This study focused on the association between prognostic awareness and quality of life among patients with advanced cancer. Our findings indicate that accurate prognostic awareness in this population is significantly associated with worse quality of life. This was confirmed by using two different methods for measuring patients’ quality of life and a composite measure of prognostic awareness based on the most widely used tools for measuring this phenomenon. However, our detailed analysis showed that the worse quality of life reported by patients who are aware of their prognosis might be influenced only by worse physical symptoms rather than by emotional distress or other aspects of quality of life.
A number of studies reported a negative relationship between accurate prognostic awareness and overall quality of life [16, 24, 26, 27, 42, 43]. Similar to our findings, at least one study [44] showed that the emotional aspects of quality of life were not significantly different between prognostically aware and unaware patients, but the sum score and the score in other subscales (such as physical activity, role limitation, cognitive activity) differed. These results are also supported by findings from previous studies which found that accurate prognostic awareness is associated with shorter survival [15, 43], worse performance status [41, 45] or physical wellbeing [46], suggesting that patients with more severe health impairment near the end of life have better understanding of their poor prognosis. Although in our study we did not find significant association between PA and emotional wellbeing, even though the tendency was similar as in several studies which contradict our results as they found a significant negative association of accurate PA with emotional domains of quality of life [24, 42]. Moreover, several studies identified a negative relationship of accurate PA and depression and anxiety [16, 23, 26, 41].
On the other hand, there are several studies which found that accurate prognostic awareness is associated with a better quality of life [9, 21, 47, 48]. Regarding emotional domain of quality of life, it seems that this association might be more complicated and possible influenced by confounding factors. Ray and her colleagues [9] found that the association of PA and quality of life was influenced by peacefulness, and if patients were aware and peaceful, they were less sad and had better quality of life. Other studies found that the emotional domain of quality of life was associated with the patient’s acceptance of diagnosis and prognosis [49] and also with coping strategies [26]. On the other hand, Kim et al. [43] found that depression did not work as confounding factor as the significant association between worse quality of life and accurate prognostic awareness remained even if the level of depression was statistically controlled. This evidence suggests that the personality of patients might be an essential factor which can influence the acceptance of prognosis and play a crucial role in the relationship between quality of life and PA.
Different results regarding the association of quality of life and prognostic awareness might be also explained by the fact that the inclusion criteria for patients with advanced cancer were different across studies: some of them included all patients undergoing chemotherapy [50], patients on stage III or IV [24] or stage IV with unresponsiveness to current treatment [49], patients having metastasis or failure of first-line chemotherapy [9] or having metastasis and low performance status [16] or not receiving treatment with curative intent [26, 51]. Other studies used the estimation of prognosis by physicians with the surprise question [43]; this was the case of this presented study. Additionally, it is also important to note that the above-mentioned studies [42–44, 49, 8, 9, 48, 21, 22] used different tools for measuring quality of life which means that operationalisation of domains is different and comparability of the results is limited [52].