Michelle writes in “Any Day with Hair Is a Good Hair Day“:

Whatever your beliefs are—or aren’t—it’s just as important to nourish your soul as it is to feed your body. For whatever reason, it’s often when we’re in crisis that we begin to explore things of the spirit, whether by prayer, meditation, listening to Bach or Mozart, or simply being quiet with our eyes closed.
The National Institute of Mental Health has even determined that people with cancer often have less anxiety, depression, and even pain when they feel strong spiritual connections.
Many studies have shown conclusively that prayerful consciousness has been shown to inhibit the growth of cancer cells, increase the supply of oxygen to the blood, protect red blood cells, and alter blood chemistry. Some studies have even shown that prayer on behalf of a sick person has some positive effect on the healing process.

Prayer has always been an important part of my life. But after I was diagnosed, it became even more so. Not only did I find myself praying more intensely and mindfully than before, but I also wanted to be prayed for. In fact, when people wanted to know what they could do for me, I found myself asking them to pray—not only for me, but also for my husband and family and my medical team. That was the gift I wanted most. Trust me, I’m pretty materialistic, so no one was more surprised at this desire for prayer than me.
Most of the time, my own prayers consisted of my just talking to God (not out loud—the last thin I needed was to be given a second diagnostic: psychotic). Much of the time, I was pretty mad at him for letting this happen to me. I hadn’t married until I was 45, and I’d been married for only two years. What if I didn’t make it? So I’d rail at him. “What were you thinking?” I’d ask. I figured that if God is God, then he can take my yelling at him. But I also asked for peace and strength and comfort—and healing, of course. During the process, I became less angry and more peaceful.