Late toxicity after adjuvant radiochemotherapy for gastric adenocarcinoma

Abstract

14042 Background: There is limited late toxicity data following adjuvant radiochemotherapy for resected gastric cancer. Methods: We reviewed radiation dose volume histograms (DVHs) and toxicity outcomes for gastric cancer patients (stage Ib to IV) who received adjuvant conformal radiochemotherapy between November 2000 and May 2005. Charts were reviewed to determine survival, late clinical toxicity, and biochemical markers of renal or hepatic toxicity (creatinine, bilirubin, ALP, AST, ALT). DVHs for kidneys and liver were correlated with toxicity outcomes. Overall (OS), disease-free (DFS) and event (death or late toxicity) -free (EFS) survival were calculated. Results: 80 of 88 patients’ DVHs were available for review. Mean age was 58 years (range: 22 - 75), with 53 (66%) males and 27 (34%) females. Stage distribution was: IB - 13 (16%), II - 32 (40%), IIIA - 24 (30%), IIIB - 4 (9%) and IV - 7 (9%). 3D conformal radiotherapy (45 Gy/25 fractions) was used. In 69 patients, chemotherapy was standard as per the INT-116 study; 11 study patients received infusional 5FU (200mg/m2/day for 12 weeks) and cisplatin in escalating dose (4 cycles q 2 weeks, 0–30 mg/m2). All treatment was completed in 56 (70%) patients; 9 (11%) did not complete radiotherapy and 22 (27.5%) had chemotherapy dose omissions. Median follow up is 30 months (range 6–62). At 2 years, OS was 84% (95% CI 73%-90%), DFS was 66% (95% CI 53%-75%) and EFS was 61% (95% CI 49–72%). Clinical late toxicity occurred in 6 patients 9 to 53 months following treatment: bowel obstruction/perforation (2) and anastomotic stricture (4), in volumes treated to 45 Gy. No clinical symptoms of renal or hepatic toxicity were reported. Grade 1 (CTCAE v3.0) elevation of creatinine was observed in 8 (10%) patients; at least one liver test was altered in 22 (27.5%) patients, (grade 1–17; 2–4; 3–1). Abnormal bloodwork occurred 9 days to 55 months following treatment and did not correlate with higher kidney and liver doses. Conclusions: In our cohort of patients treated with conformal radiochemotherapy, small bowel and anastomotic toxicity was most common, with no clinical renal or hepatic toxicity observed. Biochemical renal and hepatic changes were not related to clinical toxicity or dose delivered. Further assessment with longer follow-up in a larger sample is planned. No significant financial relationships to disclose.