Preoperative irradiation in the treatment of clinically operable lung cancers.

Summary The structure of the criteria for accession of patients to the protocol automatically selected the group for preoperative irradiation which have the poorest prognosis, that is, those on whom a positive bronchoscopy could be obtained. The other group of patients studied were those who were deemed nonresectable at the time of initial exploration and represented a "salvage" group. Cognizance should also be given to the fact that all of these patients were treated by pneumonectomy. Results should be viewed in this frame of reference. This study has again supported previous observations that primary tumors and lymph nodes can be sterilized by irradiation. When it is used as an adjuvant, sterilization may not necessarily have a desirable result and might contribute to an increased morbidity because of the pathologic changes induced in normal tissue. Since the cells in the tumor most vulnerable to radiation therapy are those on the periphery, it seems reasonable that tumors proved nonresectable would yield to subsequent resection following irradiation after having been declared nonresectable at previous thoracotomy. Most of the resectional surgery was done or supervised by a single operator (N. P. R.), and it is his impression that operation is not made more difficult by preoperative radiation. The most consistent finding was some degree of opacification of the visceral and parietal pleurae. The interval from radiation to surgery in most cases was 4 to 6 weeks, which seems to be optimum. The criteria of resectability varies from place to place and from person to person. These should be unified and hopefully accepted by most investigators, but this would require a consensus on a number of currently debatable problems and cannot be pursued further here. In our series of operable bronchogenic carcinomas, we have a high resection rate. We think that our criteria of resectability or nonresectability are as discriminatory as is reasonable. The large number of undifferentiated neoplasms found in this group would add bias in the direction of a decreased survival. There is a slightly increased morbidity in the preoperative irradiation group. We cannot overlook the occasional case that seems to represent the entity known as "radiation pneumonitis." One man in the study did not come to operation because of bilateral diffuse pulmonary infiltrates (Case 26). Two patients, who unexpectedly died of congestive heart failure, have made us consider the possibility of deleterious irradiation effect on cardiac function.2 The addition of preoperative irradiation to this group of patients is, in essence, a surgical adjuvant. The dosage should probably be reduced, which hopefully would decrease the morbidity associated with this mode of treatment. Some cancers may be locally extensive but with a better over-all prognosis if the disease can be completely resected. "Sterilization" of the periphery of the tumor by irradiation results in fibrous scar tissue which can be transected without great fear of leaving viable tumor. This situation may account for a reasonable resectability rate in the "salvage" group (Group 2). The effort of combined irradiation-resection regimen is being continued.