Adenocarcinoma Lung Cancer: What You Need to Know
Written by North Editorial Staff | Clinically reviewed by Laura Morrissey, RN, BSN | Last reviewed: March 2026
Key Takeaways
Lung adenocarcinoma is the most common type of lung cancer overall, accounting for roughly 40% of all lung cancer diagnoses in the United States.
It arises in the outer regions of the lungs and often causes no symptoms until it has grown or spread — which is why screening matters.
Adenocarcinoma has the highest rate of actionable gene mutations of any lung cancer type, making biomarker testing essential before any treatment decision.
Targeted therapy options now exist for mutations in EGFR, ALK, ROS1, KRAS, BRAF, MET, RET, and NTRK — and results for mutation-positive patients have dramatically improved survival.
Clinical trials are actively expanding treatment options, particularly for rarer mutations and for patients whose cancer has progressed on first-line therapy.
What Is Adenocarcinoma of the Lung?
Adenocarcinoma of the lung is the most common subtype of non-small cell lung cancer (NSCLC), accounting for approximately 40% of all lung cancers diagnosed in the United States. It arises from glandular epithelial cells — cells that normally produce mucus — located in the peripheral (outer) regions of the lungs, rather than in the central airways.
This origin sets it apart from the other major NSCLC subtype, squamous cell carcinoma, which typically develops in the central airways near the bronchi. It is also entirely distinct from small cell lung cancer, which behaves more aggressively and has a different treatment approach. Understanding which type you have is the essential first step, because treatment strategies vary significantly between subtypes. You can read more in our overview of types of lung cancer.
Lung adenocarcinoma itself encompasses several growth patterns, acinar, papillary, micropapillary, solid, and lepidic, and the mix of these patterns influences prognosis. On the less aggressive end of the spectrum sit adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA), both of which have excellent cure rates when caught and surgically removed.
Who Gets Lung Adenocarcinoma?
Lung adenocarcinoma does not follow the same demographic profile as lung cancer as a whole. Several features set it apart:
It occurs more often in women. Adenocarcinoma has consistently been the most prevalent histologic type among women over the past three decades. Researchers continue to study the hormonal and genetic factors that may contribute to this pattern.
It is more common in non-smokers than other lung cancer types. While smoking remains a significant risk factor, a substantial proportion of lung adenocarcinoma diagnoses, particularly among younger patients, occur in people who have never smoked. According to studies of NSCLC in patients aged 20 to 46, younger patients tend to be female, non-smokers, and are often diagnosed with adenocarcinoma at an advanced stage.
It tends to occur at a younger age than squamous cell carcinoma, which is more strongly tied to decades of heavy smoking.
EGFR mutations — one of the most important actionable genetic drivers of adenocarcinoma — are found more frequently in women, non-smokers, and people of East Asian ancestry.
For people who have never smoked, other exposures become more relevant:
Radon gas — a naturally occurring radioactive gas that seeps from soil and rock into homes; the second leading cause of lung cancer in the US after smoking
Secondhand smoke — a well-established cause of lung cancer in non-smokers
Air pollution and fine particulate matter (PM2.5) — linked to increased lung cancer risk, particularly adenocarcinoma
Occupational exposures — asbestos, diesel exhaust, and certain industrial chemicals
Symptoms of Lung Adenocarcinoma
Because lung adenocarcinoma arises in the outer lung tissue rather than in the central airways, it often grows silently for months or years before causing any symptoms. By the time symptoms appear, the cancer has frequently grown larger or spread.
When symptoms do develop, they may include:
Persistent cough that does not resolve or gradually worsens
Shortness of breath, particularly with exertion
Chest discomfort or aching, often vague and felt in the peripheral chest rather than the center
Unexplained weight loss and loss of appetite
Fatigue that does not improve with rest
Unlike central lung tumors, peripheral adenocarcinomas are less likely to cause coughing up blood (hemoptysis), because they do not erode into large central airways. Some adenocarcinomas — particularly those with a lepidic (spreading) growth pattern — may mimic pneumonia on imaging and present as a persistent “pneumonia-like” opacity that fails to clear with antibiotics.
If you have any of these symptoms, particularly if they persist or you have risk factors for lung cancer, speak with your doctor. You can also find a fuller discussion of warning signs at our lung cancer symptoms resource.
Diagnosing Lung Adenocarcinoma
The diagnostic process for lung adenocarcinoma involves imaging, tissue sampling, and — critically — molecular testing.
Imaging typically begins with a CT scan of the chest. On CT, adenocarcinoma often appears as a peripheral nodule, mass, or ground-glass opacity in the outer thirds of the lung. A PET scan is usually added to evaluate metabolic activity and assess whether cancer has spread to lymph nodes or distant sites.
Tissue biopsy is required to make a definitive diagnosis. Because adenocarcinoma arises peripherally, it is often out of reach for bronchoscopy (a camera passed through the airways). CT-guided percutaneous needle biopsy or video-assisted thoracoscopic surgery (VATS) are more commonly used for peripheral lesions. Under the microscope, adenocarcinoma shows a glandular or acinar growth pattern and is typically positive for the marker TTF-1 (thyroid transcription factor-1) on immunohistochemistry, which helps distinguish it from other cancer types.
Biomarker testing is not optional for lung adenocarcinoma — it is essential. Comprehensive molecular profiling of the tumor tissue (and ideally liquid biopsy as well) should be performed on all patients with metastatic or advanced disease before any treatment begins. The following alterations all have FDA-approved targeted therapies:
EGFR mutations (exons 18–21, including exon 20 insertions)
ALK rearrangements
ROS1 rearrangements
KRAS G12C mutation
BRAF V600E mutation
MET exon 14 skipping mutations
RET fusions
NTRK fusions
PD-L1 expression testing is also performed to guide immunotherapy decisions. Learn more about the full diagnostic process at our lung cancer diagnosis page.
Staging Lung Adenocarcinoma
Lung adenocarcinoma is staged using the standard TNM (Tumor, Nodes, Metastasis) system, ranging from Stage I (localized) through Stage IV (distant metastases). Staging determines which treatments are appropriate and shapes prognosis. Our lung cancer stages guide walks through what each stage means in practical terms.
Within the adenocarcinoma category, the growth pattern carries its own prognostic weight:
Adenocarcinoma in situ (AIS): a small (3 cm or less), non-invasive lesion with pure lepidic growth — cancer cells spread along existing alveolar walls without destroying them. When completely resected, AIS has near-100% 5-year survival.
Minimally invasive adenocarcinoma (MIA): 3 cm or less with a small invasive component (5 mm or less). Also associated with excellent surgical outcomes.
Lepidic-predominant adenocarcinoma: invasive but with a dominant lepidic component; generally associated with a more favorable prognosis than solid or micropapillary patterns.
At the other end, micropapillary and solid-predominant adenocarcinoma tend to be more aggressive and are associated with a higher risk of recurrence after surgery.
Treatment for Lung Adenocarcinoma
Treatment is determined by stage, biomarker profile, and overall health. Because adenocarcinoma has the highest rate of targetable genetic alterations of any lung cancer type, molecular testing results are the single most important factor in shaping the treatment plan.
Surgery
For early-stage disease (Stages I–II and selected Stage IIIA), surgery is the primary treatment and offers the best chance of cure. The standard operation is a lobectomy — removal of the lobe of the lung containing the tumor. For small AIS or MIA lesions, a more limited resection (segmentectomy or wedge resection) may be appropriate. Adjuvant targeted therapy — for example, osimertinib after resection of EGFR-mutant Stage IB–IIIA disease — has significantly improved rates of disease-free survival.
Targeted Therapy
Adenocarcinoma’s rich landscape of actionable mutations has made targeted therapy the dominant treatment strategy for many patients with advanced disease.
EGFR mutations are found in approximately 15% of US patients with lung adenocarcinoma and up to 50% of patients of East Asian ancestry. Osimertinib (Tagrisso) is the preferred first-line treatment for common EGFR mutations (exon 19 deletions and exon 21 L858R). The FLAURA2 trial, with final results published in the New England Journal of Medicine in 2025, showed that osimertinib combined with platinum-based chemotherapy achieved a median overall survival of 47.5 months — the longest reported in any global Phase III trial in EGFR-mutated advanced lung cancer. For patients with EGFR exon 20 insertion mutations, amivantamab (Rybrevant) and sunvozertinib (Zegfrovy) are FDA-approved options.
ALK rearrangements occur in approximately 3–5% of lung adenocarcinomas. Alectinib and lorlatinib are preferred first-line options. Alectinib is also approved for adjuvant use after resection of ALK-positive disease. Brigatinib is an option in certain settings.
KRAS G12C mutations are among the most common KRAS alterations in lung cancer. Sotorasib (Lumakras) and adagrasib (Krazati) are both FDA-approved for previously treated KRAS G12C-mutant NSCLC.
BRAF V600E: The combination of encorafenib (Braftovi) plus binimetinib (Mektovi) is FDA-approved for BRAF V600E-mutant metastatic NSCLC.
ROS1 rearrangements: Entrectinib, crizotinib, repotrectinib (Augtyro), and taletrectinib (Ibtrozi) are all FDA-approved options.
MET exon 14 skipping mutations: Capmatinib (Tabrecta) and tepotinib (Tepmetko) are both approved agents.
RET fusions: Selpercatinib (Retevmo) and pralsetinib (Gavreto) are FDA-approved for RET fusion-positive NSCLC.
NTRK fusions: Larotrectinib and entrectinib are approved for NTRK fusion-positive solid tumors, including lung.
See our lung cancer treatment guide for a fuller overview of how these therapies are used.
Immunotherapy
Immunotherapy with checkpoint inhibitors has transformed outcomes for patients without targetable mutations. PD-L1 expression, measured on the biopsy specimen, guides decisions:
High PD-L1 expression (50% or above): pembrolizumab (Keytruda) monotherapy is a standard first-line option.
Lower PD-L1 expression, or in combination regimens: combinations of platinum-based chemotherapy with pembrolizumab or other checkpoint inhibitors are standard of care.
Immunotherapy is generally not the primary approach for EGFR- or ALK-positive tumors, where targeted therapy has superior outcomes.
Chemotherapy
Platinum-based chemotherapy, most commonly carboplatin or cisplatin paired with pemetrexed, remains important for patients with advanced adenocarcinoma who lack targetable mutations and are not candidates for immunotherapy alone. Pemetrexed is particularly active in non-squamous histologies, making it a natural fit for adenocarcinoma.
Clinical Trials
The clinical trial landscape in lung adenocarcinoma is among the most active in oncology. Ongoing studies are investigating novel EGFR mutation inhibitors, next-generation KRAS inhibitors, bispecific antibodies, and antibody-drug conjugates. For patients who have progressed on first-line targeted therapy, trials often represent access to the next generation of approved agents before they reach standard care. Learn more at our lung cancer clinical trials page.
Prognosis and Survival Rates
Survival in lung adenocarcinoma depends heavily on stage at diagnosis and, increasingly, on molecular profile. The following 5-year relative survival rates are drawn from SEER data and reflect population averages for NSCLC. Individual outcomes vary based on many factors, and survival statistics are improving as treatment advances.
Stage | Approximate 5-Year Relative Survival |
Stage I (localized) | ~65–82% |
Stage II | ~59% |
Stage III | ~16% |
Stage IV (distant) | ~10% |
These numbers do not fully capture the impact of targeted therapy for mutation-positive patients. In stage IV adenocarcinoma, patients with EGFR mutations have a 5-year survival rate of approximately 19%, compared to 11% for those without — and outcomes have continued to improve. FLAURA2 data from 2025 showed that EGFR-positive patients treated with osimertinib plus chemotherapy achieved a median overall survival of 47.5 months, with some patients living well beyond that mark. For ALK-positive patients on lorlatinib, 5-year overall survival rates above 60% have been reported in some studies.
Statistics represent population averages across everyone diagnosed with a given stage. Your own prognosis depends on your specific mutation profile, overall health, the center where you’re treated, and your response to therapy. Speak openly with your oncologist about what the data mean for your situation. You can also explore our lung cancer survival rates page for more context.
Frequently Asked Questions
What is the most common type of lung cancer?
Adenocarcinoma is the most common type of lung cancer in the United States, accounting for approximately 40% of all diagnoses. It is the most common lung cancer subtype in both men and women, and the most prevalent type among non-smokers.
What is the survival rate for lung adenocarcinoma?
Survival rates vary significantly by stage. For localized (early-stage) disease, the 5-year relative survival rate is approximately 65–82%. For distant (metastatic) disease, the overall rate is around 10%, though patients with targetable mutations like EGFR or ALK who receive modern targeted therapies have meaningfully better outcomes — with median overall survival now approaching or exceeding four years in some EGFR-positive populations.
Do you need to smoke to get adenocarcinoma of the lung?
No. While smoking is a risk factor for lung adenocarcinoma, a significant proportion of patients — particularly women and younger patients — have never smoked. Radon exposure, secondhand smoke, air pollution, and hereditary factors all contribute to risk in non-smokers. Adenocarcinoma is the lung cancer type most commonly diagnosed in people who have never smoked.
What biomarker testing should be done for lung adenocarcinoma?
All patients with advanced or metastatic lung adenocarcinoma should receive comprehensive molecular profiling before starting treatment. This includes testing for EGFR, ALK, ROS1, KRAS, BRAF V600E, MET exon 14, RET, and NTRK alterations, as well as PD-L1 expression. Both tissue-based next-generation sequencing (NGS) and liquid biopsy (circulating tumor DNA from blood) may be used. Results directly determine whether a targeted therapy is appropriate — and selecting the right therapy first makes a significant difference in outcomes.
Lung adenocarcinoma, particularly when driven by actionable mutations, has an active clinical trial pipeline.
Ready to explore trial options that may be right for you? Start your search with North’s trial finder.
References
American Cancer Society. (2025). Lung Cancer Survival Rates. https://www.cancer.org/cancer/types/lung-cancer/detection-diagnosis-staging/survival-rates.html
AstraZeneca. (2025). TAGRISSO plus chemotherapy demonstrated a median overall survival of nearly four years in EGFR-mutated advanced lung cancer — FLAURA2 final results. https://www.astrazeneca-us.com/media/press-releases/2025/TAGRISSO-osimertinib-plus-chemotherapy-demonstrated-a-median-overall-survival-of-nearly-four-years-the-longest-benefit-ever-reported-in-a-global-Phase-III-trial-in-EGFR-mutated-advanced-lung-cancer.html
National Cancer Institute SEER Program. (2024). Cancer Stat Facts: Lung and Bronchus Cancer. https://seer.cancer.gov/statfacts/html/lungb.html
Lung Cancer Research Foundation. (2025). FDA Approvals in Lung Cancer Treatment. https://www.lungcancerresearchfoundation.org/research/why-research/treatment-advances/
Tan, A.C., Tan, D.S.W. (2022). Targeted Therapies for Lung Cancer Patients with Oncogenic Driver Molecular Alterations. Journal of Clinical Oncology, 40(6), 611–625. https://doi.org/10.1200/JCO.21.01626
PMC / National Library of Medicine. (2025). Lung Cancer: Targeted Therapy in 2025. https://pmc.ncbi.nlm.nih.gov/articles/PMC11941068/
Kratzer, T.B., et al. (2024). Lung cancer statistics, 2023. Cancer, 130(8), 1330–1348. https://acsjournals.onlinelibrary.wiley.com/doi/full/10.1002/cncr.35128