Radiation dose is associated with prognosis of small cell lung cancer with superior vena cava syndrome.

Approximately 10% of small cell lung cancer (SCLC) cases develop superior vena cava syndrome (SVCS). Many SCLC patients with SVCS have relatively limited disease, requiring curative rather than palliative treatment. Besides chemotherapy, radiotherapy is important for treating SCLC with SVCS. We retrospectively evaluated the influence of radiotherapy dose on the prognosis of 57 patients with SCLC with SVCS treated with concurrent chemoradiotherapy. The mean biological equivalent radiation dose was 71.5 Gy. We administered etoposide/cisplatin as sequential and concurrent chemotherapy. All patients received at least one cycle of concurrent chemotherapy. All patients had partial or complete response; SVCS-associated symptoms were reduced in 87.7% (50/57) of patients within 3-10 days after treatment. Radiation dose did not affect 2-year local control (74.2% vs. 80.8%). Patients who received high-dose radiation had a lower 2-year overall survival rate than those who received low-dose radiation (11.6 vs. 33%; P = 0.024). The high dose group median survival was 15.0 months (95% confidence interval [CI]: 11.2-19.0) compared with 18.7 months (95% CI: 13.9-23.6) in the low dose group. Grade 3/4 neutropenia occurred in 22/26 high dose patients (84.6%) and 21/31 low dose patients (67.7%). In the high dose group, 30.8% of patients had grade 3/4 esophagitis compared with 19.4% of low dose patients. Only 29.0% of low dose patients received < 4 cycles of chemotherapy in the first 12 weeks after treatment began compared with 46.2% of high dose patients. Concurrent chemoradiotherapy is a tolerable modality for treating stage IIIA/IIIB SCLC with SVCS. Moderate-dose radiotherapy is preferable.