Out of the fear of cancer and the increase of health care awareness, more and more people are having regular medical checkups. Among the three major gynecological cancers, cervical cancer is the easiest to be detected early through regular screening. Cancer, if detected at an early stage, is basically not a cause for fear and can be completely cured with standardized treatment. Active medical checkups are commendable, but the findings of screening reports often exceed the general public’s perception, such as atypical squamous epithelial cells of unknown significance, and often even gynecologists’ explanations to patients are ambiguous, which inevitably bring more misunderstanding and panic to patients. What is atypical squamous epithelial cells of undetermined significance? It is called in English: Atypical Squamous Cells of Undetermined Significance, or ASCUS for short, which is a description based on the TBS classification proposed by the American International Cancer Society in 1988, and is clinically performed using TCT or LCT for exfoliative cytology of the cervix. In fact, it is not alone, the TBS system in the latest 2014 edition of the guidelines has several other classifications of cervical atypical cells: atypical squamous epithelial cells (ASC) ASCUSASC-H (cannot exclude HSIL) atypical glandular epithelial cells (AGC) cervical ductal cells, endometrial cells, glandular cells, cervical ductal cells (tumor-prone), glandular cells (tumor-prone). As we can see, there are many types of “atypical” cervical cancer screening, but the most common is ASCUS, which accounts for about 5% of all screened people. As for how to define these categories, it is the work of pathologists, so we, the people, do not have to look into it. But the question that is relevant to all of us is, does it matter? How to treat it? Most ASCUS is not important. Here we start with ASCUS, which is often defeated by the word “unknown”. The range of unknown significance is very wide, from cancer to inflammation. However, some studies suggest that more than half of them are not problematic, such as inflammation, postmenopausal changes, IUD reactions or quality of sampling, etc. The probability that it is really cervical cancer is very low, and some of them are in between normal and cancerous stages: precancerous lesions. ASCUS can be considered a warning that there may be a risk of abnormality, but it is not the final confirmation of the diagnosis. ASCUS can often be left alone Since more than half of ASCUS is not a problem, does that mean it can be left alone. That is half right. As said before, don’t be afraid of ASCUS, but don’t let your guard down. If there is no clinically abnormal vaginal bleeding (especially after snapping) or a larger amount of vaginal fluid, then there is less danger. Next, it is best to get a cervical high-risk HPV test, and if the virus is also negative, then the risk is reduced by another level. If the virus is negative, then the risk level is lowered. Of course, some people say, I’m scared, everything is normal I have to do colposcopy too. No problem, colposcopy is considered a non-invasive test anyway and cervical biopsy is minimally invasive, there is no major harm. Your doctor will advise you, but won’t forcefully refuse you, after all, there is still a very small risk of missing the test if you don’t do it, and in China, it could be a big deal. If you are HPV positive, or have clinically abnormal vaginal bleeding or fluid, or if someone has had a previous cervical lesion and ASCUS was found on review after LEEP or cold knife treatment, then it is best to have a colposcopy + cervical biopsy. Several others are best treated further in a timely manner Several other atypical cells, although rare, are at much greater risk of eventually being confirmed to have lesions or cancer. ASC-H, which means that HSIL (high grade squamous intraepithelial lesion) cannot be excluded, is less than 1%, but the relative risk of having problems is much higher, with nearly half of them showing HSIL or cancer after follow up. Because cervical adenocarcinoma is not as common as squamous carcinoma, the detection rate of AGC is probably only about 1%. However, about 20-30% are eventually confirmed as moderate to severe cervical intraepithelial neoplasia or cancer. A recent larger study found that 2.6% of the population of more than 10,000 with AGC developed invasive cervical cancer within 15.5 years. Because it is often overlooked, the windfall of AGC developing into invasive cancer within the first few years of follow-up is even higher than that of HSIL, so although rare, it should be taken more seriously. Therefore, in these cases, it is better to deal with them further by doing colposcopy + cervical biopsy. AGC many times requires cervical canal scratching or even diagnostic scraping, and some may end up with a diagnosis of endometrial hyperplasia or cancer. Of course, if combined with HPV testing, then there is a better predictive value. The point of regular screening is to detect the disease early, at a time when you may not have the slightest symptom of discomfort. Therefore, you should neither guess blindly nor feel good and unconcerned about the results of screening. Most places now use TCT or LCT for cervical exfoliation cytology and their results are presented in the TBS reporting system, which is relatively more complicated, so please follow your doctor’s advice.