Has anyone completed the 5 day radiation instead of the 20 for breast

I had the exact same question so I fully understand your concern. I had stage 1, ILC, 18mm. I had a lumpectomy (July 2026) with clean margins, and then 5 days of full breast radiation at 26 gy (vs spot) and completed the 5 days on September 25, 2026. I asked the radiologist how she made the decision for 5 days vs 15 (all other friends who have been through this did 15). She said that the longer treatment was typically always done but the medical community started testing fewer days and different doses (gy or gray) and it was shown that it was medically evidenced (can’t recall her term) that it was the same outcome for 5 days and better for the patient. She also said that other countries have been doing 5 days for many years. She commented that the hospital makes more money with a longer treatment and she is grateful her administration cares about the ethical side and what’s best for the patient versus prioritizing making money. On a related note I also had test called an AidaBreast test on the lump/tissue they removed which is used to assess the 10 year locoregional recurrence and predict the radiation benefit for early stage invasive breast cancer (this was approved by the FDA in April 2026). This gave me more specificity of the chance of recurrence even with radiation which is 6% which I’m not thrilled with but at least I know.

When I had the radiation I used MepitalOne film which can only be purchased from the UK (another one can be purchased on Amazon, but you most get MepitalOne). I had zero skin issues and sailed thru radiation. P.S. You could ask the same question on how they determined 5 days vs more. Push until you're satisfied. Good luck

I also considered the genetic testing and family history. I do have an older sister who had DCIS but it was 17 years ago and no new/recurrence. No other breast, ovarian cancer in family. I had no genetic markers (although they now test for a few more than in 2022).

I’ve always been a bit concerned about the fat level I carry. Fat = estrogen, not great for estrogen positive cancer risk. I work to keep off the weight I lost during this whole process, probably anxiety driven. Even now at a BMI of 22 I have disportioncate fat to muscle. So I did decide on taking tamoxifen. I know all the right things to do to change that fat level . . . working on that. I fear I fail often.

I did 5 days for 1.6 cm DCIS stage 0, no nodes. I only had 1 mm margin, but the cancer center said because it was 1 mm at a focal point that it would be okay. I did this 4 years ago, 60cGy ea, 5 days, total 30 Gy. They usually do a little less now. I’ve had no recurrence.

It really depends on the type bc, and specifics. The FAST Forward clinical trial followed patients for 10 years. AI pulled this info together, that might be helpful:
The 5-day radiation regimen is specifically validated and indicated for patients meeting the following clinical profile:
Disease Stage: Early-stage invasive breast cancer or ductal carcinoma in situ (DCIS) typically classified in trials as pT1–3, pN0–1, M0.
Surgical Status: Patients who have undergone conservative breast-conserving surgery (lumpectomy) or, in specific contexts, those evaluated post-mastectomy.
Node Status: Primarily node-negative or with limited regional node involvement, depending on institutional and national oncology guidelines (such as NICE or ASTRO).

Best wishes for next week!

@triciaot I was also offered 5 days, one time a day for node negative, .7mm, clear margins, LCIS ER+ PR+ and HER2+ It is a bit stronger but takes much less timea and hopefully you have less chances for them to make a mistake when it is so close to your heart and lungs. 3 years later after Chemo, Immunotherapy, Radiation, and 3 years of AI's, so far so good. Having my 6 month check up in 2 days!

@triciaot I had cancer every four years since 2016 - 1 colon, 2 breast. All treatable. My mom had two cancers and died from colon cancer. Because of these cancers I was offered a genetic test. It revealed Li Fraumeni syndrome which is
a hereditary pathogenic gene. My siblings and daughter have 50% risk of this damaged gene - and if they have it, the same 90% cancer risk I have. I had 5 radiation treatments with each breast cancer; none with the colon. After the genetic result I will have full body MRI, including brain, yearly. I wish you the very best as you go forward. The right treatment at the right time.

@triciaot I had cancer every four years since 2016 - 1 colon, 2 breast. All treatable. My mom had two cancers and died from colon cancer. Because of these cancers I was offered a genetic test. It revealed Li Fraumeni syndrome which is
a hereditary pathogenic gene. My siblings and daughter have 50% risk of this damaged gene - and if they have it, the same 90% cancer risk I have. I had 5 radiation treatments with each breast cancer; none with the colon. After the genetic result I will have full body MRI, including brain, yearly. I wish you the very best as you go forward. The right treatment at the right time.

@triciaot I was also offered 5 days, one time a day for node negative, .7mm, clear margins, LCIS ER+ PR+ and HER2+ It is a bit stronger but takes much less timea and hopefully you have less chances for them to make a mistake when it is so close to your heart and lungs. 3 years later after Chemo, Immunotherapy, Radiation, and 3 years of AI's, so far so good. Having my 6 month check up in 2 days!