A prospective study examining a
trimodality treatment approach in localized bladder cancer cases using adaptive
image-guided, intensity-modulated radiation therapy (IG-IMRT) found that the
bladder preservation rate at three years was 83 percent.
150,000 people worldwide die every year as a result of urinary bladder cancer.
Patients with moderately advanced bladder cancer typically undergo surgery with
removal of the bladder resulting in the use of an external urine bag. The
trimodality plan, which consists of the transurethral resection of the bladder
tumor (TURBT), IG-IMRT and chemotherapy, was
developed as a bladder conservation protocol to preserve bladder function with
good oncological outcomes.
“Adaptive IGRT [with]
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,” said
Vedang Murthy, MD, radiation oncology, Tata Memorial Centre, Mumbai, India and lead
author of the study, “Clinical Outcomes
With Dose-Escalated Adaptive Radiation Therapy for Urinary Bladder Cancer: A
Prospective Study,” published in the International Journal of Radiation Oncology
• Biology • Physics (Red Journal).
“With adaptive IGRT, increasing the dose
becomes possible, and serious side effects may be kept low, ensuring a good quality
of life for our patients,” Dr. Murthy said.
The study looked at 44 patients between
August 2008 and August 2014. Thirty nine (88 percent) patients were male and five
(11 percent) were female, ranging in ages from 55 to 72. Eighty-eight percent of
patients had stage 2 disease. Patients underwent maximal safe resection of
bladder tumor and concurrent platinum-based chemotherapy, and those with large
tumors were offered induction chemotherapy.
RT planning was done using either three
(n=34) or six (n=10) non-concentrically grown planning target volumes (PTV).
Patients received 64 Gy in 32 fractions to the whole bladder and 55 Gy to the
pelvic nodes. If appropriate, they received a simultaneous integrated boost to
the tumor bed to 68 Gy. Daily megavoltage imaging was used to find the most
appropriate PTV encompassing bladder for the particular day with the plan-of-the-day
At six to ten weeks post-treatment,
all patients had a complete response. The study had a median follow-up of 30
months. Overall survival at the last follow up was 77 percent (34 patients).
Among those who died, three died from comorbidities and were disease free at the
time of death.
The three-year locoregional control
(LRC), disease-free survival and overall survival (OS) rates were 78 percent,
66 percent and 67 percent, respectively. Rates of LRC and OS were better in
patients who received dose escalation. Acute
and late Radiation Therapy Oncology Group (RTOG) grade 3 genitourinary toxicity
was seen in five (11 percent) and two (four percent) patients, respectively. No
acute or late RTOG grade 3 or higher gastrointestinal toxicity occurred.
RT (ART) further helps in reduction of doses to normal tissues and improves
accuracy of delivery,” Dr. Murthy said. “These procedures, in theory, should
result in less acute and late toxicity, while allowing for dose escalation to gross
tumor to improve outcomes.”
“Although a number of investigators
have conceived and developed a variety of ART techniques, there are few
clinical outcome data to validate this dosimetric concept. The present
proof-of-concept prospective study was conducted with the aim of establishing
the safety, efﬁcacy, and feasibility of IG-IMRT-based ART in clinical
practice,” he said.
with larger groups of patients is needed to establish the novel technique as
the standard, Dr. Murthy said, but results from the study have shown the
possibilities of ART in bladder cancer patients.
provide proof of concept of using adaptive IGRT in the clinic,” Dr. Murthy
said. “This will hopefully lead to more and more suitable patients undergoing
bladder preservation around the world.”
information, contact ASTRO’s Press Office at email@example.com. For the study abstract, visit www.redjournal.org/article/S0360-3016(15)03321-0/abstract. For more information aboutRed Journal, visit www.redjournal.org.
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