The overall rate of new cases of CLL is 4.6 per 100,000 per year. It is more frequent in men, 6.3 per 100,000, than for women, 3.3 per 100,000. It predominantly affects older adults, with the median age at diagnosis being around 70 years. CLL accounts for approximately 25-30% of all leukemia cases in adults.

The exact cause of CLL is unknown, but several factors are believed to contribute to its development:

• Genetic mutations

• Family history of CLL or other blood cancers

• Exposure to certain chemicals (e.g., Agent Orange, pesticides)

• Older age (most common in individuals over 60)

This disorder may be hereditary as about 5% of people who are affected by CLL have family members with the condition. Relatives of an individual who has been diagnosed with CLL have a 5 to 7 times greater chance of developing CLL. In CLL, usually an abnormal chromosome is present in the patient, meaning there was either a deletion a the loss of part of a chromosome. The loss of part of chromosome 13 is common, as well as the deletion of chromosome 11 and 17. These abnormalities are important in the causation of the disorder, but the genes involved in the development of CLL have not yet been determined.

Many people with chronic lymphocytic leukemia have no symptoms at first. Signs and symptoms can develop as the cancer progresses. They may include:

• Enlarged, but painless, lymph nodes

• Fatigue

• Fever

• Pain in the upper left portion of the abdomen, which may be caused by an enlarged spleen

• Night sweats

• Weight loss

• Frequent infections

Those who do develop early symptoms may experience: enlarged lymphnodes, liver, or spleen; fatigue, night sweats, fever, loss of appetite, weight loss, frequent infections, and abnormal bruising. The patient loses the ability to fight off infections as the disorder advances causing viral infections to become an increasing concern. CLL can invade other organs as well including the eye socket, lungs, heart, and gastrointestinal tract. Jaundice, swelling and yellow pigmentation of the skin can also occur.

• Blood tests showing high levels of lymphocytes.

• Flow cytometry to analyze the characteristics of the lymphocytes.

• Bone marrow biopsy and aspiration.

• Imaging tests (CT scans, ultrasound) to check for lymph node enlargement and organ involvement.

• Genetic tests to identify specific chromosomal abnormalities associated with CLL.

Patients who are first diagnosed with CLL do not show symptoms therefore they are commonly discovered by chance through blood testing. In the blood test, an abnormally high white blood cell count indicates the possibility of CLL. The diagnosis is then confirmed through a bone marrow biopsy, a lymph node biopsy, or blood tests including a complete blood count, (measures the number of each typer of blood cell), and flow cytometry, (screens blood cells to determine if they are cancerous). Regular blood tests and physician exams are used to watch for signs of progression because early-stage CLL can take years to progress. Being aware about the stages of CLL is also important to know appropriate treatment options for each stage.

• Watchful waiting (for early-stage or slow-growing CLL).

• Chemotherapy (e.g., fludarabine, cyclophosphamide).

• Targeted therapy (e.g., ibrutinib, venetoclax).

• Monoclonal antibodies (e.g., rituximab, obinutuzumab).

• Stem cell transplant (for aggressive or refractory cases).

• Supportive care to manage symptoms and side effects.

The treatment for Chronic Lymphocytic Leukemia depends on the stage of condition of the patient. Those in an early stage do not typically show symptoms therefore they do not need any treatments. In the intermediate and more advanced stages the treatment options are considered based on the the symptoms the individual shows. Some treatment options include: Chemotherapy: a drug treatment the kills cancer cells which is administered intravenously or taken as a pill.); Targeted Drug Therapy: a treatment which uses drugs or other substances to identify and and attack specific cancer cells. Drugs that are used for treatment include: Rituxan, CAMPATH, and Arzerra. Bone marrow stem cell transplant: strong chemotherapy drugs are used to kill the stem cells in the bone marrow which are creating the diseased lymphocytes. Healthy adult stem cells from a donor are infused into the patients' blood to travel to the bone marrow and start making new, healthy blood cells.

• CLL is generally a slow-growing cancer, and many patients live for many years with the disease.

• Prognosis varies depending on factors such as age, overall health, stage at diagnosis, and specific genetic mutations.

• Median survival can range from several years to over a decade, with newer treatments continually improving outcomes.

Detection of CLL at an early stage fresults in a more favorable prognosis. If there is bone marrow involvement, showing a diffuse pattern of lymphocytes in a bone marrow biopsy, the prognosis is less favorable. Older patients have a less favorable prognosis, as do patients having a higher number of abnormal lymphocytes. Women have a more favorable prognosis than men, and deletions of part of chromosome 13 give a more favorable prognosis.

1. American Cancer Society: [Chronic Lymphocytic Leukemia (CLL)](https://www.cancer.org/cancer/chronic-lymphocytic-leukemia.html)

2. Leukemia & Lymphoma Society: [Chronic Lymphocytic Leukemia (CLL)](https://www.lls.org/leukemia/chronic-lymphocytic-leukemia)

3. National Cancer Institute: [Chronic Lymphocytic Leukemia (CLL) Treatment](https://www.cancer.gov/types/leukemia/patient/cll-treatment-pdq)

4. Mayo Clinic: [Chronic Lymphocytic Leukemia (CLL)](https://www.mayoclinic.org/diseases-conditions/chronic-lymphocytic-leukemia/symptoms-causes/syc-20352428)