Anxiety and depression among long-term survivors of cancer in Australia: results of a population-based survey

Cancer is a life-changing diagnosis that will affect one in two men and one in three women living in Australia by the age of 85 years.1 The psychological morbidity associated with cancer is significant, with evidence suggesting that 15%–23% of cancer patients experience clinically significant anxiety and 20%–35% experience depression. The impact of these psychological disorders can be considerable, and can have major effects on relationships as well as social and occupational functioning.2 With the overall rate of death from cancer declining, the number of people living with or beyond cancer is growing; it is estimated that there are about 340 000 cancer survivors in Australia, representing about 2% of the population.3 For many, cancer becomes a chronic disease, yet relatively little is known about the psychological wellbeing of long-term cancer survivors (those surviving more than 5 years).

In contrast to the general public’s perception of cancer as an insidious and relentless disease,4 there is an emerging body of evidence suggesting that the psychosocial wellbeing of long-term cancer survivors is comparable to or only slightly lower than that of the general population.5-7 However, as most studies in this field were conducted in the United States and Europe with homogeneous samples of cancer survivors, it is unknown if these findings are indicative of the psychological wellbeing of the diverse and growing population of long-term survivors in Australia.

Understanding the extent to which cancer affects long-term survivors, and identifying the characteristics of those most likely to benefit from targeted intervention, is essential for guiding the development and delivery of suitable services, and the optimal allocation of limited resources. We undertook Australia’s first large-scale, population-based study to assess the prevalence and predictors of anxiety and depression among a heterogeneous sample of adult long-term cancer survivors at 5–6 years after diagnosis.

Long-term cancer survivors who had been diagnosed with a new histologically confirmed cancer (local or metastatic) 5–6 years earlier, were aged between 18 and 75 years at the time of diagnosis, currently alive, and living in New South Wales, were randomly selected from potentially eligible patients with cancer who were diagnosed between 1 April and 30 November 1997, still alive in 2002, and registered at the NSW Central Cancer Registry. The Registry confirmed with survivors’ general practitioners or referring doctors that they could read and understand English adequately, were physically and mentally capable of participating, aware of the cancer diagnosis, and could be contacted about the study. The Registry contacted eligible survivors, and asked for their permission to forward their contact details to the researchers.

Between 1 April 2002 and 20 October 2003, survivors who agreed to being contacted by the researchers were mailed a self-administered scannable survey consisting of a number of instruments. Non-responders were followed up with one reminder survey (3 weeks later) and one reminder telephone call (6 weeks later). Survivors’ personal and clinical information was obtained from the cancer notification held by the Registry, including date of birth, sex, date of diagnosis, primary cancer type and spread of disease at diagnosis.

The human research ethics committees of the University of Newcastle and the Cancer Council NSW approved the study.

There were 6854 potentially eligible patients with cancer registered at the NSW Central Cancer Registry, of whom 2029 were randomly selected. Of these, 1374 were identified as eligible and were contacted by the Registry for permission to be contacted by us for our study. A total of 1008 survivors who agreed to be contacted were mailed the self-administered survey, and 863 survivors indicated their consent to participate by returning a completed survey; this gave an overall participation rate of 63% of eligible patients. There were no significant differences between those who did and did not return a completed survey in terms of cancer type, spread of disease, age, sex, country of birth, and Aboriginal and Torres Strait Islander status.

Participants were surveyed at a mean of 5.5 years after diagnosis (SD, 3 months), and their median age was 63 years (range, 26–76 years). A little more than half (55%) were female; most were diagnosed with breast (29%), prostate (15%), melanoma (15%) or colorectal (13%) cancer; and 58% had localised disease at the time of diagnosis. Many had had surgery (85%), radiotherapy (45%), chemotherapy (25%) and/or hormone therapy (24%). Compared with all 6854 patients with cancer diagnosed in NSW from 1 April to 30 November 1997 and still alive in 2002, the study sample was not representative in terms of age (χ2 = 11.97; df, 3; P = 0.007) and cancer type (χ2 = 26.59; df, 7; P < 0.001). Our sample included significantly fewer survivors aged 18–39 years (9%) than expected (13%), and more breast cancer survivors (29%) than expected (23%).

Contrary to popular opinion,4 the results of this study suggest that life after cancer is not all doom and gloom. By 5–6 years after a cancer diagnosis, most survivors in Australia appear to have adjusted well to their cancer experience, with levels of anxiety and depression generally comparable with those of the general Australian population.15 Although we did not have an age- and sex-matched control group to compare our survivors’ rates of anxiety and depression against, our findings are consistent with other previously published research conducted in the US and Europe.5-7 On the basis of these findings, we are currently undertaking a longitudinal study to identify the critical time-point in the lives of cancer survivors when psychological wellbeing returns to population levels.

Our study’s major strengths were its large-scale, population-based approach and the diversity of cancer survivors included. Our participation rate of 63% of all eligible survivors is comparable with or better than participation rates achieved by other Australian population-based studies.16,17 Given that our sample shows evidence of selection bias on only two of five key characteristics (age and cancer type), we are confident that our results are, by and large, representative of and generalisable to long-term cancer survivors in NSW. As it is known that younger age is associated with an increased risk of psychosocial problems,2 the under-representation of younger survivors (aged 18–39 years) in our sample is likely to have resulted in a slight underestimation of the true levels of anxiety and depression.

Nevertheless, our study suggests that there is a small and important group of long-term cancer survivors who continue to experience adverse psychological effects and need assistance. Our findings suggest that long-term cancer survivors with a history of psychological or psychiatric illness, maladaptive coping styles and poor social support should be routinely monitored as they have an increased risk of psychological problems. To date, most research seeking to identify risk factors for impaired psychosocial wellbeing has focused on demographic, disease and treatment variables.18 Our study has extended this body of research by identifying modifiable risk factors that can be targeted for intervention or prevention.

That more than half of anxious or depressed survivors in our sample reported seeing their GP suggests that primary care providers need to be equipped to identify and address the psychological issues facing long-term cancer survivors. However, less than 10% of the long-term survivors with clinically important levels of anxiety or depression also reported receiving specialised psychological care from a psychologist, social worker, counsellor or psychiatrist in the 6 months before being surveyed. This suggests that monitoring of psychological wellbeing and referring patients when appropriate need to be integrated into routine care for cancer survivors.

1 Prevalence of clinically important levels of anxiety and depression among long-term cancer survivors compared with the general population

* Hospital Anxiety and Depression Scale normative data.14 † Australian Bureau of Statistics data.15