What are the stages of treatment for leukemia? What are the different purposes of each phase?
Leukemia treatment can generally be divided into two main phases: induction remission therapy and post-remission therapy, which can be further divided into two phases: consolidation therapy, intensive therapy and maintenance therapy. The purpose of induction remission is to rapidly minimize leukemic cells and restore the hematopoietic function of the bone marrow to normal to achieve the standard of complete remission. The purpose of post-remission treatment is to further destroy the remaining leukemia cells in the body by using consolidation and intensive treatment that lasts for a longer period of time to prevent the recurrence of leukemia, prolong remission and survival time, and strive for a cure of leukemia. What is considered a complete remission of leukemia?
Complete remission of leukemia requires the following conditions.
(1) Clinical absence of signs and symptoms due to leukemic infiltration and a normal or near-normal life.
(2) Routine blood tests showing hemoglobin ≥ 100 g/L (men) or ≥ 90 g/L (women and children), absolute neutrophil values > 1.5 × 109/L, platelets ≥ 100 × 109/L, and no leukemic cells found in peripheral blood.
(3) Primitive cells in bone marrow ≤ 5%, normal red blood cells and megakaryocyte lineage.
A patient is in complete remission when he/she meets all the above three criteria; if the patient’s bone marrow examination meets the relevant criteria, but the clinical or routine blood tests have not yet reached the corresponding criteria, the patient is considered to be in partial remission; otherwise, the patient is not in remission.
If there is no leukemia remission for 3-5 years from the date of complete remission after treatment, the patient is said to be in continuous complete remission.
What is clinical cure of leukemia?
A leukemia patient is considered to be clinically cured if there is no relapse of the disease after 5 years of stopping chemotherapy or if the patient has survived for 10 years without disease.
Is a sustained complete remission of leukemia considered a clinical cure of leukemia?
Although both leukemia in complete remission and leukemia clinical cure are considered to be long-term survival states (those who have survived disease free or with disease for 5 years or less from the date of diagnosis of leukemia), they are not equivalent. Patients in sustained complete remission are considered clinically cured only if they continue to maintain leukemia without relapse for more than 5 years after termination of chemotherapy.
Why continue chemotherapy after a complete remission of leukemia?
In patients with untreated leukemia, the leukemic self-cells in their bodies are about 5×1010~1013. In patients in complete remission, although the clinical symptoms and signs of leukemia have completely disappeared and the blood and bone marrow images have basically returned to normal, there are still a considerable number (108~109 or less) of leukemic cells remaining in their bodies, and there can still be leukemic infiltrates in some hidden places outside the bone marrow. These residual leukemia cells can cause relapse of the disease. In order to further destroy the residual leukemia cells, prevent relapse, prolong remission and survival, and strive for a leukemia cure, aggressive consolidation and intensive therapy is still needed after complete remission and for a considerable period of time (2-3 years).
What is meant by leukemia microscopic residual disease?
Microscopic leukemia residue refers to the state in which a small number of leukemia cells remain in the body after a complete remission of leukemia with induction chemotherapy or after bone marrow transplantation. The total number of leukemia cells in the body at the time of consultation is considered to be about 1012, and after induction of chemotherapy to complete remission, the number of leukemia cells can be reduced to 1010. These residual cells become the source of leukemia recurrence.
What is the significance of testing for microscopic residual leukemia?
The significance of detecting microscopic residual leukemia is that.
(1) To help predict the recurrence of leukemia earlier; to guide the clinical treatment of leukemia and to decide whether to continue chemotherapy or stop treatment based on the number of leukemic cells in the body.
(2) It helps to detect early whether the leukemia cells are resistant to drugs and guide the clinical selection of more sensitive and lethal therapeutic measures accordingly.
(3) It helps to evaluate the purification effect of autologous hematopoietic stem cell transplantation.
How to determine the relapse of leukemia?
A patient with leukemia in complete remission after treatment is said to have relapsed if any of the following occurs later in the course of the disease.
(1) Primary cells or promonocytes + juvenile monocytes or prolamins + juvenile lymphocytes > 5% but < 20% in the bone marrow, who have not reached the criteria for complete remission in the bone marrow after one course of effective anti-leukemia therapy
(2) Progranulocytes (promonocytes + juvenile monocytes or prolamins + juvenile lymphocytes) >20% in the bone marrow
(3) Those with leukemic cell infiltration outside the bone marrow, such as green tumor, central nervous system leukemia and testicular leukemia, etc.