MedWire News: The majority of breast cancer survivors still have at least one physical or functional treatment-related side effect 6 years after they were treated, study findings indicate.
Until now, most research on the on the prevalence of rehabilitation-responsive adverse effects arising from breast cancer treatment has focused on single factors and lacked long-term follow up, explain Kathryn Schmitz (University of Pennsylvania, Philadelphia, USA) and colleagues.
Better understanding of these effects is therefore needed to establish multidisciplinary care that includes rehabilitation and exercise for breast cancer survivors, they add.
To address this, Schmitz and team conducted the Pulling Through Study, which evaluated the prevalence of adverse effects in 287 Australian women (mean age 55 years) diagnosed with invasive, unilateral breast cancer.
The women were followed up for a median of 6.6 years and prospectively assessed for treatment-related complications at 6, 12, and 18 months and 6 years after diagnosis.
Assessments included postsurgical complications, skin or tissue reaction to radiation therapy, upper-body symptoms, lymphedema, 10% weight gain, fatigue, and upper-quadrant function. All of these adverse effects are amenable to rehabilitative intervention, the researchers note.
At 6 months after diagnosis, 89.7% of the women were experiencing one or more side effects and 61.7% had two or more. By 6 years, the proportion reporting one or more side effects was still high, at 61.9%, while 27.3% still had two or more concerns.
Most of the adverse effects appeared within the first year patients were assessed, and then, with the exception of lymphedema and weight gain, decreased over the course of the study. Lymphedema remained relatively stable, at approximately 10% at each measurement timepoint, while the proportion with weight gain increased from 18% at 6 months to 24% at 6 years.
The researchers acknowledge that the causes of weight gain may extend beyond adverse cancer treatment effects. However, when weight gain was removed from the list of adverse treatment effects, the prevalence of one or more complication remained more than 50% at all timepoints, they note.
The team also suggests that, by not including treatment-related sequelae such as cardiotoxicity, bone health, arthralgias, and peripheral neuropathy, they may have underestimated the prevalence of long-term side effects.
Nevertheless, "our work provides the first accounting of the true magnitude of the post-treatment problems suffered by breast cancer patients, and serves as a call to action for proper monitoring and rehabilitation services to care for them," said Schmitz in a press statement.
"We can no longer pretend that the side effects of breast cancer treatment end after patients finish active treatment. The scope of these complications is shocking and upsetting, but a ready solution for many of them already exists in rehabilitative exercise," she concluded.
The study data are published in a special issue of Cancer that explores the physical late effects of breast cancer treatment and identifies strategies to prevent, monitor for, and treat these conditions.
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