Would you offer radiation for suspected retroperitoneal nodal metastases in a patient with metastatic colorectal cancer with a single liver metastasis who had an excellent response to neoadjuvant chemotherapy?
Would you offer radiation for suspected RP nodal mets in patient with CRC with a single liver metastasis who had an excellent response to neoadjuvant chemo?
Join Mednetto vote and see how they answered.
Yes, in the setting of all other disease likely controlled and response to systemic, the control of the RP nodes (gross and microscopic) should be considered definitive and curative. RP/PA nodes should be considered N2 rather than M1. As such, elective nodal RT should also be given with IMRT, not SBRT. Elective nodal coverage a common omission as ROs are programmed by "SBRT group think".
The nodal spread could be from the liver met or more likely from the primary tumor. I most commonly treat the entire PA nodal chain with an SIB to the enlarged nodes. These nodal mets are relatively resistant compared to the primary, like liver mets are. Early in my career, I started by trying lower doses and now think an ablative dose should be given. I would choose 67.5 Gy in 15 fractions or 75 Gy in 25 fractions with concurrent capecitabine. That choice depends on the proximity of luminal GI OARs. Typically, that is D3. I always include a microscopic dose to the nodes behind D3 because that is the worst place to have a nodal recurrence from CRC due to the anatomical limitation of salvage IMRT posed by D3.