Cancer patients who receive high-tech proton therapy experience similar
cure rates and fewer serious side effects compared with those who undergo
traditional X-ray radiation therapy, according to a study led by Washington
University School of Medicine in St. Louis and the Perelman School of Medicine
at the University of Pennsylvania.
The reduction in
side effects — particularly lower hospitalization rates and fewer emergency
room visits — could offset the higher initial cost of proton therapy, which
often is not covered by private insurance because of its higher upfront expense
and limited data on its effectiveness compared to X-ray radiation, according to
the researchers.
The study is published Dec. 26 in JAMA Oncology. Some of the
findings also were presented in June at the American Society of Clinical
Oncology’s annual meeting, in Chicago.
“We observed
significantly fewer unplanned hospitalizations in the proton therapy group,
which suggests the treatment may be better for patients and, perhaps, less
taxing on the health-care system,” said first author Brian C. Baumann, MD, an
assistant professor of radiation oncology at Washington University and an
adjunct assistant professor of radiation oncology at Penn. “If proton therapy
can reduce hospitalizations, that has a real impact on improving quality of
life for both our patients and their caregivers.”
While radiation
therapy can be curative for certain cancers, it also causes severe side effects
— such as difficulty swallowing, nausea and diarrhea — that reduce quality of
life and can, in some cases, require hospitalization, said Baumann, who treats
patients at Siteman Cancer Center at Barnes-Jewish Hospital and Washington
University School of Medicine.
The study, which
included almost 1,500 patients from Penn Medicine, is the first large review of
data across several cancer types — including lung, brain, head and neck,
gastrointestinal and gynecologic cancers — to show a reduced side-effect
profile for proton therapy compared with X-ray radiation therapy for patients
receiving combined chemotherapy and radiation. None of the patients had
metastatic cancer, in which a tumor has spread to other parts of the body.
The researchers
found no differences between the two groups in survival and cancer control,
suggesting that proton therapy is just as effective in treating the cancer even
as it caused fewer side effects. Overall survival at one year for the proton
therapy group was 83 percent versus 81 percent for the X-ray radiation therapy
group. This difference tipped slightly in favor of proton therapy but was not
statistically significant.
The difference
in side effects was more pronounced. Forty-five of 391 patients receiving
proton therapy experienced a severe side effect in the 90-day time frame (11.5
percent). In the X-ray radiation therapy group, 301 of 1,092 patients
experienced a severe side effect in the same period (27.6 percent). The
patients receiving proton therapy experienced fewer side effects despite the
fact that they were, on average, older and had more medical problems than those
receiving standard X-ray radiation therapy. After taking steps to control for
these differences, the researchers found that patients receiving proton therapy
experienced a two-thirds reduction in the relative risk of severe side effects
within the first 90 days of treatment, compared with patients receiving X-ray
radiation therapy.
Both types of
radiation therapy are approved by the Food and Drug Administration for cancer
treatment. X-ray beams are made up of photons, which are electromagnetic
particles that have almost no mass, allowing them to travel all the way through
the body, passing through healthy tissue on the way out. Protons are relatively
heavy, positively charged particles that hit their target and stop, essentially
eliminating the exit dose of radiation.
Since the study
found proton therapy to have fewer adverse events, Baumann said it could prompt
radiation oncologists to design clinical trials to investigate whether
increasing the dose of proton radiation would help patients do better, while
still maintaining acceptable levels of side effects.
Similarly, the
reduced side effects of proton therapy could allow older patients with
additional medical conditions — who are typically excluded from clinical trials
because of their frailty — to participate in trials investigating more
intensive treatments that could be beneficial.
“Clinical trials
often are limited to patients who have serious cancers but are otherwise quite
healthy, and that’s not the real-world cancer population,” said Baumann.
“Doctors, rightly, are concerned about toxicity. But with the reduced toxicity
that we found with proton therapy, this might open the doors to the possibility
of older patients with multiple medical problems getting cancer therapy they
can tolerate that is more likely to be curative.
“With our aging
population, this could have a big impact on a lot of patients,” he added. “To
me, that’s an exciting implication of this research.”
Source: https://myfusimotors.com/2019/12/29/proton-therapy-as-effective-as-standard-radiation-with-fewer-side-effects/
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