Sinus cancer after treatment. Image 2 of 2. Endoscope view of the ethmoid and maxillary sinuses (two of the air-filled cavities that lie behind the face) after treatment for sinus cancer. Chemotherapy (the use of anti-cancer drugs) has removed a tumour that was growing at the junction between these sinuses (centre). The tumour was growing towards one of the openings of the nasal cavity (choana, upper left), and could have blocked the patient's airway if it was left untreated. Treatments for cancer include radiotherapy, chemotherapy and surgical removal of the cancerous cells. For a view of the tumour before chemotherapy treatment, see image M131/384.