Against the motion
Plan library approaches for adaptive radiotherapy treatments are easy to set up and allow for an efficient workflow.1 In pelvic radiotherapy sites such as the bladder, majority of patients will only require three treatments plans to be developed. These were large, medium, and small bladder plans and were able to keep V95% prescription dose to over 99% of CTV over 96.3% of the time.2
Plan library approaches for adaptive radiotherapy have been shown to be effective, well-tolerated and feasible with up to 82% of patients retaining disease-free bladders at 3 years after treatment.3 There is no data yet to prove benefits of real time adaption for the additional time they spend on the couch.
Real time daily adaption does not consider intrafraction motion.4 Bladder filling can increase in volume up to 150cm3 within a treatment session.4 Lengthier times required on the treatment couch during online adaptive therapy will increase the risk of bladder expanding out of target fields.5
Against the motion: rebuttal
Daily real time adaption is expensive and won’t be applicable and accessible to all patients. Generally, oART requires specialist staff such as a Radiation Oncologist (RO), dosimetrist and Radiation Oncology Medical Physicist (ROMP) to be present in addition to the RTT treatment team. Human resources and training are clearly barriers to widespread implementation of oART6
Majority of patient cases do not benefit clinically from daily adaptation, assuming the initial plan is good quality and option of efficient replan is available.
References
1. Hafeez S, Webster A, Hansen VN, McNair HA, Warren-Oseni K, Patel E, et al. Protocol for tumour-focused dose-escalated adaptive radiotherapy for the radical treatment of bladder cancer in a multicentre phase II randomised controlled trial (RAIDER): Radiotherapy planning and delivery guidance. BMJ Open. 2020; 10(12) doi:10.1136/bmjopen-2020-041005.
2. Foroudi, F, Wong J, Haworth A, Baille A, McAlpine J, Rolfo A, et al. Offline adaptive radiotherapy for bladder cancer using cone beam computed tomography. J Med Imaging Radiat Oncol. 2009 Apr; 53(2): 226-33. doi:10.1111/j.1754-9485.2009.02066.x.
3. Murthy V, Gupta P, Baruah K, Krishnatry R, Joshi A, Prabhash K, et al. Adaptive radiotherapy for carcinoma of the urinary bladder: long-term outcomes with dose escalation. Clin Oncol (R Coll Radiol). 2019 Sep; 31(9): 646-652. doi:10.1016/j.clon.2019.06.005.
4. Cabaille M, Khalifa J, Tessier AM, Belhomme S, Crehange G, & Sargos P. A review of adaptive radiotherapy for bladder cancer. Cancer Radiother. 2021 May; 25(3): 271–278. doi:10.1016/j.canrad.2020.08.046.
5. Murthy V, Master Z, Adurkar P, Mallick I, Mahantshetty U, Bakshi G, et al. ‘Plan of the day’ adaptive radiotherapy for bladder cancer using helical tomotherapy. Radiother Oncol. 2011 Apr; 99(1):55-60. doi:10.1016/j.radonc.2011.01.027.
6. Shepherd M, Graham S, Ward A, Zwart L, Cai B, Shelley C, Booth J. Pathway for radiation therapists online advanced adapter training and credentialing. Tech Innov Patient Support Radiat Oncol. 2021 Dec; 20:54-60. doi:10.1016/j.tipsro.2021.11.001.