- Higher doses of radiation therapy
does not increase the survival rates in prostate cancer patients.
- Patients who received higher doses
of radiation experienced more side effects which sometimes manifested
years after treatment.
- Higher doses should only be opted
for when these doses can be safely delivered to the patient without
causing adverse side effects down the line.
Higher doses of radiation do not
improve survival rates in patients with prostate cancer compared to standard
radiation therapy, shows study. The study was conducted by a research team at
Washington University School of Medicine and published in JAMA Oncology.
This was the first large scale study
designed to examine, if improved new therapies for
prostate cancer translate into longer survival for patients.
Previous studies have indicated
that gradually escalating the radiation dose slows tumor growth and results in
lower levels of prostate-specific
, an indicator of cancer growth. This study was
conducted to determine if the advances in treatment improved survival rates in
patients with prostate cancer.
The study included nearly 1,500 patients with intermediate-risk prostate
. This category of patients had PSA scores of 10-20 ng/ml and a
Gleason score of seven, which is a measure of tumor aggressiveness.
‘Putting prostate cancer patient on escalating radiation doses does not improve their survival rates.’
The patients were divided into two groups, the standard group received a
radiation dose of 70.2 gray delivered over 39 treatment visits. The
investigational group received increasing doses up to 79.2 gray delivered over
44 visits. Both treatment groups received external beam radiation.
Of the patients receiving
standard treatment, 75% were still alive after 8 years of follow-up and among
the patients who received the dose-escalation treatment, 76% were alive at the
8 year mark. The difference is not statistically significant.
- At the 8 year mark, the
death rate due to prostate cancer for patients receiving standard treatment was
4% compared with 2% for patients receiving the escalating dose. The rates were
also were not statistically different.
- Patients in the
escalating dose group experienced more side effects such as urinary irritation
or rectal bleeding, sometimes years after treatment.
"Our goal is to improve survival, but we didn't see that despite
advances in modern radiotherapy
," said first author Jeff M.
Michalski, MD, the Carlos A. Perez Distinguished Professor of Radiation
Oncology. "But we did see significantly lower rates of recurrence, tumor
growth and metastatic disease - tumors that spread - in the group that received
the higher radiation dose. Still, that didn't translate into better survival.
The patients in the trial did better than we anticipated, and part of that may
have been because of improvements in metastatic cancer therapy over the 10 years
of the trial."
Looking at the side
effects of higher doses of radiation
, Michalski said: "If we can
safely deliver the higher dose of radiation, my opinion is to do that. It does
show lower risk of recurrence, which results in better quality of life. But if
we can't achieve those 'safe' radiation dose goals, we shouldn't put the
patient at risk of serious side effects down the line by giving the higher
dose. If we can't spare the rectum or the bladder well enough, for example, we
should probably back off the radiation dose. It's important to develop treatment
plans for each patient on a case-by-case basis." Reference:
- Michalski JM, Moughan J, Purdy J, Bosch W, Bruner DW, Bahary JP, Lau H, Duclos M, Parliament M, Morton G, Hamstra D, Seider M, Lock MI, Patel M, Gay H, Vigneault E, Winter K, Sandler H. Effect of standard vs. dose-escalated radiation therapy for patients with intermediate-risk prostate cancer: The NRG Oncology RTOG 0126 randomized clinical trial. JAMA Oncology. (2018) DOI: 10.1001/jamaoncol.2018.0039