( CNN ) -- I 'm tired of being surrounded by cancer . Over the past two years , I lost my sister , my mother and nearly lost my girlfriend to breast cancer and its complications . It 's an epidemic , and it seems we all just accept that as fact . I think it 's high time we said : enough . My lifelong friend Bill Couzens has been similarly affected by cancer . He has made it his life 's mission to change the way we think about this dreaded disease . It 's a different way of fighting a war on cancer : Instead of focusing on treatments , drugs and experimental surgeries , it looks at what is going on in our environment and what we are eating , and considers what role those factors might play in the cancer epidemic . It 's not a popular place on the spectrum of debate about cancer . Frankly , the corporations that pollute our environment and process our food do n't want to go anywhere near the message that comes from LessCancer.org . It is simply not good for business . So I am riding to help people think about what causes cancer . Sure , there is a genetic component to all of this . But that 's just part of the story . The other part of the story for me , is a very personal journey . Four-and-a-half months ago , I had an accident that led to the amputation of my left arm . One of my goals for returning to normalcy was to get back on a bicycle -- something that was very important to me before I lost my arm . I probably would n't have decided to ride 300 miles over two days without the LessCancer.org event . As a matter fact , if I did , you might think I was a little bit crazy . As it is , a lot of people think it is ill-advised to set the bar so high so soon after my accident . And I 've been thinking a lot about why I have been pushing so hard , so soon . Over the past few weeks I have been talking with CNN Chief Medical Correspondent Dr. Sanjay Gupta about my recovery . During my time with Sanjay , he repeatedly expressed incredulity over the pace that I have been keeping since I returned to my life minus an arm . He , like so many others , wonders if I 'm going too fast and not taking enough time to pause , reflect and grieve . When I stop to think about it , I too wonder if I am ultimately doing myself a disservice . Should I be spending more time taking care of myself ? But then I think about how I would feel if I put myself on the sidelines at this point . I would be left wondering what I can do and what I may not be able to do . I simply need to know now . There might be a time bomb of grief ticking inside me that will explode later , but at least I 'll know my abilities when that time comes . I also think about the challenges that I have set for myself . Three months after the accident , I was with my longtime friend and colleague Kate Tobin camping on a Denali glacier in Alaska for a story we are doing on climate change . We snowshoed for miles , and I was shooting a lot of video in some very arduous conditions -- including at the bottom of a 15-foot hole in the ice . I had definitely jumped into the deep end of my first big assignment after the accident . I was really nervous about how it might go , but after we had done the trip and we were sitting in the airport for our respective flights home , Kate turned to me and said , `` I did n't see a bit of difference in your performance on this trip . '' I could not have asked for better medicine than that . So I guess setting big goals in short order is n't such a bad idea , assuming you reach them . This goal -- 300 miles on a bicycle in two days -- is a reach , to be sure . But I am going to do my best . I have a fallback plan or two , including a tricycle called `` Monomano '' that is ideally suited for a one-armed rider , and a cousin who has a tandem bicycle with a seat reserved for me . If all else fails , there 's always the sag wagon for a segment or two . But here 's what will keep me pedaling : I will be thinking about my sister , my mother , my ex-mother-in-law , both of my grandmothers , my girlfriend and everyone else I know whom I lost or nearly lost to cancer . Their courage and grace while fighting this disease is an inspiration to me and should be to all of us . Yes , I have a new challenge in my life , but frankly it pales by comparison when I consider what it 's like to be caught up in the cancer epidemic . We must find a way to stop it . I am neither a doctor nor a scientist -- although I play the latter on TV ! But in reality , what can we do ? For me , the answer is to pedal hard and long to Mackinac .
Earlier this year , Miles ##tone 's left leg was broken after an accident . He plans to ride his bike 100 miles from Port Huron to Mackinac , Michigan . O'Brien says his struggle ` ` pales by comparison '' to others .