Why Is There a Need for Rapid Advancements in POCT for Cancer Diagnostics?
Author: Holly Young
One in two people develop cancer in their lifetime (1). Early diagnosis broadens treatment options available that can improve patient prognosis. This drives the increasing demand for Point of care test (POCT) devices; current diagnostic methods, whilst effective, are costly and have limitations that affect the quality of patient care.
Point of care (POC) devices are increasingly popular as they can produce rapid results, using less invasive methods, and their availability across a variety of locations.
Figure 1: Adapted image illustrating key factors influencing the demand for POCT in the diagnosis of Cancer (2).
The benefits of POCT can help tackle some of the factors influencing the demand for POC diagnostics in cancer in Figure 1.
POC devices must pass the ASSURED guidelines set out by WHO before going to market; the device must be affordable, highly sensitive, specific, user-friendly, rapid, robust, no complex equipment should be involved and deliverable to end-users (3). This article will explore some of the rapid advancements of POC and novel technology that can improve cancer diagnostics in the future.
Cost
Costs of current cancer diagnostic methods accumulate with the use of expensive equipment, trained medical personnel and hospital and laboratory facilities; extensive periods of hospitalisation for biopsies, surgery, and treatments further increase costs.
In the UK, the NHS partially fund these treatments to relieve some of the financial burdens whereas patients in the US pay for their own medical care; therefore, their financial situation determines the quality of hospital care and treatment received.
POCT devices are designed to be compact and cost-effective, facilitating bulk manufacture; this would relieve costs exhausted accumulated from current diagnostic tests as POCT devices don’t need expensive equipment and material to function (3).
Time
Time is a critical factor in cancer diagnosis. Waiting times between samples being collected, sent, analysed and the results being obtained can be lengthy. During the recent pandemic, waiting times have increased significantly; this will have negatively impacted millions of patients’ diagnoses and prognoses.
POCT can bring testing procedures closer to patients’: enabling faster medical decisions in hospitals, ambulances, doctor’s offices, in low-resource areas and in times like this where the whole world stopped momentarily. With fast result turnover, this can significantly reduce waiting times for appointments and results: an issue that delayed patient treatment greatly. This can improve patient prognosis as they have more treatment options available with early diagnosis (3).
Sample Preparation
Blood is the typical sample used in POC devices. It is simple to obtain however, processing it is lengthy and complex with risks of contamination. Current technologies are also not sensitive enough to detect low levels of analytes in the blood. Shortages of laboratory personnel have resulted in an increase in the demand for automated and self-contained processes; POCT overcomes this issue as processes are much simpler and user-friendly meaning doctors and nurses.
POCT can integrate sample preparation steps within the device, eliminating extensive handling steps: reducing contamination risk (4).
Multiplexing
Multiplexing involves simultaneous analysis of many substances from a single sample. Multiplexing can advance cancer diagnostics as different stages of cancer have varying quantities of different biomarkers: the more we understand cancer and its biomarkers the better we can exploit the potential of multiplexing for cancer diagnostics (4).
Prostate-Specific antigen (PSA) in prostate cancer has been successful using lab-on-chip technology in combination with microfluidics. Previous methods involved complex packaging and high costs. A passive microfluidic system with a complementary metal-oxide silicon (CMOS) sensor chip has overcome this issue, allowing the measurement of multiple metabolites from a single drop of plasma. A study conducted to test this system analysed human plasma from 10 healthy men and 16 men with prostate cancer. They found the test sensitivity was high at 94% whilst specificity reached 70% when comparing samples: exceeding current PSA tests available, which miss around 15% of tumours (1).
Figure 2: a) Image illustrating the cartridge where the drop of plasma is placed to obtain the measurement. b) The cartridge device used, the CMOS chip, passive microfluidics and an optical assembly (1).
Multiplexing of various biomarkers gives a greater understanding of how biochemical pathways become altered during cancer progression. Therefore, provides a better understanding of the cancer stage and its potential response to different treatments (5).
Electrochemical biosensors
Electrochemical biosensors can identify and quantify biomarkers in a cost-effective manner. They can be miniaturised without compromising the high sensitivity and specificity, portability, and quick turnaround time. An electrochemical biosensor has been proven to detect vascular endothelial growth factor (VEGF) and PSA in human serum to facilitate the early diagnosis of prostate cancer (6). Electrochemical biosensors can potentially be used in implantable biosensing for monitoring changes in cancer biomarkers in the future (7).
Biosensors have great potential in monitoring changes in an individual disease state. They use biology substrates, such as antibodies or DNA, to detect specific analytes present: when analytes bind to the immobilised substrate, it generates an electrical signal through a transducer that quantifies the signal to give the result. (5).
Our graphene-based electrode, Gii-Sens, has great potential to tackle the issues mentioned within this article as at the price of carbon. With our 98% graphene foam acting as the transducer with our Gii-Sens, it enables higher sensitivity and lower limits of detection compared to other noble metals used in other commercially available electrodes. Gii-Sens is easily integrable and can be customised for your design.
If you are developing a cancer POCT device, get in touch with us today to see how we can enhance your design with our Gii-Sens and services.
Conclusion
Many cancers still lack effective non-invasive screening diagnostics, making POCT extremely attractive for cancer diagnostics. Detection is not necessarily limited to when cancer is thought to be present; samples could be collected years in advance as part of a large-scale screening process to monitor any changes in analytes/biomarkers that can indicate very early signs of cancer. The potential of POCT to revolutionise cancer diagnostics is outstanding as we are facing a rapid rise in cases year upon year (8).
Rapid advances in novel technology for POCT has great potential in the early detection of cancer due to its benefits; especially in resource-scarce areas where cancer prevalence is high, and the incidence is increasing yearly due to lack of healthcare facilities available. This is vital as currently most cancers are detected too late resulting in costly treatment and a reduced life expectancy. Moreover, it can greatly improve cancer prognosis in developed countries where there is a great potential for further diagnostic development due to continuously evolving research that is well funded (1, 2).
References:
Annese, V.F., Patil, S.B., Hu, C. et al.A monolithic single-chip point-of-care platform for metabolomic prostate cancer detection. Microsyst Nanoeng 7, 21 (2021). https://doi.org/10.1038/s41378-021-00243-4
FutureBridge 2021. Simplifying Cancer Detection using point-of-care Technologies - FutureBridge. DOI: https://www.futurebridge.com/industry/perspectives-life-sciences/simplifying-cancer-detection-using-point-of-care-technology
Gami, Umesh. (2018). Emerging Technologies for Point-of-Care (POCT) Testing: A future outlook for Scientists and Engineers.
Can Dincer, Richard Bruch, André Kling, Petra S. Dittrich, Gerald A. Urban, Multiplexed Point-of-Care Testing – xPOCT, Trends in Biotechnology, Volume 35, Issue 8, 2017, 728-742, ISSN 0167-7799, https://doi.org/10.1016/j.tibtech.2017.03.013.
Hayes B, Murphy C, Crawley A, O'Kennedy R. Developments in Point-of-Care Diagnostic Technology for Cancer Detection. Diagnostics (Basel). 2018;8(2):39. Published 2018 Jun 2. doi:10.3390/diagnostics8020039
Lung-Hsuan Pan, Shin-Hung Kuo, Tzu-Yang Lin, Chih-Wen Lin, Po-Yu Fang, Hung-Wei Yang, An electrochemical biosensor to simultaneously detect VEGF and PSA for early prostate cancer diagnosis based on graphene oxide/ssDNA/PLLA nanoparticles, Biosensors and Bioelectronics, Volume 89, Part 1, 2017, Pages 598-605, https://doi.org/10.1016/j.bios.2016.01.077.
M. Gray, J. Meehan, C. Ward, S.P. Langdon, I.H. Kunkler, A. Murray, D. Argyle, Implantable biosensors and their contribution to the future of precision medicine, The Veterinary Journal, Volume 239, 2018, Pages 21-29, https://doi.org/10.1016/j.tvjl.2018.07.011.
Chen, X., Gole, J., Gore, A. et al. Non-invasive early detection of cancer four years before conventional diagnosis using a blood test. Nat Commun 11, 3475 (2020). https://doi.org/10.1038/s41467-020-17316-z