Quality of life in home-dwelling cancer patients aged 80 years or older
Our systematic search yielded more than 4,000 articles, most of them including home-dwelling cancer patients aged 80 years and older in their cohorts. Interestingly, only three studies conducted subgroup analyses by age, thus generating very limited evidence of QoL in the subgroup of 80 years and older and limited results for our synthesis. This finding represents a paradox as the population of elderly cancer patients aged over 80 years old is increasingly growing. The cumulative impact of old age, cancer and multimorbidity is important to study in relation to QoL, as older adults often lack the physiological reserves required to effectively recover from cancer treatment. In turn, this may lead to problems related to QoL, encompassing physical, emotional, and social functioning [10, 11]. The concept of quality of life is multidimensional, and includes several different domains . The relevance of a specific domain may vary according to stage and type of illness, age, and cultural background . The “COSMIN Study Design checklist for Patient-reported outcome measurement instruments”  recommends using age- and diagnosis- specific instruments, such as the EORTC- QLQ- ELD15  in regard the specific needs of aged cancer patients. None of the included studies in this review had used an age specific QoL instrument.
Krahn et al.  found monotonic declines in QoL for each decade of age in a geographically diverse sample of long-term prostate cancer survivors in Ontario, Canada. Comorbidity was the most consistent patient-related predictor of QoL . As this is one specific diagnosis group, the results cannot be directly applied to other cancer patient groups, but cancer patients over the age of 80 often have multiple health issues and comorbidities, and therefore cancer treatment can be more challenging and complex [5, 6].
Cancer patients over the age of 80 represent a population who are vulnerable and frail . Gessink et al.  found that frailty is associated with comorbidity and that dealing with cancer was associated with lower QoL in older patients under the age of 80. They furthermore found that there was a significant association between increasing frailty and lower QoL . This may indicate that cancer patients over the age of 80, being even more frail and vulnerable, are particularly exposed to declining QoL. Frailty in geriatric oncology reports has mainly been evaluated in relation to patients’ ability to tolerate cancer treatment, mostly taking morbidity and survival into consideration, not a direct relationship with QoL .
Thome et al.  found in a study of women and men aged 75 and above with cancer, and a matched group without cancer that the only significant difference in EORTC QLQ-C30 between age groups within the study group was in physical functioning between the youngest (75–79) and the oldest (80–91) age group. No differences were found in SF-12 between age groups within the study group. Furthermore, older people under the age of 79 seem to be more affected when stricken by cancer, whilst cancer in patients over 80 years old seems to be more integrated with age-associated conditions such as declining functional ability, increasing complaints and comorbidity . This may be explained by the increase of comorbidity and frailty at more advanced ages and a change in life expectations when getting older.
When studying elderly persons newly diagnosed with cancer (65 + years) in relation to age, contact with the health-care system, ability to perform activities of daily living (ADL), hope, social network, support, and QoL, Esbenzen et al.  found no significant differences among the four age groups in the three subscales studied in EORTC QLQ-C30. Factors significantly associated with low QoL in global health status/QoL were ‘No other incomes than retirement pension’ and ‘Low level of hope’ . Low income and financial difficulties are associated with a significantly worse overall clinical HRQoL . Esbezen’s findings on QoL must be seen in conjunction with the significant differences among age groups regarding dependency in instrumental activities of daily living (IADL) and PADL . The oldest age group (80 + years) had significantly (P = 0.001) fewer stays in hospital within the preceding 6 months (73.9%) and received more at-home care than the other three age groups . There were no differences among age groups in ‘need [of] more help’ and 75.8% of the total group needed more help in their daily lives. The results from this study indicate that the oldest age group (80 + years) had a poorer social network and needed more support from at-home care services than the younger participants.
Among older home-dwelling cancer patients, women report significantly higher scores of anxiety and depression than men . Women also experience higher emotional distress than men . Solvik et al.’s study on pain, fatigue, anxiety and depression in older home‐dwelling people with cancer reports a significant difference between men and women in terms of civil status, ongoing treatment, anxiety and depression. In their study there were more single women and more women who underwent treatment than men . Also, women participating in studies are older than men [5, 6]. As frailty increases with age, this could explain the higher scores reported by the women. Economic issues, pain, and other symptoms, such as anxiety and depression and being dependent on help from others may impact QoL [9, 13, 14]. The oldest age group (80 + years) had significantly (P = 0.001) fewer stays in hospital within the preceding 6 months (73.9%), although the oldest age group also had a poorer social network and needed more support from at-home care services . Having fewer stays in hospital in spite of poorer social support is interesting and should be examined further. One explanation may be that having a poorer social network increases the need of at-home care services, which may secure a more pro-active provision of at-home care and therefore prevent hospital admission.
Receiving help in everyday life contributed strongly to low QoL in Thome et al.’s  study. Furthermore, women with cancer were more vulnerable than their male counterparts in terms of QoL. It is up for debate whether needing help in everyday life is associated with a lower QoL, or if a lower QoL is responsible for the increased need of at-home care services. This, and why women are more vulnerable in terms of QoL, should be investigated further. Other factors associated with low QoL in older people with cancer besides receiving help for their everyday lives, were comorbidity, degree of complaints and pain [19, 20]. This indicates that assessment of symptoms and adequate symptom treatment could prevent a decrease in QoL. There seem to be differences in the assessment of symptoms and QoL between patients and health care workers in home care settings, this includes anxiety level, personal thoughts, practical matters, and information received , indicating the need for regular patient self-assessment of symptoms and QoL.
Thome et al.  state that cancer in older age appears to be more integrated in age-associated conditions such as declining functional ability, increasing complaints and comorbidity, indicating that providing high-quality care to the younger segment of elderly people with cancer may require a focus on the disease, while care for the oldest may require a more comprehensive assessment of age associated conditions as well as cancer. This implies a need for an age specific approach in the health care services, and Berntsen et al.  argue that using an individual-oriented and pro-active approach when caring for multimorbid elderly can reduce the risk of high-level emergency care, increase use of low-level planned care, and substantially reduce mortality risk.
QoL Instruments used
The included studies used both generic and disease-specific QoL instruments. The EORTC QLQ-C30  was employed by both Esbezen  and Thome et al. . Thome additionally used the generic 12-Item Short Form Health Survey (SF-12) . Only Krahn et al.  used diagnosis-specific instruments, FACT-P, PCI, PORPUS . None of the included studies used instruments specifically designed and approved for elderly cancer patients. Taking into consideration the complexity and multidimensionality of older cancer patients’ situation [5,6,7], this represents a limitation of all the included studies. Multidimensional and age-specific scales such as the EORTC-QLQ-ELD  should be used to secure valid and reliable information on all the dimensions of QoL to provide a better understanding of how the elderly patients experience their QoL.
None of the QoL instruments used in the three studies include spirituality as a core domain. Earlier research suggests that categories that include spirituality, such as meaning and hope, might be important aspects of QoL that may be particularly important in the context of life-threatening illness such as cancer . In line with Padilla et al.’s definition of health- related QoL , spiritual well-being should be evaluated “at a point in time when health, illness, and treatment conditions are relevant”. The perception of Quality of life is subjective, and therefore, patients' viewpoints may substantially differ from the judgement of physicians. The relevance of a specific domain may vary according to stage and type of illness, age, social support, spiritual preferences and cultural background. If it is universally accepted that patients should measure their own quality of life, then patients themselves should also select what to measure, and weight the relevance of each domain and subdomain included in a QoL instrument . This is in line with the “COSMIN Study Design checklist for Patient-reported outcome measurement instruments” .
Several methodological issues limit the conclusions of this review. Our systematic review was restricted to the English language, potentially introducing a language bias, and other studies may have been missed. The fact that we only succeeded in finding three studies that performed subgroup analysis of QoL in home-dwelling cancer patients aged 80 years or older is the strongest limitation.
The three included studies differed in many respects, such as design, population, sample size, age range, aim, instruments used and outcome, thus making it impossible to make a meta-analysis, as well as compromising the ability to provide a clear and unambiguous conclusion. Furthermore, none of the studies applied an age specific instrument, yielding a validity challenge. The medium methodical quality of the included studies also represents a limitation. Especially considering confounding factors in one of the studies , and the missing confidence interval of the QoL outcomes in all three studies [23,24,25]. Therefore, the validity of the QoL results cannot be conclusive. This further implies that the results must be interpreted with caution.