John, a senior engineer, has had less-than-ideal lifestyle habits for years. He often stays up late, has irregular eating patterns, favors high-fat and high-sugar foods, and seldom exercises. These unhealthy practices led to a gradual increase in his weight and a decline in his health. One day, he noticed a lump under his arm while showering, which prompted him to seek medical attention. After a series of medical examinations, John was diagnosed with non-Hodgkin's lymphoma. This case serves as a reminder that long-term poor lifestyle habits are potential triggers for serious diseases like lymphoma.

Lymphoma is a cancer that originates from the lymphatic system, the body's primary immune tissue, which includes lymphocytes, lymph nodes, the spleen, and the tonsils. Lymphoma affects the body's ability to fight infections and diseases. Based on the type of cancer cells, lymphoma is categorized into Hodgkin's lymphoma and the more common non-Hodgkin's lymphoma. If not treated promptly, it can spread rapidly throughout the body, posing a severe threat to health. While the exact causes of lymphoma are not fully understood, unhealthy lifestyle habits are believed to contribute to its development.

**Primary Causes of Lymphoma**:

1. **Genetic Factors**: Some genetic mutations can increase the risk of lymphoma, although genetic factors typically need to interact with other environmental factors to lead to lymphoma.

2. **Immune System Abnormalities**: Dysfunctions in the immune system may result in uncontrolled proliferation of lymphocytes, increasing the risk of lymphoma.

3. **Viral Infections**: Certain viruses, such as the Epstein-Barr virus (EBV) and human immunodeficiency virus (HIV), are associated with the development of lymphoma.

4. **Environmental Factors**: Exposure to certain chemicals, radiation, or other environmental factors may increase the risk of lymphoma.

**Treatment Methods for Lymphoma**:

1. **Drug Therapy**:

   - **Chemotherapy**: Chemotherapeutic agents are used to kill malignant lymphoma cells. This approach is suitable for both early-stage and advanced lymphoma patients and typically requires several weeks to several months of treatment.

   - **Targeted Therapy**: Targeted therapies interfere with the growth signals of lymphoma cells and apply to specific subtypes of lymphoma.

   - **Immunotherapy**: Utilizing the immune system to attack lymphoma cells, including immune checkpoint inhibitors and CAR-T cell therapy.

2. **Radiation Therapy**: Radiation therapy is employed to selectively kill lymphoma cells, usually in cases where localized lymph nodes are affected.

3. **Surgical Treatment**: Surgery is generally used for early-stage lymphoma patients and involves the removal of affected lymph nodes or lymphatic tissue.

**Applicable Patient Groups or Stages and Treatment Effects**:

1. **Chemotherapy**: Suitable for advanced lymphoma patients, it can reduce tumor size in a short time but may have noticeable side effects. Treatment effectiveness typically becomes apparent within weeks to months, depending on individual factors and disease severity.

2. **Targeted Therapy**: Applicable to specific lymphoma subtypes, it can be effective for some patients. Treatment effectiveness generally manifests within weeks to months.

3. **Immunotherapy**: Suitable for some lymphoma patients, it may result in long-term remission or a cure. The timeframe for effectiveness varies among individuals.

4. **Radiation Therapy**: Commonly used for local control, its effects can be seen within a few weeks.

5. **Surgical Treatment**: Appropriate for early-stage lymphoma patients, post-surgery recovery typically takes some time.

In summary, the treatment of lymphoma varies depending on the patient's disease stage, the severity of the condition, and the lymphoma subtype. During treatment, patients should collaborate closely with their medical team, follow medical advice, and have regular follow-ups to monitor treatment effectiveness and manage side effects. The timeframes and effectiveness of treatment can vary among individuals, so patients should maintain patience and a positive attitude. Additionally, preventive measures such as regular check-ups, a healthy lifestyle, and avoiding potential carcinogens are essential for reducing the risk of lymphoma.