3D Conformal vs. Intensity Modulated vs Volumetric Arc Radiotherapy Therapy for Muscle Invasive Bladder Cancer

This poster was originally presented at the RANZCR Faculty of Radiation Oncology Meeting 2012, July 26-28, in Cairns/AU. www.ranzcr.edu.au

Congress:

RANZCR FRO 2012

Poster Number:

RO-0030

Type:

Scientific Exhibit

Keywords:

Urinary Tract / Bladder, Oncology, CT, Radiation therapy / Oncology, Neoplasia

Authors:

F. Foroudi¹, L. Wilson², M. Bressel, A. Haworth¹, C. Hornby², S. Gill¹, K. H. Tai¹, T. Kron¹; ¹East Melbourne/AU, ²East Melbourne /AU

DOI:

10.1594/ranzcrfro2012/RO-0030

DOI-Link:

https://dx.doi.org/10.1594/ranzcrfro2012/RO-0030

Fig. 2: Figure 2 IMRT Dose Distribution

Fig. 1: Figure 1 3D-CRT dose distribution

Fig. 3: Figure 3 VMAT dose distribution

Fig. 4: Figure 4 IMRT Simultaneous Infield Boost to 74Gy

Purpose

Three-dimensional conformal radiotherapy (3D-CRT) has historically been the standard modality for external beam radiotherapy (RT) for bladder cancer. The morbidity of bladder cancer treated with conventional radiotherapy is well known with a RTOG update showing that 7% of their patients experienced late grade 3+ pelvic toxicity1. Intensity modulated radiation therapy (IMRT) can treat less of the surrounding normal tissues potentially reducing normal tissue side effects. Hsieh et al2 found that IMRT provided good locoregional progression free survival particularly in the elderly bladder cancer group. Another...

Methods and Materials

All 15 participant images were from a human ethics approved bladder cancer protocol, full details of this protocol have been previously published15.Patients underwent CT simulation using 3mm thick slices by 3mm spacing, after emptying their bladder completely. Immobilisation was with ankle stocks and a bolster under the knees. A single radiation oncologist (FF) completed contouring of the bladder, primary tumour, rectum, and non-rectal bowel prior to commencement of the project. All 3D-CRT, IMRT and VMAT plans were created prospectively using the unique set of contours...

Results

Dosimetric Outcome Figure 1, 2 and 3 a respresentive dosimetric outcomes of the plans created using a 3D-CRT, IMRT or VMAT technique respectively. PTV Conformity Index (CI) and Homogenity Index (HI) The mean PTV conformity (CI) index for 3D-CRT was 1.32, for IMRT 1.05, and for VMAT 1.05. The PTV HI index was 0.080 for 3D-CRT, 0.073 for IMRT and 0.086 for VMAT. Planning Time The total planning time was found to be a mean of 30.7 minutes (range 10-45 minutes) for 3D-CRT; 49.33 minutes...

Conclusion

Radiotherapy to the bladder is complicated by the fact that bladder volume may increase during delivery. If bladder cancer patients are to benefit from modern radiotherapy such as IMRT, it is essential to deliver the treatment as fast as possible. We were able to demonstrate that IMRT and VMAT plans are similar in terms of dose distributions and both have superior conformity indices when compared to 3DCRT. Given the benefits in terms of reduced MU as well as treatment time, VMAT appears to be the...

Personal Information

Dr Farshad Foroudi is a Consultant Radiation Oncologist and Director of the Uro-Oncology Service at the Peter MacCallum Cancer Centre. He has an interest in bladder cancer, image guided radiotherapy and adaptive radiotherapy.

References

1. Efstathiou JA, Bae K, Shipley WU, et al. Late pelvic toxicity after bladder-sparing therapy in patients with invasive bladder cancer: RTOG 89-03, 95-06, 97-06, 99-06. J Clin Oncol 2009;27:4055-61. 2. Hsieh CH, Chung SD, Chan PH, et al. Intensity modulated radiotherapy for elderly bladder cancer patients. Radiat Oncol 2011;6:75. 3. Cilla S, Caravatta L, Picardi V, et al. Volumetric Modulated Arc Therapy with Simultaneous Integrated Boost for Locally Advanced Rectal Cancer. Clin Oncol (R Coll Radiol) 2011. 4. Lee TF, Ting HM, Chao PJ,...