There was a new study, because we needed a new study to keep the researchers busy, that says if you have a social life, you are more likely to survive breast cancer. I would assume this is the same as with other cancers. This even makes sense to my tiny little chemo brain.
There have been other studies showing that women who participate in breast cancer support groups have better outcomes and cope with treatment better.
If you have friends and a social life, even if you aren't going out three nights a week, it means you are talking to people, communicating your feelings, and interacting which saves you from sitting around and being depressed about your health, medical bills, or latest side effect.
When faced with a cancer diagnosis, many so called 'friends' run for the hills and you never see them. Then your real friends stand by you. Those are the ones who are important and you should spend your time with.
Also, going to a support group where you meet other people going through the same thing is very supportive as I noted above. Finally, online groups - whether Inspire, Facebook, or elsewhere - can help you find more and more support. The more people you can help and can help you, the better you will feel. While online friends are not the same as in-person friends, they can greatly contribute to your well being especially when you are not feeling well enough to get out.
So while cancer drives some friends away, go find real ones to compensate who will help you unknowingly.