Whole pelvis radiation for patients with muscle-invasive bladder cancer was linked with better survival outcomes versus radiation to the bladder alone.
A recent study published in the Journal of Clinical Oncology included a total of 599 patients with muscle-invasive bladder cancer who were evaluated. Of this total of patients, 369 underwent whole pelvis radiation, the researchers noted.
Among the patients in the study, researchers found that patients from the whole pelvis radiation group tended to be younger, had an ECOG status of 0 or 1, had clinically node-positive cancer and were previously treated with presurgical chemotherapy.
“In this large multi-institutional retrospective analysis, we have shown that irradiation to pelvic nodes in addition to the bladder was associated with better cancer-specific survival (CSS) and overall survival (OS) for patients with muscle-invasive bladder cancer treated with radiation-based therapy after adjusted analysis,” the researchers wrote in the study.
READ MORE: Removing More Lymph Nodes May Not Improve Survival in Muscle-Invasive Bladder Cancer
Glossary:
Whole pelvis radiation: using radiation rays to target cancer cells in the pelvic lymph nodes.
Muscle-invasive bladder cancer: a type of bladder cancer in which the cancer has spread into the layer of muscle in the bladder.
ECOG status: a measure of patients’ performance statuses, with 0 being fully independent and 4 being unable to complete tasks independently.
Clinically node-positive: patients who have cancer in their lymph nodes.
Cancer-specific survival (CSS): time from the beginning of treatment until death from the cancer.
Overall survival (OS): time patients live with their cancer, regardless of their disease status, until death of any cause.
Hydronephrosis: when the kidneys swell because of urine buildup.
Locoregional disease: cancer that has spread to nearby lymph nodes, but not distantly.
Survival Outcomes With Whole Pelvis Radiation Versus Bladder Radiation Alone
At a median follow-up of 54 months, 149 bladder cancer-related deaths were reported, according to the study. The median CSS was 44 months in the group of patients who received radiation to only the bladder. Patients who received whole pelvis radiation had a median CSS of 84, the researchers noted.
The median OS was 44 months in patients from the bladder radiation alone group, the researchers found. This was compared with a median OS of 71 months in patients from the whole pelvis radiation group.
Factors that may influence the results of the median OS included advanced age, ECOG status of 2 or higher, the presence of hydronephrosis and having received presurgical chemotherapy, the researchers stated.
READ MORE: Navigating Nutrition, Frailty During Kidney or Bladder Cancer Is Key
“After a median follow-up of 5 years, whole pelvis radiation and bladder-only radiation were associated with similar 5-year disease-free survival and OS,” the researchers wrote. “Additionally, the safety profile was not statistically different between the two radiation therapy volumes but pointed toward a lower proportion of patients with acute grade 3 or 4 (severe to life-threatening) toxicity in the bladder-only radiation versus the whole pelvis radiation group.”
More About the Study and Limitations
Patients in the study were evaluated by the researchers within three months after their last dose of radiation therapy, according to the study.
A complete response to radiation therapy was reported when patients showed negativity after a tumor biopsy. Complete response was also determined if patients did not show any signs of locoregional disease on cross-sectional imaging after radiation therapy.
Regarding the study’s limitations, the researchers noted the median follow-up of 54 months may have been too short and could have affected their results. However, they emphasized that a similar study published in The New England Journal of Medicine demonstrated that 91% of patient deaths occurred within the first 36 months of follow-up.
“Our study showed that whole pelvis radiation was associated with better survival compared with bladder radiation alone after adjusted analysis,” researchers wrote. “As bladder-preserving approaches are being expanded to patients with high-risk muscle-invasive bladder cancer, pelvis lymph node irradiation may become more pertinent.”
Reference
“Benefit of Whole-Pelvis Radiation for Patients With Muscle-Invasive Bladder Cancer: An Inverse Probability Treatment Weighted Analysis” by Dr. Gautier Marcq, et al., Journal of Clinical Oncology.
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