Determining the Prognosis
Prognosis is a forecast of the probable course and outcome of a disorder or disease. In this article, prognosis refers to the likelihood of survival (or death) from cancer, and may also be expressed as life expectancy.
Determining and communicating prognosis to the patient with cancer and his or her family is important to allow them to make informed decisions about treatments. Determination of prognosis is also important to establish patient eligibility to receive hospice services, should this be desired by the patient and family at some time during the illness.
Among the Centers for Medicare and Medicaid's eligibility criteria for hospice care for Medicare beneficiaries is the requirement that the patient's prognosis, as estimated by the attending physician and the hospice medical director, is for a life expectancy of 6 months or less if the terminal illness runs its normal course. Medicare does not require the physician's estimate of prognosis to be a certainty in each patient's case, only that death within 6 months is the likely outcome if the disease runs its normal course.
Sources of prognostic information include physician predictions, stage-specific survival data, performance status, signs and symptoms, and integrated models of prognosis. At diagnosis, recognized tumor-specific prognostic factors (eg, molecular markers, stage, grade, etc), modified by treatment- and patient-specific factors (eg, comorbid illness, performance status, and disease signs and symptoms), provide general prognostic information.
Prognostication for advanced cancer, which depends on a physician's clinical experience and intuition, is generally inaccurate.
Overestimation. Physicians' estimates of prognosis for patients in palliative care programs are overly optimistic by a factor of 3- to 5-fold -- that is 300% to 500% more optimistic than observed.[8,9] Other studies bolster the finding that physicians overestimate survival. Overall physician estimates do correlate with actual survival and are more accurate in patients with the shortest overall survival (Table 1).[7,8,10,11]
In 7 of the 8 studies listed in Table 1, physicians overestimated survival in patients with advanced disease. Actual survival (AS) and clinical predictions of survival (CPS) from the trials cited are shown. The median CPS was 42 days, whereas the actual median survival was 29 days.
Table 1. Studies of Clinical Predictions of Survival vs Actual Survival
|Study (lead author)||No. of Patients||Median CPS (days)||Median AS (days)|
|Parkes||71||28 (24-56)||21 (9-34)|
|Evans ||42||81 (28-182)||120 (43-180)|
|Heyse-Moorel ||50||56 (33-84)||14 (7-28)|
|Maltoni ||100||42 (28-56)||32 (13-63)|
|Maltoni ||530||42 (28-70)||32 (13-62)|
|Oxenham||21||21 (14-35)||15 (9-25)|
|Maltoni||451||42 (21-70)||33 (14-62)|
|Christakis ||325||77 (28-133)||24 (12-58)|
|Overall||1,591||42 (28-84)||29 (13-62)|
A meta-analysis of these studies suggests that survival is generally 30% shorter than predicted by CPS. CPS was within 1 week of actual survival in 25% of cases and overestimated survival by 4 or more weeks in 27%. Physician input is most effective when it is added to statistical or other predictive models.[8,10,15]
The "surprise" question. In a prospective cohort study of more than 850 patients with breast, lung, or colon cancer who were seen by their oncologists for scheduled follow-up visits at the cancer center clinic, oncologists were asked, with reference to each patient, to answer the question "Would I be surprised if this patient died in the next year?" A "no" response by oncologists identified patients with cancer who had a 7 times greater hazard of death in the next year compared with patients in the "yes" group. The "surprise" question was found, in this study, to be a simple, feasible and effective tool to identify patients with cancer who have a greatly increased risk for 1-year mortality.
Stage of Cancer and Prognosis
Survival data for specific cancers, by stage, are widely available but not very useful to assess the prognosis of an individual patient. Natural history studies, although they generally reflect the experience of a single institution, provide insight into the variable course and prognosis of advanced cancer.
Similarly, randomized trials that include a "best supportive care" arm provide further natural history information -- essential information to communicate to patients when relating the anticipated survival benefits from treatment for advanced disease.
For example, patients with untreated, advanced breast cancer have a median survival of more than 2 years, whereas those with untreated advanced head and neck cancer have a median survival of about 4 months.[20,21]
Performance status quantifies the functional status of cancer patients, and with some tools, such as the Karnofsky Scale, also captures medical care requirements. Since the beginning of modern oncology in the 1940s, the ability of a patient to perform routine activities of daily living has shown the best correlation with prognosis. The development of scales to quantify performance status was stimulated by the desire to test new therapies in the patients who had the best chance of doing well.
Karnofsky. The Karnofsky Performance Scale (KPS), when used by trained clinicians, is a reliable, valid, simple, and reproducible measure of patient function and is an independent predictor of survival.[22,23] The predictability of the KPS for survival is, however, valid only for patients with scores less than 50.[13,16] Data from the 1592 patients in the National Hospice Study identified the KPS as the most important clinical factor for estimating prognosis. The KPS differentiates the survival time of 3 distinct patient groups: (1) KPS ≥ 50 (86.1 days); (2) KPS = 30-40 (49.8 days); and (3) KPS =10-20 (16.8 days) (Table 2).
Table 2. Prognosis for Patients on Hospice on Basis of KPS
|Able to carry on normal activity and to work; no special care needed||100||Normal; no complaints; no evidence of disease; no special care needed||86.1 days|
|90||Able to carry on normal activity; minor signs or symptoms of disease|
|80||Normal activity with effort; some signs or symptoms of disease|
|Unable to work; able to live at home and care for most personal needs; varying amount of assistance needed||70||Cares for self; unable to carry on normal activity or do active work|
|60||Requires occasional assistance, but is able to care for most personal needs|
|50||Requires considerable assistance and frequent medical care|
|Unable to care for self; requires equivalent of institutional or hospital care; disease may be progressing rapidly||40||Disabled; requires special care and assistance||49.8 days|
|30||Severely disabled; hospital admission is indicated although death not imminent|
|20||Very sick; hospital admission necessary; active supportive treatment necessary||16.8 days|
|10||Moribund; fatal processes progressing rapidly|
Loprinzi and colleagues have also demonstrated the ability of the KPS to define 3 advanced cancer patient populations with statistically distinct survival curves by univariate and multivariate analyses. The strength of the association between performance status and survival appears to be time-dependent; the Karnofsky performance scale is of greater prognostic value when the anticipated survival is less than 3 months.
Eastern Cooperative Oncology Group/World Health Organization.Performance Status. A simpler scale was developed by Zubrod and found to be as useful as the Karnofsky performance scale, but more easily applied by untrained observers.The Eastern Cooperative Oncology Group (ECOG) and the World Health Organization (WHO) have adopted this scale. In all studies, a score of 3 correlates with a prognosis of less than 3 months. A score of 4 correlates with a prognosis of less than 1 month.
Table 3. Prognosis by ECOG/WHO Performance Status
|0||Fully active, able to carry on all predisease performance without restriction|
|1||Restricted in physically strenuous activity but ambulatory and able to carry out work of a light or sedentary nature (eg, light housework, office work)|
|2||Ambulatory and capable of all self-care but unable to carry out any work activities; up and about more than 50% of waking hours|
|3||Capable of only limited self-care, confined to bed or chair more than 50% of waking hours||< 3 months|
|4||Completely disabled; cannot carry on any self-care; totally confined to bed or chair||< 1 month|
Palliative performance scale. The Palliative Performance Scale (PPS) is a modification of the KPS that uses ambulation, activity level, extent of disease, ability to perform self-care, oral intake, and level of consciousness to assess function (Table 4).
Table 4. Palliative Performance Scale
|PPS Level||Ambulation||Activity and Evidence of Disease||Self-care||Intake||Conscious Level||Median Survival||Chance of Death at 6 mo.a|
|100%||Full||Normal activity & work. No evidence of disease||Full||Normal||Full|
|90||Full||Normal activity & work. Some evidence of disease||Full||Normal||Full|
|80||Full||Normal activity with effort. Some evidence of disease||Full||Normal or reduced||Full|
|70||Reduced||Unable to perform normal job/work. Some disease||Full||Normal or reduced||Full|
|60||Reduced||Unable to perform hobby or house work. Significant disease.||Occasional assistance necessary||Normal or reduced||Full or confusion|
|50||Mainly sit/lie||Unable to do any work. Extensive disease.||Considerable assistance required||Normal or reduced||Full or confusion||18-55 d||81%|
|40||Mainly in bed||Unable to do any work. Extensive disease.||Mainly assistance||Normal or reduced||Full or drowsy or confusion||7-37 d||89%|
|30||Totally bed-bound||Unable to do any work. Extensive disease.||Total care||Reduced||Full or drowsy or confusion||7-37 d||89%|
|20||Totally bed-bound||Unable to do any work. Extensive disease.||Total care||Minimal to sips||Full or drowsy or confusion||1-9 d||96%|
|10||Totally bed-bound||Unable to do any activity. Extensive disease.||Total care||Mouth care only||Drowsy or coma||1-9 d||96%|
aThis column applies only to patients who have been admitted to a hospice program
From Wilner FS, Arnold R. Available at: https://www.eperc.mcw.edu/fastFact/ff_125.htm
PPS scores are correlated with survival when the PPS is 50%. Various investigators have looked at the correlation between PPS score and length of survival.[33,34,35] In general, PPS scores of 10-20 indicate that death is imminent (median survival from 1-9 days), PPS scores of 30-40 indicate that death will occur within weeks (median survival 7-37 days), and a PPS of 50 indicates that death is likely within 1-2 months (median survival 18-55 days). When viewed from another vantage point, patients who have been admitted to hospice with a PPS score of 10-20 have a 96% chance of dying within 6 months; those whose scores are 30-40 have an 89% chance of dying within 6 months, and those whose scores are ≥ 50 have an 81% chance of dying within 6 months.
Clinical Signs and Symptoms as Prognostic Factors
Integrating the impact of various physical symptoms with performance status improves predictive capability. A systematic review of prognostic factors in advanced cancer from 24 studies examined more than 100 variables and identified cognitive factors, weight loss, dysphagia, xerostomia, anorexia, and dyspnea as independent survival factors for patients with advanced cancer. Laboratory data such as leukocytosis, lymphocytopenia, and high C-reactive protein (CRP) have also been associated with poor prognosis, and can aid in the determination of prognosis if these test results are already available in the patient's medical record.
The Glasgow Prognostic Score (GPS) is an inflammation-based prognostic score formed from standard thresholds of CRP and albumin, that provides additional prognostic information for patients with several types of advanced cancer.[36,37]
CRP > 10 mg/L, and albumin < 35 g/L = score 2;
CRP > 10 mg/L with a normal albumin = score 1; and
Normal CRP and normal albumin = score 0.
In a study by Brown and colleagues who followed patients with advanced lung and gastrointestinal cancer, patients with GPS scores of 2 or 1 had significantly shortened life expectancies (respectively, means of 1 and 4 months) compared with patients who had GPS scores of 0 (mean 15.4 months).
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Cite this: Linda Emanuel, Frank D. Ferris, Charles F. von Gunten, et. al. Communicating Diagnosis and Prognosis to Patients With Cancer: Guidance for Healthcare Professionals - Medscape - Jan 07, 2011.