Would you offer PMRT to ER/PR+ patients with synchronous bone metastasis?

This is a more common scenario despite data suggesting a local survival benefit with the addition of local therapy to patients with metastatic breast cancer.

With synchronous bone mets- we usually start with systemic therapy, ER+ would be endocrine therapy + CDK 4/6 inhibitor commonly. If stable/responding disease and limited mets (< 3), some will go to local therapy. In these cases I consider the following:

1. Treat with PMRT using similar features to non-metastatic disease- nodal involvement, T3/4. However, if I consider this, I am also considering definitive treatment to bone mets (30 Gy/3 fractions) in cases of 1-3 mets.

We now have a prospective, randomized trial addressing this issue and it does NOT show an Overall Survival Benefit. Although it was associated with improved locoregional control, this had NO overall impact on quality of life either.

Khan et al., PMID 34995128

In general, once local treatment (surgery) route is taken in MDT then follow PMRT for anyone with high risk features (stage III disease) understating that we don’t know of its benefits in terms of survival. Clinical trials done had their own limitations and none added local treatment to metastatic site [two (ECOG and TATA) were negative trials and one Turkish trial with benefit in a subset].