Management of locally advanced anal canal carcinoma with intensity-modulated radiotherapy and concurrent chemotherapy

Abstract

The best curative option for locally advanced (stages II-III) squamous-cell carcinomas of the anal canal (SCCAC) is concurrent chemo-radiotherapy delivering 36-45 Gy to the prophylactic planning target volume with an additional boost of 14-20 Gy to the gross tumor volume with or without a gap-period between these two sequences. Although 3-dimensional conformal radiotherapy led to suboptimal tumor coverage because of field junctions, this modality remains a standard of care. Recently, intensity-modulated radiotherapy (IMRT) techniques improved tumor coverage while decreasing doses delivered to organs at risk. Sparing healthy tissues results in fewer severe acute toxicities. Consequently, IMRT could potentially avoid a gap-period that may increase the risk of local failure. Furthermore, these modalities reduce severe late toxicities of the gastrointestinal tract as well as better functional conservation of anorectal sphincter. This report aims to critically review contemporary trends in the management of locally advanced SCCAC using IMRT and concurrent chemotherapy.

Pooled Analysis of external-beam RADiotherapy parameters in phase II and phase III trials in radiochemotherapy in Anal Cancer (PARADAC)

“…Considering the impact of OTT on outcomes of combined therapy for anal cancer, strategies have been developed to shorten OTT while attempting to reduce toxicity. IMRT and VMAT have been proven to be feasible and current results show less skin, hematological and gastro-intestinal toxicity with comparable outcomes to results from 3D-conformal RT treatments [12][13][14]16,43]. These results should be interpreted with caution.…”

“…Indeed, they found a decrease of treatment breaks, resulting in shorter OTT in patients receiving IMRT, but without significant improvement of severe gastro-intestinal or hematological toxicity. The authors hypothesize this may be due to incorrect planning or delivery, which highlights the need to follow international guidelines and homogenize contouring practices to improve these results, not only in terms of toxicity, but also in terms of outcomes [14,15,31,44]. A single center study which reviewed 45 patients treated by 3D- Toxicity results from this meta-analysis were difficult to interpret due to heterogeneous toxicity scoring and reporting.…”

“…Despite attempts to improve this treatment, the standard treatment for locally advanced disease remained unchanged for years with the most recent contributions confirming the efficicacy of RT with 5-FU and MMC [7][8][9][10]. The most concrete improvement is the introduction of new modalities of RT delivery, Intensity Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT), allowing a better toxicity profile with comparable outcomes [11][12][13][14][15][16]. However, many questions remain a matter of debate.…”

Additional Value of 2-[18F]FDG PET/CT Comparing to MRI in Treatment Approach of Anal Cancer Patients

“…Chemoradiotherapy (CRT) is a well-known standard approach in the treatment of ACa in the majority of patients, and surgery is preserved for salvage therapy [ 6 , 19 , 20 ]. A precise determination of the radiotherapy field is of substantial importance to reduce toxicities, becoming bolder by the introduction of novel sophisticated methods [ 21 , 22 ].…”