Role of upper abdominal reirradiation for gastrointestinal malignancies: a systematic review of cumulative dose, toxicity, and outcomes on behalf of the Re-Irradiation Working Group of the Italian Association of Radiotherapy and Clinical Oncology (AIRO).

PURPOSE: Abdominal recurrences of gastrointestinal malignancies are common. Evidence in clinical studies has shown that re-irradiation (Re-I) is tolerable and efficient in different tumor locations. In contrast, little clinical data are available on normal long-term Re­I tolerance doses. A systematic review of upper abdominal Re­I was performed with the aim of exploring the cumulative dose, toxicity, and outcomes. METHODS: A computerized search was undertaken in MEDLINE, EMBASE, OVID, and the Cochrane database. Only studies reporting toxicity and/or outcomes were taken into consideration. To improve the comparability of the different Re­I regimens and assess the relationship between Radiotherapy (RT) dose and toxicity, the equivalent dose in 2­Gy fractions was calculated according to the linear quadratic model. RESULTS: Sixteen studies met the inclusion criteria, with the total patients numbering 408. Median follow-up Re­I ranged from 5.9 to 45 months. The median time elapsed since previous RT treatment was 15 months (2-162 months). Re­I prescription doses were variable (22.5 Gy in 3 fractions to 126.5 Gy with 125I). Cumulative doses calculated for acute- and late-responding tissues ranged from 67.25 to 136 Gy and 30.3 to 188.38 Gy, respectively. Comprehensively, the pooled ≥G3 toxicity was 12% (95%CI: 7.6-19%). The overall 1­year survival and local recurrence-free survival rates were 53.7% (95%CI: 45.6-63.2%) and 66.5% (95% CI: 58.7-75.4%), respectively. Pain improvement was reported in 66.9% of patients. CONCLUSION: Due to limited evidence as a result of the retrospective design of the majority of the studies, our review suggests that upper abdominal Re­I is effective in terms of local control and palliation, with a moderate rate of severe toxicities.