The intraoperative radiation therapy given in those studies was by either temporary or permanent radioactive implants (Table 4). The majority of the patients also received postoperative external-beam radiation therapy. The results (Table 5) are superior to those reported for high-dose external-beam radiation therapy alone, but these are selected uncontrolled series. A small study utilizing electron-beam intraoperative radiation therapy demonstrated high toxicity; this approach needs further refinement.
Postoperative Radiation Therapy: Postoperative radiation therapy with a dose of 45 to 56 Gy is commonly recommended in patients with completely resected stage 2 and 3 lung cancer (Table 6). Its use is supported by retrospective series suggesting a marked improvement in survival in patients with N1 or N2 disease so treated. Compared to a 0% to 3% 5-year survival in patients not given postoperative radiation (Table 7), the 5-year survival in patients who received radiation therapy was 28% to 35%. Patients with close or involved surgical margins also appear to benefit from postoperative radiation therapy.
The single controlled trial of postoperative radiation therapy done to date, although demonstrating a significant reduction in ipsilateral lung and mediastinal recurrences, did not demonstrate a survival improvement (28% in both arms).
Table 4—Indications for Intraoperative Radiation Therapy
|Stage 1 and 2 tumors discovered to be unresectable at surgery Incompletely resected stage 3 tumors|
Table 5—Results of Intraoperative Radiation Therapy
|TumorStage||Reference||No. of Patients||5-Year Survival, %|
|1 and 2||11||55||32|
Table 6—Indications for Postoperative Radiation Therapy
|Hilar node involvement|
|Mediastinal node involvement|
|Involved or close resection margins (disease confined to one hemithorax)|
Table 7—Value of Postoperative Radiation Therapy in Node-Positive Lung Cancer
|NodalStage||Reference||No. of Patients||5-Year Survival, %|
|Surgery||Surgery and Radiation Therapy|
|N1 or N2||14*||219||3||35|
|N1 or N2||17t||230||28||28|