Here's what I know about this. The thing is even when CTs show no lymph involvement, 30% of the time they are wrong. 30% oif the time there is "occult" metastasis that does not show up on scans but shows up when the nodes are removed and tested. So yes, removing some lymph nodes even when the scans show no cancer is fairly normal, especially if treatment following that will depend on whether any cancer is found in the nodes.

OTOH, if it is already clear there IS cancer in the nodes and treatment is going to be the full thing (chemo and radiation), then it seems sometimes doctors are less likely to remove nodes until after treatment and even then only if there is some sign the treatment may not have gotten rid of the cancer in the nodes.

Hope this helps--it was definitely a relevant issue when I was undergoing the beginnings of treatment so that's why I ;learned this.

Nelie