In other news: Breast cancer treatment effects
medwireNews: The focus this month is on early and late treatment effects in patients with breast cancer, including effects on endometrial cancer risk, cardiotoxicity, and skin toxicity.
Adjuvant tamoxifen treatment for 10 years in women with estrogen receptor-positive breast cancer is associated with a significant twofold increased risk for endometrial malignancy relative to the standard 5 years, find Christina Fleming and colleagues from St Vincent’s Hospital Group in Dublin, Ireland.
This result is derived from a meta-analysis of four randomized controlled trials comprising 21,361 participants, showing that the cumulative risk rose from 1.5% with the shorter treatment duration to 3.2% with extended tamoxifen.
Reassuringly, however, endometrial cancers tended to develop in postmenopausal women and were generally diagnosed at an early stage and grade, and thus were associated with a less than 1% increase in mortality, the authors note in BJS.
Two independent studies – one based on Dutch hospital registries and the other on US claims data – report on cardiotoxicity following treatment for breast cancer.
The Dutch study, which included 14,645 patients diagnosed in 1970–2009 at a median age of 47 years, focused on internal mammary chain irradiation and anthracycline-based chemotherapy, finding that the risk for various cardiovascular diseases was increased with both modalities.
The heart failure risk was especially high when the modalities were combined, at an adjusted hazard ratio (HR) of 9.23, say Flora van Leeuwen (Netherlands Cancer Institute, Amsterdam) and team in the British Journal of Cancer.
Mariana Chavez-MacGregor and co-researchers, from The University of Texas MD Anderson Cancer Center in Houston, USA, similarly observed a higher risk for heart failure with versus without anthracyclines and also with trastuzumab use; the corresponding adjusted HRs were 1.53 and 2.01.
But neither radiotherapy nor taxane use was associated with an increased heart failure risk in their study of 16,456 participants (median age 56 years) diagnosed between 2009 and 2014.
“The number of cancer survivors is expected to increase over time, and we will continue to see patients develop treatment-related cardiotoxicity,” writes the team in JACC: Cardiovascular Imaging.
“Thus, more research, evidence-based guidelines, and tools for prediction of cancer treatment-related cardiotoxicity are needed.”
Researcher Jennifer Hu (University of Miami Miller School of Medicine, Florida, USA) and co-workers have confirmed a previously reported relationship between high-sensitivity C-reactive protein (hsCRP) and adjuvant radiotherapy-induced early skin toxicity in stage 0–IIIA breast cancer, additionally finding that the association is modified by BMI.
Specifically, post-radiotherapy changes in hsCRP levels above the median were a significant predictor of grade 4 or worse skin toxicity in nonobese patients (BMI<30 kg/m2; odds ratio=2.80), but not in those who were obese.
These data “may help to predict [radiotherapy] responses and guide decision making,” Hu et al conclude in the Journal of Clinical Oncology.
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