BBC News reports that "a fifth of cancer patients experience post-traumatic stress disorder (PTSD)".
Around half of these 400 people experienced significant anxiety or depression symptoms in the weeks after diagnosis. One in five of these 200 people met diagnostic criteria for PTSD or had associated symptoms (such as flashbacks or feeling numb) that just fell under the diagnostic threshold (called subsyndromal PTSD).
However, this actually amounts to only 1 in 10 of all people with cancer diagnosis having PTSD symptoms. Therefore the proportion of cancer patients having PTSD is not as high as the BBC reported.
While it is common for people to experience psychological distress after a cancer diagnosis, this is one of the first studies to suggest people could actually have PTSD symptoms.
These are interesting findings, but as a single study in one country it can't tell us that much about how common PTSD is among cancer patients. Rates may be very different in people with cancer in other countries.
Also, the study didn't explore factors that may be linked to an increased risk of developing symptoms of PTSD, such as age, type of cancer, or the type of support network available to the patient.
If you or a loved one has been diagnosed with cancer and you are experiencing any form of psychological distress, it's important to discuss this with a health professional so that you can get the support you need.
Where does the study come from?
The study was conducted by researchers at the National University of Malaysia and University Malaya Medical Center in Malaysia, and Harvard Medical School and Dana-Farber Cancer Institute in Boston, US.
It was funded by the National University of Malaysia and the authors declare no conflicts of interest. The study was published in the peer-reviewed medical journal Cancer.
BBC News' reporting was generally accurate though the "one in five" figure quoted in the article is misleading. This doesn't relate to all people with a cancer diagnosis, but only to a sub-group who were further assessed for PTSD.
What kind of research was this?
This was a cohort study that included people with various types of cancer. Patients with significant psychological distress within one month of diagnosis were followed up at six months and also four years later for signs of PTSD.
As the researchers say, depression and anxiety are known to affect people with cancer, but PTSD specifically represents a new area for study.
A study such as this can provide early insights, but as a single sample of a relatively small number of people with cancer, it can't give us definite answers on how common PTSD is, or tell us about all the factors that could make someone more likely to get PTSD.
What did the researchers do?
The study was carried out at a single medical centre and included patients who had received a diagnosis of cancer within the past month.
Participants completed the Hospital Anxiety and Depression Scale (HADS) at recruitment, 4 to 6 weeks later, 1 year later, then 4 years later.
The HADS is the most commonly used measure of psychological distress in cancer studies. Significant distress was defined as a total score of 8 out of 21 or higher for each of the depression and anxiety subscales, or a total score 16 out of 42 or higher.
Those with raised HADS scores at the 4-6 week also completed the PTSD section of the Structured Clinical Interview six months into the study. All participants then completed the PTSD section after four years regardless of their early HADS scores.
Patients were diagnosed with PTSD according to valid clinical criteria using the Diagnostic and Statistical Manual of Mental Disorders (DSM). The researchers also looked at "subsyndromal" diagnoses that didn't quite meet full diagnostic criteria.
A total of 469 people completed the assessments up to six months after recruitment, and 247 completed the assessments after four years (the remainder had died, with a handful lost to follow-up).
But the study has many limitations :
- PTSD prevalence rates need to be interpreted very carefully, The 1 in 5 figure relates only to those who already had signs of anxiety and distress, not to all people with a cancer diagnosis. It is actually less than 1 in 10 of all people diagnosed with cancer who were diagnosed with PTSD.
- These figures are also more lenient as they include subsyndromal symptoms of PTSD not meeting diagnostic criteria. If we only look at PTSD diagnoses the rates are actually 6% of all people at six months, and 4% of all people surviving for four years.
- The numbers of people with PTSD are far too small to allow any reliable analysis of factors that may influence the likelihood of developing PTSD symptoms. For example, age, gender, type of cancer or prior mental health diagnoses.
- This was a single sample of people with cancer from one centre in South East Asia. Prevalence rates may be very different in other countries.
It is without question very important that symptoms of psychological distress or of PTSD in people with cancer are recognised and that these patients are given the necessary care and support. PTSD in cancer patients is definitely an area of research worth exploring further.
If you or a loved one has been diagnosed with cancer and you are experiencing any form of psychological distress, talk to a health professional so that you can get the support you need.
Many people find it easier to talk to someone over the phone. There are a number of
helplines, mostly run by charities, including:
- Macmillan Cancer Support 0808 808 0000
- Cancer Research UK 0808 800 4040
- Marie Curie Cancer Care 0800 090 2309