Smalley, Steven R.

4515 Background: INT0116 (SWOG 9008) was a prospectively randomized phase III trial of postoperative adjuvant therapy utilizing 5-FU/leucovorin plus external beam radiation in 582 eligible cases of resected stage IB-IV(M0) stomach and gastroesophageal junction cancers. Initial results (NEJM 345: 725, 2001) showed both overall and disease free survivals improved by chemoradiation. Methods:We now report INT0116 results with >10years median follow-up. Exploratory subset outcomes are also reported. Results: INT0116 continues to show benefit for chemoradiation with hazard ratios (HR) for survival (HR=1.32, p=.004) and disease free survival (HR=1.51, p<.001) favoring chemoradiation. Subset analyses were performed for sex, race, T and N stage, D-level of surgical resection, tumor location (proximal or other), histology (intestinal or diffuse) and Maruyama index. Chemoradiation benefited all subsets with the exceptions of women and diffuse histology. In women the HR for therapy was 1.0(0.68–1.45). The HR for therapy in diffuse histology cases was 0.97(0.62–1.40). Interaction between these factors is suggested as women were significantly more likely to have diffuse histology than men (56% versus 33%). A multivariate analysis of sex and histology did not detect an effect of sex once histology was included. These data suggest that sex may not be an independent variable for lack of response to chemoradiation but that diffuse histology may be. Long term toxicities were examined. Thirty-five second tumors occurred in 31 cases. Twenty-two occurred in chemoradiation cases and 9 in surgery only cases. Second tumors represented a spectrum of types of neoplasms commonly occurring in this age group (median age 60 years). Excessive numbers of tumors known to be caused by radiation and/or chemotherapy were not noted. More tumors may have occurred in the treated patients since their death rates were less than surgery only cases. Conclusions: With >10 years median follow-up, survival remains improved in stage IB-IV (M0) gastric cancer cases treated with post-operative chemoradiaiton. All subsets benefit from this treatment with the exception of cases with diffuse histology. Women may be more likely to have diffuse histology gastric cancers. No increases in late toxic effects were noted. No significant financial relationships to disclose.

Purpose To determine survival and relapse rates by T and N stage and treatment method in five randomized phase III North American rectal adjuvant studies. Patients and Methods Data were pooled from 3,791 eligible patients enrolled onto North Central Cancer Treatment Group (NCCTG) 79-47-51, NCCTG 86-47-51, US Gastrointestinal Intergroup 0114, National Surgical Adjuvant Breast and Bowel Project (NSABP) R01, and NSABP R02. Surgery alone (S) was the treatment arm in 179 patients. The remaining patients received adjuvant treatment as follows: irradiation (RT) alone (n = 281), RT + fluorouracil (FU) ± semustine bolus chemotherapy (CT; n = 779), RT + protracted venous infusion CT (n = 325), RT + FU ± leucovorin or levamisole bolus CT (n = 1,695), or CT alone (n = 532). Five-year follow-up was available in 94% of surviving patients, and 8-year follow-up, in 62%. Results Overall (OS) and disease-free survival were dependent on TN stage, NT stage, and treatment method. Even among N2 patients, T substage influenced 5-year OS (T1-2, 67%; T3, 44%; T4, 37%; P < .001). Three risk groups of patients were defined: (1) intermediate (T1-2/N1, T3/N0), (2) moderately high (T1-2/N2, T3/N1, T4/N0), and (3) high (T3/N2, T4/N1, T4/N2). For intermediate-risk patients, those receiving S plus CT had 5-year OS rates of 85% (T1-2/N1) and 84% (T3/N0), which was similar to results with S plus RT plus CT (T1-2/N1, 78% to 83%; T3/N0, 74% to 80%). For moderately high-risk lesions, 5-year OS ranged from 43% to 70% with S plus CT, and 44% to 80% with S plus RT plus CT. For high-risk lesions, 5-year OS ranged from 25% to 45% with S plus CT, and 29% to 57% with S plus RT plus CT. Conclusion Different treatment strategies may be indicated for intermediate-risk versus moderately high- or high-risk patients based on differential survival rates and rates of relapse. Use of trimodality treatment for all patients with intermediate-risk lesions may be excessive, since S plus CT resulted in 5-year OS of approximately 85%; however, 5-year disease-free survival rates with S plus CT were 78% (T1-2/N1) and 69%(T3/N0), indicating room for improvement.