Clinical Outcomes With Dose-Escalated Adaptive Radiation Therapy for Urinary Bladder Cancer: A Prospective Study

Journal Article · Fri Jan 01 04:00:00 EST 2016 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2015.09.010· OSTI ID:22645051

Murthy, Vedang ^[1]; Masodkar, Renuka; Kalyani, Nikhil; Mahantshetty, Umesh ^[1]; Bakshi, Ganesh; Prakash, Gagan ^[2]; Joshi, Amit; Prabhash, Kumar ^[3]; Ghonge, Sujata; Shrivastava, Shyamkishore ^[1]

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1. Department of Radiation Oncology, Tata Memorial Centre, Parel, Mumbai (India)
2. Department of Surgical Oncology, Tata Memorial Centre, Parel, Mumbai (India)
3. Department of Medical Oncology, Tata Memorial Centre, Parel, Mumbai (India)

Purpose: The purpose of this study was to assess feasibility, clinical outcomes, and toxicity in patients with bladder cancer treated with adaptive, image guided radiation therapy (IGRT) for bladder preservation as a part of trimodality treatment. The role of dose escalation was also studied. Methods and Materials: Forty-four patients with localized bladder cancer were enrolled in a prospective study. They underwent maximal safe resection of bladder tumor and concurrent platinum-based chemotherapy. Patients with large tumors were offered induction chemotherapy. Radiation therapy planning was done using either 3 (n=34) or 6 (n=10) concentrically grown planning target volumes (PTV). Patients received 64 Gy in 32 fractions to the whole bladder and 55 Gy to the pelvic nodes and, if appropriate, a simultaneous integrated boost to the tumor bed to 68 Gy (equivalent dose for 2-Gy fractions assuming α/β of 10 [EQD2]{sub 10} = 68.7 Gy). Daily megavoltage (MV) imaging helped to choose the most appropriate PTV encompassing bladder for the particular day (using plan-of-the-day approach). Results: Most patients (88%) had T2 disease. Sixteen patients (36%) received neoadjuvant chemotherapy. A majority of the patients (73%) received prophylactic nodal irradiation, whereas 55% of the patients received escalated dose to the tumor bed. With a median follow-up of 30 months, the 3-year locoregional control (LRC), disease-free survival, and overall survival (OS) were 78%, 66%, and 67%, respectively. The bladder preservation rate was 83%. LRC (87% vs 68%, respectively, P=.748) and OS (74% vs 60%, respectively, P=.36) rates were better in patients receiving dose escalation. Instances of acute and late Radiation Therapy Oncology Group (RTOG) grade 3 genitourinary toxicity was seen in 5 (11%) and 2 (4%) patients, respectively. There was no acute or late RTOG grade 3 or higher gastrointestinal toxicity. Conclusions: Adaptive IGRT using plan-of-the-day approach for bladder preservation is clinically feasible, with good oncological outcomes and low rates of acute and late toxicities. Dose escalation is safe and possibly improves outcomes in bladder preservation.

• OSTI ID: 22645051
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 1 Vol. 94; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BIOMEDICAL RADIOGRAPHY
BLADDER
CHEMOTHERAPY
DOSE EQUIVALENTS
GY RANGE 10-100
NEOPLASMS
PATIENTS
RADIOTHERAPY
TOXICITY