Early diagnosis of cancer is linked with improved patient outcomes. People who receive a diagnosis at earlier stages are more likely to survive. They are also more likely to have better experiences of care, enhanced quality of life, and reduced treatment mobility in comparison with patients diagnosed at later stages.
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Data shows the true impact of recognizing cancer in its early stages: the one-year survival rate for colorectal cancer diagnosed at stage 1 is 97.7%, which falls to 43.9% if detected at stage 4; the one-year survival rate of lung cancer is 87.3% if recognized at stage 1, at stage 4 this falls to 18.7%.
In the UK, the three types of cancer with the highest five-year survival rates are those that have the highest percentage of cancers diagnosed at stages one and two (testis, melanoma, thyroid). This data highlights the vital importance of diagnosing cancer in its early stages. The importance of early cancer diagnosis has been reflected in the policies of international charity and policy initiatives, which have identified efforts to improve early diagnosis at the forefront of their agendas.
Improving early diagnostics for cancer and disease, in general, will involve a multi-pronged approach. Public awareness and willingness to come forward with symptoms will play an important role alongside the capabilities of technologies in the hands of health care professionals. Advances in optical imaging represent one route to improving these technologies, giving health care professionals the tools to detect cancer in its early stages. Here, we will discuss how optical imaging has transformed cancer and rapid diagnostics testing.
Optical Imaging Offers a Route to Early Diagnosis
Optical imaging offers an opportunity to identify malignant tissues at earlier stages, giving patients increased chances of survival and better treatment experiences and outcomes. Optical imaging helps visualize biological systems from organs to cells. Its capability of looking into cells has evoked much interest in further advancing the technology in the field of medical imaging. Optical imaging has diverse contrast mechanisms at its disposal for identifying pathologic tissues.
In general, optical imaging involves the absorption of light by either endogenous or exogenous chromophores, generating a visual contrast between healthy and pathologic tissue. The theory behind optical imaging and its execution is relatively simple in comparison to other imaging techniques. It also offers non-invasive methods of detecting pathologic tissue.
According to many cancer surveillance guidelines, random biopsies are recommended to detect cancer in its early stages. However, the approach is limited due to being relatively inefficient, time-consuming, and not widely adopted across healthcare systems. On the other hand, targeted optical contrast agents produce detailed images identifying cancerous tissue and providing information on its structure.
Biopsies are not immune to false negatives, i.e. failing to find a malignancy when there is one. Biopsies can also fail to identify premalignant lesions, which means they miss the opportunity to initiate treatment at early stages. Optical imaging can detect these lesions that are often missed in biopsies.
Another benefit to optical imaging is that they are less off-putting to the patient. The early detection of cancer is limited, in part, by patient willingness to come forward with symptoms. This is influenced by many factors, such as disease awareness, access to healthcare, and patient perception. For example, for some people, getting a biopsy may be something to fear as they are invasive. The implementation of optical imaging as a method of early detection may help to overcome this factor.
Optical Imagining in Early Cancer Detection and Future Directions
Numerous studies have proven optical imaging to enhance the surgical efficacy in various cancers, including head and neck cancer, breast cancer, and colorectal cancer. The data also shows that optical imaging can improve early disease detection, particularly via endoscopy (in esophageal cancer, for example) via the use of fluorescent labels associated with disease-specific biomarkers. In vivo fluorescence imaging has been used to predict cancer and Crohn’s disease therapeutic outcomes.
The future of optical imaging in cancer and rapid diagnostics will depend on how and if the field overcomes the various hurdles it faces. Standardization and quantification of procedures and data will be important, as will establishing a pathway to allow optical imaging to enter the standard of care. There is an opportunity to build on molecular imaging and develop a technique that complements currently used molecular imaging platforms. If optical imaging can overcome its limitations, it will likely be fundamental to facilitating the early detection of cancer. This will likely improve patient outcomes and open the door to potential new therapies focused on treating early-stage cancer.
References and Further Reading
Noltes, M.E., van Dam, G.M., Nagengast, W.B. et al. 2021 Let’s embrace optical imaging: a growing branch on the clinical molecular imaging tree. Eur J Nucl Med Mol Imaging 48, 4120–4128. https://link.springer.com/article/10.1007/s00259-021-05476-z
Solomon, M., Liu, Y., Berezin, M. and Achilefu, S., 2011. Optical Imaging in Cancer Research: Basic Principles, Tumor Detection, and Therapeutic Monitoring. Medical Principles and Practice, 20(5), pp.397-415. https://www.karger.com/article/pdf/327655
Whitaker, K., 2020. Earlier diagnosis: the importance of cancer symptoms. The Lancet Oncology, 21(1), pp.6-8. https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(19)30658-8/fulltext