Clinical outcomes of conventional HDR intracavitary brachytherapy combined with complementary applicator-guided intensity modulated radiotherapy boost in patients with bulky cervical tumor

Objective: To investigate the clinical outcomes and toxicity in patients with locally advanced cervical cancer treated with supplementary applicator guided-intensity modulated radiation therapy (IMRT) based on conventional intracavitary brachytherapy (IC/IMRT). Population Large high risk clinical target volume (HR-CTV) volume (>40cc) at the time of brachytherapy cervical cancer patients were recruited. Methods This study is a retrospective analysis of 76 patients with locally advanced cervical cancer (FIGO IIB-IVA) treated with concurrent chemo-radiotherapy followed by IC/IMRT between June 2010 and October 2016. External radiotherapy (45 Gy in 25 fractions) with cisplatin chemotherapy treated before IC/IMRT. The prescription dose for HR-CTV and IR-CTV were 6 Gy and 5 Gy per fraction for 5 fractions respectively. Results: Mean HR-CTV was 65.8±23.6 cc at the time of brachytherapy. D90 for HR-CTV and IR-CTV were 88.7±3.6 Gy and 78.1±2.5 Gy. D2cc for bladder, rectum, sigmoid and small intestine were 71.8±3.8 Gy, 64.6±4.9 Gy, 63.9±5.3 Gy and 56.7±8.7 Gy respectively. Median follow-up was 85 months (47.9-124.2 months). Five-year local recurrence free survival rate, metastasis recurrence free survival rate, disease free survival rate and cancer special survival rate were 87.6%, 82.4%, 70.9% and 76.3%, respectively. The grade 1+2 gastrointestinal and urinary late toxicities were 15.8% and 21.1%, while grade 3 late toxicities were 3.9% and 5.2%, respectively. Neither acute nor late grade 4 gastrointestinal or urinary toxicities were seen. Conclusions: The combination of ICBT with an applicator-guided supplementary IMRT boost achieved an excellent local control and overall survival with low toxicity for bulky residual cervical tumor