Regular blood tests in prostate cancer patients could significantly improve their chances of long-term survival, according to new research.
Blood tests before and during chemotherapy could help doctors determine if their patient is resistant or developing resistance to docetaxel – a commonly used drug.
This could allow them to switch the patient to other drugs to treat their cancer without the need for painful biopsies.
Men with prostate cancer that has spread to other parts of the body are often treated with docetaxel, a type of chemotherapy that can significantly improve survival.
Blood tests before and during chemotherapy could help doctors determine if their patient is resistant or developing resistance to docetaxel – a commonly used drug
As part of the new study, researchers at the Barts Cancer Institute at Queen Mary University of London looked at cancer markers in the blood known as circulating tumor cells (CTCs).
CTCs are cancer cells that entered the bloodstream either from the original cancer site or from tumors in the body where the cancer has spread.
The scientists took blood samples from 56 patients with advanced prostate cancer who were being treated at St. Bartholomew’s Hospital in London.
Samples were collected over a period of six to eight months and covered the time before patients started docetaxel treatment, after their first dose of chemotherapy, before their fifth dose, and after all doses were stopped.
Specifically, they looked for patterns in the data of men who responded to treatment and those who did not and whose cancer was more advanced and at what speed.
The results showed that men who had more than six CTCs detected per 7.5 ml of blood prior to their second dose of chemotherapy were more likely to have their disease recur or worsen within three months and were more likely to die within 18 months.
On the other hand, men with fewer than six CTCs per 7.5 ml of blood likely survived 17 months without their cancer progressing and had an overall survival time of three years.
A high number of CTCs towards the end of treatment also suggested that men were more likely to experience rapid spread of their cancer and earlier death.
Caitlin Davies, who led the study, said, “Using these patterns, we can apply them to future patients to predict whether they will respond to therapy and preventively decide the best course of action with the maximum benefit.
“For example, an increase in CTC counts may indicate a lack of response to treatment.
“In addition, by monitoring the occurrence of potentially drug-resistant CTCs, we can change treatment tactics at an early stage, on a patient-by-patient basis and promptly.”
Tissue biopsies are currently used to show how aggressive prostate cancer could be and how likely it is to spread to other parts of the body. However, these can be painful and the results can take up to 10 days.
However, testing for CTCs in blood samples, also known as a liquid biopsy, is painless and easily repeatable, with results within two to three days.
The scientists are now investigating how a clinical study on patients could help them validate their results, which were presented at the festival of the National Cancer Research Institute.
Hashim Ahmed, Chair of the NCRI Prostate Group and Professor of Urology at Imperial College London, said, “These are promising results and have the potential to change clinical practice if confirmed by further research.
‘Assessing an individual patient’s tumor response to docetaxel treatment using blood tests will allow clinicians to more easily and effectively personalize cancer treatment without the patient having to undergo invasive procedures such as tissue biopsies.
“It could also help prevent patients from undergoing uncomfortable systemic treatments that are unsuccessful.”
WHAT IS PROSTATE CANCER?
How many people does it kill?
More than 11,800 men a year – or one every 45 minutes – die from the disease in the UK, compared with around 11,400 women who die from breast cancer.
It means prostate cancer is just behind the lungs and colon in terms of how many people it kills in the UK.
In the United States, 26,000 men die from the disease every year.
Even so, it receives less than half of breast cancer research funding, and treatments for the disease are at least a decade behind.
How fast is it developing?
Prostate cancer usually develops slowly, so according to the NHS, there has been no sign of anyone suffering from it for many years.
If the cancer is early and not causing symptoms, a policy of “watchful waiting” or “active surveillance” can be put in place.
Some patients can be cured if the disease is treated at an early stage.
But if it is diagnosed at a later date, when it has spread, it becomes incurable and treatment revolves around relieving symptoms.
Thousands of men are discouraged from making a diagnosis because of the known side effects of treatment, including erectile dysfunction.
Tests and Treatment
Tests for prostate cancer are arbitrary and accurate tools are only just beginning.
There is no national prostate screening program because the tests have been too imprecise for years.
Doctors have difficulty distinguishing between aggressive and less severe tumors, making it difficult to decide which treatment to use.
Men over 50 are entitled to a “PSA” blood test, which gives doctors a rough idea of whether a patient is at risk.
But it’s unreliable. Patients who get a positive result usually receive a biopsy, which is also not foolproof.
Scientists aren’t sure what causes prostate cancer, but age, obesity, and sedentary lifestyle are known risks.
Anyone with concerns can speak to Prostate Cancer UK Specialist Nurses on 0800 074 8383 or visit prostatecanceruk.org