What is considered the least common but most lethal form of lung cancer?

Small-cell (oat cell) carcinoma is recognized as the least common but most lethal form of lung cancer primarily due to its aggressive behavior and rapid progression. This type of lung cancer accounts for about 10-15% of all lung cancer cases. The cells in small-cell carcinoma proliferate quickly, leading to a high likelihood of metastasis, which often occurs even at the time of diagnosis.

This cancer is strongly associated with smoking and tends to respond initially to chemotherapy, but it also has a high rate of recurrence and is linked to a poorer prognosis compared to other lung cancer types. The rapid development of this cancer type means that it often presents with advanced disease at diagnosis, which contributes significantly to its lethality. In contrast, other forms of lung cancer, such as adenocarcinoma and squamous cell carcinoma, while also serious, tend to have better overall outcomes when caught early and may be more treatable.