Total (half-body) systemic irradiation for occult metastases in non-small cell lung cancer: an Eastern Cooperative Oncology Group pilot report.

Abstract

There is a high probability for patients with locally advanced, unresectable, nonmetastatic, nonsmall-cell bronchogenic carcinoma (NSCBC) to harbor subclinical distant metastases at diagnosis. Approximately 30% will disseminate in the first three months and an additional 50% will disseminate before a year has elapsed. Twenty advanced nonmetastatic patients with NSCBC were treated with localized split-course chest irradiation (LCI) plus total body body (upper and lower half-body) irradiation for occult metastases. Thirty equally advanced, nonmetastatic patients, who were treated with only localized split-course chest irradiation, were matched and served as a retrospective control group. The first 11 patients received HBI after LCI (Pilot Study No. 1), but five (45%) had evidence of distant metastases before UHBI was delivered. This was not different from the control group where 11 (37%) of the patients had evidence of distant dissemination less than 2 1/2 months from the onset of treatment. The remaining nine patients received UHBI first followed by LCI and LHBI (Pilot Study No. 2); only one (11%) had evidence of distant metastases in the first 2 1/2 months. Apparently, the median recurrence free survival, metastatic free interval, and median survival were significantly prolonged, and there was a decrease in the incidence of liver metastases in patients receiving HBI for occult metastases over the patients of the control group. An increase in local tumor control was seen when large single doses of UHBI were added to LCI. Although elective HBI seems to delay the appearance of distant metastases, it did not prevent their occurrence, alter patterns of first relapse, or significantly improve the overall survival. Nevertheless, a therapeutic gain may have been achieved and is discussed. These two high-risk Phase II Pilot Studies for the Eastern Cooperative Oncology Group (ECOG) have served as the basis for a larger randomized protocol where this therapeutic strategy will be tested against other therapies. The incidence of radiation pneumonitis with 800 rad of UHBI corrected for lung transmission was 9%, or one of 11 patients. A hypothesis and rationale for a more effective combined modality therapy in these patients is given.