Radiotherapy changes to muscle


I had triple negative breast cancer.  The tumor didn’t respond to chemo and I ended having a full mastectomy with delayed reconstruction followed by radiotherapy. 

Approximately 18 months after radiotherapy I had a DIEP reconstruction (February 2023).  About a month after surgery I noticed a weird bulge on my chest - it’s about 2 inches above my new breast and 2 inches below my collarbone and 2 inches away from my armpit.  It’s not a lump as such.  And it’s not a seroma. It’s a hard or thickened area under the skin. You can’t see it (only feel it).  It’s not red, sore or itchy.

I rang the breast care team and they suggested it was a muscle knot and to massage it.  This seemed to make sense - it could be the top of my pectoral muscle above my breast.

I’ve mentioned this to the breast physio on the phone (who discharged me on the first appointment) and on the phone tooncology (who also discharged me and said they wouldn’t contact me anymore, but to call Breast care team if I had symptoms in the future). Neither of them seemed worried, but as they were telephone appointments they couldn’t examine me.

The area is definitely bigger and now radiates to my armpit.  It’s quite firm. It’s started to ache and pull too.  I’m wondering if it’s actually radiotherapy changes to the pectoral muscle.

I have a follow up appointment with my plastic surgeon on Friday - the first face to face appointment since surgery and since I spotted the bulge.  I will get him to examine it.

In the meantime, does this sound like radiotherapy changes? How can you determine what is radiotherapy changes and what is recurrence? Do you think the surgeon will want me to have further tests.  If it’s radiotherapy changes, what can I do to improve it, and stop it getting worse.

Thanks for anything you can say to put my mind at rest.

Hello Snookie  

Thanks for posting asking about the bulge you have in your reconstructed breast. It’s good to know you are seeing your surgeon on Friday.   

As you say it can be difficult to know what the cause of a symptom is, whether it’s a side effect of treatment or symptoms of recurrence. It’s important to report any new and persistent changes to your treatment team so they can establish the cause.  

Surgery and radiotherapy to the breast can both cause changes in and around the treated area. Our information about reconstruction reconstruction describes some of the complications that can occur which can result in the formation of a lump or swelling. Lymphoedema can also develop in the breast, chest and arm.  

Or it may be something unrelated so it’s difficult for us to say what it is. Your surgeon may be able to determine what is causing this bulge by examining you or they may suggest further investigations, perhaps with an ultrasound to begin with. Once they know the cause they can suggest ways to resolve it.  

Our information and course about moving forward after breast cancer might be of interest. The aim of these resources is to help you’ll find the tools you need to feel more empowered, confident and in control.  

We are currently evaluating this service and would appreciate your feedback. Please click here to the survey. It should take approximately 10 minutes to complete.   

Do call our helpline if you would like to talk this through or have any further questions. The helpline team have time to listen to your concerns, talk things through and signpost you to more support and information. Your call will be confidential, and the number is free from UK landlines and all mobile networks. The number is 0808 800 6000, (Relay UK - prefix 18001). 

If you would prefer one of our nurses to call you. To do this, please complete this form t** icking the box agreeing to a call back.**  

Our usual opening hours are Monday to Friday 9am - 4pm and 9am - 1pm on Saturday.   

We are closed Monday the 29th May for the bank holiday.  

Out of hours you can leave a message and we will call you back when we next open.   

Best wishes   


Breast Care Nurse   

Please read the Ask Our Nurses disclaimer  Full details on how we collect and use your data can be found in our Privacy Policy    

This thread will now be closed from further replies. If you have any additional questions or would like to provide feedback, please start a new thread.