Lung Carcinoma Cell Type Unspecified Recurrent

Recurrent lung cancer occurs when cancer cells return after successful treatment and a period without detectable signs of disease. Understanding the patterns of recurrence, warning signs, and treatment options can help patients and caregivers navigate this challenging phase of the cancer journey.

Table of contents

• What Is Lung Cancer Recurrence?
• How Common Is Recurrence?
• Types of Lung Cancer Recurrence
• What Causes Lung Cancer to Recur?
• Signs and Symptoms of Recurrence
• Treatment Options for Recurrent Lung Cancer
• Follow-Up Care After Treatment

What Is Lung Cancer Recurrence?

Recurrent lung cancer is lung cancer that has returned after treatment and after a period during which there were no detectable signs of the disease^[16]. When doctors find cancer cells after treatment that was successful in the short term, this is called a recurrence. If cancer appears within a year of initial treatment, doctors usually consider it a progression of the disease rather than a true recurrence^[16].

Even after successful treatment that eliminates cancer cells from the lungs, some cells may remain in the body. These lingering cells can be undetectable for months or years before they begin growing again^[16]. This is why follow-up care and regular monitoring remain important even after completing treatment.

How Common Is Recurrence?

The chance that lung cancer comes back depends on several factors, including the type of lung cancer, the stage at initial diagnosis, and the treatments received^[16]. Most often, lung cancer recurrence happens between two and five years after the original diagnosis^[16].

For non-small cell lung cancer (NSCLC), which accounts for over 80% of lung cancer cases^[1], the risk of recurrence varies by stage. Approximately 3 in 10 people diagnosed with stage I lung cancer will experience a recurrence, typically within five years. For those diagnosed with stage IV, the chance of relapse increases to 7 in 10^[16]. Stage II NSCLC has recurrence rates ranging from 11% to 27%, while stage III sees recurrences in 24% to 40% of patients^[20].

Small cell lung cancer (SCLC), which represents about 15% of lung cancer diagnoses^[6], is more aggressive and has a higher recurrence rate. About 7 in 10 people with SCLC will experience a recurrence, most commonly within one to two years^[16]. For extensive-stage SCLC, recurrences occur in about 90% of patients within the first two years after treatment^[20]. However, after five years of cancer-free survival, the chance that SCLC comes back becomes less likely^[16].

Types of Lung Cancer Recurrence

Lung cancer can recur in three primary ways, depending on where the cancer cells reappear in the body^[16]:

• Local recurrence: Cancer comes back in the same lung or area near the location of the original tumor^[16].
• Regional recurrence: Cancer returns in the lymph nodes near the location of the original tumor^[16].
• Distant recurrence: Cancer cells return to other parts of the body, such as the brain, bones, liver, or adrenal glands^[16]. This is also called metastatic recurrence.

For both non-small cell and small cell lung cancer, recurrences are in most cases metastatic, meaning the cancer has spread to distant parts of the body^[16]. Small cell lung cancer typically spreads to lymph nodes, bones, brain, liver, and adrenal glands^[6].

What Causes Lung Cancer to Recur?

Even after successful treatment, there may be lingering cancer cells that are undetectable with current testing methods. The spread of these original cancer cells is the main cause of recurrence^[16]. These cells can cause the growth of a new tumor at the original location or in distant parts of the body. This is why lung cancer can recur in the form of, for example, a brain tumor.

The risk of recurrence also depends on the choices people make after treatment. Smoking alone can increase the risk of lung cancer recurrence more than seven-fold^[16]. Since smoking is the most common cause of lung cancer, accounting for an estimated 90% of cases^[2], continuing to smoke after treatment significantly raises the chance that cancer will return.

Other risk factors for developing lung cancer initially also play a role in recurrence, including exposure to secondhand smoke, radiation from cancer treatments or imaging scans, radon gas, and workplace hazards like asbestos, arsenic, nickel, tar, or toxic chemicals^[2].

Signs and Symptoms of Recurrence

The symptoms of cancer recurrence depend on where the cancer has returned in the body. If the cancer recurs in the lungs, symptoms may be similar to those experienced during the initial diagnosis. Common signs include^[3]:

• A new cough that does not go away
• Chest pain or discomfort
• Coughing up blood, even a small amount
• Hoarseness
• Shortness of breath or difficulty breathing
• Wheezing
• Fatigue
• Loss of appetite
• Unexplained weight loss

If the cancer has spread to other parts of the body, symptoms may include bone pain, headache, facial swelling, or swollen neck veins^[6]. Many of these symptoms are similar to other less serious conditions. Having one or more of these symptoms does not necessarily mean cancer has returned, but if you notice these types of symptoms, especially if you have a history of lung cancer, it is important to talk to a healthcare provider^[6].

Treatment Options for Recurrent Lung Cancer

Treatment options for recurrent lung cancer depend on several factors, including where the cancer has returned, what treatments were used initially, and the patient’s overall physical condition^[13]. With appropriate treatment, recurring lung cancer can, in some cases, be brought back into remission^[16].

Locoregional relapse (cancer that returns in or near the original location) can be treated using the same approaches as initial lung cancer, including surgery, radiotherapy (treatment using radiation), chemotherapy (treatment using drugs that kill cancer cells), or combined treatment^[13]. Approximately 1% to 2% of all recurrent lung cancer cases are treated with curative reoperation, though outcomes can be challenging^[13].

Radiation therapy has been used effectively for both post-surgical recurrences and recurrences after previous radiation treatment. For isolated bronchial stump recurrences (cancer returning at the site where a bronchus was closed during surgery), external beam radiation therapy has shown promising results, with a median survival time of approximately 28.5 months and a 5-year survival rate of approximately 31.5%^[13].

For recurrent lung cancer, treatments may also include immunotherapy (treatment that helps the body’s immune system fight cancer), targeted drug therapies, and supportive measures to manage symptoms and improve quality of life^[1].

Follow-Up Care After Treatment

Regular follow-up care after lung cancer treatment is essential for detecting any recurrence early. The schedule and type of follow-up tests depend on the type and stage of lung cancer and the treatments received.

For non-small cell lung cancer patients who had stage I or II disease and underwent surgery with or without chemotherapy, follow-up typically includes seeing a healthcare provider, having a physical exam, and getting a chest CT scan (a detailed imaging test) every 6 months for 2 to 3 years, then once a year starting at year 4^[25].

For patients with stage III or IV non-small cell lung cancer, follow-up is more frequent, with visits, physical exams, and chest CT scans every 3 to 6 months for 3 years, then every 6 months for 2 years, and once a year after 5 years^[25].

Small cell lung cancer patients with limited-stage disease should see their healthcare provider every 3 months for the first 2 years after treatment, then every 6 months in year three, and once a year after that. Brain MRI (magnetic resonance imaging) scans are recommended every 3 to 4 months in the first year and every 6 months in year 2^[25].

For extensive-stage small cell lung cancer, follow-up is more intensive, with visits every 2 months in the first year, every 3 to 4 months during years 2 and 3, every 6 months in years 4 and 5, and then once a year^[25].