Post-radiotherapy breast telangiectasiae predict late heart complications
MedWire News: Radiotherapy-related telangiectasiae in breast cancer patients is not just a cosmetic issue, say UK researchers who believe the dilated blood vessels may identify women at increased risk for late cardiovascular damage from the treatment.
The research, presented at the National Cancer Research Institute conference held this week in Birmingham, UK, also demonstrated a link between radiation damage and cup size in breast cancer patients.
Chris Talbot (University of Leicester) and co-workers explain that late side effects of radiotherapy, occurring after 90 days, are heritable. For example, patients carrying the TT genotype of a transforming growth factor 1 (TGFb1) single nucleotide polymorphism have a 15-fold increased risk for fibrosis after radiotherapy compared with women carrying the CC genotype.
Hypothesizing that women with radiotherapy-related cutaneous telangiectasiae may have an increased risk for late cardiovascular effects, the team followed-up 153 breast cancer patients 4 years after radiotherapy.
Overall, 15 women had cardiovascular issues, nine of which developed after left-sided radiotherapy. Of note, telangiectasia occurred in 16% of women with cardiovascular disease compared with just 3% of those without, yielding an odds ratio of 6.3.
“This result supports the hypothesis and suggests that some women have a vascular endothelium which is genetically predisposed to radiation damage,” Talbot and colleagues said.
“It should now be possible to find genetic polymorphisms that predict both radiation-induced telangiectasiae and heart damage.”
The team also reported results supporting anecdotal evidence that breast size predicts the risk for radiation-related fibrosis. In a group of 137 breast cancer patients, 41% of women with a DD cup size or larger developed the late complication compared with 21% of women with a D cup, 9% of those with a C cup, 6% of those with a B cup, and none of the A cup patients.
A similar correlation was also found between cup size and risk for telangiectasia and atrophy in the women.
Talbot told MedWire News that this effect may be due to dose heterogeneity during radiotherapy, due to a greater risk for radiation “hot spots” in larger than smaller breasts. Noting that some surgeons recommend breast reduction before treatment, Talbot suggested future research to identify the threshold for this in order to prevent the risk for late complications in breast cancer patients.
Talbot et al concluded that a combination of phenotype and genotype information will allow accurate predictions of patients most at risk for complications.
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By Lynda Williams