Poor sleep quality and breast cancer

Poor sleep quality has been linked as a risk factor to many other health conditions. Here is an article from the Huffington Post that outlines the association between poor sleep and breast cancer. A potential question for Rank the Research? What do you think?

http://www.huffingtonpost.com/society-for-womens-health-research/poor-quality-sleep-a-silent-source-of-disability-in-breast-cancer_b_7268764.html?ir=Canada%2BLiving&ncid=tweetlnkcahpmg00000003

I began having sleep problems around the time I was diagnosed with Stage 0 DCIS breast cancer. I'm not saying that there is a connection between the two. But my sleep problem continued for several months after surgery and radiation therapy. I reported the sleep problem to my PCP. Can't say if there was a cause and effect. The sleep problem may have been a pre-existing condition. My PCP referred me to a neurologist who had me go through a sleep study. I was diagnosed with mild OSA and placed on CPAP.