In advanced stages of colon cancer, metastases to the abdominal organs usually occur first, with pulmonary metastases appearing later. If pulmonary metastases are present, they are indicative of widespread metastasis, and survival is usually not longer than six months.
Pulmonary metastases from colon cancer are mostly hematogenous, with the possibility of multiple metastatic lesions occurring at the same time. In a short period of time, it can be life-threatening because of pleural effusion and respiratory failure. However, the specific survival time is also affected by the malignancy of the tumor and the method of treatment used.
Colon cancer that is sensitive to chemotherapy, even if it has metastasized to the lungs, can be suppressed with regular chemotherapy treatment and has a relatively long survival time, potentially six months to a year, or even more than a year.
If a colon cancer that is not sensitive to chemotherapy is not suitable for chemotherapy and radiotherapy, it can be treated with nutritional support, symptomatic treatment, and other measures, and the survival time is mostly several weeks to several months.
When the patient is in poor health and has difficulty with symptomatic treatment, the natural course of the disease is rapidly progressive and can often be life-threatening within weeks.