Relief of non-metastatic shoulder pain with mediastinal radiotherapy in patients with lung cancer.

Three patients with lung cancer and shoulder pain for which no local cause could be found are described. All three benefited from a course of palliative radiotherapy to ipsilateral mediastinal disease remote from the site of the pain. It is suggested that the pain is referred from intrathoracic involvement of the phrenic nerve by cancer, and that palliative irradiation of the mediastinum should be considered if investigations fail to reveal a local cause for ipsilateral shoulder pain.