Non-Small Cell Lung Cancer Stage IIIA

Stage IIIA non-small cell lung cancer represents a complex middle ground in cancer care—the disease has spread beyond the lungs to nearby lymph nodes but has not reached distant parts of the body. About 30% of people with non-small cell lung cancer are diagnosed at stage 3, facing challenging but potentially treatable disease that requires a carefully coordinated approach from multiple medical specialists.

Table of contents

• Understanding Stage IIIA Non-Small Cell Lung Cancer
• The Varied Nature of Stage IIIA Disease
• Where the Cancer Can Spread
• Treatment Approaches
• Outlook and Survival

Understanding Stage IIIA Non-Small Cell Lung Cancer

Stage IIIA non-small cell lung cancer (a type of cancer that forms in the tissues of the lung, with cells that appear larger under a microscope than those in small cell lung cancer) represents a specific point in the disease’s progression where the cancer has grown beyond the initial site but remains within the chest area^[3][4]. This stage is sometimes called locally advanced cancer, meaning the tumor has spread to nearby areas but not to distant organs^[3].

In stage IIIA disease, the cancer may have spread to lymph nodes (small bean-shaped structures that are part of the body’s immune system) on the same side of the chest where the cancer started^[4]. The lymph nodes affected are typically in the area where the windpipe divides, called the carina, or in the space between the lungs called the mediastinum^[3].

Stage IIIA can describe several different situations. The cancer might be small (3 centimeters or less) but have spread to lymph nodes in the chest. Or it might be between 3 and 7 centimeters in size with specific patterns of growth or lymph node involvement. In some cases, the tumor may be larger than 7 centimeters and have grown into nearby structures like the diaphragm, the center area of the chest, the heart, major blood vessels, or the windpipe, with varying degrees of lymph node involvement^[3].

The Varied Nature of Stage IIIA Disease

Stage IIIA non-small cell lung cancer is not a single, uniform condition but rather encompasses a wide range of situations^[6][5]. This variety makes it one of the most complex stages to treat, as different patients within this same stage may have very different types of disease.

The disease can range from small tumors with lymph node involvement to larger tumors that have invaded the chest wall or other nearby structures^[6]. Some patients may have cancer in multiple locations within the same lobe of the lung, while others might have disease spread across different lobes on the same side^[3].

Because of this complexity, treatment decisions for stage IIIA disease must be made by a team of specialists working together, including medical oncologists (doctors who treat cancer with medications), radiation oncologists (doctors who treat cancer with radiation), lung specialists, and thoracic surgeons (surgeons who specialize in chest operations)^[6][5]. The treatment plan should be tailored to each patient’s specific situation.

An important consideration is whether the cancer can be removed with surgery, termed resectable disease, or whether it cannot be safely or completely removed, called unresectable disease^[4]. The majority of stage 3 non-small cell lung cancer is unresectable, meaning surgery alone cannot remove all the cancer^[4].

Where the Cancer Can Spread

• Lungs
• Lymph nodes
• Bronchi (main airways)
• Diaphragm (breathing muscle)
• Chest wall (ribs, muscles, or skin)
• Pleura (lung lining)
• Pericardium (heart lining)
• Phrenic nerve (nerve near the lung)
• Mediastinum (space between lungs)
• Heart
• Blood vessels
• Trachea (windpipe)
• Esophagus (food pipe)
• Spine

In stage IIIA non-small cell lung cancer, the disease may have reached various structures within the chest^[3][4]. The cancer might grow into the bronchi, which are the main breathing tubes leading into the lungs. It can also spread to the membrane covering the lung, called the visceral pleura, or the inner lining of the chest wall, known as the parietal pleura^[3].

The tumor may extend into the chest wall itself, affecting the ribs, muscles, or skin. It can also involve the phrenic nerve, which controls the diaphragm—the muscle that helps you breathe. In more advanced stage IIIA cases, the cancer might grow into the layers of the sac that covers the heart, called the mediastinal pleura and parietal pericardium^[3].

Sometimes the cancer spreads to important structures in the center of the chest, including the heart itself, major blood vessels like the aorta, the windpipe (trachea), the nerve that goes to the voice box, the esophagus (the tube that carries food to your stomach), or the bones of the spine^[3]. The cancer may also cause the lung to partially or completely collapse by blocking the airway or causing inflammation of the lung tissue, a condition called pneumonitis^[3].

Treatment Approaches

Treatment for stage IIIA non-small cell lung cancer typically involves multiple approaches used together, known as multimodal therapy^[5][8]. The specific combination depends on whether the cancer can be removed with surgery and the patient’s overall health.

For patients whose cancer might be removable after initial treatment, doctors often begin with chemoradiation—a combination of chemotherapy (medications that kill cancer cells) and external radiation therapy (high-energy rays directed at the cancer) given at the same time^[15]. Common chemotherapy drugs used include cisplatin combined with etoposide, vinorelbine, gemcitabine, docetaxel, or paclitaxel^[15].

If the chemoradiation shrinks the tumor enough, surgery may then be performed to remove the cancer^[15]. The type of surgery depends on the location and size of the tumor. A lobectomy removes the section (lobe) of the lung containing the tumor. A pneumonectomy removes the entire lung. Other procedures include sleeve resection, which removes a tumor from one of the airways along with surrounding healthy tissue, or chest wall resection, which removes muscles, bones, and other tissues of the chest wall^[15].

For stage IIIA patients who cannot have surgery, chemoradiation may be given as the main treatment if they are healthy enough to tolerate it^[15]. If a patient cannot receive radiation therapy, chemotherapy alone may be given before potential surgery. Chemotherapy may also be given after surgery if none was given before, or if the cancer responded well to chemotherapy given before surgery^[15].

Newer treatments called targeted therapy and immunotherapy are increasingly important for stage IIIA disease^[15][5][8]. Targeted therapy uses medications that attack specific genetic changes in cancer cells. For example, if tests show the cancer has changes in the EGFR (epidermal growth factor receptor) gene, drugs like osimertinib may be used^[15]. Other genetic changes that can be targeted include ALK, ROS1, BRAF, NTRK, and MET mutations^[15].

Immunotherapy works by helping the body’s immune system recognize and attack cancer cells. One immunotherapy drug, durvalumab (IMFINZI), has been approved specifically for patients with unresectable stage 3 non-small cell lung cancer whose disease has not progressed after chemoradiation therapy^[4][19].

Treatment recommendations depend heavily on whether the cancer can be surgically removed and should be discussed by a team of specialists in high-volume cancer centers^[6]. In medically fit patients with removable stage IIIA tumors, an aggressive treatment approach is important to achieve the best possible survival^[6].

Outlook and Survival

The outlook for patients with stage IIIA non-small cell lung cancer varies considerably depending on the specific characteristics of their disease^[6]. This variation reflects the diverse nature of stage IIIA, which includes many different disease patterns.

Reported five-year survival rates range widely within stage IIIA, from as low as 5% in patients with bulky disease in the mediastinal lymph nodes (called N2 disease) to as high as 50% for patients with certain types of tumors, such as those in the superior sulcus (top of the lung) with involvement of nearby lymph nodes^[6]. These numbers reflect the complexity and variety within this single stage.

Several factors influence prognosis. These include the size and location of the tumor, how far it has spread to lymph nodes, whether certain organs or structures have been invaded, and the patient’s overall health and ability to tolerate treatment^[12]. The type of resection (removal) performed, when surgery is possible, also affects outcomes, with lobectomy generally being the preferred operation when the patient can tolerate it^[12].

Despite the challenges, some patients with stage IIIA disease can achieve long-term survival with aggressive, coordinated treatment^[5]. The goal of treatment is not only to extend life but also to maintain quality of life throughout the treatment process^[6]. Each patient’s situation is unique, and treatment decisions should be made together with a specialized medical team that can consider all available options.