Comparison of IMRT and 3D Conformal Radiotherapy for Adjuvant Therapy for Gastric Cancer

Abstract

Purpose/Objective(s)To compare the results of adjuvant chemoradiotherapy using conventional radiotherapy (3D CRT) versus intensity-modulated radiotherapy (IMRT) for adenocarcinoma of the stomach.Materials/Methods57 patients with stage IA-IV gastric cancers were treated with postoperative RT from December 1998 - June 2008 at Stanford, 26 (46%) received 3D CRT and 31 (54%) received IMRT. The median dose was 45Gy (range 43.2 - 54Gy). Patients received concurrent chemotherapy with capecitabine (n = 31), 5FU (n = 25), or none (n = 1). 53 patients received 1-3 cycles of chemotherapy prior to start of RT, and 45 patients received 1-2 cycles post-RT. 22 (85%) of the 3D CRT patients and 25 (81%) of the IMRT patients had carboplatin/5FU-based chemotherapy.ResultsMedian age at diagnosis was 58.7 years (range 28.9-82.8 years). Median follow-up time from diagnosis is 2.4 years (range 0.4-9.9 years). 52 patients had adenocarcinoma and 1 had undifferentiated carcinoma. 22 patients had signet ring features. At last follow-up, 20 patients have died, 4 patients are alive with progressive disease, and 33 patients are alive with no evidence of disease. The 2-year overall survival (OS) was 58%. The 2-year OS for the IMRT patients versus the 3D CRT patients was 66% and 49%, respectively, (p = NS). The 2-yr local control for IMRT versus 3D CRT patients was 80% and 81%, respectively, (p = NS). The 2-yr disease-free survival for the IMRT versus the 3D CRT patients was 51% and 61% (p = NS). Four local regional failures occurred each in the 3D CRT (15%) and the IMRT (13%) patients. No feeding tube placement was required due to treatment toxicity. 5 patients required treatment breaks due to toxicity in the 3D CRT group and only 1 patient required a break in the IMRT group. 61.5% and 61.2% of patients experienced Grade 2 or more acute GI toxicity among the 3D and IMRT group, respectively. For 3D CRT patients, grade 3 late toxicity was experienced by 4 patients who had small bowel obstruction (SBO) (n = 4). For IMRT patients, grade 3 late toxicity was experienced by 4 patients (SBO in 2 patients, strictures in 1 patient, lysis of adhesions in 1 patient), and grade 5 late toxicity by 1 patient (SBO causing death). The median pre-RT and most recent post-RT serum creatinine level was unchanged for patients treated with IMRT. However, an increase in the median creatinine levels in pre-RT versus post-RT was observed among patients treated with 3D CRT (0.82 and 0.93, respectively, p = 0.002). The median V20 for both kidneys was 22% (range 2-47%) and 17.5% (8.5-65.2%) for 3D and IMRT, respectively (p = 0.02). The median V30 for the liver was 28% (range 10-38%) and 16.1% (1-36.6%) for 3D and IMRT, respectively (p = 0.001).ConclusionsIMRT provides similar efficacy results with improved sparing of normal structures including kidneys and liver, possibly translating into sparing of organ function. Purpose/Objective(s)To compare the results of adjuvant chemoradiotherapy using conventional radiotherapy (3D CRT) versus intensity-modulated radiotherapy (IMRT) for adenocarcinoma of the stomach. To compare the results of adjuvant chemoradiotherapy using conventional radiotherapy (3D CRT) versus intensity-modulated radiotherapy (IMRT) for adenocarcinoma of the stomach. Materials/Methods57 patients with stage IA-IV gastric cancers were treated with postoperative RT from December 1998 - June 2008 at Stanford, 26 (46%) received 3D CRT and 31 (54%) received IMRT. The median dose was 45Gy (range 43.2 - 54Gy). Patients received concurrent chemotherapy with capecitabine (n = 31), 5FU (n = 25), or none (n = 1). 53 patients received 1-3 cycles of chemotherapy prior to start of RT, and 45 patients received 1-2 cycles post-RT. 22 (85%) of the 3D CRT patients and 25 (81%) of the IMRT patients had carboplatin/5FU-based chemotherapy. 57 patients with stage IA-IV gastric cancers were treated with postoperative RT from December 1998 - June 2008 at Stanford, 26 (46%) received 3D CRT and 31 (54%) received IMRT. The median dose was 45Gy (range 43.2 - 54Gy). Patients received concurrent chemotherapy with capecitabine (n = 31), 5FU (n = 25), or none (n = 1). 53 patients received 1-3 cycles of chemotherapy prior to start of RT, and 45 patients received 1-2 cycles post-RT. 22 (85%) of the 3D CRT patients and 25 (81%) of the IMRT patients had carboplatin/5FU-based chemotherapy. ResultsMedian age at diagnosis was 58.7 years (range 28.9-82.8 years). Median follow-up time from diagnosis is 2.4 years (range 0.4-9.9 years). 52 patients had adenocarcinoma and 1 had undifferentiated carcinoma. 22 patients had signet ring features. At last follow-up, 20 patients have died, 4 patients are alive with progressive disease, and 33 patients are alive with no evidence of disease. The 2-year overall survival (OS) was 58%. The 2-year OS for the IMRT patients versus the 3D CRT patients was 66% and 49%, respectively, (p = NS). The 2-yr local control for IMRT versus 3D CRT patients was 80% and 81%, respectively, (p = NS). The 2-yr disease-free survival for the IMRT versus the 3D CRT patients was 51% and 61% (p = NS). Four local regional failures occurred each in the 3D CRT (15%) and the IMRT (13%) patients. No feeding tube placement was required due to treatment toxicity. 5 patients required treatment breaks due to toxicity in the 3D CRT group and only 1 patient required a break in the IMRT group. 61.5% and 61.2% of patients experienced Grade 2 or more acute GI toxicity among the 3D and IMRT group, respectively. For 3D CRT patients, grade 3 late toxicity was experienced by 4 patients who had small bowel obstruction (SBO) (n = 4). For IMRT patients, grade 3 late toxicity was experienced by 4 patients (SBO in 2 patients, strictures in 1 patient, lysis of adhesions in 1 patient), and grade 5 late toxicity by 1 patient (SBO causing death). The median pre-RT and most recent post-RT serum creatinine level was unchanged for patients treated with IMRT. However, an increase in the median creatinine levels in pre-RT versus post-RT was observed among patients treated with 3D CRT (0.82 and 0.93, respectively, p = 0.002). The median V20 for both kidneys was 22% (range 2-47%) and 17.5% (8.5-65.2%) for 3D and IMRT, respectively (p = 0.02). The median V30 for the liver was 28% (range 10-38%) and 16.1% (1-36.6%) for 3D and IMRT, respectively (p = 0.001). Median age at diagnosis was 58.7 years (range 28.9-82.8 years). Median follow-up time from diagnosis is 2.4 years (range 0.4-9.9 years). 52 patients had adenocarcinoma and 1 had undifferentiated carcinoma. 22 patients had signet ring features. At last follow-up, 20 patients have died, 4 patients are alive with progressive disease, and 33 patients are alive with no evidence of disease. The 2-year overall survival (OS) was 58%. The 2-year OS for the IMRT patients versus the 3D CRT patients was 66% and 49%, respectively, (p = NS). The 2-yr local control for IMRT versus 3D CRT patients was 80% and 81%, respectively, (p = NS). The 2-yr disease-free survival for the IMRT versus the 3D CRT patients was 51% and 61% (p = NS). Four local regional failures occurred each in the 3D CRT (15%) and the IMRT (13%) patients. No feeding tube placement was required due to treatment toxicity. 5 patients required treatment breaks due to toxicity in the 3D CRT group and only 1 patient required a break in the IMRT group. 61.5% and 61.2% of patients experienced Grade 2 or more acute GI toxicity among the 3D and IMRT group, respectively. For 3D CRT patients, grade 3 late toxicity was experienced by 4 patients who had small bowel obstruction (SBO) (n = 4). For IMRT patients, grade 3 late toxicity was experienced by 4 patients (SBO in 2 patients, strictures in 1 patient, lysis of adhesions in 1 patient), and grade 5 late toxicity by 1 patient (SBO causing death). The median pre-RT and most recent post-RT serum creatinine level was unchanged for patients treated with IMRT. However, an increase in the median creatinine levels in pre-RT versus post-RT was observed among patients treated with 3D CRT (0.82 and 0.93, respectively, p = 0.002). The median V20 for both kidneys was 22% (range 2-47%) and 17.5% (8.5-65.2%) for 3D and IMRT, respectively (p = 0.02). The median V30 for the liver was 28% (range 10-38%) and 16.1% (1-36.6%) for 3D and IMRT, respectively (p = 0.001). ConclusionsIMRT provides similar efficacy results with improved sparing of normal structures including kidneys and liver, possibly translating into sparing of organ function. IMRT provides similar efficacy results with improved sparing of normal structures including kidneys and liver, possibly translating into sparing of organ function.