Radiation for DCIS Patients- Is It Worth It?

Is adding on radiation treatment after a successful lumpectomy for DCIS worth it? Why should I do this extra treatment if the DCIS was removed with clear margins? This is a complicated question to untangle, and I’ve addressed this topic before on the blog. So why am I bothering to write a new article on this? 

Well, I read a new article today that I think is worth sharing. 

Radiation Reduces Recurrence Risk Significantly

A study published in the Journal of Clinical Oncology shows that radiation cuts the long-term risk of recurrence for DCIS in the same breast nearly in half. This study’s data demonstrates a radiation benefit over a median of 13.9 years. Since I was diagnosed at 41, I’m always taking note of studies that present this type of long-term data.

One of the things that I appreciated about this study is that it tries to assess the radiation benefit of “good risk” DCIS patients. What does this mean? I’ll get into some of the specifics below.

What DCIS Patients Were Included?

DCIS patients in this study had mammogram-detected DCIS under 2.5 centimeters that was removed with margins of greater than or equal to 3 millimeters. The grade of DCIS included in this study was low to intermediate grade, just like mine! This is a study that has my diagnosis all over it! 

Six hundred thirty-six women in this study were enrolled from 1999 to 2006. These patients were randomized to a radiation arm and a non-radiation arm.

Tamoxifen use in this study was optional. 

The purpose of this study is to see if patients have a recurrence in the same breast (ipsilateral). It doesn’t address opposite breast events (contralateral).  

What Are the Results?

When the first set of results was released after seven years, the radiation arm had a recurrence of .8%, and the observation arm had recurrence at 7.2%. This latest data release indicates that the radiation arm had a 15-year cumulative recurrence at 7.1%, and the observation arm had a 15-year recurrence rate of 15.1%.  

To break the data down even further, the rate of invasive recurrence was 5.4% for the radiation arm and 9.5% for the observation arm.

The data show that radiation cuts the recurrence rate in half, and this benefit persists for 15 years. 

According to this study, radiation therapy does have a significant and long-term impact on same breast recurrence, even for “good risk” DCIS patients.

What are the Implications of this Study?

One of the things about doing research, especially randomized studies, is that sometimes the findings aren’t what one hopes to discover.

This quote by Dr. Beryl McCormick is full of candor and perspective, “And personally I was hoping the radiation would not do as much as it did, because I was really convinced we could leave radiation out for some of those women.” 

The radiation benefit was so significant that Dr. Elizabeth Nichols states in an article, “These long-term data continue to affirm a benefit to RT (radiation therapy) even in those with favorable features and continue to affirm that RT potentially has more of an impact in risk reduction than tamoxifen, which can be critical information when counseling patients who only opt for one therapy.”

Clearly, radiation benefits DCIS patients, and that benefit might be even more significant than that of tamoxifen.  

There is much research being done to evaluate effective treatment for DCIS patients. Is it observation, surgery, radiation, endocrine therapy, or some custom combination of these treatments?

Is Radiation Worth It? 

Radiation isn’t an easy treatment to endure. It was one of the most challenging parts for me in many ways. But, reducing that risk of recurrence was important, so I did it. It was worth it for me.  

The data from this study show that radiation reduces the risk of recurrence in the same breast after a lumpectomy. But, it doesn’t reduce the risk to zero. So, we are faced with making important decisions for our personal life situations. It is worth it to take the time to learn, process, and then proceed. 

Untangling treatment decisions isn’t easy. I’ve been there, and I have written many posts about them. Ultimately we all need to make the decisions that make the most sense for us at the time and then move on. We take the information we gather, the recommendations from our team, and then proceed.

Sources:

• Beryl McCormick, MD, on Radiation Therapy vs Observation for Good-Risk DCIS– Radiation continued to show benefit in a tightly defined patient group, Jeff Minard, MedPage Today, https://www.medpagetoday.com/reading-room/asco/breast-cancer/96715
• Data Affirm Benefit of Radiation Therapy in Good-Risk DCIS– Also that RT potentially has more impact on risk reduction than tamoxifen, Elizabeth Nichols, MD, MedPage Today, https://www.medpagetoday.com/reading-room/asco/breast-cancer/96713
• Randomized Phase III Trial Evaluating Radiation Following Surgical Excision for Good-Risk Ductal Carcinoma In Situ: Long-Term Report From NRG Oncology/RTOG 9804, DOI: 10.1200/JCO.21.01083, Journal of Clinical Oncology 39, no. 32 (November 10, 2021) 3574-3582.(paywall)