Introduction
The association between psychosocial factors and cancer survival has been convincingly demonstrated only during recent decades [
1‐
12]. The psychological processes and constructs investigated have varied among studies [
4,
8]. Many of the earlier studies were retrospective, biological prognostic factors were not sufficiently controlled for, and only certain factor(s) were investigated. In many of the prospective studies, the survival follow-up time was very short [
4,
8‐
10,
13,
14]. In addition, socioeconomic factors were not often taken into account [
4,
15,
16].
Studies suggest that some psychosocial factors, such as emotional expression and psychological stress, are more likely to have an effect on survival compared with other factors [
4]. Specifically, emotional non-expression (“repression”) [
6,
17‐
19], hopelessness [
7,
20,
21], depression [
1,
10,
11,
20], and stress-related psychological factors [
8,
12,
20] have been suggested to predict a shorter survival, whereas social support [
22] and denial or minimizing coping response to the cancer to predict a more favorable prognosis [
2,
5‐
8,
12,
21]. Factors related to well-being and quality of life (QOL) have shown contradictory results [
2,
5‐
7,
9,
23]. In some studies, a good reported QOL has shown an association with a poorer prognosis [
6,
7,
9].
Among the number of studies investigating the impact of psychosocial factors on cancer progression, very few have dealt with prostate cancer. However, prostate cancer is the most common cancer among men in developed countries, including Finnish men (
http://www.cancerregistry.fi). In most countries, the average age at prostate cancer diagnosis is greater than 70 years. The incidence is increasing worldwide in part due to the aging populations and the widespread testing for prostate-specific antigen (PSA) [
24‐
27]. Today, most prostate cancers are detected when they are localized or at most locally invasive, and the prognosis is generally good [
24‐
28].
A major limitation of many previous studies was that the effect of psychosocial factors has been investigated in isolation from other related factors or processes [
4,
13,
29‐
31]; however, the effect of these factors does not occur in isolation. Investigating their impacts separately results in over-simplification and misleading results. In particular, connections between coping and personality processes are important [
18,
32,
33]. Therefore, the effect of psychological and psychosocial factors and their relative impact can be identified only when several factors are investigated and analyzed jointly, adjusting their effects on each other.
The psychobiological mechanisms that are thought to have an impact on cancer survival are related to psychological stress [
4,
8,
34,
35]. According to psychological stress theories, the effects of stress on health outcomes depend on how a person can cope with the stress, coping being the main mediator in the process from stressful events to outcomes such as psychological symptoms and somatic illness [
36,
37]. Social support and personality factors modify the coping process [
38]. In the process-oriented view [
36,
37,
39], coping is defined as “the person’s constantly changing cognitive and behavioral efforts to manage specific external and/or internal demands that are appraised as taxing or exceeding the person’s resources.” There are no in built assumptions on good or bad coping. The actual coping process refers to the person’s efforts to reduce, minimize, master or tolerate the person–environment transaction that has been appraised to be demanding. Psychological stress processes have been linked with biological immune down-regulation in cancer [
34].
According to a model proposed to guide research in psycho-oncology [
33], the impact of cancer disease and treatment effects are mediated by personal (including personality and coping style, adjustment, and sociodemographic factors), medical, social-environmental, and life stressor factors [
3,
12,
29,
33]. The outcomes of these pathways are QOL and survival. In particular, a personality-related coping response called non-expression of negative emotion is potentially associated with poorer cancer progression [
4,
7,
17‐
19,
40]. Non-expression of negative emotion refers to a tendency to suppress (i.e., not to express) negative feelings [
17,
32], such as anger and fear, and leads to less effective coping in stressful situations. It has been described as being emotionally contained and “maintaining a facade of contentment” in social relationships. Related concepts, such as emotional defensiveness (antiemotionality, i.e., suppression and control of emotions) has also been found to predict reduced survival in cancer [
6,
17]. Furthermore, there is a suggested cancer-prone Type C response style [
18,
19], which is a multidimensional construct that includes non-expression of negative emotions as a core element, where helplessness/hopelessness in stressful situations, and self-sacrificing, over-cooperative, and appeasing behavior are added. Type C response style has been found to be associated with reduced survival in cancer.
We previously presented a conceptual model on the psychosocial predictors of wellbeing of cancer patients [
35]. In the model, we assume that both QOL and survival are outcomes in a stress process, which is mediated by psychological stress processes and initiated by cancer and treatment. Coping with cancer is the main mediator in the process, and social support and personality factors modify the coping process. Furthermore, we assume that these processes are interfered by non-cancer life stresses. We previously applied the model for studying baseline psychosocial predictors of survival outcomes in localized melanoma [
7,
12] and breast cancer [
6] patients under 72 years of age. We identified some gender differences, indicating that men may respond to different types of psychosocial factors compared with women [
12].
In the present study, on the basis of the model and experiences from our previous studies, we investigated the baseline and early predictors of disease-free and overall survival times in prostate cancer patients of all ages and treated with external beam radiotherapy in Finland. We hypothesized that specific factors in the psychological stress processes (patterns of coping, anger expression traits, non-cancer life events), and components of patient-reported QOL evaluated at the time of primary treatment are associated with disease-free time and survival in localized prostate cancer.
Discussion
Overall survival and disease-free time in patients with localized prostate cancer were predicted by socioeconomic status, psychological factors, and patient-reported QOL. Different QOL measures demonstrated contradictory results as either a favorable or an unfavorable impact. Surprisingly, we found that the patients’ reports of no or few physical complaints predicted shorter survival, whereas reported pain was prognostic for longer survival. In addition, a longer PSA-relapse-free time was predicted by responding to the cancer diagnosis with a Cognitive Avoidance/Denial coping pattern, whereas problems in social functioning, hopelessness, and—contradictorily—reporting an excellent QOL, predicted a shorter PSA-relapse-free time. We suggest an explanation for these surprising findings, i.e., that the observed survival decreasing effect of high scores in certain simple QOL measures may reflect a trait of non-expression of negative emotions (a tendency not to express negative feelings and to keep ‘facade of contentment’), that has been found potentially associate with cancer progression. We propose that the patients who scored exceptionally low/high in simple wellbeing/QOL measures may have been those with high non-expression of negative emotions and that they thus over-reported their wellbeing.
Few earlier studies on psychosocial factors and cancer survival have addressed prostate cancer [
8,
52,
53] or male patient samples that also include the oldest age-groups. We were able to collect a relatively small but regionally representative sample of newly diagnosed prostate cancer patients. At the time of the data collection, the prostate cancer therapy was different than today (e.g., active surveillance was hardly used) and the active treatment modes have improved ever since. There were no population PSA-screening programs going on in Finland. The study sample was limited to patients who underwent curative radiotherapy, and the other major definite therapy mode, radical prostatectomy, was not represented. However, younger and healthier patients more often undergo operation, whereas external radiation is received by a wider patient cohort [
54]. For practical reasons, the timing of the measurement since diagnosis varied (2–9 months); the onset of the radiotherapy differed, and the patients were willing to take part to the interview at different time points during their radiotherapy.
We investigated both overall survival and disease-free times because they are very different outcomes in cancer types with good prognoses, such as prostate cancer, and may thus be predicted by different mechanisms; we found that they were indeed predicted by different factors. The potential predictors were simultaneously investigated to account for their relative impact, and were either derived from a theoretical model [
35] or were previously demonstrated to exhibit an association with cancer survival [
4,
20,
33]. Most of the predictor variables were subscales of established validated questionnaires. The radiotherapy was currently going on in all patients. The analyses were carefully adjusted for age, known biological prognostic factors, and treatment.
3
We found that a higher socioeconomic status predicted a longer survival both independently and when evaluated with the psychological and QOL factors. The survival prolonging effect of socioeconomic status in cancer is well known [
15,
16,
55], and has been previously reported in prostate cancer patients receiving curative treatment [
53]. However, previous studies often considered its effect alone without other potential predictors [
52,
53,
56]. We concur with previous studies suggesting that socioeconomic status should be taken into account to obtain valid information on the impact of QOL on survival in prostate cancer [
57].
The measures associated with poorer outcomes appeared to be the simple indicators of self-reported wellbeing, i.e., low scores in perceived physical symptoms and an excellent score in an overall QOL index. We did not find negative association between established QOL measures and the survival outcomes, or if there was an association, it was positive. We suggest that these results may reflect the harmful effect of non-expression of negative emotions, which has been defined to refer a tendency not to express negative feelings and to keep ‘facade of contentment’[
17]. According to this theory, individuals with high non-expression of negative emotions potentially under-report their symptoms as they are prone to a repressive coping style, i.e., tend to avoid a negative affect, and consequently answer wellbeing measures overly positively [
17,
32]. This idea was supported by the finding that the Anger control personality trait was associated with less reported symptoms and a better QOL.
One supporting factor to our argument is that scoring low in symptom measures and very high in overall QOL at the time of recent cancer diagnosis and ongoing radiation treatment may not reflect the true objective situation. Instead, these scores may reflect a personality trait or coping behavior at a stressful situation (recent cancer diagnosis, ongoing radiotherapy). Furthermore, when e.g., the quality-of-life index was tested as a total scale (very poor–excellent) it predicted a longer survival. So, our results did not indicate that reporting a good QOL was hazardous, but that reporting an ‘excellent’ QOL was. Individuals with a repressive coping style have also previously been found to score low in self-reported physical symptom scales [
58]. Up to 20% of the population has been found to answer self-report scales in an overly positive fashion [
32], which corresponds with our finding that the hazardous effect on survival was identified when the scores were divided into two categories: no/very few symptoms or an ‛excellent’ QOL versus other (both were present in approximately 18% of the patients).
The results obtained on simple wellbeing/QOL indicators support the conclusions we have made in our previous studies [
6,
7], i.e., that simple global-rating methods are not suitable of eliciting information on QOL of all cancer patients. Certain subgroups (“repressors”) seem to understate their condition and over-report their wellbeing. There is a risk that the simple global-rating measures actually provide more information on non-expression of negative emotions behavior than QOL. It has been suggested [
32] that to elicit information from repressors measures requiring specific answers should be used instead of single-item indexes or symptom lists.
Prostate-area symptoms (urinary, sexual, bowel) and fatigue—as evaluated with well-established validated measures comprising specific questions—were prognostic for shorter survival, as expected. These are common adverse effects in external radiation and are likely to be well recorded at the oncology clinic, and patients may be less likely to under-report them. This measurement was, however, not congruent because the timing of the interview during the radiotherapy varied, which potentially affects the level of side effects. However, the survival model also held when the overall QOL index (total score 1–7) was tested instead of the prostate-area symptoms. These factors both indicated the wellbeing/ill-being of the patient during the primary treatment. Self-evaluation of the wellbeing status is continuously presented to be a reliable indicator of an individual’s current and future health.
The obtained results on problems in social functioning and hopelessness, and a shorter relapse-free time may also relate to concepts close to non-expression of negative emotions, such as antiemotionality (“emotional defensiveness”) [
17] and Type C response style [
18,
19]. Antiemotionality (suppression and control of emotions) is manifested in self-sacrificing behavior, which may eventually lead to problems in social functioning. Helplessness/hopelessness in stressful situations is a component of the Type C style. We previously found that antiemotionality predicted shorter survival in breast cancer [
6] and hopelessness in melanoma [
7]. Hope at cancer diagnosis is essential [
59] and it may predict survival [
1,
11]. Hopelessness has been found to affect cancer mortality at the population level [
60], especially in older populations [
61], to which most prostate cancer patients belong. Moreover, the observed favorable effects of pain and number of stressful life events may be related to non-existence of non-expression of negative emotions: those without may have reported more symptoms and events.
In accordance with our previous studies [
6,
7,
12], we identified only one protective psychological factor: the Cognitive Avoidance/Denial coping pattern, and it predicted only the disease-free time. As noted above, overall survival and PSA-relapse-free time are very different outcomes in prostate cancer; the former is less affected by the cancer because of the good prognosis, whereas the latter is cancer-specific. This result is in line with cumulating research suggesting that a favorable prognosis in cancer is predicted by responding to the cancer diagnosis by a coping pattern of denying [
21] or, nowadays more often called, ‘minimizing’ the fact of having cancer [
1,
2,
4‐
7,
17,
20,
29]. This concept refers, according to definition of coping, the patients’ efforts to manage demands caused by the cancer by minimizing impact of the disease, not the consequent negative affect. However, denying/minimizing may at a later point of time have a different effect [
59].
Our results provide an explanation for why good self-reported QOL in some previous studies appeared to have had an unfavorable impact on cancer survival outcomes. Patient reports of a good wellbeing in simple measures may reflect non-expression of negative emotions. Thus, very high reports of wellbeing in newly diagnosed cancer patients may indicate a psychological risk factor for reduced survival outcomes. It may be good for the patients to have complaints at the time of primary treatment. This finding may have clinical relevance given that patients who report no or few problems (no symptoms, excellent QOL) may actually be vulnerable and in need of extra attention and care. However, more research is needed, e.g., to investigate the issue in patients with different cancer types/different diseases, in both genders, in different phases of care and rehabilitation, and in prospective designs.
Clinicians are to interpret scores of validated questionnaires on wellbeing and QOL as usual. A clinician who interprets the scores should know the patient’s situation, e.g., phase of treatment and time since diagnosis. Conclusions of the patients’ wellbeing should not be based on a single measurement. Validated questionnaires are good tools for screening of state of QOL, which may require further clinical examination. Our criticism is targeted to simple QOL indicators which are easily influenced by other factors, e.g., non-expression of negative emotions.
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