Primary, Adjuvant, and Palliative Radiation Therapy (3)
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|