Angiosarcoma observed in 1 in 1,000 patients after radiotherapy for breast cancer
About 1 in 1,000 patients with breast cancer who underwent radiotherapy later developed radiotherapy-associated angiosarcoma, a serious complication for which surgery alone may be the most effective treatment, according to study results in a research letter published in JAMA Oncology.
“I do not think oncologists should stay away from using radiotherapy in [patients with] breast cancer,” Anouk J.M. Rombouts, MD, lead study author from the department of surgery at Radboud University Medical Center in the Netherlands, told HemOnc Today. “The benefits of radiotherapy definitely exceed the risk for developing [radiotherapy-associated angiosarcoma].”
In the prospective Dutch population-based study, Rombouts and colleagues sought to determine incidence, latency period and outcomes of radiotherapy-associated angiosarcoma.
The researchers used the Netherlands Cancer Registry to identify 296,577 patients with stage 1 to stage 3 breast cancer (median age at diagnosis, 58 years; range, 18-97) treated with or without radiotherapy between 1989 and 2015.
None of the patients who did not receive radiotherapy (n = 111,754) developed an angiosarcoma. Among the 184,823 patients who received radiotherapy, 209 (0.1%) developed angiosarcoma of the breast and/or chest wall. Results showed median latency period from breast cancer treatment to development of radiotherapy-associated angiosarcoma of 8 years (range, 3-20).
Older patients with breast cancer appeared at increased risk for radiotherapy-associated angiosarcoma (HR = 1.05; 95% CI, 1.04-1.06), whereas patients who underwent a mastectomy for primary tumor appeared at lower risk than patients who underwent breast-conserving therapy (HR = 0.22; 95% CI, 0.1-0.49).
Among the 194 patients for whom radiotherapy-associated angiosarcoma treatment data were available, 166 (79%) underwent surgery only; 19 (9.1%) underwent surgery and radiotherapy, 13 of whom also received hyperthermia therapy; six (2.9%) underwent chemotherapy or radiotherapy only; and three (1.4%) underwent surgery and chemotherapy.
Researchers observed OS rates of 40.5% (95% CI, 33.1-47.9) after 5 years and 25.2% (95% CI, 17.4-33) after 10 years, regardless of radiotherapy-associated angiosarcoma treatment.
The addition of radiotherapy to surgery for radiotherapy-associated angiosarcoma did not significantly increase survival (HR = 0.61; 95% CI, 0.28-1.34).
Rombouts said that although the cohort was the largest of its kind to date, the number of patients who received radiotherapy again for their secondary sarcoma was too low to confirm a relation to survival outcomes.
“However, we do know from other malignancies, such as rectal cancer, that radiation therapy can be helpful in recurrent cancer even if the primary cancer was also treated with radiation therapy,” Rombouts said. “Based on the current information available, we cannot rule out a benefit of radiotherapy; however, we also have not been able to confirm it. I therefore believe that we should make treatment decisions regarding adjuvant therapy for radiotherapy-associated angiosarcoma on an individual basis.” – by John DeRosier
For more information:
Anouk J.M. Rombouts, MD, can be reached at email@example.com.
Disclosures: Rombouts and the other study authors report no relevant financial disclosures.