Joining the oligo-archy of metastatic disease.

Last week we talked about a phase II trial of SBRT (or SAbR if you’re into that) for oligometastatic lung cancer. Never to lose the limelight for long, breast cancer also has recent data from a phase 2 Italian trial of consolidative radiation for oligomets. Women with primary tumor control and 5 or less sites of metastatic disease (including nodes) were treated with either 6-7 Gy x 3 or 2.4 Gy x 25. Progression-free survival (PFS) was an impressive 75% and 53% at 1 and 2 years, respectively. Here we go again: Is PFS really a good endpoint for such a trial? The argument is that initial sites of disease are the most likely sites of eventual progression. Furthermore, if you’re a true oligo-SBRT patriot, you are aware of the growing argument that populations of cancer cells survive and thrive through inter-metastasis communication and evolution rather than a single site of seeding. In that light, it really is impressive that 75% of patients with metastatic cancer can be alive without any new disease at one year. So really here we go again, waiting for more maturing trial data such as the NRG BR-002 to determine the true dynasty of oligo-SBRT.