Cancer accounts for ~9.6 million worldwide deaths annually. We often owe this to inadequate or late diagnosis, or individuals making poor life choices. The methods of old, for cancer diagnosis are invasive, time-consuming and expensive. The evidence points to the microbiome’s capabilities in this field; it being capable of bringing about all the intended advantages while avoiding the other pitfalls.
The methods of old prove effective, but still, poor diagnosis is leading to lives lost.
There are various threats to global health, and of these, cancer holds a top position on the podium. In 2018, there were 18.1 million cases, with 9.6 million deaths worldwide, making it the second leading cause of deaths globally. Of the many forms of the disease, one of the hardest groups to detect is Colorectal Cancer (CRSC), with it being second only to lung cancer in terms of mortality rates.
The greatest risk factor is old age; but when looking into its mortality, it is owed to late diagnosis, since late diagnosis means the disease has already spread within the body, making it less treatable, thus reducing the chances of survival. Some of the most common cancer types, such as breast cancer, and CRC have high survival rates when detected early, but on average cancer is diagnosed in late stage II, this being around the time it spreads to the outer lymph nodes and other organs. Although the likelihood of survival differs with the cancerous type, the odds are 4-7x higher with cancers diagnosed in stage I as opposed to stage II. So, why is late cancer diagnosis seemingly the norm? There are various theories and explanations:
- Lack of screening tests or poor accuracy.
- We often trivialise symptoms, thus making us bad patients.
- Many cancerous diseases lack symptoms until they are at advanced stages.
- Doctors being inadequate as backstops.
Tests of Old
Scientists have adopted various approaches to CRC screening. These tests share a common goal: detection of early stage carcinomas. Two main screening methods are being used: The Faecal Occult Blood Test (FOBT), and the Faecal Immunochemical Test (FIT) both coupled with a colonoscopy, but these tests are often inaccurate, with moderate sensitivity (69–86%) to detect CRC.
The role of the Microbiome
Thanks to advances in AI and organoids, the microbiome is being explored in ways we could not possibly have done before. It is being heavily studied, with over 30,000 publications. Although the microbiome has been heavily researched, clinical trials on CRC association only began in 2010 due to increased curiosity in its potential.
Several studies have compared the accuracy of the gut microbiome as a screening tool to FOBT and FIT. Scientists created a screening model that combined metagenomic data with FOBT results, which led to an increase in sensitivity compared to FOBT alone, showing some ability to distinguish colorectal cancer from a distinct bowel condition. It was further found that a model comprising of BMI, microbiome data, and FOBT was more accurate at distinguishing adenoma from carcinoma than FOBT alone. It was also found that combining microbiome data, and the FIT is more sensitive than FIT alone. Scientists also later identified four bacterial species (one being Fusobacterium nucleatum) by QPCR that could distinguish colorectal carcinoma from healthy subjects with greater accuracy than FIT.
Microbial markers have recently emerged as a promising additional factor to consider in early screenings. Various companies have been set up to use the microbiome’s potential, such companies include Qualigen Therapeutics Inc and Metabiomics, both founded in 2004.Most of these firms are based in the USA, but to date, no commercialisation has taken place.
There is much potential for the microbiome within both cancer diagnostics and therapy. Research suggests that there is potential for microbiome analysis to both be amplified and integrated within existing screening methods. Without better ways for cancer diagnostics, the number of new patients with cancer will continue to outpace treatments available. The likely solution for prolonging quality of life and reducing the cancer death rate lies in our future ability to leverage the human microbiome to help provide sustainable, long-term control of the disease.
Authors: Shallom Iriele, Dr Aswini Misro