Split-Dose Intensive Radiation Therapy in the Treatment of Advanced Lung Cancer: A Randomized Study

Abstract

Because of our dissatisfaction with results of the routine fractionated therapy in patients with inoperable carcinoma of the lung, a pilot study in which split-dose intensive therapy was used was instituted approximately two and a half years ago. Initially encouraging results led to a prospective randomized study comparing intensive split-dose therapy and routine fractionated therapy in patients with inoperable squamous-cell carcinoma of the lung. An initial report has been given previously (10). This paper will report the current status and the follow-up of the results of our pilot study. Initially 18 patients with far-advanced or inoperable bronchogenic carcinoma were treated with split-dose intensive radiation therapy. This consisted of 1,800 rads tumor dose delivered in three days through opposing anterior and posterior thoracic ports large enough to cover the tumor and a 1 em margin of normal tissue. A similar course was instituted twenty-eight days afterward so that altogether 3,600 rads total tumor dose was given in thirty-one days. A Theratron 80 cobalt-60 unit (80 cm SSD) or the 2 MV Van de Graaff generator (100 cm SSD) was employed, and the initial results were favorable and encouraged further study. In the past two and a half years all patients with carcinoma of the lung referred for radiation therapy have been categorized into a protocol group and a non-protocol group. In the protocol group are those with a histologic diagnosis of bronchogenic squamous-cell carcinoma, who are considered by our surgeons as unresectable even though the disease be limited to one hemithorax. Protocol patients were assigned by a random table of numbers to be given either the split-dose intensive or routine fractionated therapy to a tumor dose of 6,000 rads. The intensive split-dose method has been described above. In routinely fractionated patients radiation was given through opposed anterior and posterior ports large enough to cover the lesion and a 1 cm margin of normal tissue to a dose of 4,000 rads. Therapy to the posterior opposing field was then stopped and posterior oblique ports added. The patients were then treated to a total dose of 6,000 rads in a period of six to eight weeks. Patients with palpable supraclavicular nodes or positive scalene node biopsy had these areas treated with the same time-dose sequence as the thorax. During the same period all patients considered inoperable for medical reasons, e.g., poor respiratory reserve, and those who were operable but refused surgery were given routine fractionated radiotherapy to a tumor dose of 5,000 to 6,000 rads. In addition, all patients who had radical surgery for bronchogenic carcinoma and were thought by the surgeons to have residual tumor had routine fractionated radiotherapy to a tumor dose of 5,000 to 6,000 rads in six to eight weeks to the area of suspected residual tumor and mediastinum.