Hematology Oncology Facts - Viewpoints from Expert Doctors
Last updated date: 25-Feb-2022
16 mins read
The body contains around 4 to 5 liters of blood circulating in our bodies all the time, all day long, every day. The fact that blood is essential for life because it circulates and delivers important nutrients and oxygen to the body’s cells. It also takes the metabolic waste products away from these cells.
Blood is very unique in its composition, it can’t be manufactured or made. The only source of blood for patients in need of blood transfusion is generous blood donors.
Four main components make the human blood, and they are:
- Red blood cell
- White blood cells.
Red blood cells
They represent 40% to 45% of the blood volume. They are made in the bone marrow at a rate of four to five billion per hour. They have a lifespan of 120 days, then they are replaced.
They are the smallest blood cells. They look like small plates in their inactive form. Platelets are amazing. They control bleeding whenever a wound occurs. When there is an injury, the blood vessel sends a signal to the platelets, when they receive the signal, they travel to the injury area and transform into their active form. They gather in the shape of clusters and plug the wound until it heals.
Plasma is the liquid portion of the blood. its yellowish and is mainly made up of water, but it also contains some proteins, sugars, hormones and salts. It is also responsible for transporting water and nutrients to the body’s tissues.
White blood cells
Although they only represent 1% of the blood volume, they are very important. White blood cells are the defense line of the body. They are essential for a healthy body and protection against infections and illnesses. They are constantly generated from the bone marrow. They circulate the tissues and attack foreign bodies like bacteria and viruses.
Hematology and oncology
Hematology oncology definition
Blood consists of four components, as we just explained. They oxygenate our organs, attack foreign bodies and stop bleeding. However, some components may indicate an abnormality, which can lead to blood cancer eventually. This is when hematology oncology comes into play.
It refers to the combined medical practice of hematology, the study of blood physiology, and oncology, the study of cancer. This field is responsible for studying, diagnosing and treating blood cancers.
You will be advised to go to a hematologist-oncologist in cases of:
- Hodgkin lymphoma
- non-Hodgkin lymphoma
- Multiple myeloma
- Iron deficiency anemia
- Sickle cell disease
- Polycythemia vera
- Clotting disorders
- Von Willebrand disease
Leukemia is the cancer of blood and bone marrow. Usually, leukemia cells are immature white blood cells. In fact, the word leukemia comes from the Greek words for white.
As a general role, cancer is defined as the uncontrollable division and growth of abnormal cells. Cancer can develop anywhere in the body. In leukemia, this rapid uncontrollable growth of cells occurs in the bone marrow of bones. Then these abnormal cells spill into the bloodstream. Unlike other cancers, blood cancer doesn’t form into a mass or tumor that can be seen using imaging tests.
There are many types of leukemia, some are more common in children, others are more common in adults.
- Bone marrow definition
Bone marrow is a soft spongy tissue in the center cavity of all bones. The bone marrow is the space where all types of cells are made and all types of nutrients and other resources are supplied to help these cells grow.
Hundreds of millions of blood cells are produced every day in the bone marrow to provide the body with a constant fresh supply of cells.
How does it develop? And how does it affect the body?
It begins in the newly developing blood cells in the bone marrow. All blood cells start as hematopoietic stem cells. Then, they undergo multiple divisions until they reach their adult form.
At the beginning of the division process, they develop into either myeloid cells or lymphoid cells. If they were to continue to develop normally, they will go as follows:
- Myeloid cells develop into red blood cells, platelets, and certain types of white blood cells, which are basophils, eosinophils, and neutrophils.
- Lymphoid cells develop into certain types of white blood cells which are lymphocytes and natural killer cells.
- The stem cells then divide and multiply into the needed type of blood cells. They divide into red blood cells, white blood cells and platelets.
In leukemia, however, one of these cells begins to divide rapidly in an out-of-control manner into abnormal blood cells called leukemia cells. Then these abnormal cells begin to take over space inside the bone marrow. This is so harmful in so many ways:
- Unlike other blood cells, leukemia cells are harmful and of no use.
- Other cell types have very little space and support to continue growing and multiplying.
- The final results are fewer normal blood cells are made and released into the bloodstream, and more leukemia cells are made. Without an adequate number of normal cells, the body organs will not get enough oxygen and nutrients.
Types of leukemia
Doctors usually classify leukemia according to how fast the disease worsens and according to the type of cells involved. There are two classifications. The one related to the speed of the progress of the disease consists of:
- Acute leukemia
In this case, leukemia cells are rapidly dividing and the disease worsens very quickly. People with acute leukemia feel sick within a few weeks from leukemia cell formation. It is the most common cancer in children.
Acute leukemias are distinguished by abnormal cells that are less mature, grow rapidly, and exit the bone marrow as defective cells known as "blasts." These blasts push out healthy cells in the bone marrow, causing symptoms to appear quickly. Blasts typically account for 1% to 5% of marrow cells, and having more than 20% blasts in the bone marrow is necessary for a diagnosis of acute leukemia.
- Chronic leukemia
In this type, cells have features of both mature and immature cells. Some of the cells may have matured to the point that they do part of their function but not at full capacity. This disease worsens more slowly than acute leukemia. Patients don’t notice any symptoms for years. It is more commonly seen in adults.
Chronic leukemias grow slowly and symptoms may appear years later. They are mostly made up of more developed and functioning cells, and there aren't a lot of blasts in there.
Leukemia is classified according to the cell type into:
- Myeloid leukemia
It means that leukemia has developed from the myeloid cell line. It can be subdivided into acute and chronic myeloid leukemia. Acute myeloid type is the most common type of leukemia and it is more common in older adults.
Myeloid cells include monocytes, macrophages, neutrophils, basophils, eosinophils, erythrocytes, and megakaryocytes.
- Lymphocytic leukemia
It means that leukemia has developed from the lymphoid cell line. It can be subdivided into acute and chronic as well. The acute type is the most common in children, teens and young adults.
Lymphoid cells include T cells, B cells, and natural killer cells.
As such, the four major subtypes of leukemia are:
- Acute lymphoblastic leukemia (ALL): ALL develops when primitive white blood cells of lymphoid origin proliferate but do not mature into normal B and T cells. It is the most prevalent leukemia in children, accounting for up to 80% of cases in this age range compared to 20% of cases in adults.
- Acute myelogenous leukemia (AML): AML is similarly distinguished by blast hyperplasia, but this time of myeloid origin. It accounts for half of all leukemia cases diagnosed in teens and young adults. It is the most prevalent kind of adult acute leukemia.
- Chronic lymphocytic leukemia (CLL): CLL develops when mature but aberrant lymphoid white blood cells undergo hyperplasia, resulting in a monoclonal population of malfunctioning lymphocytes. The majority of occurrences occur in persons between the ages of 60 and 70.
- Chronic myelogenous leukemia (CML): CML is characterized by a monoclonal population of self-renewing, defective myeloid cells (e.g., neutrophils, basophils, eosinophils, macrophages). The majority of instances affect persons between the ages of 25 and 60.
Epidemiology of leukemia
- It is the tenth most common cancer according to newly diagnosed cases every year.
- Males have a greater illness burden than females (incidence rate of 6.1 per 100,000 vs. 4.3 per 100,000), as does the mortality rate (4.2 vs. 2.8 per 100,000 in males vs. females).
- Although it is considered a disease of children, it usually affects adults more. Surprisingly, the likelihood of developing this cancer increases with age. It is more common in men than women.
- Chronic leukemia has a unimodal age distribution, with incidence and death rates increasing with age. ALL and AML, which are serious illnesses that affect both children and adults, exhibit bimodal age distributions.
- Worldwide, the total number of leukemia cases grew by 26% between 2005 and 2015, with population growth and age accounting for all but 3% of this rise.
Causes of leukemia
Leukemia occurs when a single cell’s DNA in the bone marrow changes. It becomes mutated so it doesn’t develop or function normally. When this abnormal cell multiplies, all the daughter cells are mutated and abnormal as well.
Several risk factors are associated with a higher risk of developing leukemia:
- Worldwide, the total number of leukemia cases grew by 26% between 2005 and 2015, with population growth and age accounting for all but 3% of this rise.
- Exposure to benzene is a risk factor for adult leukemia, particularly AML.
- Chemotherapy, particularly alkylating drugs and topoisomerase inhibitors, raises the chance of developing acute leukemia later in life.
- A history of any hematologic malignancy increases the likelihood of getting another subtype of leukemia.
- Viral infections (for example, human T-cell leukemia virus and Epstein Barr virus) have been associated to ALL subtypes.
- Several genetic disorders (for example, Down syndrome, Fanconi anemia, Bloom syndrome, and Li-Fraumeni syndrome) have been linked to an elevated risk of AML and ALL.
Leukemia develops as a result of the malignant transformation of pluripotent (i.e., capable of producing both myeloid and lymphoid progenitors) hematopoietic stem cells. Rarely, it may also feature a more dedicated stem cell with a restricted ability for self-renewal.
These malignant cells in acute leukemias are typically immature, poorly differentiated, aberrant leukocytes (blasts) that can be lymphoblasts or myeloblasts. These blasts can undergo clonal growth and proliferation, resulting in the replacement and interference of normal blood product formation and function by malignant cells, resulting in clinical symptoms.
Symptoms of leukemia
- Acute Leukemia
Acute leukemia typically presents without warning, however the most frequent symptoms are fever, tiredness, and bleeding. Hepatosplenomegaly, lymphadenopathy, and musculoskeletal complaints (particularly in the spine and long bones) can also be indicators of the disease's presence. Adults may also experience more pronounced anemia-related symptoms, such as shortness of breath, or thrombocytopenia-related symptoms, such as excessive bruising or heavy menstrual periods.
- Chronic Leukemia
Adults are nearly entirely affected by chronic leukemia subtypes. Many individuals are asymptomatic at the time of diagnosis, and are discovered by chance when a CBC for another cause reveals significant leukocytosis.
In certain cases, hepatosplenomegaly and lymphadenopathy can be seen, but bleeding and bruising are less prevalent, showing characteristics similar to acute leukemia subtypes.
Here are some of the most common signs and symptoms:
- Little energy
- Tire easily
- Pale skin tone
- Frequent infections
- Shortness of breath
- Night sweats
- Unexplained weight loss
- Swollen lymph nodes in the neck, underarms, groin, stomach, and enlarged spleen or liver
- Easy bruising and bleeding such as nosebleeds and bleeding gums
- Bone and joint pain or tenderness
- Pain or full feeling under the ribs on the left side.
But you have to keep in mind that if you have a chronic type of leukemia, you may not have any noticeable signs or symptoms.
Diagnosis of leukemia
Multiple tests are required to confirm a diagnosis and, later, to stage the condition. A complete blood count (CBC), complete metabolic panel (CMP), liver function test (LFT), and coagulation panel are all useful initial examinations that are frequently followed by a peripheral blood smear and a bone marrow samples.
A bone marrow aspiration and biopsy are frequently necessary to diagnose acute leukemias. Peripheral blood analysis is frequently sufficient for chronic leukemias, and an invasive bone marrow biopsy may not be required.
Management of leukemia
To begin therapy, patients with leukemia should be referred to a hematologist-oncologist. The treatment for leukemia varies greatly depending on the subtype and patient variables (e.g., age, comorbid conditions). Most treatments include chemotherapy as a staple; however, radiation therapy, monoclonal antibodies, and stem cell transplantation are all possibilities.
Notably, supportive care is critical during induction chemotherapy for acute leukemias. Because chemotherapy depletes normal blood cells, there is an increased risk of infection and bleeding; as a result, antibacterial medicines and blood-production transfusions may be necessary.
Antibiotics, antifungal, anti-nausea medicine, and blood product transfusions are all given to help the patient during induction. Vaccines against the flu and pneumonia are also indicated.
Because leukemia is a wide diagnosis with non-specific symptoms, the differential diagnosis is extensive as well. Infection, medication side effects, vitamin/micronutrient deficits, and other myelodysplastic diseases that might produce abnormalities in blood cell lines must be ruled out.
Consider the following when seeing abnormalities in the blood count:
- B12 and folate deficiencies
- Copper deficiencies
- Viral Infections (e.g., HIV, Cytomegalovirus, Epstein Barr virus)
- Drugs (chemotherapeutic agents, valproic acid, ganciclovir, mycophenolate mofetil)
- Autoimmune conditions (e.g., systemic lupus erythematosus)
Long-term survival with leukemia varies greatly depending on the subtype of leukemia, cytogenetic and molecular findings, patient age, and comorbid diseases. In general, the 5-year cancer survival rate for leukemia has grown from 33% in 1975 to 59% in 2005.
Complications of leukemia
- Tumor lysis syndrome (TLS)
TLS is a chemotherapeutic complication that can occur when tumor cells die rapidly. The extensive cellular death releases intracellular materials into the circulation, overburdening the kidneys and resulting a dangerously high serum potassium, phosphorus, uric acid, and blood urea nitrogen levels.
- Disseminated intravascular coagulation (DIC)
DIC is a leukemia consequence in which the proteins that regulate blood clotting become hyperactive, resulting in both thrombosis and bleeding. DIC is frequently related with acute promyelocytic leukemia, however it can also be found in other forms of leukemia.
Immunosuppression caused by chemotherapy, stem cell transplantation, or leukemia raises the risk of severe infections. In an immunocompromised patient, fever with neutropenia should prompt an urgent assessment for infection cause and the beginning of broad-spectrum antibiotic treatment.
Survivors of leukemia are more likely to get other malignancies. The Childhood Malignancy Survivor Study, for example, found that the 30-year cumulative incidence of any cancer following leukemia was 5.6 percent.
The approximate duration between the initial malignancy and the incidence of the subsequent cancer was nine years. Different subtypes of leukemia or lymphoma are the most prevalent second neoplasms among childhood leukemia survivors.
To ensure that you get a comprehensive picture and understand everything related to Hematological cancers, we invited Dr. Seoree Kim who is a leading doctor at Bucheon St. Mary's Hospital, Korea to address any questions you may have from an experienced medical point of view.
1- What is hematology?
Hematological oncology deals with treatment of cancers within the construct of blood physiology. We do diagnosis, treatment plans, educate the patient and the caretaker, hospice care after the treatment. We take care of all the steps necessary to treat hematological cancers.
2- What is the role of health providers, other than doctors, in this cancer?
The treatment for cancer is done by a team and not just one doctor. We need many specialists. There are medical oncologists like us who use chemotherapy to treat, then there are surgical oncologists, and there are radiation oncologists who treat with radiation. Then, there are those who treat skin called dermatologists. Also, pathologists who can pinpoint the illness precisely. There are those who use imaging such as CT scans to locate the tumors called radiologists. Then, there are palliative medical specialists who assists with hospice care. In order to treat patients correctly, we have 34 divisions and 14 specialists who together treat the cancers. The medical oncologists act as a maestro in a concert who coordinates all the necessary efforts to treat a patient.
3- What is the role of other health providers other than doctors in cancer care?
In order to treat cancer patients, we not only need the help of doctors but a team of supporting specialists. The nursing staff helps in a variety of efforts to heal the patient. Also, act as liaison with the patient and act as their advocates. The nutritional specialists help the patient in the treatment process. Social workers consider environmental and social factors to help the patient in various ways. We deliver a total service package from a variety of points that can help the patient achieve their goals in a smooth manner.
4- What role does the multidisciplinary tumor board play in the case of treatment?
Nowadays, most hospitals that treat cancer have a multidisciplinary tumor board. Many specialists from multiple disciplines pitch in during brainstorms on how to best treat a cancer patient. The level of care and planning changes to a higher level and the various specialists throw their opinions and results in a better care level for the patient overall.
5- Where was patient is treated by tumor board?
Most recently, a male in his 50’s, was originally misdiagnosed but a team of specialists including a heart specialist was able to ascertain that the cancer had originally begun in the heart. Through chemotherapy we achieved complete remission and is currently living a healthy life. Also, we had a patient who came from Kazakhstan with prostate cancer. While performing urological exams, we conferenced with his caretaker who was 4,200 miles apart who was an integral part of setting a plan for the treatment. Also, a patient who came from Cameroon, we conferenced with his caretakers from 8,000 miles away to set a treatment plan who we treated successfully and has returned home. Aside from those cases, specialists in lung cancer, colon cancer, head & neck cancer, liver cancer, etc. meet together do add to the expertise and aid in the process of the multidisciplinary tumor board.
6- What is precision medicine and how is it used in the treatment of some patients?
Precision medicine is a new paradigm that is part of cancer treatment. Specific to a patient’s own genetic, clinical and environmental information, we use those information to come up with a highly tailored diagnostics and treatments as well as follow-ups post-surgery. The technology today is very precise and can tailor each patient’s genetic markers when treating their cancers. Long ago, cancer patients were treated in standard formats for their conditions but today we use genomics to fingerprint all the necessary markers to tailor a specifically made treatment for each patient. Depending on a patient’s MSI biomarkers, we treat each patient uniquely in a personalized therapy based on chemotherapy that considers one’s immune system. At our hospital, we use MSI biomarkers to refine our treatments to be specific to the patient’s needs and adjust the therapy accordingly. A young breast cancer patient who was in dire condition was able to achieve good results through genetic counseling and biomarkers detection. We found out her family had members who had breast and ovarian cancers through our diagnosis. Once we were ready to pinpoint a personalized treatment process, we used radiation and chemotherapies to achieve positive results. We widened the knowledge base of cancer diagnosis and treatments as well as any genetic mutations present. Thus, we are able to deliver personalized treatments that consider much more information as well as the patient’s choices of the various options we have today.
7- For a patient who is taking treatment of cancer, what kind of precautions or efforts he should do?
Even if you are diagnosed with cancer, do not lose hope. Try to think you can live with cancer and think positively. If you allow us to diagnose and treat, I believe there will be good results. Just as it takes a while to recover from a wound when fallen, it takes a longer while to readjust after cancer treatments. If there are issues, trust us to take care of them together and ultimately arrive at good results. In order to facilitate the process, we need cooperation in obtaining clinical analysis, bloodwork, imaging, etc. Also, we need transparency in terms of any potential drugs one is consuming without prescription. This would help us focus more on the patient and treatment. Cancer treatments are advancing rapidly. We are at the forefront of the development’s news. We treat patients as if they were my friends or family. We believe that our devotion to our patients is shown in the good results we pride ourselves in.
Hematological malignancies are tumors that affect the blood, bone marrow, and lymphatic systems. Lymphoma, leukemia, myeloma, myelodysplastic syndromes, and myeloproliferative neoplasms are the most common types. There are other lymphoma and leukaemia subtypes, as well as more uncommon haematological malignancies that have their own classifications.
Acute organ failure and pathogen aggressiveness are the only factors that predict short-term outcome. As a result, it does not appear acceptable to admit patients with nonterminal hematologic malignancies to the intensive care unit solely based on the prognosis of their underlying hematologic malignancy.
To accomplish successful treatment, reduce adverse events, and maintain quality of life, healthcare experts from many specializations and disciplines - doctors, nurses, physical therapists, dietitians, and so on - must be involved. Patient-centered communication and collaborative decision-making are critical to achieving positive patient outcomes.