What Is Leukemia?

Leukemia is a malignant clonal disease of hematopoietic stem cells. Clonal leukemia cells proliferate and accumulate in bone marrow and other hematopoietic tissues due to uncontrolled proliferation, differentiation disorders, and blocked apoptosis, and infiltrate other non-hematopoietic tissues and organs, while inhibiting normal hematopoietic function. Clinical manifestations of varying degrees of anemia, bleeding, infection fever, liver, spleen, lymph node enlargement and bone pain. According to reports, the incidence of leukemia in various regions of China occupies the sixth place among various tumors.

Basic Information

English name

leukemia

Visiting department

Hematology

Common causes

Caused by viral infections, chemicals, radiation and heredity

Common symptoms

Fever, anemia, significant bleeding tendency, or bone and joint pain, etc.

Contagious

no

Causes of leukemia

Viral factor

Leukemia-causing effects of RNA viruses in mice, cats, chickens, and cattle have been confirmed. Most of the leukemias caused by these viruses belong to the T cell type.

2. Chemical factors

Some chemicals have a role in causing leukemia. People exposed to benzene and its derivatives have a higher incidence of leukemia than the general population. There have also been reports of leukemias induced by nitrosamines, butepine and its derivatives, and chloramphenicol. Certain anti-tumor cytotoxic drugs, such as nitrogen mustard, cyclophosphamide, methyl benzylhydrazine, VP16, VM26, etc. all have leukemia-causing effects.

3. Radiation factor

There is evidence that a variety of ionizing radiation can cause human leukemia. The occurrence of leukemia depends on the dose of radiation absorbed by the human body. Leukemia can be induced by the whole body or part of the body after receiving medium or large doses of radiation. Whether low-dose radiation can cause leukemia remains uncertain. The incidence of leukemia has increased significantly in those who are frequently exposed to radiation (such as cobalt-60). High-dose radiation diagnosis and treatment can increase the incidence of leukemia.

4. Genetic factors

The incidence of leukemia is higher in people with chromosomal aberrations than in normal people.

Leukemia classification

It can be divided into acute and chronic leukemia according to the degree of differentiation of leukemia and the length of the natural course. Acute leukemia cell differentiation is stagnated at an early stage, mainly primordial and early immature cells, the disease develops rapidly, and the course of disease is several months. Chronic leukemia cells are well differentiated, mainly immature or mature cells, which develop slowly and have a course of several years. Classified by diseased cell series, including myeloid granulocytes, monocytes, red, megakaryotic, and lymphatic T and B cell lines. Leukemia is often classified clinically into lymphocytic leukemia, myeloid leukemia, and mixed cell leukemia.

Clinical manifestations of leukemia

Children and adolescents often have acute leukemia. Common first symptoms include fever, progressive anemia, significant bleeding tendency, or bone and joint pain. Most of the patients with slow onset were elderly and some young patients, and their condition gradually progressed. In addition, a few patients can have convulsions, blindness, toothache, swollen gums, pericardial effusion, and paraplegia of the lower extremities as the first symptoms.

Fever

It is one of the most common symptoms of leukemia, manifested by varying degrees of fever and fever. The main cause of fever is infection, of which pharyngitis, stomatitis, and perianal infection are the most common. Pneumonia, tonsillitis, gingivitis, and perianal abscess are also common. Ear inflammation, enteritis, dysentery, and pyelonephritis can also be seen. Severe cases can occur such as sepsis and sepsis. Fever can also be a symptom of acute leukemia itself without any sign of infection.

2. infection

Pathogens are more common in bacteria, and in the later stages of the disease, the probability of fungal infections is gradually increasing due to chronic granulocytes below normal and the use of broad-spectrum antibiotics. Viral infections, although rare, are dangerous and require attention.

3. bleeding

The bleeding site can be all over the body, with skin, gums, and nasal bleeding being the most common. There can also be major bleeding in the internal organs such as retina, ear bleeding and intracranial, digestive, and respiratory tract. Menorrhagia is also more common in women and can be the first symptom.

4. Anemia

It can appear early, and a few cases can develop myelodysplastic syndrome (MDS) months or years before diagnosis, and then develop leukemia later. Patients often have symptoms such as fatigue, pale, palpitations, shortness of breath, and edema of the lower limbs. Anemia can be seen in all types of leukemia, and it is more common in elderly patients.

5. Bone and joint pain

Leukemia infiltration of bone and periosteum causes bone pain, which can be diffuse pain in the limbs or the back, or can be limited to joint pain, which often causes difficulty in movement. More than a third of the patients have sternal tenderness, which is helpful for the diagnosis of this disease.

6. Hepatospleen and lymph node enlargement

Mild to moderate hepatosplenomegaly is more common. ALL has a higher incidence of hepatosplenomegaly than AML, and chronic splenomegaly is more common and more severe than acute leukemia. Lymph node enlargement ALL is more common than AML, and may involve superficial or deep lymph nodes such as the mediastinum, mesentery, and retroperitoneum.

7. Central nervous system leukemia (CNSL)

CNSL is a serious complication of acute leukemia. It is common in M4 and M5 in ALL and AML, but other types are also seen. Because common chemotherapeutic drugs are difficult to penetrate the blood-brain barrier, they have become blind spots and difficulties in the treatment of modern acute leukemia. The infiltrated site mostly occurred in the arachnoid and dura mater, followed by the parenchyma, choroid or cranial nerve. Severe cases include headache, vomiting, qiang, optic nipple edema, and even the typical manifestations of increased intracranial pressure such as convulsions and coma, which can be similar to intracranial hemorrhage, and mild cases only complain of mild headache and dizziness. The cranial nerve (No. VI, mainly cranial nerve) involvement may appear visual impairment and facial paralysis.

8. Infiltration of other tissues and organs

ALL skin infiltration is less common than AML, but testicular infiltration is more common. Testicular leukemia also often occurs in remission ALL, manifested as painless enlargement of unilateral or bilateral testicles, hard texture and no tenderness, and is the source of extramedullary recurrence of leukemia second only to CNSL. Leukemia infiltration can also affect various tissues and organs such as the lungs, pleura, kidneys, digestive tract, heart, brain, uterus, ovaries, breasts, parotid glands and eyes, and show dysfunction of corresponding organs.

9. Symptoms of chronic myelogenous leukemia

Slow onset, often without symptoms in the early stages, mostly due to health examinations or medical treatment for other diseases only found abnormal blood or splenomegaly and diagnosed. With the development of the disease, symptoms such as fatigue, hypothermia, hyperhidrosis or night sweats, and weight loss may occur. Due to splenomegaly, she felt symptoms of left upper quadrant bulging and fullness after eating. The most prominent part of the examination was splenomegaly, which often reached the umbilical plane at the time of medical treatment. The condition can be stable for 1 to 4 years, and then enter an accelerated period, anemia and more symptoms quickly appear, and then quickly enter a period of rapid change, which can rapidly change to AML or ALL. The clinical manifestation is exactly the same as that of acute leukemia, and the treatment effect and prognosis are worse Acute leukemia is worse and usually dies quickly.

Leukemia treatment

Because the classification and prognosis of leukemia are complicated, there is no one-size-fits-all treatment method, and it is necessary to develop a treatment plan based on detailed classification and prognosis. At present, there are the following types of treatment methods: chemotherapy, radiation therapy, targeted therapy, immunotherapy, stem cell transplantation, etc. Through reasonable comprehensive treatment, the prognosis of leukemia has been greatly improved, a considerable number of patients can be cured or long-term stability, the era of leukemia is "incurable disease" has passed.

1.AML treatment (non-M3)

Usually need to be combined with chemotherapy, the so-called "induction chemotherapy", commonly used DA (3 + 7) scheme. After induction therapy, if remission is achieved, further intensive consolidation chemotherapy or stem cell transplantation procedures can be continued according to the prognostic stratification arrangement. After consolidation treatment, maintenance treatment is usually not performed at present. You can stop the drug observation and follow up regularly.

2.M3 treatment

Due to the success of targeted therapy and induction of apoptosis therapy, PML-RAR-positive acute promyelocytic leukemia (M3) has become the best prognostic type in the entire AML. More and more studies show that all-trans retinoic acid combined with arsenic treatment can cure most patients with M3. The treatment needs to be carried out strictly according to the course of treatment, and the length of the later maintenance treatment is mainly determined based on the residual condition of the fusion gene.

3.ALL treatment

Induction chemotherapy is usually performed first, and there are differences in the commonly used protocols for adults and children. However, in recent years, studies have suggested that the results of treating children with adults may be better than traditional ones. Continuation of consolidation and maintenance treatment is required after remission. High-risk patients have the conditions to do stem cell transplantation. Patients with a positive Ph1 chromosome are recommended to be treated with a tyrosine kinase inhibitor.

4. Treatment of chronic myelogenous leukemia

Chronic phase is preferred for tyrosine kinase inhibitors (such as imatinib). Early and adequate treatment is recommended. Delayed use and irregular use can easily lead to drug resistance. Therefore, if you decide to use imatinib, don't delay first, and you must continue to take it for a long time (near life), and do not reduce or stop taking it without authorization, otherwise it may easily lead to drug resistance. Accelerated and sudden changes usually require targeted treatment (imatinib dose or second-generation drugs), and then choose the opportunity to arrange an allogeneic transplant as soon as possible.

5. Chronic lymphocyte therapy

Early asymptomatic patients usually do not require treatment, and in the later stages, multiple chemotherapy options can be selected, such as Liu Coran monotherapy, fludarabine, cyclophosphamide combined with melova, and other chemotherapy. The new drugs bendamustine and anti-CD52 monoclonal antibody are also effective. In recent years, it has been found that targeted therapy of BCR pathway inhibitors may have significant effects. Conditional refractory patients can consider allogeneic transplantation.

6. Treatment of central nervous system leukemia

Although ALL, AML, M4, M5 and other types are often combined with CNSL, other acute leukemias can also occur. Because common drugs are difficult to penetrate the blood-brain barrier, these patients often need a lumbar puncture to prevent and treat CNSL. Some intractable patients may require total craniocerebral spinal cord radiotherapy.

7. Stem Cell Transplant

Except for a few special patients who may benefit from autologous transplantation, the vast majority of patients with leukemia should undergo allogeneic transplantation. With the advancement of transplantation technology, donor selection, transplantation risks, and long-term prognosis have all improved significantly. Therefore, allogeneic transplantation is currently an important radical method for various high-risk leukemias.

8. Prospects for new treatments

Although transplantation can achieve better survival effects, complications such as graft-versus-host disease may seriously affect the quality of life of patients. Therefore, selective immunotherapy and various molecular targeted therapies are the hope of curing leukemia in the future, such as tumor vaccines, cell therapy, cell signal pathway regulators, and so on.

Leukemia prognosis

In addition to chronic myelogenous leukemia, acute leukemia and chronic lymphocytic leukemia have a variety of different prognostic indicators. According to different indicators, these patients can be divided into different prognostic levels, and different intensity treatments can be taken. Therefore, modern medicine's understanding of leukemia is becoming more and more detailed. After diagnosis, all patients should complete the comprehensive examination required for various prognostic stratifications as much as possible, and then develop individualized treatment plans. Among these prognostic indicators, chromosomal and various genetic abnormalities are particularly important. ^[1-3]