Purpose: To evaluate dosimetric and clinical findings of MRI-guided HDR brachytherapy (HDR-B) for cervical carcinoma.
Material and methods: All patients had a CT, MRI and pelvic-paraaortic lymphadenectomy. Treatment: pelvic (+/-)para-aortic3D/IMRT radiotherapy (45 Gy), weekly cisplatin and HDR-B and pelvic node/parametrial boost 60 Gy until interstitial brachytherapy was done. Two implants: 2008-2011: 5 fractions of 6 Gy, 2011: 2016, 4 fractions of 7 Gy. MRI/TAC were done in each implant. The following were defined: GTV, CTH-HR, CTV-IR; OAR: rectum, bladder and sigmoid.
Results: From 2007 to 2016: 57 patients. Patients: T1b2-T2a: 4p, T2b 41p, T3a: 2p; T3B 8p T4a: 2p; N0: 32p, N1 21p, no lymphadenectomy: 4p. Median follow up: 74.6 m (16-122 m), recurrence: 5p local, 6p node, 9p metastasis and 37p without recurrence.Local control 5 years: 90.1%; Ib2-IIB: 94.8%, III-IVa: 72.2%. (p:0.01). RDFS 5y was 92.5%; IB2-IIB: 93%, III: 85% (p:0.024); for pN0: 100%; pN+ iliac-paraaortic: 71.4% (p: 0.007). MFS 5y was 84.1%. Overall survival (OS) at 5y: 66.6% and the cancer specific survival (CEOS) was 74%. Univariate analysis survival: stage Ib2-II 83% vs. III-IVa 41% (p = 0.001); histology: squamous 78%, adenocarcinoma 59.7% (p: ns); lymph node: N0 85% vs. PA+P- 72%, and PA+P+ 35% (p = 0.010). In relation with: HR-CTV dose > 85 Gy, CEOS: 82.5% vs. 77%, and volume CTV-HR < 30 cc: 81.8% and >30 cc: 67%; p: ns. Acute grade 2-3 toxicity: rectal 15.7%, intestinal 15.7% and vesical 15.5%.
Conclusion: Use of interstitial HDR-BQ guided by RM increased CTV-HR dose and local control, like EMBRACE results. Nodal boost improves RDFS and perhaps OS.
Keywords: Brachytherapy; Cancer; Cervix; IG-HDR; IMRT; MRI.