Guidelines on when Post Mastectomy radiotherapy would be recommended

Hi, I posted this under a topic I has previously created under surgery sub-forum, but realise it’s probably more appropriate here so am posting again.

Post Mastectomy (Feb 23) & Axillary Dissection (Apr 23) final result (Primary BC): G2 IDC ER8 PR8 HER2- LVI, 1/25 lymph nodes involved. [T2, N1, M0]

I’m not quite sure if I’m asking a question here or just looking for thoughts from others who may have been in a similar situation to me. Subsequent to receiving my oncotype score (no chemo due to low score) I was referred to meet the clinical oncologist to get a better understanding of why chest wall radiotherapy isn’t being recommended for me. 

I’m due to have a follow-on consultation after digesting all the information I was given and am now wondering what if anything else I should ask. It’s almost like the radiotherapy risk/benefit ratio is borderline but tilted towards higher risk when compared to benefit. If anyone was in a similar position to me I’d appreciate any information on what was recommended & or your thoughts.

I certainly learnt a lot more than I had anticipated from the appointment. A summary of what the oncologist said:

  • For primary BC patients who have a tumour size in excess of 5cm & or skin involvement, radiotherapy to the chest wall would prevent future local recurrence & that this can increase to around 20-25%. If more than 3 lymph nodes are involved, then this % may marginally increase further. For such patients he would recommend chest wall (+/- lymph area if no ALND was done) radiotherapy with the aim of bringing down the risk to around 5%.  

  • In my case as the largest tumour size is 35mm (others 1-3 mm in size), and the fact that only 1 lymph node was affected he doesn’t feel the risk reduction (10% risk of recurrence) would be significant enough when taken in junction with longer term radiotherapy toxicity risks even though those are small / very small when each are looked at individually (e.g. late rib toxicity:pain/fracture, lung toxicity/cancer, primary skin cancer, exacerbated future risk of lymphoedema) that come with the treatment 

  • The multi-focal nature of the cancer does not make a difference when it comes to this recommendation, nor does the tumour proximity to the chest wall. He explained that the spread would be via the lymph nodes/vessels and not the chest wall as I had initially incorrectly thought that the latter was another method of spread.

  • There are apparently some randomised studies (radiotherapy vs no radiotherapy) for my BC profile 1 node, post-mastectomy but these results are not yet available. He mentioned that there are a minority/some NHS trusts that have suggested that they would offer radiotherapy in this situation while awaiting the outcome of the studies.

  • He also explained the process of radiotherapy planning, which I hadn’t really thought of much before the appointment. He mentioned that before covid the normal recommendation was to offer 15 factions (total 40Gy) over 3 weeks. However on the basis of the fast-forward randomised BC radiotherapy trial it is now suggested that 5 fractions (26Gy) would have equivalent (if no implant reconstruction or lymph nodes are considered).

Thats the summary in case any of the information helps anyone else, as well as to get thoughts from anyone who may have been in a similar situation as me. I’m feeling that there are possibly differences in the treatment recommendations depending where you are being treated (MDT/NHS Trust variances/Private etc…).

Appreciate your thoughts. xx 


Thank you for your post. I am hoping my post will help our members to see it and share their thoughts.

You may find it helpful to speak to one of our Breast Care Nurses on the free Helpline, 0808 800 6000.

Alternatively you can get in touch with our Nurses in the Ask Our Nurses area of the Forum and they can respond to you online.

Sending you our best wishes,


Thank you Zoe. I’m guessing this isn’t a topic many have experience on.

But just thought I’d post an update, I went for a second opinion due to the grey areas. The second opinion was different so now I have effectively received two different tilts, one swaying towards chest wall radiotherapy and the other against it. The results from the SUPREMO trial are still outstanding.

I’m planning to make my decision this week.

Before I do that I was hoping to get input from others who have had “left side chest wall” radiotherapy in terms of both preparation and post radiotherapy side-effects. I’m wondering if the side effects (short term - skin or other, long term) are more severe than when compared to radiotherapy given after a lumpectomy and also if there was anything else that they wish they had known/considered/prepared before making the decision to go ahead.