A diagnosis of unresectable stage III non-small cell lung cancer (NSCLC) means the cancer is locally advanced. This signifies the tumor is in the lung and may have spread to nearby lymph nodes in the chest, but it has not metastasized to distant parts of the body. In the United States, about a quarter of individuals with NSCLC are diagnosed at this stage.
The term “unresectable” indicates that the tumor cannot be completely removed through surgery. This is often because the tumor is too large or is located near important structures within the chest, such as major blood vessels or the heart. A multidisciplinary team of medical professionals determines if a tumor is unresectable based on a careful review of all diagnostic information.
Determining the Diagnosis
The diagnostic process begins with imaging tests, such as a computed tomography (CT) scan of the chest, which provides detailed pictures of the tumor’s size and location. Following a CT scan, a positron emission tomography (PET) scan is often performed. For this test, a small amount of a radioactive sugar is injected, and because cancer cells are more metabolically active, they absorb more sugar, causing them to “light up” on the scan.
This helps doctors see if the cancer has spread to lymph nodes in the mediastinum, an important part of staging. While imaging provides a map, a biopsy is necessary to confirm the diagnosis. A pathologist examines a small tissue sample from the tumor, obtained through a procedure like a bronchoscopy or a needle biopsy, to identify it as non-small cell lung cancer.
Primary Treatment with Chemoradiation
For patients with unresectable stage III NSCLC, the standard initial treatment is concurrent chemoradiation. This approach is delivered with curative intent, meaning the goal is the complete eradication of the tumor. The two treatments are given at the same time to maximize their effectiveness, as chemotherapy can make cancer cells more sensitive to radiation.
Radiation therapy uses high-energy beams to target and destroy cancer cells directly in the chest. Modern techniques like intensity-modulated radiation therapy (IMRT) allow for precise shaping of the radiation beams to conform to the tumor, which helps to spare surrounding healthy tissues. Treatment is delivered in daily sessions over several weeks.
Simultaneously, chemotherapy is administered intravenously. This systemic treatment allows the drugs to circulate throughout the body and kill cancer cells that may have broken away from the primary tumor. Common chemotherapy combinations include a platinum-based drug, like cisplatin or carboplatin, paired with another agent such as etoposide or paclitaxel.
Many patients experience fatigue as their body works to repair healthy cells damaged during treatment. One of the most common issues is esophagitis, an inflammation of the esophagus that can cause pain and difficulty swallowing. Another potential side effect is pneumonitis, or inflammation of the lung tissue, which requires careful monitoring.
Consolidation Immunotherapy
After the completion of the chemoradiation regimen, immunotherapy may be initiated as consolidation therapy. This is given to patients whose cancer has not progressed after the initial phase of treatment. Its purpose is to empower the body’s own immune system to find and eliminate any remaining cancer cells, reducing the risk of the cancer returning.
The standard of care for this consolidation phase is a checkpoint inhibitor. These drugs work by blocking proteins that cancer cells use to hide from the immune system. For instance, the drug durvalumab blocks the PD-L1 protein, which releases a brake on immune cells, allowing them to recognize and attack the cancer.
This treatment is administered as an intravenous infusion every few weeks for up to one year. The introduction of consolidation immunotherapy has significantly improved long-term outcomes for patients, leading to better progression-free and overall survival rates.
The side effects of immunotherapy are different from those of chemotherapy and are related to inflammation as the immune system becomes more active. These can include skin rashes, diarrhea, or inflammation of glands like the thyroid.
Long-Term Outlook and Follow-Up Care
The use of concurrent chemoradiation followed by consolidation immunotherapy offers a chance for long-term control of the disease. Survival rates are statistical averages and cannot predict an individual’s specific outcome, but this treatment regimen has improved the prognosis for many patients.
After treatment is completed, diligent follow-up care is important. This involves a regular schedule of appointments with the oncology team to monitor for any signs of cancer recurrence and to manage any lingering side effects from treatment.
This surveillance includes periodic CT scans of the chest every few months for the first couple of years, with the frequency decreasing over time. This ongoing monitoring allows for the early detection of any potential recurrence, which provides the best opportunity for effective intervention.