Comparison of intensity-modulated radiotherapy and 3-dimensional conformal radiotherapy as adjuvant therapy for gastric cancer

BACKGROUND: The current study was performed to compare the clinical outcomes and toxicity in patients treated with postoperative chemoradiotherapy for gastric cancer using intensity-modulated radiotherapy (IMRT) versus 3-dimensional conformal radiotherapy (3D CRT). METHODS: Fifty-seven patients with gastric or gastroesophageal junction cancer were treated postoperatively: 26 with 3D CRT and 31 with IMRT. Concurrent chemotherapy was capecitabine (n = 31), 5-fluorouracil (5-FU) (n = 25), or none (n = 1). The median radiation dose was 45 Gy. Dose volume histogram parameters for kidney and liver were compared between treatment groups. RESULTS: The 2-year overall survival rates for 3D CRT versus IMRT were 51% and 65%, respectively (P = .5). Four locoregional failures occurred each in the 3D CRT (15%) and the IMRT (13%) patients. Grade ≥2 acute gastrointestinal toxicity was found to be similar between the 3D CRT and IMRT patients (61.5% vs 61.2%, respectively) but more treatment breaks were needed (3 vs 0, respectively). The median serum creatinine from before radiotherapy to most recent creatinine was unchanged in the IMRT group (0.80 mg/dL) but increased in the 3D CRT group from 0.80 mg/dL to 1.0 mg/dL (P = .02). The median kidney mean dose was higher in the IMRT versus the 3D CRT group (13.9 Gy vs 11.1 Gy; P = .05). The median kidney V20 was lower for the IMRT versus the 3D CRT group (17.5% vs 22%; P = .17). The median liver mean dose for IMRT and 3D CRT was 13.6 Gy and 18.6 Gy, respectively (P = .19). The median liver V30 was 16.1% and 28%, respectively (P < .001). CONCLUSIONS: Adjuvant chemoradiotherapy was well tolerated. IMRT was found to provide sparing to the liver and possibly renal function.