RTOG 0529: A Phase 2 Evaluation of Dose-Painted Intensity Modulated Radiation Therapy in Combination With 5-Fluorouracil and Mitomycin-C for the Reduction of Acute Morbidity in Carcinoma of the Anal Canal
Mené sur 63 patients atteints d'un carcinome anal de stade II, IIIA ou IIIB, cet essai multicentrique de phase II évalue l'intérêt d'une radiothérapie avec modulation d'intensité et "dose-painting" pour réduire les effets indésirables de grade 2+ et la toxicité gastro-intestinale et génito-urinaire associés à une chimioradiothérapie par 5-fluorouracile et mitomycine-c
A multi-institutional phase 2 trial assessed the utility of dose-painted intensity modulated radiation therapy (DP-IMRT) in reducing grade 2+ combined acute gastrointestinal and genitourinary adverse events (AEs) of 5-fluorouracil (5FU) and mitomycin-C (MMC) chemoradiation for anal cancer by at least 15% compared with the conventional radiation/5FU/MMC arm from RTOG 9811. T2-4N0-3M0 anal cancer patients received 5FU and MMC on days 1 and 29 of DP-IMRT, prescribed per stage: T2N0, 42 Gy elective nodal and 50.4 Gy anal tumor planning target volumes (PTVs) in 28 fractions; T3-4N0-3, 45 Gy elective nodal, 50.4 Gy ≤3 cm or 54 Gy >3 cm metastatic nodal and 54 Gy anal tumor PTVs in 30 fractions. The primary endpoint is described above. Planned secondary endpoints assessed all AEs and the investigator’s ability to perform DP-IMRT. Of 63 accrued patients, 52 were evaluable. Tumor stage included 54% II, 25% IIIA, and 21% IIIB. In primary endpoint analysis, 77% experienced grade 2+ gastrointestinal/genitourinary acute AEs (9811 77%). There was, however, a significant reduction in acute grade 2+ hematologic, 73% (9811 85%, P=.032), grade 3+ gastrointestinal, 21% (9811 36%, P=.0082), and grade 3+ dermatologic AEs 23% (9811 49%, P<.0001) with DP-IMRT. On initial pretreatment review, 81% required DP-IMRT replanning, and final review revealed only 3 cases with normal tissue major deviations. Although the primary endpoint was not met, DP-IMRT was associated with significant sparing of acute grade 2+ hematologic and grade 3+ dermatologic and gastrointestinal toxicity. Although DP-IMRT proved feasible, the high pretreatment planning revision rate emphasizes the importance of real-time radiation quality assurance for IMRT trials.
International Journal of Radiation Oncology, Biology, Physics