(Sarah Coughlin and her father John, who were diagnosed with cancer within months of each other, prepare for the 2012 Pan Mass Challenge.)

Duxbury resident John Coughlin has lived in Duxbury for more than 30 years. CEO of a medical instrument company in Norwood and father of three, Coughlin, 60, is a nine-year cancer survivor.

He was diagnosed in September 2003, two months after his daughter, 21 at the time, had been diagnosed with cancer herself. I am that daughter.

Simultaneously we faced this awful disease together and even traveled to and from Boston for treatments at Dana Farber Cancer Institute.

As “living proof” that money raised for cancer research is critical, my father and I now ride in the two-day, 192-mile Pan Mass Challenge (PMC) bike-a-thon together every August. The PMC raises more money for charity than any other fundraising event in the country; this year the collective goal is $36 million. Aug. 4 will mark our fifth year riding alongside one another.

As John Coughlin’s daughter, I’m honored to have spent some time “visiting” with him and talking about the PMC, life as a cancer survivor, and how devoted he is to raising money for such an important cause.

How difficult was it watching your daughter go through treatment for cancer?

It was much tougher than my own treatment. The mental anguish of watching your child far exceeds any physical pain and suffering that you experience yourself.

What was it like to hear you had cancer two months after my diagnosis?

At first I was angry. It wasn’t fair. I didn’t want to expend any energy on my own cancer, I wanted to focus on my daughter’s treatment. Eventually I came to accept that life is unfair and that if I didn’t rise to the challenge then I wouldn’t be around for my daughter either.

What was the most challenging aspect of going through treatment for cancer?

I was treated with radiation, two major surgeries and about eight months of chemotherapy. I hated chemo. It’s like having the flu for a very long time.

Do you think it was harder to be a cancer patient or the parent of one?

You learn that you can physically tolerate much more that you think is possible. Having your child undergo treatment and watching it unfold is much more difficult.

Do you feel your experience brought you closer to me?

We both understand that we are incredibly lucky. Having gone through treatments, we understand exactly how the other feels. This is a special bond that transcends the normal parent-child relationship.

What gave you hope during the most difficult moments?

There were days when I didn’t have hope, but they were few. I’m an optimist by nature so I planned for success. Also, I realized early on that we were in the best possible hands medically speaking.

When did you first decide to ride in the Pan Mass Challenge?

There’s a footbridge to the Dana Farber Cancer Center dedicated to the PMC. While I was going through chemotherapy, I would cross that bridge every week. Near the end of treatment, when I was weakest, I was dragging myself over that bridge yet again. I finally stopped to rest, and as I did so, I started looking at the pictures of prior PMC riders. I decided at that very point to ride the following year. That was in May of 2004 and your mother didn’t believe me since I could barely walk to the parking lot. However, I kept that promise and rode my first PMC in 2005.

What is the most special part of the PMC weekend?

The crowds that cheer you on. Many are survivors and they hold signs thanking us for our effort. Remember Jack? He’s at the same rest stop every year with a sign that says “Thank you for riding. I am X years old because of you…” He’s been doing that since the age of three and last year his sign read “I am 16 because of you… ” Amazing.

Where is the money raised directed?

One hundred percent goes to fund innovative research and treatment at Dana Farber. It arrives with “no strings attached.”

What is your fundraising secret?

I don’t know if I have a secret. I send every donor a letter each year including a stamped self-addressed return envelope. Over the years, I’ve discovered that people are generous beyond belief. I’ve received donations from people I’ve never met and from as far away as California and the Netherlands.

Why do you continue to ride?

I ride to give back and help others. I ride as a way of thanking all of the wonderful medical professionals that treated us. I ride in the hopes that the collective effort of the PMC will maybe save one patient’s life. As long as I can crank the pedals I’ll ride. We ride now with hope that your baby daughter Fiona will never have to do so.

Do you think we push each other and keep each other going?

Well, I usually end up chasing you. You’re a fast cyclist. (Actually, Dad, this year I’ve been chasing you during training rides. Finding time to train isn’t easy with a baby!)

How did it feel to cross the finish line of the Pan Mass with me for the first time?

Very emotional. It symbolized a victory of sorts for both of us. Just to be able to go from the devastation of treatment to riding a bicycle marathon gives you confidence that you can overcome anything.

Note from Sarah: I’m proud of you, Dad. As a new mom, I now understand how much love a parent has for her child. Only now can I imagine how painful it must have been to watch me go through what I did. I know how hard it was to see my father, my hero, sick, but I also know our experience has not only made us stronger and bonded us closer, but enabled us to meet so many wonderful people, to ride in honor and support of those we know facing the disease themselves, and to truly appreciate every day as if it were the last. Cancer does not define us, but has certainly shaped our current perspective on life. I will always look forward to PMC weekend every August, where I get to spend two amazing days with my dad and some of the most generous, selfless, inspiring people out there.

To learn more about the Pan Mass Challenge or to donate to my father, John Coughlin, please visit pmc.org and click on “donate.”