The rapid development of science and technology has improved the survival rate of leukemia patients, but tumor cells are always tenacious and try to hide in hidden corners to avoid the pursuit of various drugs. Once the human immune system is slightly lax, or after acquiring new means of camouflage through evolution, they quickly replicate and make a comeback. These malignant cells that escape the attack and quietly lurk are called "microscopic residuals" - a state in which a small number of leukemia cells remain in the body after a leukemia patient has achieved hematological remission after chemotherapy and bone marrow transplantation. To uncover these lurking agents, it is now possible to use flow cytometry, a combination of quantitative genetic testing and second-generation genetic sequencing to monitor for "fugitive" fish.
Before the advent of residual leukemia monitoring, the effect of chemotherapy was assessed by looking at bone marrow smears and counting the percentage of leukemic cells under a microscope. This method required more experience and smear quality from the reader and was more subjective, so it was not always possible to accurately assess the extent of a patient's disease. Leukemia residual monitoring can, firstly, provide a more accurate assessment of the effect of chemotherapy, as tests showing a lower number of residual leukemia cells and a faster decline indicate a better chemotherapy effect; secondly, it can predict the risk of relapse, and if residual leukemia cells continue to rise during treatment or follow-up, this indicates a higher risk of relapse.
The level of residual leukemia plays a very important role in the selection of treatment regimen and the adjustment of treatment dose during chemotherapy, especially in the high-risk group of patients with persistently high residual levels during chemotherapy, suggesting that patients are not sensitive to chemotherapy and HSCT is the only treatment. Moreover, if the leukemia residuals are reduced to a more desirable level before transplantation, the risk of relapse after transplantation will be greatly reduced.
After the patient has completed all chemotherapy and transplantation and entered the follow-up phase, leukemia residual monitoring becomes even more important. If leukemia residual levels remain low and are maintained for 3 to 5 years, the chances of leukemia cure are high. However, if there is a trend of elevated residual levels, intervention needs to be given as soon as possible: because elevated peripheral blood residual levels generally precede bone marrow relapse by about 1 to 3 months, pharmacologic intervention before leukemic cells have fully recovered can have a multiplier effect. If treatment is given after bone marrow relapse, the efficacy will be greatly reduced.
With the rapid development of genetic technology, immune technology, and information technology, in order that more and more technologies will be applied to the treatment of diseases and improve the health of human beings.