Evaluation and radiotherapy implications of chest relapse patterns in small cell lung carcinoma treated with radiotherapy‐chemotherapy: Study of 34 cases and review of the literature

The value of chest irradiation in small cell lung carcinoma (SCLC) has been recently questioned. To investigate this issue, we undertook a retrospective study of 34 cases of SCLC treated with chemotherapy and radiotherapy to the chest and brain. Emphasis was placed on analysis of patterns of chest disease relapse, chest complications, and sites of initial chest disease relapse in relation to volume treated by radiation. These results were compared with published reports. Of 17 cases with disease limited to the chest (LD), nine (53%) died of chest related complications, seven of these (41%) with chest disease recurrence. However, in five of these seven cases (72%), recurrences appeared initially outside the irradiated volume, in spite of 1–2 cm of safety margin, mostly in the ipsilateral lung, while the primary was without evidence of growth. Hence, chest disease relapse does not necessarily mean radiotherapy failure, as only 2 of the 17 cases (12%) had definite tumor growth in the irradiated field. This point is not properly emphasized in the literature, where marked discrepancies among authors reporting chest disease relapses are present. We elaborate about factors that will affect results, like frequency of follow‐up x‐rays, tumor size, site of chest disease relapse, and criteria to define tumor relapse. More autopsy and chest diagnostic studies are needed to investigate patterns of tumor spread within the lung. Survival alone is too broad a factor to measure the impact of radiotherapy in treatment. We need more understanding of the mechanisms of chest disease relapse to obtain a better design of radiotherapy ports. Systemic disease was the main cause of death in 17 patients with extensive small cell lung carcinoma, and routine chest irradiation cannot be justified although it might be of help for chemotherapy responders who are expected to have long survival.