Yes. Bronchial carcinoid tumors are malignant (cancerous). They develop when pulmonary neuroendocrine cells mutate into cancerous ones.
Not all tumors that form in the lungs are signs of cancer, though. For example, those with the MEN1 gene are at a higher risk of both bronchial carcinoid tumors and benign neoplasms (noncancerous growths) forming in their body.
Doctors can see if there are cancer tumors in your body with imaging scans and a biopsy.