Families come in all varieties. Some we’re born into; others we get to choose; still others are accidental. Thirty-five years ago, I unwittingly (and unwillingly) joined the Memorial Sloan Kettering Cancer Center family when I became a patient there.

On that evening, when I was alone and afraid hours before surgery for metastatic testicular cancer, a young man entered my room in that famous New York hospital wearing a pale blue coat. Alan explained that he was a hospital volunteer, a member of what was then called the “patient-to-patient” program; it took me 30 minutes to realize that meant he was a testicular cancer survivor who had been matched to me.

That night Alan left me a gift: hope for life after cancer. For years after I’d phone him with my many worries about recurrence, side effects and life in general. Alan turned out to be the older brother I never had.

All hospitals, but especially cancer centers, rely on a volunteer corps to help with hospital and patient life. More than one-third of adults in the United States, about 77 million people, volunteered in 2017, 6 percent of them doing so in a health-related field, according to the Corporation for National and Community Service, a federal agency that includes AmeriCorps and Senior Corps.

At the University of Texas MD Anderson Cancer Center, rated the nation’s best cancer hospital in the most recent U.S. News & World Report rankings, more than 1,000 “volunteers work alongside patients, caregivers, faculty and staff to help make a difference by providing comfort, hope, support and education,” said Susan French, associate vice president of volunteer services and merchandising. I know. When I was there recently for a family member’s appointment, we could not have been more pleased with the volunteers who stepped up to help.

Not long after my release from Memorial Sloan Kettering, my brother and sister, who had been with me every day during my 14-day hospitalization, joined the hospital’s volunteer corps, wanting to help others.

As for me, a little more than a decade after my surgery I was drawn back to the hospital, returning as one of the hospital’s “blue coats.” Like Alan, I hoped to be a role model to others — or just an empathetic ear. I recounted one such visit in a talk to other Memorial Sloan Kettering volunteers 20 years ago:

“Curled up in bed, [Peter] looks more like a 14-year-old boy than a 40-year-old dad. With just wisps of hair on his head and a baby-soft face — your beard often stops growing with chemo — he greets me tentatively. ‘My name is Steven,’ I say. I tell him I’m a volunteer. We’re instructed not to say the word ‘cancer’ because you never know what a person actually understands about his or her disease. But Peter knows what’s wrong with him. He tells me about his orchiectomy [the procedure for removing a cancerous testicle] and I tell him about mine. He recounts his chemo experience [with the hateful platinum drugs] and I tell him about mine.

“Now, he’s really paying attention and he looks up at me, his eyes focused on my whole body but especially my hair. It’s like all the pieces have suddenly come into focus and he says incredulously, ‘You’re a cancer survivor?’ ‘Yes, I’m a cancer survivor,’ I say to him. And at that moment, the ability to say those words out loud is what my survival is all about.”

We are family.

In 2013, my mother learned she had lung cancer. She chose to have her treatment at Sloan Kettering because she was convinced my surgeon there had saved my life (I agree), and because of her thoracic surgeon’s reputation — and good looks (Mom always called her doctor, James Huang, “Doctor Handsome”). But she also chose this hospital because she’d been influenced by the staff members and volunteers she’d met during my experience there.

During Mom’s hospitalization, I came to realize that volunteers deliver a kind of magic along with their books, games and conversation, reminding me of a Mary Oliver poem called “The Uses of Sorrow”:

Someone I loved once gave me

a box full of darkness.

It took me years to understand

that this, too, was a gift.

I’ve long believed that the hospital’s volunteers are part of the gift in this “box of darkness” called cancer.

Which brings me to the latest chapter in our family story.

In late 2017, my sister, Julie, once a Memorial Sloan Kettering volunteer, sadly became a patient herself. Julie, too, has spoken with a patient-to-patient volunteer and enrolled in the hospital’s Visible Ink program, which matches volunteers who are professional writers with patients who want to write about their illnesses. Because of Julie, I rejoined the center’s volunteer ranks, as a mentor in the Visible Ink program.

I’m but one of the hospital’s 900 volunteers, who range in age from 14 to 90. I’ve felt a connection to many, including Jeanne Scungio, who has spent the past four years in the hospital’s “Welcome Flowers program.” In addition to learning how to “fluff a flower for maximum cheeriness,” Scungio says she’s gotten so much by making “a connection” to the patients, which gives her a sense of “belonging and purpose.”

During my tenure as a volunteer, I’ve seen the hospital’s blue-coated volunteers do so many tangible things: greet patients, deliver books, sit in silence together, take them on walks, lead art workshops, bring certified therapy dogs to visit and, yes, deliver flowers fluffed for maximum cheeriness.

It would be tough to do all that for a stranger, but these patients are actually the newest members of our clan — the “cancer club.” Even though they didn’t choose us, I hope they’ll come to think of us as family, just as I did with my “big brother” Alan 35 years ago.