Small Cell Lung Cancer Treatment

Small cell lung cancer (SCLC) is an aggressive form of pulmonary carcinoma that usually originates in the bronchi, the main air passages that branch away from the windpipe (trachea) and lead into each lung. Accounting for approximately 10 to 15% of all lung cancer cases, SCLC is less common than non-small cell lung cancer (NSCLC).

The leading cause of small cell lung cancer is smoking, which is responsible for the vast majority of cases. Symptoms can include a persistent cough, shortness of breath, chest pain, weight loss and fatigue. SCLC grows and spreads rapidly, and in many cases, the symptoms have progressed and become severe by the time the tumor is diagnosed.

Surgery for small cell lung cancer

Surgery is not a common treatment option for SCLC because the cancer tends to grow and spread quickly, often becoming pervasive before it is detected. However, in cases of early, limited-stage small cell lung cancer, surgery may be considered to remove a small tumor that is confined to one lung.

Surgical treatment for SCLC usually involves removing part of the lung (lobectomy) or, in some cases, the entire lung (pneumonectomy), depending on the size and location of the tumor. Surgery is typically followed by chemotherapy and/or radiation therapy to target any remaining microscopic cancer cells and reduce the risk of recurrence.

In most cases, chemotherapy and radiation therapy are the preferred treatments for small cell lung cancer, mainly because these therapies can address the primary tumor as well as any cancerous cells that may have spread to other parts of the body.

Chemotherapy for small cell lung cancer

The main treatment for both limited-stage and extensive-stage SCLC, chemotherapy enters the bloodstream and travels throughout the body to target and destroy widespread cancer cells. Given the aggressive nature of SCLC and its tendency to spread early, systemic treatment is essential.

A typical chemotherapy regimen for small cell lung cancer includes platinum-based drugs, such as cisplatin or carboplatin, combined with etoposide or irinotecan. Chemo drugs are administered in cycles consisting of a period of active treatment followed by a period of rest. This allows the body time to recover between treatment sessions.

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For limited-stage SCLC, chemotherapy is usually combined with radiation therapy for heightened effectiveness. For extensive-stage SCLC, chemotherapy may be administered as a standalone treatment. While not curative at this stage, chemo can shrink tumors, relieve symptoms and improve the patient’s quality of life.

Chemotherapy can cause side effects, such as fatigue, nausea, hair loss and increased susceptibility to infection. However, chemo is the cornerstone of SCLC treatment due to its potential effectiveness.

Radiation therapy for small cell lung cancer

An important treatment for SCLC, radiation therapy is often used in conjunction with chemotherapy to maximize treatment effectiveness. Its role varies depending on the stage of the tumor:

• Limited-stage SCLC – In this early stage, radiation therapy is commonly combined with chemotherapy in an approach known as concurrent chemoradiation. The goal is to target the cancer cells in the lung and nearby lymph nodes. Usually administered over several weeks, radiation therapy can help shrink tumors, improve symptoms and reduce the risk of recurrence.
• Extensive-stage SCLC – In this advanced stage, radiation therapy may be used to alleviate symptoms, such as pain and difficulty breathing, or target cancer that has spread to other areas of the body, such as the brain. Prophylactic cranial irradiation (PCI) is sometimes used to prevent cancer from spreading to the brain, a common SCLC metastasis site.

Radiation therapy can cause side effects, such as fatigue, skin irritation and lung inflammation (radiation pneumonitis). Still, it remains an essential component of SCLC treatment, especially for controlling localized tumors and improving overall outcomes.

Immunotherapy for small cell lung cancer

Immunotherapy is an emerging treatment option for small cell lung cancer, particularly extensive-stage SCLC. Unlike chemotherapy and radiation therapy, which directly target cancer cells, immunotherapy works by boosting the natural ability of the body’s immune system to recognize and destroy tumor cells.

The most commonly used immunotherapy drugs for small cell lung cancer are immune checkpoint inhibitors, such as atezolizumab and durvalumab, which block certain proteins (PD-L1 or PD-1) that prevent immune cells from attacking cancer. These drugs are typically combined with chemotherapy in the first-line treatment of extensive-stage SCLC to improve the response rate and outcome.

In some cases, immunotherapy can help maintain remission for a longer period. However, it is not effective for all patients. Additionally, side effects, such as fatigue, skin rash, diarrhea and organ inflammation can occur due to an overactive immune response.

While the effectiveness of immunotherapy for SCLC is still being studied in clinical trials, this innovative treatment approach shows promise, particularly in cases where the cancer is advanced and has spread beyond the lungs.

Bispecific T-cell engager (BiTE) therapy for small cell lung cancer

Recently, the FDA granted accelerated approval to tarlatamab-dlle (Imdelltra), a BiTE specifically designed for treating extensive-stage small cell lung cancer that has progressed after platinum-based chemotherapy. As a BiTE therapy, Imdelltra binds to both T cells and tumor cells, precisely targeting the DLL3 protein that is overexpressed in SCLC cells. This dual-binding effect activates the body’s immune system to attack the cancer cells more effectively.

In clinical trials, Imdelltra has demonstrated a 40% objective response rate, with some patients experiencing a long-lasting response. However, BiTE therapy carries some potentially serious risks, including cytokine release syndrome (CRS) and neurologic toxicity, which require careful monitoring during treatment​.

Tumor-infiltrating lymphocyte (TIL) therapy for small cell lung cancer

Approved by the U.S. Food and Drug Administration (FDA) for treating advanced melanoma, TIL therapy is now being evaluated in clinical trials for solid tumors, including SCLC. An advanced immunotherapy approach, TIL therapy involves harvesting the patient’s own immune cells, specifically lymphocytes (T cells) that have already launched an attack and successfully infiltrated a tumor. The harvested cells are then multiplied in a laboratory to create a large quantity of tumor-targeting T cells. Once expanded, the T cells are reinfused to the patient to help the immune system attack and destroy cancer cells more effectively.

By leveraging the patient’s own immune cells that have naturally penetrated a tumor and enhancing the potency of the cells through ex vivo expansion, this personalized therapy offers promise for treating small cell lung cancer, which is known for its rapid progression and limited treatment options.

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If you would like to learn more about small cell lung cancer treatment, you can request an appointment with a specialist in our Thoracic Oncology Program by calling 1-888-663-3488  or submitting a new patient registration form online. We do not require referrals.