Rep. Mark DeSaulnier has leukemia.

But his cancer has responded well to treatment. His prognosis is good. And he has even felt well enough to resume his meditative 8-mile runs on Mount Diablo.

As for the lingering political question, the 64-year-old freshman congressman stands ready and determined to continue his campaign for a second term — although last year he wasn’t so sure.

He was scared while awaiting a diagnosis that could have been much worse. He recalls “walking around the Supreme Court and the Library of Congress on a beautiful day” and thinking “this is interesting. I (just) became a member of Congress. It’s going to be a short run.”

But he thought better of making a rash decision he might regret. It was during a later visit to James Madison’s home at Montpelier that DeSaulnier, a history buff, decided to seek re-election. He recalls thinking, “You can’t give up. It took a lot of work to get you here.”

Now DeSaulnier, a longtime advocate of health care access for all, has a new policy mission centered around cancer: To fight for more research funding, improve the accessibility of costly drugs to those who cannot afford them, and improve how physicians discuss the disease with their patients.

“With all the respect to the doctors, their talent is not communication,” he said earlier this week as he sat in the living room of his Concord home discussing his cancer experience publicly for the first time.

Since his diagnosis in July, DeSaulnier had kept his illness under wraps, sharing it with only a few friends and relatives, his two grown sons and his chief of staff.

Before telling others, he said, he wanted to make sure he could keep doing his job and see how well he would emerge from a half-year of chemotherapy, which he received two days a month in Washington, D.C.

DeSaulnier considers himself fortunate. He has had full access to health care. And his disease was treatable, thanks to major advances over the past 20 years.

“I’ve benefitted from countless researchers I will never know who have come up with this treatment, so I’ll be able to live to see my kids have their kids.”

He was reminded of his good fortune as he sat at the Georgetown Lombardi Cancer Center for four- to six-hour stretches with the chemo — bendamustine and rituxan — slowly dripping into his system.

He wasn’t alone. “There were 25 people in there, and you don’t know the acuity of everyone else. … I felt when I went in there I was one of the lucky ones because of the diagnosis, because of the kind of cancer I had.”

DeSaulnier has chronic lymphocytic leukemia, or CLL, one of the most common types of leukemia among adults. Some patients can have it for years without needing treatment.

And when they do, the treatment can usually control the disease for years or decades but usually won’t cure it. In DeSaulnier’s case, he’s been told by his doctor that he’s had a “dramatic remission, but not complete.”

That means more scans and regular blood tests. Keeping the cancer controlled might require follow-up with new oral medications.

His ordeal began when he saw a doctor to have some small, unrelated skin cancers removed. It was the dermatologist who noticed swollen lymph nodes under his neck and arms, a symptom of his disease in which abnormal blood cells grow, divide more rapidly and can live longer, crowding out healthy cells.

DeSaulnier was immediately sent for a scan and blood tests. For a week, as he awaited the results, he didn’t know if he had an aggressive leukemia that could quickly kill him, or the much more manageable CLL.

“What I went through is this emotional roller coaster,” he said. “People hear cancer and they hear chemo and they immediately jump to, you’re dead. It was scary.”

Even after the diagnosis, he had anxieties about his fate. The doctors “have a lot of confidence in the treatment working, but it’s not absolute. They’re not sure until they get to the end.”

Then there was the difficult moment when his post-treatment test results came back. His general practitioner told him that they showed he wasn’t in full remission.

“I interpreted that as being really bad, and it turns out it wasn’t,” as he learned the next day from his oncologist, who was pleased with his progress.

It’s those sorts of doctor-patient miscommunications that DeSaulnier wants to correct. As a cancer patient, “you’re only hearing one in four words because your mind is going in a million directions.”

He wants to incentivize physicians to provide clear written material to their patients to help them better understand their diagnosis, statistical chances of survival and treatment options.

He hasn’t figured out yet exactly how to do that. But he has a much deeper understanding of the problem.

DeSaulnier has always been contemplative, but his illness has left him, as with most cancer patients, more self reflective. “When you confront mortality you get … a sharper focus on what’s important and what isn’t.”

Daniel Borenstein is a staff columnist, editorial writer and cancer survivor. Reach him at 925-943-8248 or dborenstein@bayareanewsgroup.com. Follow him at Twitter.com/BorensteinDan.