This is the first study to longitudinally examine the use of discrepancy in ECOG as a predictor of anxiety and depression in cancer patients in a comparative assessment over time. We propose the use of the ECOG as a brief screening instrument for depression and anxiety in cancer patients and hypothesise that poorer or more discrepant patient-rated ECOG scores may be an indicator of greater psychological distress. Given the high prevalence of anxiety and depression in cancer, screening is critical in increasing case recognition to deliver appropriate interventions and prioritise referrals.
While the ECOG was originally developed as a measure of PS, its brevity and simplicity makes it feasible for widespread adoption as a surrogate tool to detect anxiety and depression. Most oncologists lack familiarity with psychiatric nosology.1
Screening for anxiety and depression using the ECOG PS scale does not require special training because PS is routinely assessed by oncologists across all cancer types.
There is an emerging trend towards simplifying the assessment of depression and anxiety in outpatient cancer settings,17
particularly as treatment and care has shifted to ambulatory settings. Shorter than any other standard assessment such as the HADS and Beck Depression Inventory, the ECOG functions much like the single-item Distress Thermometer. We predict that the acceptability of the ECOG as a measure would likely be higher and less likely to burden the clinic in terms of time and cost compared to any other form of assessment.
Patients have been shown able to accurately assess their own PS.13
The single-item ECOG PS is also easy for patients to rate, especially with the emergence of different versions of the PS scale in visual analogue format13
suitable for paediatric or illiterate cancer populations, or simply where communication issues might arise from a language barrier.
While data which come directly from those experiencing the cancer afford an insightful perspective, there is greater practical value in using the ECOG to comparatively measure discrepancy in PS scores, rather than solely relying on either patient-rated or oncologist-rated scores. Discrepancy on the ECOG is also easy to eyeball, while scores can be quickly compare over time when reviewed at each visit.
This study carries several important implications for oncology clinic practice, in that discrepancy in ECOG scores, or patient-rated ECOG can be used as a patient-reported outcome measure to raise, discuss as well as routinely monitor psychological concerns.11
Asking patients to score their own ECOG opens up avenues for discussion of psychological concerns and reduces the likelihood of measurement, cultural and educational bias.
Special attention should be given to cancer patients who demonstrate poorer self-rated PS. As suggested by Ando,12
patients who rate themselves significantly higher on ECOG scores compared with assessment by their oncologist may actually be presenting a subconscious bid for care and reassurance towards their oncologists. This is consistent with the local cultural influence which is not dissimilar to those of other Asian cultures where emotions are suppressed.18
Owing to indefinite symptomatology such as fatigue, lack of appetite and weight loss,19
differentiating symptoms caused by cancer and its treatment from standard criteria-based syndromes of major depression and clinical grade anxiety is not easy.20
The use of the ECOG can indicate the presence of psychological distress that does not exclude psychosomatic distress. Multiple sociocultural barriers are inherent in seeking medical and psychosocial information, treatment and care.18
Regardless of physical disease,17
it is not uncommon for mood disorders to be expressed as somatic rather than psychological symptoms across a number of cultures, partly to avoid the perceived stigma of a psychiatric disorder.1
Patients from Asian cultures tend to focus on somatising and physiologic symptomatology rather than mental symptoms18
and to be culturally constrained where it comes to reporting emotional states such as depression.21
Physicians too are often reluctant to probe into psychological concerns.2
This may be, in part, due to the biomedical training and orientation of oncologists, who may prove wary of forming attachment to patients, which is also a barrier to supportive care. A rigid biomedical agenda also means oncologists are more comfortable treating somatic symptoms such as pain, nausea and dyspnoea. It is likely that physicians who are trained locally would be even less comfortable addressing distress due to cultural constraints. This gives rise to the question of how likely oncologists are to refer patients for further psychological or psychiatric assessment. Previous studies report the consultation rate from oncologists to consultation-liaison psychiatrists to be only 4–10% among cancer patients.5
The majority of cancer patients with (clinically significant) anxiety and depression do not see mental health professionals but do see their oncologists. However, relatively few oncologists have sufficient knowledge and expertise to assess and treat psychological distress.3
Prior research in this context shows that oncologists are often unable to detect depression and anxiety, often stemming from a lack confidence in assessing distress and using psychometric instruments.23
By no means, however, should assessment of psychological distress using the ECOG replace comprehensive psychiatric evaluation.5
Systematic screening using the ECOG can nonetheless increase case recognition and allow for referral of distressed patients for consultation-liaison or ideally psycho-oncology services.2
Further study is needed to determine whether the relationship between PS and anxiety and depression is predictive, prognostic, causal or merely associative.