Catherine, Princess of Wales, has announced she has now completed a course of preventive chemotherapy.

The news comes nine months after the princess first revealed she was being treated for an unspecified form of cancer.

In the new video message released by Kensington Palace, Princess Catherine says she’s focused on doing what she can to stay “cancer-free”. She acknowledges her cancer journey is not over and the “path to recovery and healing is long”.

While we don’t know the details of the princess’s cancer or treatment, it raises some questions about how we declare someone fully clear of the disease. So what does being – and staying – “cancer-free” mean?

What’s the difference between being cancer-free and in remission?

Medically, “cancer-free” means two things. First, it means no cancer cells are able to be detected in a patient’s body using the available testing methods. Second, there is no cancer left in the patient.

These might sound basically the same. But this second aspect of “cancer-free” can be complicated, as it’s essentially impossible to be sure no cancer cells have survived a treatment.

It only takes a few surviving cells for the cancer to grow back. But these cells may not be detectable via testing, and can lie dormant for some time. The possibility of some cells still surviving means it is more accurate to say a patient is “in remission”, rather than “cancer-free”.

Remission means there is no detectable cancer left. Once a patient has been in remission for a certain period of time, they are often considered to be fully “cancer-free”.

Princess Catherine was not necessarily speaking in the strict medical sense. Nonetheless, she is clearly signalling a promising step in her recovery.

What happens during remission?

During remission, patients will usually undergo surveillance testing to make sure their cancer hasn’t returned. Detection tests can vary greatly depending on both the patient and their cancer type.

Many tests involve simply looking at different organs to see if there are cancer cells present, but at varying levels of complexity.

Some cancers can be detected with the naked eye, such as skin cancers. In other cases, technology is needed: colonoscopies for colorectal cancers, X-ray mammograms for breast cancers, or CT scans for lung cancers. There are also molecular tests, which test for the presence of cancer cells using protein or DNA from blood or tissue samples.

For most patients, testing will continue for years at regular intervals. Surveillance testing ensures any returning cancer is caught early, giving patients the best chance of successful treatment.

Remaining in remission for five years can be a huge milestone in a patient’s cancer journey. For most types of cancer, the chances of cancer returning drop significantly after five years of remission. After this point, surveillance testing may be performed less frequently, as the patients might be deemed to be at a lower risk of their cancer returning.

Measuring survival rates

Because it is very difficult to tell when a cancer is “cured”, clinicians may instead refer to a “five-year survival rate”. This measures how likely a cancer patient is to be alive five years after their diagnosis.

For example, data shows the five-year survival rate for bowel cancer among Australian women (of all ages) is around 70%. That means if you had 100 patients with bowel cancer, after five years you would expect 70 to still be alive and 30 to have succumbed to the disease.

These statistics can’t tell us much about individual cases. But comparing five-year survival rates between large groups of patients after different cancer treatments can help clinicians make the often complex decisions about how best to treat their patients.

The likelihood of cancer coming back, or recurring, is influenced by many factors which can vary over time. For instance, approximately 30% of people with lung cancer develop a recurrent disease, even after treatment. On the other hand, breast cancer recurrence within two years of the initial diagnosis is approximately 15%. Within five years it drops to 10%. After ten, it falls below 2%.

These are generalisations though – recurrence rates can vary greatly depending on things such as what kind of cancer the patient has, how advanced it is, and whether it has spread.

Staying cancer-free

Princess Catherine says her focus now is to “stay cancer-free”. What might this involve?

How a cancer develops and whether it recurs can be influenced by things we can’t control, such as age, ethnicity, gender, genetics and hormones.

However, there are sometimes environmental factors we can control. That includes things like exposure to UV radiation from the sun, or inhaling carcinogens like tobacco.

Lifestyle factors also play a role. Poor diet and nutrition, a lack of exercise and excessive alcohol consumption can all contribute to cancer development.

Research estimates more than half of all cancers could potentially be prevented through regular screening and maintaining a healthy lifestyle (not to mention preventing other chronic conditions such as heart disease and diabetes).

Recommendations to reduce cancer risk are the same for everyone, not just those who’ve had treatment like Princess Catherine. They include not smoking, eating a nutritious and balanced diet, exercising regularly, cutting down on alcohol and staying sun smart.

Amali Cooray, PhD Candidate in Genetic Engineering and Cancer, WEHI (Walter and Eliza Hall Institute of Medical Research) ; John (Eddie) La Marca, Senior Research Officer, Blood Cells and Blood Cancer, WEHI (Walter and Eliza Hall Institute of Medical Research) , and Sarah Diepstraten, Senior Research Officer, Blood Cells and Blood Cancer Division, WEHI (Walter and Eliza Hall Institute of Medical Research)

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Have you ever heard something that others cannot – such as your name being called? Hearing voices or other noises that aren’t there is very common. About 10% of people report experiencing auditory hallucinations at some point in their life.

The experience of hearing voices can be very different from person to person, and can change over time. They might be the voice of someone familiar or unknown. There might be many voices, or just one or two. They can be loud or quiet like a whisper.

For some people these experiences are positive. They might represent a spiritual or supernatural experience they welcome or a comforting presence. But for others these experiences are distressing. Voices can be intrusive, negative, critical or threatening. Difficult voices can make a person feel worried, frightened, embarrassed or frustrated. They can also make it hard to concentrate, be around other people and get in the way of day-to-day activities.

Although not everyone who hears voices has a mental health problem, these experiences are much more common in people who do. They have been considered a hallmark symptom of schizophrenia, which affects about 24 million people worldwide.

However, such experiences are also common in other mental health problems, particularly in mood- and trauma-related disorders (such as bipolar disorder or depression and post-traumatic stress disorder) where as many as half of people may experience them.

Why do people hear voices?

It is unclear exactly why people hear voices but exposure to prolonged stress, trauma or depression can increase the chances.

Some research suggests people who hear voices might have brains that are “wired” differently, particularly between the hearing and speaking parts of the brain. This may mean parts of our inner speech can be experienced as external voices. So, having the thought “you are useless” when something goes wrong might be experienced as an external person speaking the words.

Other research suggests it may relate to how our brains use past experiences as a template to make sense of and make predictions about the world. Sometimes those templates can be so strong they lead to errors in how we experience what is going on around us, including hearing things our brain is “expecting” rather than what is really happening.

What is clear is that when people tell us they are hearing voices, they really are! Their brain perceives voice experiences as if someone were talking in the room. We could think of this “mistake” as working a bit like being susceptible to common optical tricks or visual illusions.

Coping with hearing voices

When hearing voices is getting in the way of life, treatment guidelines recommend the use of medications. But roughly a third of people will experience ongoing distress. As such, treatment guidelines also recommend the use of psychological therapies such as cognitive behavioural therapy.

The next generation of psychological therapies are beginning to use digital technologies and virtual reality offers a promising new medium.

Avatar therapy allows a person to create a virtual representation of the voice or voices, which looks and sounds like what they are experiencing. This can help people regain power in the “relationship” as they interact with the voice character, supported by a therapist.

Jason’s experience

Aged 53, Jason (not his real name) had struggled with persistent voices since his early 20s. Antipsychotic medication had helped him to some extent over the years, but he was still living with distressing voices. Jason tried out avatar therapy as part of a research trial.

He was initially unable to stand up to the voices, but he slowly gained confidence and tested out different ways of responding to the avatar and voices with his therapist’s support.

Jason became more able to set boundaries, such as not listening to them for periods throughout the day. He also felt more able to challenge what they said and make his own choices.

Over a couple of months, Jason started to experience some breaks from the voices each day and his relationship with them started to change. They were no longer like bullies, but more like critical friends pointing out things he could consider or be aware of.

Gaining recognition

Following promising results overseas and its recommendation by the United Kingdom’s National Institute for Health and Care Excellence, our team has begun adapting the therapy for an Australian context.

We are trialling delivering avatar therapy from our specialist voices clinic via telehealth. We are also testing whether avatar therapy is more effective than the current standard therapy for hearing voices, based on cognitive behavioural therapy.

As only a minority of people with psychosis receive specialist psychological therapy for hearing voices, we hope our trial will support scaling up these new treatments to be available more routinely across the country.

We would like to acknowledge the advice and input of Dr Nadine Keen (consultant clinical psychologist at South London and Maudsley NHS Foundation Trust, UK) on this article.

Leila Jameel, Trial Co-ordinator and Research Therapist, Swinburne University of Technology; Imogen Bell, Senior Research Fellow and Psychologist, The University of Melbourne; Neil Thomas, Professor of Clinical Psychology, Swinburne University of Technology, and Rachel Brand, Senior Lecturer in Clinical Psychology, University of the Sunshine Coast

This article is republished from The Conversation under a Creative Commons license. Read the original article.