Comparison between helical tomotherapy and intensity-modulated radiotherapy on acute toxicity in patients with rectal cancer / 肿瘤研究与临床

ABSTRACT

Objective To compare acute toxicity for stage Ⅱ-Ⅲ patients with rectal cancer irradiated with helical tomotherapy (HT) and conventional five-field intensity-modulated radiotherapy (5-IMRT).Methods The data of 84 stage Ⅱ-Ⅲ patients with rectal adenocarcinoma treated with concurrent chemoradiotherapy (CRT) were retrospectively analyzed.19 patients underwent postoperative CRT,and 65 patients underwent preoperative CRT.43 patients received radiotherapy with HT and 41 patients with 5-IMRT.The delineation on clinical target volume (CTV) and gross tumor target (GTV) was similar for two groups.The CTV to plan tumor volume (PTV) margins were 1.0 cm for patients with 5-1MRT and 0.5 cm for patients with HT.For all patients,a dose of 45.0-50.4 Gy,in daily fractions of 1.8 Gy,was delivered to PTV.For 45 patients with high risk factors,simultaneous integrated boost (SIB) was given to the tumor or tumor bed of a total dose of 55.0-60.0 Gy,in daily fractions of 2.1-2.3 Gy.Before treatment,the patients treated with HT underwent scanning by the tomotherapy-integrated megavoltage computed tomography (MVCT) scan modality and were positioned by co-registration of these images to the original kilovoltage planning CT image set.Concurrent capecitabine every day 1 600 mg/m2,twice daily on every day in the week.Results The rates of grade ≥ 2 acute cystitis were 7.0 ％ (3 cases) in HT group and 2.4 ％ (1 case) in 5-IMRT group (P =0.616),and ≥3 grade acute diarrhea were 4.7 ％ (2 cases) and 12.2 ％ (5 cases),respectively (P =0.259).≥2 grade leukopenia were 48.8 ％ (21 cases) and 19.5 ％ (8 cases),respectively (P =0.005),≥1 grade anemia were 34.9 ％ (15 cases) and 14.6 ％ (6 cases),respectively (P =0.032),and ≥1 grade thrombocytopenia were 23.3 ％ (10 cases) and 14.6 ％ (6 cases),respectively (P =0.314).Conclusions There is no significant difference in acute diarrhea and cystitis for patients treated with HT and 5-IMRT.Leukopenia and anemia in patients treated with HT are worse than those in patients with 5-IMRT,and thrombocytopenia is similar in the two groups.