Well, that was definitely an interesting study. I would also recommend doing a little more research on the topic if you can at all. If GLA is the key component in the evening primrose oil that is combating the cancer, then it seems you should focus on that a bit more
Borage oil does have a higher concentration of GLA than evening primrose oil, so it seems like that might be the better option between the two. I'm not sure why the study wouldn't have focused more on that. However, I'm not an expert in that area, and it would probably be a good idea to do a bit more research into the two. And definitely talk with your onc about both before adding either into your daily supplement regime.