Clinical trials of breast conserving surgery have shown that most local recurrence following Breast Cancer Surgery occurs in the region where the tumour was removed from the breast, the “tumour-bed”.
Currently, standard breast radiotherapy requires treatment to the entire breast followed by an additional boost treatment to the tumour bed region in woman at higher risk of recurrence.
The use of breast radiotherapy after local breast cancer surgery for invasive breast cancer is now mandatory and has been shown to reduce the chance of local recurrence by around 60%.
If a patient requires a radiotherapy boost to the tumour-bed, it is important for the radiotherapist to be able to tell where the tumour was located prior to breast cancer surgery and for many years this has been carried out clinically using a combination of information including the pre-operative mammogram, the Breast Surgeon’s operation note, clinical palpation of the surgical scar, and the patient’s recollection of the site of the mass.
In the past, the position of the scar has been relied on heavily to assist with locating the tumour bed as it usually was placed directly over the tumour bed. However, breast surgery has developed and oncoplastic techniques have been introduced, with the scar frequently being placed some distance from the site of the tumour in order to achieve a better cosmetic result.
A number of clinical trials are now underway to compare standard whole breast radiotherapy with partial breast radiotherapy, where the treatment is centered on the tumour bed for patients at lower risk of recurrence.
These trials aim to test the hypothesis that by limiting radiotherapy to the region containing the tumour bed, harm to the remainder of the breast tissue can be reduced while still keeping local recurrence rates low.
Breast surgeons can now insert small inert titanium metal clips around the perimeter of the tumour bed following breast cancer surgery. These are the same clips used to divide blood vessels during many types of surgery and they can be left indefinitely in the body without causing any harm.
The titanium clips can then be seen on imaging during the radiotherapy planning appointment so that the radiotherapy can be targeted to the area where the tumour has been removed.
The insertion of these marker clips has been endorsed by the Association of Breast Surgeons and should now be considered by all breast surgeons in the UK.