Viani G.A.,Marilia Medicine School |
Stefano E.J.,Marilia Medicine School |
Soares F.V.,Marilia Medicine School |
Afonso S.L.,Marilia Medicine School
International Journal of Radiation Oncology Biology Physics | Year: 2011
Purpose: To evaluate whether the risk of local recurrence depends on the biologic effective dose (BED) or fractionation dose in patients with resectable rectal cancer undergoing preoperative radiotherapy (RT) compared with surgery alone. Methods and Materials: A meta-analysis of randomized controlled trials (RCTs) was performed. The MEDLINE, Embase, CancerLit, and Cochrane Library databases were systematically searched for evidence. To evaluate the dose-response relationship, we conducted a meta-regression analysis. Four subgroups were created: Group 1, RCTs with a BED >30 Gy10 and a short RT schedule; Group 2, RCTs with BED >30 Gy10 and a long RT schedule; Group 3, RCTs with BED ≤30 Gy10 and a short RT schedule; and Group 4, RCTs with BED ≤30 Gy10 and a long RT schedule. Results: Our review identified 21 RCTs, yielding 9,097 patients. The pooled results from these 21 randomized trials of preoperative RT showed a significant reduction in mortality for groups 1 (p = .004) and 2 (p = .03). For local recurrence, the results were also significant in groups 1 (p = .00001) and 2 (p = .00001).The only subgroup that showed a greater sphincter preservation (SP) rate than surgery was group 2 (p = .03). The dose-response curve was linear (p = .006), and RT decreased the risk of local recurrence by about 1.7% for each Gy10 of BED. Conclusion: Our data have shown that RT with a BED of >30 Gy10 is more efficient in reducing local recurrence and mortality rates than a BED of ≤30 Gy10, independent of the schedule of fractionation used. A long RT schedule with a BED of >30 Gy 10 should be recommended for sphincter preservation. © 2011 Elsevier Inc.
Viani G.A.,Marilia Medicine School |
De Fendi L.I.,Marilia Medicine School |
Fonseca E.C.,Marilia Medicine School |
Stefano E.J.,Marilia Medicine School
International Journal of Radiation Oncology Biology Physics | Year: 2012
Purpose: Postoperative adjuvant treatment using β-radiotherapy (RT) is a proven technique for reducing the recurrence of pterygium. A randomized trial was conducted to determine whether a low fractionation dose of 2 Gy within 10 fractions would provide local control similar to that after a high fractionation dose of 5 Gy within 7 fractions for surgically resected pterygium. Methods: A randomized trial was conducted in 200 patients (216 pterygia) between February 2006 and July 2007. Only patients with fresh pterygium resected using a bare sclera method and given RT within 3 days were included. Postoperative RT was delivered using a strontium-90 eye applicator. The pterygia were randomly treated using either 5 Gy within 7 fractions (Group 1) or 2 Gy within 10 fractions (Group 2). The local control rate was calculated from the date of surgery. Results: Of the 216 pterygia included, 112 were allocated to Group 1 and 104 to Group 2. The 3-year local control rate for Groups 1 and 2 was 93.8% and 92.3%, respectively (p =.616). A statistically significant difference for cosmetic effect (p =.034), photophobia (p =.02), irritation (p =.001), and scleromalacia (p =.017) was noted in favor of Group 2. Conclusions: No better local control rate for postoperative pterygium was obtained using high-dose fractionation vs. low-dose fractionation. However, a low-dose fractionation schedule produced better cosmetic effects and resulted in fewer symptoms than high-dose fractionation. Moreover, pterygia can be safely treated in terms of local recurrence using RT schedules with a biologic effective dose of 24-52.5 Gy 10.. © 2012 Elsevier Inc.