Introduction to drug treatment for lung cancer and medications used at different stages

August 24, 2024

Introduction to drug treatment for lung cancer and medications used at different stages

Lung cancer is one of the most common cancers with the highest morbidity and mortality worldwide. It is mainly divided into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) according to histological classification. There are many treatments for lung cancer, and drug therapy is a very important part of it, especially when surgery cannot cure it or the tumor has spread. This article will introduce in detail the drug treatments for lung cancer at all stages, including targeted drugs, chemotherapy drugs, immunotherapy drugs and their use methods.

1. Early stage lung cancer (stage I and II)

In early-stage lung cancer (stages I and II), the cancer is usually confined to the lungs or nearby lymph nodes. Surgery is often the main treatment, followed by drugs to reduce the risk of recurrence.

1. Adjuvant chemotherapy

For patients with stage II lung cancer, adjuvant chemotherapy is often recommended after surgery to eliminate possible tiny residual tumor cells and reduce the risk of recurrence. Commonly used chemotherapy drugs include:

Cisplatin: Cisplatin is a platinum-based drug that works by interfering with DNA replication in cancer cells and is usually used in combination with other chemotherapy drugs.

Pemetrexed : This is an antifolate drug that is particularly useful for non-squamous non-small cell lung cancer. It works by inhibiting several key enzymes in DNA synthesis to stop the proliferation of cancer cells.

These chemotherapy regimens are generally given in cycles of 3 weeks, for a total of 4-6 cycles. Side effects include nausea, vomiting, fatigue, hair loss, bone marrow suppression, etc.

2. Targeted therapy

For patients with early-stage lung cancer who carry specific gene mutations (such as EGFR mutations and ALK rearrangements), postoperative adjuvant targeted therapy may be more effective. Commonly used drugs include:

Gefitinib and erlotinib : Patients with EGFR mutations can use these first-generation EGFR tyrosine kinase inhibitors (TKIs) to effectively block signaling pathways and inhibit tumor growth.

Osimertinib: A third-generation EGFR-TKI that is particularly effective against the T790M mutation and is often used as an adjuvant therapy after surgery to prevent recurrence.

These drugs are usually taken orally daily and the treatment course may last for several years. The main side effects include rash, diarrhea, interstitial pneumonia, etc.

2. Locally advanced lung cancer (stage III)

In stage III lung cancer, the tumor has spread to nearby lymph nodes or into the chest cavity but has not spread to distant organs. Treatment usually requires a combination of approaches, including radiation therapy, chemotherapy, targeted therapy, and immunotherapy.

1. Concurrent chemoradiotherapy

The standard treatment for stage III non-small cell lung cancer is usually concurrent chemoradiotherapy, which means that radiotherapy and chemotherapy are given at the same time. This approach can enhance the effect of chemotherapy drugs and increase the local tumor control rate. Commonly used chemotherapy drugs include:

Cisplatin or carboplatin: Both are platinum drugs that can enhance the effect of radiation therapy.

Etoposide: Often used in combination with cisplatin, it can inhibit cell division.

Paclitaxel: It prevents cell division by stabilizing microtubules and is more effective when used in combination with carboplatin.

The main side effects are bone marrow suppression, esophagitis, radiation pneumonitis, etc.

2. Immunotherapy

For patients with unresectable stage III non-small cell lung cancer, immune checkpoint inhibitors can be used to further consolidate the treatment effect after stabilization by radiotherapy and chemotherapy. Typical drugs include:

Durvalumab: A PD-L1 inhibitor that can enhance the immune system’s ability to recognize and attack tumor cells. Common side effects include skin reactions, fatigue, pneumonia, etc.

Immunotherapy is usually given as an intravenous infusion every two weeks for a year or until the disease progresses.

3. Advanced or metastatic lung cancer (stage IV)

Stage IV lung cancer means that the tumor has spread to distant organs, such as bones, liver, brain, etc. The treatment goal at this stage is to control the disease, prolong survival, and improve quality of life. Drug therapy is the main means.

1. Targeted therapy

In stage IV non-small cell lung cancer, molecular targeted therapy has become a key treatment strategy, especially for patients with specific gene mutations. Commonly used drugs include:
EGFR-TKIs: such as erlotinib, gefitinib, osimertinib, etc., are suitable for patients with EGFR mutation-positive.

ALK/ROS1 inhibitors: such as crizotinib and ceritinib , used for patients with ALK or ROS1 gene rearrangement.

BRAF inhibitors: such as dabrafenib combined with trametinib, suitable for patients with BRAF V600E mutation.

Targeted therapy is usually taken orally daily until the disease progresses. The main side effects include rash, diarrhea, and high blood pressure.

2. Immunotherapy

Immunotherapy has become a first-line treatment option for stage IV non-small cell lung cancer, especially for patients with high PD-L1 expression. Commonly used drugs include:

Pembrolizumab: A PD-1 inhibitor that can be used alone or in combination with chemotherapy.

Nivolumab and atezolizumab: Both are immune checkpoint inhibitors and are often used as second-line treatment after chemotherapy failure.

Immunotherapy is administered via intravenous infusion, usually every 2-3 weeks, and side effects include immune-related adverse reactions such as rash, hepatitis, pneumonia, etc.

3. Chemotherapy

For patients without specific gene mutations or for whom immunotherapy is not suitable, chemotherapy remains the main treatment for stage IV lung cancer. Commonly used chemotherapy drugs include:

Pemetrexed combined with cisplatin: suitable for non-squamous non-small cell lung cancer.

Paclitaxel combined with carboplatin: suitable for squamous cell lung cancer.

Chemotherapy is usually given in cycles of 3 weeks, and the course of treatment lasts 4-6 cycles. Side effects include nausea, vomiting, hair loss, fatigue, bone marrow suppression, etc.

4. Maintenance therapy

After achieving partial remission or disease stabilization with initial treatment, some patients can receive maintenance treatment to prolong progression-free survival. Commonly used drugs include:

Bevacizumab: An anti-VEGF monoclonal antibody, often used in combination with chemotherapy.

Pemetrexed : As a maintenance treatment for non-squamous cell lung cancer, it is suitable for patients who still respond to initial treatment.

Maintenance therapy is usually continued until disease progression or unacceptable side effects occur.

IV. Drug treatment of small cell lung cancer

Due to its highly malignant and rapidly progressive characteristics, small cell lung cancer (SCLC) requires drug therapy throughout almost all stages of treatment.

1. Chemotherapy

Chemotherapy is the cornerstone of SCLC treatment. Commonly used drugs include:

Cisplatin combined with etoposide: It is the first-line chemotherapy regimen for limited-stage and extensive-stage SCLC.

Carboplatin: It can be used as an alternative to cisplatin in patients with renal impairment.

Chemotherapy cycles are usually every 3 weeks, and side effects include nausea, vomiting, bone marrow suppression, hair loss, etc.

2. Immunotherapy

Immunotherapy has become one of the standard treatments for extensive-stage small cell lung cancer. Typical drugs include:

Atezolizumab: A PD-L1 inhibitor, often used in combination with chemotherapy.

Durvalumab: Also a PD-L1 inhibitor, it is used in combination with chemotherapy to treat extensive-stage SCLC.

Immunotherapy is usually administered intravenously every 2-3 weeks, and side effects include fatigue, immune-related adverse reactions, etc.

V. Conclusion

Drug treatment options for lung cancer vary depending on the patient's specific circumstances, including the type of cancer, stage, genetic mutation status, and the patient's