Challenging conventional wisdom, new findings suggest that hormone therapy may have a greater impact than chemotherapy on long-term quality of life in women with breast cancer, particularly those who have gone through menopause.
The study, “Differential impact of endocrine therapy and chemotherapy on quality of life of breast cancer survivors: a prospective patient-reported outcomes analysis,” was published in Annals of Oncology.
Despite its proven benefits in fighting cancer, chemotherapy is widely known for its negative effects on quality of life, particularly throughout treatment and in the immediate post-chemo periods.
Aiming to avoid chemotherapy toxicities, treatments for hormone receptor (HR)-positive breast cancer patients have changed remarkably in the past years, with hormone therapies gradually replacing chemotherapy regimens.
Hormone therapies are accompanied by their own side effects and deterioration in quality of life, although clinical trials suggest only a modest effect. However, few studies have directly compared the effect of chemotherapy and hormone therapy on patients’ quality of life.
To address this, researchers at Institut Gustave Roussy in France used data from a prospective cohort study called CANTO (NCT01993498), which was aimed at quantifying the toxicity of localized breast cancer treatments up to five years after treatment.
CANTO’s participants were treated primarily with surgery and, in some cases, chemotherapy and/or radiotherapy. About three-quarters of the participants were treated with hormone therapy for at least five years.
Researchers analyzed quality of life data for 4,262 women, 2,675 of whom had gone through menopause. Quality of life was measured at diagnosis, one year after diagnosis, and one year after that. It was assessed using a general quality of life assessment called EORTC QLQ-C30 and a breast cancer-specific assessment called QLQ-BR23, the results of which were combined to generate a “summary score” called C30-SumSc, which the researchers used to assess quality of life.
Two years after diagnosis, young age, comorbidities (coexisting conditions), smoking, low income, anxiety, and depression were all significantly associated with decreased C30-SumSc scores. Treatment with hormone therapy was also associated with a significant C30-SumSc decrease at this time point, which persisted over time. Chemotherapy, on the other hand, caused only a temporary deterioration in quality of life that was not sustained at two years.
Broken out by menopausal status, hormone therapy was significantly associated with decreased C30-SumSc scores in post-menopausal individuals, but not premenopausal individuals. In contrast, chemotherapy was not significantly associated with decreased quality of life in either group.
It is important to note that these changes were in overall quality of life — both hormone therapy and chemotherapy showed significant associations with particular facets used to assess quality of life. For instance, in the total group at two years post-diagnosis, hormone therapy was significantly associated with worse scores for pain, whereas chemotherapy was significantly linked to poorer cognitive functioning.
Nevertheless, the data “challenge the common idea that [hormone therapy] is an innocent player in the [quality of life] arena and highlight that appropriate selection of women for [hormone] treatment escalation should be a research priority,” the researchers wrote.
“This analysis of the CANTO cohort shows for the first time that anti-hormonal treatments do not have lesser effects than chemotherapy on women’s quality of life. Quite the contrary, as the diminution in quality of life which is noted at diagnosis is still present two years later, whereas the impact of chemotherapy is more temporary,” Inès Vaz-Luis, MD, a researcher at Gustave Roussy who led the study, said in a press release.