BACKGROUND Surgical resection remains the treatment of choice for patients with stage I nonsmall cell lung carcinoma. However, there is a group of patients who are medically inoperable and are treated with radiotherapy alone. This review summarizes findings from published series of radiotherapy for patients with medically inoperable Stage I lung carcinoma. METHODS A literature search was used to identify studies of treatment with radiotherapy alone for patients with medically inoperable Stage I nonsmall cell lung carcinoma. Ten studies that utilized megavoltage irradiation to doses of >55 gray (Gy) in conventional fractionation were selected for analysis. RESULTS Radiotherapy doses were similar throughout the series, with a median dose of 60-66 Gy. However, treatment volumes varied considerably, from small "postage stamp" fields to comprehensive lymph node coverage. Averaging the results of these studies showed that approximately 15% of patients will be long term survivors, 25% will die of intercurrent disease, 30% will die of distant metastatic disease and 30% will die after local failure only. Eight of ten series report Grade 3-5 complications occurring in <2% of patients. Analysis of treatment factors affecting survival revealed a consistent benefit of higher radiotherapy doses in terms of local control or disease free survival. No benefit from prophylactic lymph node irradiation was demonstrated. CONCLUSIONS Despite the infirm nature of patients with medically inoperable Stage I lung carcinoma, the majority will ultimately die of uncontrolled lung carcinoma. Because complications are uncommon after doses of 60-66 Gy, trials of dose escalation to limited fields are indicated for patients with medically inoperable nonsmall cell carcinoma in an attempt to improve overall survival.