D. Manigandan, and P.K. Julka; All India Institute of Medical Sciences,. New Delhi .... B. Thomas, and S.K. Shrivastava; Tata Memorial Centre, Mumbai, India.
S436
International Journal of Radiation Oncology Biology Physics
Author Disclosure: D.L. Rash: None. Y.C. Lee: None. M. Mathai: None. R.L. Stern: None. R. Valicenti: None. J. Mayadev: None.
sequences: T2W imaging, proton density weighted (PDW) imaging, and diffusion weighted-apparent diffusion coefficient (DW-ADC) mapping. We demonstrate how use of this multi-sequence MRI technique can facilitate adaptive planning over the course of treatment. Materials/Methods: Patients were prescribed to receive high dose rate brachytherapy in 6 weekly fractions concurrently with 50.4 Gy external beam dose to the pelvis using intensity-modulated radiation therapy. Brachytherapy dose was based on stage and tumor size at time of diagnosis. For each brachytherapy fraction, the following was done. Patients were implanted with Fletcher-style titanium tandem and colpostats without shielding. MRI was performed on a 1.5-T Philips scanner using T2W, PDW, and DW imaging sequences. ADC maps were generated from the DW images. Images were imported into a brachytherapy treatment planning system and fused. T2W images were used for the definition of organs at risk (OARs) and dose points. ADC maps in conjunction with T2W images were used for target delineation. PDW images were used for applicator definition. Forward treatment planning was performed using standard source distribution rules normalized to point A. Point doses and dose-volume parameters for the tumor and OAR were entered into a spreadsheet for the individual fractions. Delivered doses were adapted for tumor shrinkage and OAR variations during the 6-week course of therapy. Results: The MRI-based imaging methodology for IGBT described here has been clinically implemented, and is carried out for each brachytherapy fraction. MR scanning sequences included T2W turbo spin echo (TSE) imaging (TR Z [3200-6500] ms, TE Z 100 ms), single-shot DW echoplanar imaging (TR Z 1300 ms, TE Z 75 ms) at b values of 0 and 800 s/ mm2, and PDW TSE imaging (TR Z [3000-6000] ms, TE Z 5.5 ms), inplane resolution 0.2 cm, section thickness 0.5 cm, parasagittal acquisition planes, 3-6 minutes per sequence. Point A dose, target doses (dose to 100% of the volume [D100], D90, equivalent dose in 2 Gy fractions [EQD2]), and OAR doses (D2cc, EQD2) are automatically exported to a spreadsheet in which cumulative doses are recorded. Total procedure time from patient preparation to delivery of treatment is typically about 2 hours per patient. Conclusions: Multiple MRI sequences allow for improved visualization of the target, critical structures, and applicator for the treatment planning of cervix cancer patients receiving intracavitary brachytherapy. Dose adaptation relative to these structures can be readily performed. Author Disclosure: J. Esthappan: None. C. Bertelsman: None. Y. Hu: None. P. Dyk: None. P. Grigsby: None.
2577 Acute Gastrointestinal and Genitourinary Toxicities in Locally Advanced Carcinoma Cervix Treated With Intensity Modulated Versus Conventional Pelvic Radiation Therapy: Results From a Prospective Randomized Study A.K. Gandhi, G.K. Rath, D.N. Sharma, V. Subramani, S. Sharma, D. Manigandan, and P.K. Julka; All India Institute of Medical Sciences, New Delhi, India Purpose/Objective(s): To compare acute gastrointestinal (GI) and genitourinary (GU) toxicities in locally advanced carcinoma cervix treated with conventional radiation therapy (CRT) vs. Intensity modulated radiation therapy (IMRT). Materials/Methods: Between January 2010 and September 2011, 43 patients of squamous cell carcinoma cervix with stage IIB-IIIB, age 25-65 years, KPS 70, Hemoglobin 10 g/dL, WBC 3,000/ml, Absolute neutrophil count (ANC) 1500 cells/mm3;Platelets 100,000 cells/ mm3;Creatinine clearance 50 mg/dL were randomized to receive either pelvic CRT or IMRT. Patients in both arms received external irradiation of 50.4 Gy in 28 fractions over 5.5 weeks with concurrent cisplatin 40 mg/m2 weekly followed by high dose rate (HDR) Intracavitary radiation therapy (ICRT) 7 Gy in 3 fractions or Interstitial brachytherapy (ISBT) 10 Gy in 2 fractions, each one week apart. For IMRT, planning constraints for organ at risks were: D Max (dose maximum) to bladder, rectum and small bowel each 49 Gy; 40% volume each of bladder and rectum to receive 40 Gy and 40% volume of small bowel to receive 32 Gy. No constraint was given to bone marrow. Patients were assessed for Radiation toxicity with CTCAE (version 3.0) weekly during concurrent chemoradiation therapy and 1 week after completion of treatment. Statistical analysis was done with SPSS (version 16.0). Chi-Square test/Fisher’s Exact test was used for comparison of two arms. p value of 0.05 was taken as significant. Results: Of 43 patients, 22 patients were treated with CRT and 21 with IMRT. Median age and KPS of patients in both the arms were 48 years and 90 respectively. In CRT arm 13 patients belonged to stage IIB and 9 to stage IIIB while in IMRT arm 12 patients were of stage IIB and 10 of stage IIIB. All patients completed radiation therapy uninterrupted except 2 patients in conventional arm whose treatment were interrupted for 4 and 7 days because of Grade 3 GI toxicity. Median number of chemotherapy cycles in both the arms was 5. There were 3 chemotherapy interruptions, 2 because of Grade 3 GI reactions and 1 due to grade 3 thrombocytopenia in CRT arm and 2 interruptions, both because of Grade 3 leucopoenia occurred in IMRTarm. Grade 2 or higher GI toxicities were lesser in IMRT vs. CRT arm (33% vs. 63%; p Z 0.04).Grade 3 or higher GI toxicities were also lesser with IMRT vs. CRT arm (4.8% vs. 27.3%; p Z 0.05).Grade 2 or higher and Grade 3 or higher GU toxicities in IMRT vs. CRT arms were respectively (31.8% vs.13.6%; p Z 0.12) and (23.8% vs. 0.00%; p Z 0.40) and was not significantly different. Conclusion: Pelvic IMRT in locally advanced carcinoma cervix leads to significantly lesser Grade 2 and 3 GI toxicities as compared to CRT. Acute GU toxicities are also lesser with IMRT than with CRT. We suggest IMRT should be used in favor of lesser radiation morbidities. Author Disclosure: A.K. Gandhi: None. G.K. Rath: None. D.N. Sharma: None. V. Subramani: None. S. Sharma: None. D. Manigandan: None. P.K. Julka: None.
2578 A Novel MRI Technique for Adaptive Cervix Cancer Brachytherapy J. Esthappan,1 C. Bertelsman,2 Y. Hu,1 P. Dyk,1 and P. Grigsby1; 1 Washington University School of Medicine, Saint Louis, MO, 2Barnes Jewish Hospital, Saint Louis, MO Purpose/Objective(s): Published guidelines for image-guided brachytherapy (IGBT) of cervix cancer recommend the use of T2-weighted (T2W) magnetic resonance imaging (MRI). Here, we introduce a novel method for MRI-guided IGBT that incorporates the use of multiple MRI
2579 Correlation of EQD2, Local Control, and Early Toxicity Following Image Guided IMRT and Interstitial Brachytherapy in Patients With Cervical Cancer A. Chinnachamy, S. Chopra, R. Engineer, S.N. Paul, U. Mahantshetty, B. Thomas, and S.K. Shrivastava; Tata Memorial Centre, Mumbai, India Purpose/Objective(s): Concurrent chemoradiation (CRT) and pelvic interstitial brachytherapy (IBT) is the standard of care for vault cancers. The present study was undertaken to evaluate correlation if any, of equivalent doses in 2 Gy (EQD2) to CTV and normal organs (OAR) with local recurrence and late sequelae respectively following CRT and IBT for vault cancers. Materials/Methods: From Jan 2010 to Oct 2011, 21 patients with vault recurrences were included. All received intensity modulated radiation therapy (IMRT) to a dose of 50 Gy/25fractions/5 weeks along with weekly cisplatin (40 mg/m2). This was followed by IBT (20 Gy/5 fractions/3 days). EQD2 for IMRT and IBT were summated for Clinical Target Volume (CTV) and 2 cc of Organs at Risk and total EQD2 for tumor and normal tissues was calculated using a/b of 10 and 3 respectively. Follow up of patients included pelvic examination MRI. Toxicity was charted using CTCAE v3.0. EQD2 of CTV and OARs in those with residual/ recurrent disease and toxicity grade II was compared with those who were clinically controlled and without toxicity. Result: The median tumor volume at baseline was 22.5cc (range, 4.1104.5). IMRT plans uniformly covered target volume with 95% isodose and mean coverage index for IBT was 0.93 (range, 0.80-0.99) with D90 of
