When a patient with stage IIIA NSCLC is treated with induction chemotherapy alone followed by surgery, and has a pCR, do you offer post-operative RT based on pre-chemo findings or omit due to complete response?

This issue comes up regularly....the assertion being that if the mediastinal disease has been cleared with chemotherapy, there is no need for RT. However, studies have shown that local failure is still quite high even when a mediastinal pCR is achieved. In the SAKK trial (B Journal of Cancer 2006;94:1099), patients who achieved a mediastinal pCR did not receive post-op RT and had a reasonably good prognosis, but local failure was a dominant site of failure (around 25% risk of local failure). Those who had residual N2 disease had a terrible prognosis, even with post-op RT.

Thus, it is entirely possible that those patients who are responding well to treatment (i.e., achieve a mediastinal pCR with pre-op chemotherapy) are the very patients that will benefit most from post-op RT...while those who are not responding to treatment (residual N2 disease after pre-op chemotherapy) will do poorly no matter what you do. This thought process is counter to what I often hear in tumor boards.

The LungART trial will hopefully provide some definitive answers regarding the role of post-op RT generally, and who benefits (or not) based on response to neoadjuvant chemotherapy specifically.

Prechemo findings