Six years after treatment for invasive, unilateral breast cancer, more than 60% of women participating in The Pulling Through Study (PTS) experienced at least one side effect amenable to rehabilitative intervention.
Whereas much prior research on the effects of breast cancer treatment has been limited to single issues and has lacked long-term follow-up, PTS provides data on prevalence of adverse effects in breast cancer survivors followed for more than 6 years.
In the current analysis, Kathryn H. Schmitz, PhD, MPH, of the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, and colleagues prospectively assessed the 287 PTS enrollees in Australia at 6 months, 12 months, 18 months, and 6 years after diagnosis for treatment-related complications. The women, who underwent partial or full mastectomy, lumpectomy, chemotherapy, radiation, and/or hormonal therapy, were assessed for the following complications, many of which can be addressed through rehabilitative exercise:
- postsurgical complications
- skin or tissue reaction to radiation therapy
- upper-body symptoms
- 10% weight gain
- problems with upper-quadrant function.
By the 6-year mark, 61.9% of the 188 women in the 6-year follow-up cohort still had up to four adverse treatment effects: 34.5% had one effect, 20.1% had two, 5.8 had three, and 1.4% had four. The remaining 38.1% of patients had no adverse treatment effects at 6 years.
The proportion of women experiencing three or more side effects decreased throughout follow-up, whereas the proportion of those experiencing no side effects remained stable, at approximately 40%, from 12 months forward. The prevalence of most impairments decreased over the course of the study, with the exceptions of lymphedema and weight gain.
The investigators pointed out in their report in the journal Cancer (2012;118[8 suppl]:2217-2225) that the observed prevalence estimate of 60% of survivors who experience at least one adverse treatment effect may well be an underestimate, given that the study did not measure several common treatment sequelae such as cardiotoxicity, bone health, arthralgias, and chemotherapy-induced peripheral neuropathy. Conversely, comorbid conditions and the natural course of aging could have given rise to some of the adverse effects included in the prevalence estimates, such as upper-body functional impairments and weight gain.
Nevertheless, “Regardless of the cause,” wrote Schmitz’s team, “if the impairments are observable and common in the population of breast cancer survivors, there is merit to surveillance if early treatment can be shown to reduce morbidity and be cost-effective compared to the current system of less frequent referral to rehabilitation and exercise.”