Impact of bladder size at radiotherapy planning scan on survival
Song, Yee Pei Choudhury, Ananya McPartlin, Andrew J Hoskin, Peter J McWilliam, Alan
Song, Yee Pei
Choudhury, Ananya
McPartlin, Andrew J
Hoskin, Peter J
McWilliam, Alan
Citations
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Abstract
Purpose or Objective
Radiotherapy is the mainstay of curative treatment for
bladder cancer patients opting for organ preservation. Historically, the entire empty bladder is included in a
single clinical target volume (CTV). An empty bladder aims
to reduce dose to organs at risk and improve
reproducibility. Advances in imaging and radiotherapy
techniques allow visualisation of the bladder wall and
delivery of higher radiation dose to the tumour bed. Such
techniques require bladder-filling to separate bladder
walls for tumour bed boost. We evaluate the impact of
bladder size in radiotherapy planning (RTP) scans on
outcomes.
Material and Methods
This retrospective study included all patients treated with
radical chemoradiotherapy for urothelial carcinoma of the
bladder in a tertiary cancer centre from 2010 to 2014. An
empty bladder imaging and treatment protocol was used.
The whole bladder and extravesicle extension of tumour
was treated to a uniform dose of 52.5Gy in 20 fractions
with weekly chemotherapy. Bladder volume was measured
on RTP scan. Overall survival (OS) was defined as time from
start of treatment to death and patients still alive were
censored at time last known alive. Progression free
survival (PFS) was defined as time to local or metastatic
recurrence. Cox proportional hazard ratio was used to
investigate the association of bladder volume with
outcomes.
Results
132 patients were included in this study. One patient had
high grade T1 disease and all others had muscle-invasive
cancers. None had distant metastases. 5 patients did not
complete radiotherapy but all had at least 16 of planned
20 fractions. 79 patients had neoadjuvant
chemotherapy. With a median follow up of 74.1 months,
the median OS of patients was 73.2 months (58.7-108.4).
Median PFS was 64.3 months (35.5-108.4). Mean bladder
volume was 109.50cm3 (39.2- 433.3). Due to the large
range of bladder volumes, a log scale was used. Larger
log(bladder volume) on RTP scan was associated with
poorer OS (HR 1.78 p=0.03) and PFS (HR 1.71 p=0.03). This
is not clinically significant after multivariate analysis Conclusion
Advances in radiotherapy technique allow more precise
treatment plans. As clinical trials adopt bladder-filling
protocols, it is vital that the impact of bladder volume on
clinical outcomes is considered. Our relatively small study
shows that bladder volume is not related to survival in a
multivariate analysis. Factors like hydronephrosis and CIS
impact survival, and should be considered in formulation
of management plans. Bladder volume in this study
reflects poor bladder emptying which may differ from
planned bladder filling. Further evaluation in a prospective
patient cohort with planned bladder filling will improve
our understanding of the impact of bladder size on
outcomes in the modern era.
Description
Date
2020
Publisher
Collections
Keywords
Type
Meetings and Proceedings
Citation
Song YP, Choudhury A, McPartlin A, Hoskin P, McWilliam A. PO-1215: Impact of bladder size at radiotherapy planning scan on survival. Radiotherapy and Oncology . 2020 Nov;152:S639–40.