With the rising prominence of tumour biomarkers and genetic profiling, it is clear that the profile of in vitro diagnostics within the cancer sector has never been higher. A government focus on improving early diagnosis in an attempt to increase survival rates, together with a shift away from non-specific chemotherapies in favour of targeted treatments, means that diagnostics are often of central importance to the UK’s approach to cancer.
It is innovation that drives progress. And so, summarised below are just a few of the novel tests that have made the headlines in the mainstream media in 2015. It is important to note that much of research discussed below is in initial stages and requires a significant amount more work before it is of practical use. This blog is intended to demonstrate the coverage of potential diagnostics in the national media.
We begin with the news at the beginning of this week, as reported by the BBC, that a ‘simple’ urine test has been developed to detect pancreatic cancer earlier than at present. Research carried out in the UK and Spain looked at nearly 500 urine samples from patients with pancreatic cancer, chronic pancreatitis, benign and cancerous liver and gall bladder conditions, and healthy volunteers, and found a protein ‘signature’ that is only present in people with pancreatic cancer. Three proteins out of 1500 found in urine samples were at much higher levels in patients with pancreatic cancer - LYVE1, REG1A and TFF1 – and this protein signature was 90% accurate in identifying the most common form of pancreatic cancer.
The potential significance of a test such as this is due to the infamously poor survival rates of people with pancreatic cancer. Only 3% of pancreatic cancer patients are alive 5 years after diagnosis at present; this drops to less than 1% for after 10 years, compared to 78% for breast cancer. Indeed, pancreatic cancer has the lowest five-year survival rate of any common cancer and this has barely improved in 40 years. These rates are so poor primarily because the disease is often very far advanced at the time of diagnosis. More than 80% of people with the disease are diagnosed when it has already spread, meaning they are not eligible for surgery to remove the tumour, currently the only potential cure.
‘Patients are usually diagnosed when the cancer is already at a terminal stage, but if diagnosed at stage 2, the survival rate is 20%, and at stage 1, the survival rate for patients with very small tumours can increase up to 60%.’ Co-author Prof Nick Lemoine, Barts Cancer Institute
‘Research like this is vital as there's been little progress in improving survival for pancreatic cancer, and innovative approaches are needed.’ Fiona Osgun, CRUK
This potential urine test follows suggestions in June, again reported by the BBC, that scientists at the University of Texas are close to a blood test for pancreatic cancer. The test looks for fat vesicles that are shed by the cancers, with one protein – proteoglycan glypican-1 – found in much higher levels in people with pancreatic cancer. Early results of this study, published in Nature, showed the test was 100% accurate at distinguishing between cancers, other pancreatic disorders and healthy tissue, findings that experts described as ‘striking and ingenious’.
Last week, it was revealed that researchers had identified 5 types of prostate cancer, as discussed in The Independent. This study analysed 100 genes in cancerous tissue from 250 men, showing each type had a distinct genetic signature. Importantly, such grouping based on genetic makeup would allow doctors to distinguish between more and less aggressive prostate cancers, allowing treatment to be tailored to the specific type of cancer. This, of course, is yet another potential example of personalised medicine in the near future, as highlighted in this blog – ‘Genome analysis stratifies prostate cancers’ – by the PHG Foundation. Dr Alistair Lamb, the study author from CRUK’s Cambridge Institute, thinks genetic information could be combined with existing tests to identify the most at-risk patients.
Prostate cancer is the most common cancer in men in the UK, with around 41,700 cases diagnosed each year. Whilst aggressive tumours can require intensive treatment, many cases are much more manageable and end up actually being over-treated. As such, the identification of the type of prostate cancer has the potential to prevent some patients receiving unnecessary treatment, and as a result saving them from possible side effects, whilst identifying those patients who may require more urgent and substantial treatment.
For a more in-depth look at this story, read CRUK’s detailed analysis of what these findings mean – ‘The five faces of prostate cancer?’.
In May, the results of a 14-year study of ovarian cancer screening, the world’s largest ovarian cancer screening trial involving over 200,000 post-menopausal aged 50 and over, revealed a new approach that can detect twice as many ovarian cancers than at present - ‘New ovarian cancer test twice as effective as existing methods’ was the headline in the Guardian.
The method uses a statistical calculation to interpret variations in the level of the protein CA125, long linked to ovarian cancer. By measuring the CA125 level once a year, a computer was able to predict the risk of ovarian cancer based on a number of factors including the original level of the protein, how this level has changed and age. This new technique correctly diagnosed 86% of women with invasive epithelial ovarian cancer, twice as many as the current diagnostic blood test which uses a certain CA125 level as a fixed cutoff point. This follows previous trials in which some women with high CA125 levels had no sign of ovarian cancer, whilst others with low levels harboured the disease.
‘Ovarian cancer is particularly hard to spot at an early stage so it’s vital that we find ways to diagnose the cancer sooner’ Dr James Brenton, ovarian cancer expert, CRUK
Final analysis of the trial later this year will show whether the cancers were detected early enough to save lives, but the team are optimistic since around 25% of women identified with cancer were in the earliest stages of cancer development, when there is a single tumour or it has only just started to spread.
In April, the media reported news of a potential breath test which can predict the risk of developing stomach cancer, as seen in the Telegraph. The test, which was developed by Israeli scientists after analysing the breath of 400 people diagnosed with cancer or pre-cancerous cells, senses small changes in the level of 8 organic compounds in exhaled breath, creating a distinctive ‘breath print’.
Stomach cancers affect about 7300 people each year in the UK, but is often diagnosed late as the symptoms can be mistaken for other diseases. It is suggested that this technology could be used to assess risk, with those deemed at high risk sent for testing by conventional endoscopy. Find out more in this NHS Choices report.
‘Diagnosing cancer in its early stages offers patients the best chance of successful treatment’ Dr Emma Smith, CRUK
Finally, a study released earlier this year, discussed by the BBC among others, revealed that the odds of a woman developing breast cancer could be predicted by identifying tiny errors in DNA. An international team analysed 77 genes, which each had a low impact on cancer risk individually, but were a powerful combination. The average woman was found to have 66 cancer-risk sites in their DNA, allowing the probability of developing breast cancer to be calculated, as shown below:
Women with no family history
Highest-risk group – 16.6% lifetime risk
Lowest-risk group – 5.2% lifetime risk
Women with a family history
Highest-risk group – 24.4% lifetime risk
Lowest-risk group – 8.2% lifetime risk
The potential significance of this research, once again, is that knowledge of an individual genetic profile may allow a personalised approach to treatment, such as determining which women need drugs like tamoxifen and raloxifene. Once again, this targeted approached could eliminate over-treatment and unnecessary side-effects, whilst allowing those who really require a certain treatment at a reduced overall cost. Equally, it may allow clinicians to identify the lowest risk women, who may not need breast screening, as well as those who are at the most risk, who might need to begin screening earlier than at present.