Although I took a very proactive approach to managing chemotherapy, I chose not to seek out formal complementary or integrative cancer care during chemotherapy (for example, as offered by the Ottawa Integrative Care Centre). Some friends have done so and found it helpful. Others have fully embraced it to little or no effect. It can be expensive and time consuming - with little firm science on whether or not it's effective. At an anecdotal level, I've had friends with good outcomes with it and others with ineffective outcomes.
There wasn't encouragement from my treating team. My surgeon, oncologist, and pharmacist expressed concern that the efficacy of supplements had not been established and, that some might interfere with the chemotherapy. In fact, the pharmacist requested that I stop taking vitamin C, vitamin E and other ‘immune boosting’ things (e.g., turmeric). In their view - a conservative one - boosting immunity during chemotherapy can work against the treatment process. This is one area where conventional care and complementary care are at loggerheads.
However, there may be convergence on the horizon. A recent review article has examined studies on supplementary and dietary vitamin C. The studies suggest that it may have beneficial effect and reduce mortality. Equivocal on vitamin E.  The same review article is very positive about vitamin D. I have taken daily Vitamin D supplements – about 2000 mg/d - throughout, given promising findings about its effect on cancer coming out of various clinical trials. On clinical trials in general, see an article in the Ottawa Citizen, “New approach to clinical trials could revolutionize cancer care” at http://ottawacitizen.com/news/local-news/new-approach-to-clinical-trials-could-revolutionize-cancer-care
As I reflect on my efforts to manage the side-effects of treatment, I think I did a lot of things that are classed as 'complementary care'. Exercise, meditation, potions and lotions, and staying connected played an important role in keeping my mind, body and soul together. I suppose, then, that I am something of a 'supplement sceptic'.
A blog that I found useful (provocative in fact) when thinking about integrative care (and the various 'alternative' treatment elixirs on the internet) is: http://scienceblogs.com/insolence/ and , in particular postings by a breast surgeon and researcher with the handle "ORAC": http://scienceblogs.com/insolence/?s=orac. A refreshing dose of science and straight talk. And education - I'm not a cancer specialist, scientist or physician. Yet, the diagnosis of breast cancer brought me into these worlds. My goal has been to develop 'just in time' understanding to help me be an informed patient. ORAC's blog posts help me navigate the 'noise' of what we hear about cancer online.
 Julia Hamer and Ellen Warner, “Lifestyle modifications for patients with breast cancer to improve prognosis and optimize overall health” (2017) 189:7 CMAJ e268 (online at: http://www.cmaj.ca/content/189/7/E268).