DCIS: What Does Radiation Therapy Contribute?

DCIS (solid type)

What You Need To Know: Survival after treatment for ductal carcinoma in situ (DCIS) of the breast is excellent. So, the question arises whether the current management approaches for DCIS (such as local excision and adjuvant radiation therapy + ant-estrogen therapy) represents overtreatment. While a recent report does not fully answer that question, it does provide long-term evidence that adjuvant radiation therapy after local excision reduces the incidence of both in situ and invasive local recurrences by a factor of 2, and results in an overall lower risk of mastectomy.

Background: Following the introduction of radiation therapy following breast conserving surgery (lumpectomy) for operable invasive breast cancer in the early 1980s, several trials aimed to investigate the value of radiation therapy for even earlier breast cancer, DCIS (Stage 0). Now we have long-term outcomes from the EORTC trial.

The Study: Results of the European Organization for the Research and Treatment of Cancer (EORTC) trial 10853 appear in the Journal of Clinical Oncology today. Between 1986 and 1996, the EORTC trial 10853 randomized 1010 women with complete local excision of DCIS to no further treatment or radiation therapy. The risk of local recurrence was roughly halved with the addition of radiation therapy (HR 0.52). The 15 year local recurrence-free rate was 69% with lumpectomy alone, compared to 82% for those who got radiation therapy. The 15 year invasive local recurrence free rates were 84% (no radiation) versus 90% (radiation).

The differences in local control did not translate into differences in disease specific or overall survival. However, local recurrence was associated with a lower breast cancer specific survival (18x more likely to die of breast cancer, compared to someone without such a recurrence), as well as overall survival (5x more likely to die). In summer, an invasive local recurrence resulted in a worse prognosis. Finally, the women who had radiation therapy had a lower chance of ever having a mastectomy (13% versus 19%).

My Take: These study  results represent long-term confirmation that radiation therapy improves local control after a lumpectomy for DCIS, but does not improve the odds of survival. Radiation therapy also reduced the chances a patient needed breast removal. Soon, we will better distinguish those DCIS lesions that can receive minimal (or no) treatment versus those that do. Prediction tools are beginning to be used, including ones that look at the genes driving the DCIS growth. I’m Dr. Michael Hunter, and I thank you for joining me today.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

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Harvard AB Yale MD UPenn Radiation Oncology Radiation Oncologist, Seattle area

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