Understanding Bone Marrow Cancer

At the centre of the bones is a soft, spongy material called the bone marrow. It consists of stem cells that give rise to RBCs, WBCs and platelets.
When these stem cells start growing abnormally or at an accelerated rate, bone marrow cancer may happen. Different types of cancer can develop in the bone marrow, such as leukaemia, multiple myeloma, lymphoma, etc.
Types
Bone marrow cancer is of the following types based on the cells affected:
1.    Leukaemia
Leukaemia is the type of cancer in which uncontrolled proliferation of WBCs occurs. These WBCs may be immature or mature and interfere with the body’s regular functioning. The body’s defence mechanism gets disrupted, increasing susceptibility to infections. Leukaemia is further divided into:
Acute Leukaemia:
In acute leukaemia, immature WBCs, called blasts, proliferate rapidly.(more than or equal to 20% in blood or Bone marrow)
Chronic Leukaemia:
In chronic leukaemia cases, more mature cells rapidly multiply.
2.    Multiple myeloma
Multiple myeloma is the type of cancer that affects plasma cells. Normal Plasma cells are responsible for making antibodies.
3.    Lymphoma
Lymphoma is the type of cancer in which lymphocytes rapidly multiply, forming tumours that compromise the body’s immune system. Lymphoma is of two types:
1.    Hodgkin’s lymphoma – affecting B lymphocytes
2.    Non-Hodgkin’s lymphoma – involving B or T lymphocytes
Symptoms
Symptoms develop depending on the type of cancer, its location, severity, and how aggressive its progression is.
Leukaemia
Leukaemia is a cancer of the WBCs. Symptoms that patients with leukaemia would present are:
●      Bone pain
●      Swollen lymph nodes
●      Unexplained weight loss of more than 10% body weight in a short period without specifically trying
●      Petechiae on the skin (pinpoint red dots)
●      Weakness and fatigue
●      Frequent infections since the body’s defence mechanisms are affected
●      Fever and chills
●      Liver and spleen enlargement
●      Bruising easily
●      Night sweats
Multiple myeloma
Multiple myeloma is a common type of bone marrow cancer. Some of the symptoms are:
●      Weakness and fatigue
●      Increased susceptibility to infections
●      Increased frequency of urination
●      Confusion, increased thirst
●      Pain in the bone and increased risk of fracture
●      Unexplained weight loss of more than 10% body weight in a short period without specifically trying
●      Nausea and vomiting
●      Backache, Bony pain
●      Fracture(Pathological fractures)
●      Renal failure
Lymphoma
Lymphoma presents with the following symptoms:
●      A persistent cough that doesn’t subside
●      lymph nodes enlargement in neck,axillary, groin
●      Itchy skin, the appearance of rashes or skin lumps
●      Fever, weight loss, night sweats
●      Loss of appetite
●      Pain in the abdomen
●      An enlarged spleen gives rise to a feeling of bloating all the time.
Causes
Causes of bone marrow cancer or non-specific. However, some contributing factors may be:
●      Immunocompromised individuals (post-transplant or those taking immunosuppressant drugs, HIV patients)
●      Exposure to harmful radiation, chemicals, fumes, pesticides
●      Genetic predisposition
●      Smoking and drinking
●      Obesity
Diagnosis
The doctor first assesses the medical history and familial history and performs a physical examination. Following tests are advised to diagnose bone marrow cancer:
●      Blood and urine tests: These are done to assess kidney function, electrolyte levels, and blood cell count. A CBC (complete blood count), tumour markers, and a complete metabolic profile may help diagnose bone marrow cancer.
●      A biopsy of the bone marrow may help check for the presence of cancer cells.
●      Specific scans such as x-rays, PET scans, CT scans, and MRI may help detect changes in the bone structure.
The confirmatory test for bone marrow aspiration & biopsy since it provides information about the specific type of cancer. Imaging techniques help assess how much the disease has progressed. In case of suspected lymphoma, lymph node biopsy is mandatory
Treatment
The treatment of bone marrow cancer depends on multiple factors such as age, the extent of spread of cancer and the overall health of the affected individual. Considering the above factors, the doctor may advise the following treatment options:
●      Chemotherapy: Specific drugs are injected into the body to find and destroy cancer cells.
●      Radiation therapy: This treatment aims to reduce the size of tumour cells, lower pain, and kill cancer cells by delivering high-energy beams to a targeted organ.
●      Transplant: The cancerous bone marrow can be transplanted with a healthy one. This procedure is also known as stem cell transplant. It is combined with chemotherapy and radiation therapy to prevent the risk of cancer relapse in the new and healthy bone marrow.
●      Targeted drug therapy (Immunotherapy): These drugs specifically target cancer cells, unlike chemotherapy.
●      Biological therapy: Immune system of the affected individual can help destroy cancer cells.(CART-T cell therapy)
Complications
If cancer is untreated, it can prove fatal owing to reduced immunity, weakness and increased susceptibility to infections.
Risk Factors
Risk factors contributing to bone marrow cancer are non-specific, and the factors given below may have a role to play:
●      Compromised immune system
●      Excessive exposure to harmful radiation, chemicals, fumes, pesticides
●      Familial history of cancer
●      Smoking and drinking
●      Obesity
Prognosis
The prognosis of patients having bone marrow cancer is highly individual specific. It depends on how an individual responds to therapy and has a lot to do with their willpower, mental health, the extent of spread of cancer and underlying conditions.
Adult Acute Leukaemia are curable in 40-70% cases (childhood acute leukaemia – 80-90%)
-Lymphoma are curable 50-60% cases
-Low grade lymphoma, life can be prolonged from 10-20 yrs
– Multiple Myeloma life can be prolonged 5-8 yrs
– The author is Director, Department of Haematology and BMT, Max Super Speciality Hospital, Saket, New Delhi