Outcomes After IMRT Compared to 3DCRT for Squamous Cell Carcinoma of the Anus

Abstract

Purpose/Objective(s)IMRT is routinely used to reduce toxicity in squamous cell carcinoma of the anus (SCCA). We report our clinical outcomes after both IMRT and 3DCRT in a cohort of patients staged by FDG-PET/CT.Materials/MethodsThe records of 110 patients that received definitive radiation therapy from 2003 to 2013 with SCCA were retrospectively reviewed with IRB-approval. The staging evaluation included FDG-PET/CT for all patients. Of these, 28 received 3DCRT and 82 underwent IMRT. Median radiation therapy dose was 50.6 Gy (Range 30-73 Gy) in the 3DCRT group and 52.3 Gy (Range 40-60 Gy) in the IMRT cohort delivered in 1.8-2.0 Gy per fraction. Within the IMRT group 28 patients received a sequential boost technique and 54 underwent a simultaneous integrated boost (dose-painted IMRT). Overall, 109 patients received chemotherapy and 94 received Nigro regimen chemotherapy consisting of Mitomycin C and 5-FU (79% of the 3DCRT cohort and 89% of the IMRT cohort; p = 0.23). There was no difference between groups in terms of age, sex, race, HIV status, T stage, N stage, AJCC stage, radiation therapy dose or chemotherapy delivery. Survival outcomes for groups were compared using the Kaplan Meier method with log rank analysis.ResultsMedian follow-up for the 3DCRT group was 36 months versus 24 months for the IMRT group. There were 8 locoregional recurrences in each group. The 3DCRT group had 8 local and 0 regional recurrences with a median time to recurrence of 10 months and the IMRT group had 4 local and 4 regional recurrences also with a median time to recurrence of 10 months. Two year local recurrence free survival was 72% for the 3DCRT and 95% for the IMRT group (p < 0.01). Recurrence free survival was 86% for the IMRT group and 72% for the 3DCRT group at 2 years (p = 0.09). Overall Survival was 88% for both groups at 2 years (p = 0.4). Within the IMRT group there were 2 local and 2 regional recurrences each in both the simultaneous integrated boost and the sequential boost groups.ConclusionsSurvival outcomes are similar when comparing IMRT to 3DCRT. There does not appear to be a difference in locoregional recurrence rates for patients treated with IMRT using dose painting or sequential boost techniques. Purpose/Objective(s)IMRT is routinely used to reduce toxicity in squamous cell carcinoma of the anus (SCCA). We report our clinical outcomes after both IMRT and 3DCRT in a cohort of patients staged by FDG-PET/CT. IMRT is routinely used to reduce toxicity in squamous cell carcinoma of the anus (SCCA). We report our clinical outcomes after both IMRT and 3DCRT in a cohort of patients staged by FDG-PET/CT. Materials/MethodsThe records of 110 patients that received definitive radiation therapy from 2003 to 2013 with SCCA were retrospectively reviewed with IRB-approval. The staging evaluation included FDG-PET/CT for all patients. Of these, 28 received 3DCRT and 82 underwent IMRT. Median radiation therapy dose was 50.6 Gy (Range 30-73 Gy) in the 3DCRT group and 52.3 Gy (Range 40-60 Gy) in the IMRT cohort delivered in 1.8-2.0 Gy per fraction. Within the IMRT group 28 patients received a sequential boost technique and 54 underwent a simultaneous integrated boost (dose-painted IMRT). Overall, 109 patients received chemotherapy and 94 received Nigro regimen chemotherapy consisting of Mitomycin C and 5-FU (79% of the 3DCRT cohort and 89% of the IMRT cohort; p = 0.23). There was no difference between groups in terms of age, sex, race, HIV status, T stage, N stage, AJCC stage, radiation therapy dose or chemotherapy delivery. Survival outcomes for groups were compared using the Kaplan Meier method with log rank analysis. The records of 110 patients that received definitive radiation therapy from 2003 to 2013 with SCCA were retrospectively reviewed with IRB-approval. The staging evaluation included FDG-PET/CT for all patients. Of these, 28 received 3DCRT and 82 underwent IMRT. Median radiation therapy dose was 50.6 Gy (Range 30-73 Gy) in the 3DCRT group and 52.3 Gy (Range 40-60 Gy) in the IMRT cohort delivered in 1.8-2.0 Gy per fraction. Within the IMRT group 28 patients received a sequential boost technique and 54 underwent a simultaneous integrated boost (dose-painted IMRT). Overall, 109 patients received chemotherapy and 94 received Nigro regimen chemotherapy consisting of Mitomycin C and 5-FU (79% of the 3DCRT cohort and 89% of the IMRT cohort; p = 0.23). There was no difference between groups in terms of age, sex, race, HIV status, T stage, N stage, AJCC stage, radiation therapy dose or chemotherapy delivery. Survival outcomes for groups were compared using the Kaplan Meier method with log rank analysis. ResultsMedian follow-up for the 3DCRT group was 36 months versus 24 months for the IMRT group. There were 8 locoregional recurrences in each group. The 3DCRT group had 8 local and 0 regional recurrences with a median time to recurrence of 10 months and the IMRT group had 4 local and 4 regional recurrences also with a median time to recurrence of 10 months. Two year local recurrence free survival was 72% for the 3DCRT and 95% for the IMRT group (p < 0.01). Recurrence free survival was 86% for the IMRT group and 72% for the 3DCRT group at 2 years (p = 0.09). Overall Survival was 88% for both groups at 2 years (p = 0.4). Within the IMRT group there were 2 local and 2 regional recurrences each in both the simultaneous integrated boost and the sequential boost groups. Median follow-up for the 3DCRT group was 36 months versus 24 months for the IMRT group. There were 8 locoregional recurrences in each group. The 3DCRT group had 8 local and 0 regional recurrences with a median time to recurrence of 10 months and the IMRT group had 4 local and 4 regional recurrences also with a median time to recurrence of 10 months. Two year local recurrence free survival was 72% for the 3DCRT and 95% for the IMRT group (p < 0.01). Recurrence free survival was 86% for the IMRT group and 72% for the 3DCRT group at 2 years (p = 0.09). Overall Survival was 88% for both groups at 2 years (p = 0.4). Within the IMRT group there were 2 local and 2 regional recurrences each in both the simultaneous integrated boost and the sequential boost groups. ConclusionsSurvival outcomes are similar when comparing IMRT to 3DCRT. There does not appear to be a difference in locoregional recurrence rates for patients treated with IMRT using dose painting or sequential boost techniques. Survival outcomes are similar when comparing IMRT to 3DCRT. There does not appear to be a difference in locoregional recurrence rates for patients treated with IMRT using dose painting or sequential boost techniques.