title: Long term experience with 3D image guided brachytherapy and clinical outcome in cervical cancer patients.
abstract: To report our 10years' experience and learning curve of the treatment of cervical cancer patients with chemo radiotherapy and MRI (or CT in 9 selected patients) guided brachytherapy using pulsed dose rate (PDR) brachytherapy (BT).
  
  
  
  Hundred and seventy consecutive patients with cervical cancer FIGO stage IB-IVB (without metastases beyond the para-aortic nodal region) were treated in our institute between 2002 and 2012. Patients received external beam radiotherapy (nodal boost to the lymph nodes positive at diagnosis)±chemotherapy followed by a pulsed or low dose rate brachytherapy boost. MRI (or CT) images were taken with the applicator in situ. The first 16 patients were treated according to X-ray-based plans, optimized on MRI. High-risk CTV, intermediate-risk CTV, bladder, rectum and sigmoid were retrospectively contoured according to the GEC-ESTRO recommendations. In all other patients, treatment plans were optimized after delineation of the target volumes and organs at risk at MRI (or CT). Doses were converted to the equivalent dose in 2Gy (EQD2) by applying the linear quadratic model. The median age of the patients was 55years (range 16-88). 41% had stage III or IV disease. Of the 170 patients, 91 patients had on imaging metastatic lymph nodes at diagnosis (62 patients pelvic lymph node involvement and 29 para-aortic). In 27 (16%) patients the intracavitary technique was combined with interstitial brachytherapy.
  
  
  
  The mean D90 and D100 for the high-risk CTV were 84.8±8.36Gy and 67.5±6.29Gy for the entire patient group. Mean D90 and D100 values for the IR CTV were 68.7±5.5Gy and 56.5±6.25Gy. There was an important learning curve between both patient groups, with an increase in mean D90 of 75.8Gy for the first 16 patients compared to 85.8Gy for the second group. At the same time, the mean dose to 2cm3of bladder and sigmoid decreased from 86.1Gy to 82.7Gy and from 70Gy to 61.7Gy, respectively. At a median follow-up of 37months (range 2-136months), local control rate for all patients was 96%, the regional control (pelvic and para-aortic) rate 81% and crude disease free survival rate 55%. The overall survival at 5years is 65%. The higher dose to the target volume resulted in an increase in local control from 88% in the first 16 patients compared to 97% in the second patient group. Regarding late toxicity, 21 patients (12%) presented grade 3-4 late morbidity. Rectal, urinary, sigmoid and vaginal morbidity was 5%, 6%, 2% and 5%, respectively. A correlation between rectal D2cm3>65Gy and grade >3 late morbidity was found (p=0.006).
  
  
  
  Although the majority of the patients presented with locally advanced carcinoma, excellent local and regional control rates were achieved. Rectal, urinary, sigmoid and vaginal grade 3-4 morbidity was 5%, 6%, 2% and 5%, respectively. A correlation between rectal D2cm3>65Gy and grade >3 late morbidity was found (p=0.006).
authors.affiliation: Department of Radiation Oncology, Leuven Cancer Institute, Belgium. Electronic address: ivone.ribeiro.gmr@gmail.com.
authors.forename: Ivone
authors.initials: I
authors.lastname: Ribeiro
authors.affiliation: Department of Radiation Oncology, Leuven Cancer Institute, Belgium.
authors.forename: Hilde
authors.initials: H
authors.lastname: Janssen
authors.affiliation: Department of Radiation Oncology, Leuven Cancer Institute, Belgium.
authors.forename: Marisol
authors.initials: M
authors.lastname: De Brabandere
authors.affiliation: Department of Radiation Oncology, Leuven Cancer Institute, Belgium.
authors.forename: An
authors.initials: A
authors.lastname: Nulens
authors.affiliation: Department of Radiation Oncology, AZ. St. Maarten, Belgium.
authors.forename: Dominique
authors.initials: D
authors.lastname: De Bal
authors.affiliation: Department of Gynecologic Oncology, Leuven Cancer Institute, Belgium.
authors.forename: Ignace
authors.initials: I
authors.lastname: Vergote
authors.affiliation: Department of Radiation Oncology, Leuven Cancer Institute, Belgium.
authors.forename: Erik
authors.initials: E
authors.lastname: Van Limbergen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods*; D012809:Colon, Sigmoid / Q000528:radiation effects; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D009367:Neoplasm Staging; D058958:Organs at Risk / Q000528:radiation effects; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D061089:Radiotherapy, Image-Guided / Q000009:adverse effects / Q000379:methods*; D012007:Rectum / Q000528:radiation effects; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D001743:Urinary Bladder / Q000528:radiation effects; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D055815:Young Adult
keywords: Cervical cancer; DVH parameters; Image-guided adaptive brachytherapy (IGABT); Local control and late rectal morbidity