The life expectancy for stage 4 non-small cell lung cancer (NSCLC) without treatment can vary widely depending on several factors. However, research indicates a median survival of approximately 2 to 8 months without intervention.

In general, untreated stage 4 NSCLC typically has a shorter life expectancy compared to cases where treatment is administered. Without interventions like chemotherapy, radiation therapy, or targeted therapies, the cancer can progress rapidly, leading to worsening symptoms and complications. The exact life expectancy varies depending on factors such as the patient’s overall health, age, and specific characteristics of the cancer.

Factors Influencing Life Expectancy: 

1. Overall Health: A person’s overall health and well-being play a crucial role in determining life expectancy. Those with existing health conditions or compromised immune systems may experience a faster decline in health.
2. Age: Age is a significant factor in determining life expectancy. Older individuals may have weaker immune systems and may be less able to tolerate the effects of cancer or its treatment. 
3. Cancer Characteristics: The specific characteristics of the cancer, such as the type of NSCLC, the presence of certain genetic mutations, and the extent of metastasis, can impact life expectancy. 
4. Symptom Management: Without treatment, managing symptoms becomes crucial in maintaining quality of life. Palliative care can help alleviate pain, improve breathing difficulties, and address other symptoms associated with advanced lung cancer. 

In conclusion, the life expectancy for untreated stage 4 non-small cell lung cancer is limited, emphasizing the critical need for early detection and timely intervention. 

Sources:

https://pubmed.ncbi.nlm.nih.gov/23379753/