Thanks for your question on HCM. Lung cancer is very notorious in spread. It can spread by both, blood and lymphnodes. Bone involvement is very common especially thoracic vertebrae. And bone metastases from lung cancer are usually osteolytic in nature. So they produce demineralisation and osteoporosis both. So these bones are highly prone to fracture even by slightest force. So your mother had osteolytic bone metastases in thoracic vertebrae and fracture after accident. Bone metastases made lung cancer stage 4 disease (inoperable). Only treatment option is palliative chemotherapy and nutritional support in the form of multivitamins, calcium and vitamin d.