Why is the surgical removal of a lung cancer so ineffective in halting the disease?

Surgical removal of lung cancer can be ineffective in halting the disease because the cancer may have already spread beyond the primary tumor site at the time of diagnosis, leading to metastasis in other organs. Additionally, lung cancer can be aggressive and may have microscopic disease that is not detectable during surgery. Even after removal, there is a risk of recurrence, particularly if cancer cells remain or if the tumor was not completely resected. Moreover, lung cancer often presents late, making surgical intervention less effective as a standalone treatment.