Patterns and Predictors of Relapse Following Radical Chemoradiation Therapy Delivered Using Intensity Modulated Radiation Therapy With a Simultaneous Integrated Boost in Anal Squamous Cell Carcinoma

Abstract

To inform intensity modulated radiation therapy delivery and future trials in anal squamous cell Purpose: Our purpose was to describe the patterns and predictors of treatment failure in patients receiving definitive chemoradiation therapy (CRT) for anal squamous cell carcinoma (ASCC), delivered using intensity modulated radiation therapy (IMRT). Methods and Materials: Our study was a retrospective cohort analysis of consecutive patients treated with curative intent for ASCC using CRT delivered with a standardized IMRT technique in 5 UK cancer centers. Patients were included from the start

Intensity modulated radiotherapy for anal canal squamous cell carcinoma: A 16-year single institution experience

“…Treatment was associated with favorable oncologic outcomes with 4-year estimates of OS, CFS, PFS, and LRR of 81%, 77%, 78%, and 9%, respectively. Toxicity rates were comparable to other IMRT series (shown in Table 4 ), and importantly, demonstrate improvements relative to historical 3DCRT series [8] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] . Prolonged overall treatment duration was associated with an increased risk of LRR and colostomy while continued tobacco smoking during CRT was associated with an increased risk of acute dermatologic toxicity.…”

“…Interesting aspects of this work include the relatively large patient cohort (n = 127), fairly homogeneous delivery of DP-IMRT (95%), mature median follow-up of 47 months (IQR: 28- 89 months), robust collection of acute and late AEs, and the availability of extensive patient, disease, and treatment characteristics which facilitated an analysis of variables associated with oncologic efficacy outcomes. Our series, in addition to the IMRT series summarized within Table 4, continue to show that IMRT is associated with a favorable toxicity profile compared to historical 3DCRT series [8,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. We identified rates of grade 3+ acute GI, dermatologic, and hematologic toxicity of 17%, 16%, and 31%, respectively.…”

“…The use of IMRT may reduce treatment-related AEs compared with 3-dimensional conformal radiotherapy (3DCRT), thereby supporting its use as the preferred treatment technique [8] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] . For instance, Radiation Therapy Oncology Group (RTOG) 0529 used a dose-painted IMRT (DP-IMRT) technique and demonstrated a reduction in grade 3+ acute gastrointestinal (GI) and dermatologic AEs and grade 2+ hematologic AEs when compared to historical controls treated with 3DCRT [8] .…”

Patterns of recurrence in anal cancer: a detailed analysis

“…The rate of LRR in our cohort compares favorably with other studies [1,2,[22][23][24][25][26][27][28][29][30][31]. However, the rate of DR is higher than in most other studies, and the ratio between DR and LRR is higher in our study than in any other study.…”

“…Using the same statistical method as comparable studies have used to estimate cumulative incidence (Kaplan-Meier), our 3-year LRR was 13.4% and our 3-year DR was 19.2%. For comparison, Shakir et al recently reported a 3-year LRR of 19.2% and a 3-year DR of 10.9%, in a series of anal cancer patients treated according to UK guidelines [31]. While the pattern of LRR in our study is very similar to the pattern of LRR in the study by Shakir et alwith a majority of LRR being infield LR, and isolated RR being very infrequent -we have no clear explanation for the different ratios between DR and LRR.…”