No abstract

494 Background: The emergence of intensity-modulated radiation therapy (IMRT) in the treatment of anal cancer has dramatically lowered the incidence of severe toxicity while maintaining excellent long-term outcomes. We compared our institutional experience using 3D conformal radiation therapy (3DCRT) versus IMRT for anal cancer. Methods: We performed a single-institution retrospective review of all non-metastatic squamous cell carcinoma anal cancer patients treated between 2000-2011 using definitive chemoradiation with curative intent. Results: This study included 89 consecutive anal cancer patients (37 3DCRT, 52 IMRT). Median follow-up for all patients, IMRT patients alone, and CRT patients alone was 26.5 months (range, 3.5-133.6), 20 months (range, 3.5-125.5), and 61.9 months (range, 7.6-133.6), respectively. Three-year overall survival (OS), progression free survival (PFS), locoregional control (LRC), and colostomy free survival (CFS) were 91.1%, 82.3%, 90.8%, and 91.3% in the IMRT cohort and 86.1%, 72.5%, 91.9%, and 93.7% for the 3DCRT patients (all p>0.1). More patients in the 3DCRT group required a treatment break (11 vs. 4; p=0.006), although the difference in median treatment break duration was not significant (12.2 vs. 8.0 days; p=0.35). Survival outcomes did not differ based on whether a treatment break was required (all p>0.1). Acute grade ≥3 non-hematologic toxicity was significantly decreased in the IMRT cohort (21.1 vs. 59.5%; p<0.0001). Acute grade ≥3 skin toxicity was significantly worse in the 3DCRT group (p<0.0001) while an improvement in late grade ≥3 GI toxicity was observed in the IMRT patients (p=0.012). Conclusions: This is the largest retrospective review comparing 3DCRT and IMRT for definitive treatment of anal cancer. In contrast to previously published data, this study demonstrates that while long-term outcomes do not significantly differ based on RT technique, a marked decrease in adverse effects and the need for a treatment break can be achieved using IMRT.

No abstract

Objective Despite excellent long-term outcomes, definitive chemoradiation (CRT) for squamous cell carcinoma (SqCC) of the anal canal with traditional radiotherapy techniques results in significant morbidity. Accruing data supports intensity-modulated radiotherapy (IMRT)-based treatment, and we report our institutional experience using this approach. Methods We reviewed patients with nonmetastatic anal canal SqCC treated with definitive IMRT-CRT. Clinically node-negative patients initially received 36 Gy to the elective pelvic and inguinal lymph nodes and 40 Gy to gross tumor volume (GTV) while node-positive patients received 45 and 50 Gy, respectively. All patients were considered for a GTV boost depending on the degree of clinical response and acute treatment-related toxicity.Results We identified 52 patients with T1-4N0-3M0 SqCC of the anal canal. Median follow-up was 21 months (range, 7.7-68.1 months). Two-year locoregional control, overall survival, disease-free survival, distant metastasis-free survival, and colostomy-free survival were 94.6, 100, 82.6, 90, and 94.7 %, respectively. Acute grade 3+ nonhematologic and hematologic toxicities were observed in 21.1 and 63.5 %, respectively. No acute grade 4 nonhematologic toxicity was observed. Conclusion Our series demonstrates that definitive IMRTbased chemoradiation with standard fractionation for anal SqCC results in excellent outcomes with minimal toxicity.

resistance in patients with NSCLC whose disease has progressed on prior EGFR-TKI. Further exploration of the osimertinib plus savolitinib combination is underway in the SAVANNAH (NCT03778229) and ORCHARD (NCT03944772) studies.