Clinical Survival Predictors in Patients With Advanced Cancer

Abstract

AT PRESENT, cancer will be diagnosed in about one third of the population in developed countries during their lifetime.¹ In approximately 50% of patients with a diagnosis of cancer, a stage is reached when active treatment will not prolong life.² Most authors have defined the period extending from this time to the patient's death as the terminal cancer phase.^3-7 The terminal cancer phase may last from days to months, but there are no validated criteria to enable adequate predictions of its length.^8-14 This prognostic uncertainty makes clinical decisions difficult for caregivers, patients, and families^15,16 and may lead to inappropriate resource expenditure or denial of potentially beneficial therapy for the terminally ill.^17,18 In the United States¹⁹ and Canada,²⁰ admission criteria for government-funded hospices or certain regional palliative care programs²⁰ require physicians to identify those patients with life expectancies of 6 months or less. In the United States, a 1993 report from the National Hospice Organization showed that more than 50% of patients with terminal cancer were not given access to hospice services²¹ or were referred too late in the course of their illness to take full advantage of the support provided by hospice programs.²² Overly optimistic survival predictions made by different health care providers have affected patient referrals to US hospice programs adversely.¹⁹ On the other hand, premature referral to hospices or palliative care programs may create organizational, financial, clinical, and emotional problems for administrators, health care providers, and patients.²³ Several studies have been conducted to elucidate the role of prognostic factors on survival of patients with advanced or terminal cancer, including simple, noninvasive, and clinically based assessments. In studies focusing on prognostic factors of survival, length of survival has been associated with the following factors: clinical estimate of survival by the treating physicians,^24-29 performance status,^30-44 some physical symptoms,^{4,17,18,35,37,38,40,41,45-50} some biological markers (eg, albumin and lactate dehydrogenase [LDH] levels and white blood cell counts),^{32,36,39,42,51-60} some psychological^61-71 and socioeconomic variables,^72-74 and tumor type and stage.^18,43,49,70