What is FIT?
FIT stands for Fecal Immunochemical Testing – The essence of this test is to look for the presence of hidden blood in faeces.
Fecal occult blood indicates the bleeding from the gastrointestinal tract and also a sign of possible related diseases such as: stomatch ulcers, ulcerative colitis, inflammatory bowel disease, Cronch and especially colorectal cancer.
According to Globocan, in 2020, colorectal cancer (CRC) is the 3rd most common cancer worldwide with >1.900.000 new cases and the second leading cause of cancer-related death with > 900.000 deaths.
In VietNam, colorectal cancer (CRC) is the 5th most common cancer followed by liver, lung cancer, breast and stomatch cancer, with >16.000 new cancer cases and >8.000 deaths.
Colorectal cancer tends to be younger, increasing gradually in the population aged 20-49 years. As in the United States, there are an averagely of 14 cases in every 100,000 people aged 20-49 years old. [3] .
85% of colorectal cancers originate from colorectal adenomas (CRA), of which 80% of adenomas have APC mutations, which accumulate many genetic mutations and gradually progress to cancer. [1, 2].
Fecal immunochemical testing (FIT) detects small amounts of blood in a fecal sample using antibodies specific to human haemoglobin. A positive FIT result alone cannot confirm a diagnosis of colorectal cancer. Further assessment using colonoscopy or CT colonography is needed to confirm diagnosis [4] .
It is recommended that a FIT threshold of fHb ≥10μg Hb/g should be used in primary care to select patients with lower gastrointestinal symptoms for an urgent referral pathway for colorectal cancer investigation[5]
Evidence shows that offering the test in primary care can identify people who are most likely to have colorectal cancer. These people can then be prioritized for referral to secondary care, while people who are less likely to have colorectal cancer can avoid unnecessary investigations. This means that colonoscopy resources can be used for people who most need them[4].
Who needs to do FIT?
The National Institute for Health and Care Excellence's (NICE) guideline on suspected cancer recommended that FIT should be used in adults:
- with an abdominal mass, or
- with a change in bowel habit, or
- with iron-deficiency anaemia, or
- aged 40 and over with unexplained weight loss and abdominal pain, or
- aged under 50 with rectal bleeding and either of the following unexplained symptoms: abdominal pain, weight loss, or
- aged 50 and over with any of the following unexplained symptoms: rectal bleeding, abdominal pain, weight loss, or
- aged 60 and over with anaemia even in the absence of iron deficiency
FIT should be offered even if the person has previously had a negative FIT result through the NHS bowel cancer screening programme. People with a rectal mass, an unexplained anal mass or unexplained anal ulceration do not need to be offered FIT before referral is considered. [4]