag effects of baseline demographic and cancer-related factors, and the concurrent effects of time-varying psychosocial factors on QOL. The effects of time were non-significant after controlling for time-varying antecedents, suggesting that the patterns of change in couple’s QOL over time are a function of survivorship context (e.g., the challenges and resources couples have at different phases of survivorship), rather than the time variable itself. These results provide evidence that otherwise might have gone undetected or misrepresented by traditional analytical methods, e.g., repeated-measure ANOVA [54
This study expanded our knowledge about the complexity of cancer experience in the context of family. Our findings of small to moderate correlations of QOL between PCa patients and partners, after accounting for the effects of covariates, are consistent with the results of a recent meta-analysis of couples’ distress during cancer survivorship [56
]. In our study, the QOL scores of patients, similar to those reported in earlier research using FACT-G [36
], were better than those of their partners. These results suggest that partners are “team members” in managing PCa, underscoring the interdependence within couples as they cope with the demands of cancer [57
]. Such evidence alerts clinicians to the need for caring for the health of the spouse, who often acts as the primary caregiver for patients by providing major emotional and tangible support on a daily basis [58
]. However, the possible influence of gender on participants’ responses to the QOL measure cannot be ruled out. Significant gender differences in reporting distress were found in couples adjusting to colon cancer, a non-gender-specific illness [59
Certain baseline demographics and time-varying physical and psychosocial variables affected couples’ QOL. Consistent with the conclusions of a prior meta-analysis based on 33 studies [61
], the association between couples’ perceived open communication and their QOL in this study confirms that open communication about cancer is beneficial to couples managing PCa: couples may maintain or improve QOL through open communication about cancer. Aging persons more frequently interact with their families, especially their spouses [62
]; their QOL may be closely related to how well they maintain those close relationships. Demands of cancer, treatment-related side effects, and age-related chronic health problems [63
] limit couples’ physical interactions and leisure activities. Open communication becomes even more important for couples to obtain emotional and tangible support from each other.
In this study, couples’ QOL was positively affected by social support from other people. This result expanded previous research findings of direct and/or indirect effects of social support on mental well-being (e.g., less depression and anxiety) in patients and partners [8
] to general QOL domains. We also confirmed that uncertainty about the illness was another factor affecting couple’s QOL; more uncertainty was associated with lower QOL. This finding was consistent with Mishel’s uncertainty theory [65
] and extended findings of previous cross-sectional studies [29
]. It also provided empirical support for interventions that aim at improving QOL through uncertainty management for both partners.
Another clinically relevant finding was that, among all PCa-specific symptoms, only patients’ sexual and hormonal symptoms (e.g., impotence and hot flashes) significantly affected couples’ QOL. Previous qualitative research reported that PCa patients considered their current QOL had little to do with their cancer or its treatment [66
]. Yet, the debilitating symptoms of PCa and treatment side effects pose major threats to patients’ masculine image and sense of control [67
]. Fewer problems in sexual and hormonal functions in patients, thus, provide reassurance to couples, especially men, and preserve their feelings of normalcy. These findings extended prior work in assessing the effects of hormonal symptoms on couples’ QOL, a rarely reported area [52
We validated the results of previous investigations that cancer patients, especially the elderly with various symptoms, had poorer physical, mental, and social QOL [8
]. It also explored the negative effects of partners’ symptoms on their QOL, which was often ignored in the past because QOL and survival of cancer patients have been the foci of clinical practice and research. Family caregivers of cancer patients have significantly poorer global QOL than caregivers of non-cancer patients. Spouse caregivers, in particular, have significantly poorer QOL than non-spousal caregivers (e.g., adult children, relatives or friends) [69
]. This research reminded us that partners provide care and support to cancer patients while managing the demands of their own health and age-related problems. Health professionals, thus, need to attend to spousal caregivers’ health needs while caring for cancer patients.
Regarding demographics, we found that couples’ QOL was related to partner’s age, patient’s education level, and family income. The association between partners’ older age and better QOL in couples may be related to the fact that, among our research participants, most (84.8%) of the younger partners (<60 years of age) worked outside the home while less than 20% of partners 60 years and older worked. Younger partners may have to care for the patient while dealing with competing demands of employment and child care. Consistent with Kim et al.’s findings [70
], this result may suggest that the more social roles and responsibilities a caregiver carries, the more likely the caregiver experiences stress and negative adjustment.
The positive association between partners’ older age and couples’ better QOL may be related to the fact that the majority of couples were married, with an average of 32 years of relationship. In this relatively elderly population with long-standing relationships, partners have developed a deeper understanding of each other, enabling their better adaptation to cancer. It is noteworthy that sexuality may no longer be considered of primary importance among some elderly, particularly in aged women [71
]. The pressure that older PCa patients put upon themselves to perform sexually may not be as great as that of younger patients who are more sexually active.
Several studies reported associations between baseline income and patients’ QOL at baseline and over time [72
]. Our results indicate higher family income predicted better QOL in both patients and partners. Financial concerns are prevalent among cancer patients and family members [74
]. More income allows couples to afford materials and human resources to better manage cancer and caregiving and thus gives couples a sense of security that reduces stress and improves QOL. The negative effects of patients’ education level on couples’ QOL are inconsistent with the results of previous studies, especially those including participants with diverse education backgrounds [75
]. However, participants of this study have relatively high education levels (mean = 16 years); our finding may not be generalized to diverse populations.
Finally, this study has limitations that warrant discussion. First, the treatment information was not included. Many individuals underwent more than one treatment. Classification would have resulted in too many treatment combinations to be analyzed with the existing sample size, i.e., too few subjects to utilize multivariate analyses to separate treatment effects statistically. Second, more patients with advanced cancer dropped from the study due to patients’ deaths. Third, participants were primarily well-educated, middle-class Caucasians. The limited number of participants from different ethnic groups or those with low socioeconomic status lessens the generalizability of our findings. Next, we could not differentiate the influences of gender from that of role (patient or partner) on couples’ QOL as PCa is a gender-specific illness. Finally, this study did not address the change of the outcome variable (i.e., QOL) as a function of the changes in predictors.
In conclusion, this study, using MLM, provided integral evidence on QOL in PCa patients and partners while controlling for baseline and time-varying contextual factors of both partners. Capturing couples’ complicated survivorship experiences, both as individuals and as a pair, this research provides information on modifiable factors that can be targeted for intervention. Research is needed to examine the effects of family-focused comprehensive interventions, e.g., uncertainty reduction, support mobilization from internal (e.g., open communication between partners) and external sources (e.g., assistance from other relatives, friends, and health providers), and symptom management. These efforts will strengthen couples’ adaptive abilities and ultimately improve their QOL.