Radiotherapy for the Second Lung Mass after Surgical Resection of the First Lung Cancer

Abstract

To estimate the outcome of 3-dimensional conformal radiotherapy (3D-CRT) and stereotactic radiotherapy (SRT) for second lung tumor after resection of lung cancer. Between March 2000 and February 2008, 3D-CRT or SRT for second lung tumor was performed in 60 patients who had undergone resection of first lung cancer (non-small cell lung cancer). According to Martini's criteria, those second lung tumors were classified into second primary lung cancer (SPLC) (50 cases) and intrapulmonary metastasis (PM) of first lung cancer (10 cases). Five patients with PM had metastasis in other sites (group A) and the other 5 did not (group B). The median interval between resection of first lung cancer and detection of second lung tumor was 40 months for SPLC (range, 11-160) and 10 months for PM (range, 4-20). Histology was adenocarcinoma in 35 patients, squamous cell carcinoma in 16 and no pathologic evidence in 9. Stage was T1 in 45 patients and T2 in 15. In SRT, total doses were 48 Gy in 4 fractions for 16 patients and 60 Gy in 10 fractions for 5. In 3D-CRT, total doses were 60-72 Gy in 10-24 fractions, 3 to 7 Gy a day, for 39 patients. The median follow-up was 32.5 months (range, 4-104). Three-year overall survival (OS) was 71% for SPLC and 60% for PM (p = 0.43). Three-year local control rate was 82% for SPLC and 88% for PM (p = 0.87). Three-year cause specific survival (CSS) was 84% for SPLC and 60% for PM (p = 0.10). 3-year CSS was 40% for group A of PM, which was significantly lower than that for SPLC (p = 0.03). However, 3-year CSS was 80% for group B of PM, which was similar to that for SPLC (p = 0.72). When SPLC and group B of PM were classified according to the biologically effective dose with an α/β ratio of 10 (BED10), 3-year CSS was 93% for BED10 >100 Gy and 80% for BED10 <100 Gy. There were one case with Grade 5 radiation-induced pneumonitis and one case with Grade 3 dyspnea. Radiotherapy was feasible treatment for second lung tumor after resection of first lung cancer and provided excellent prognosis especially when doses of BED10>100 Gy were irradiated. We suppose that SPLC and PM without any other metastasis should be aggressively treated because of their similar favorable CSS.