The radiotherapy in the management of cancer of the lung is first to cure the disease; second, to prolong useful and comfortable existence; and third, to provide comfort and relief of suffering to those who are symptomatic and incurable.
Cancers of the lung vary quite widely in their response to radiation. Those of glandular origin, the adenocarcinoma, are more often than not of modest susceptibility and sometimes quite resistant. The very undifferentiated, the so-called oat-cell cancers, are often of exquisite sensitivity, responding to irradiation almost like lymphomas. Most cancer of the lung, however, is squamous-cell carcinoma and as such may be considered to be moderately radiosensitive in much the same order of magnitude as squamous-cell carcinoma of the skin, cervix or larynx, and should, in theory, be curable by this means in the same degree. Unfortunately, this has to date not been found to be true. The reasons are principally