More than 5,400 Ground Zero responders and others who lived, worked or went to school near the fallen Twin Towers have come down with 9/11-linked cancers, a grim tally that has tripled in the past 2¹/₂ years.

As of June 30, 5,441 people enrolled in the WTC Health Program have been diagnosed with 6,378 separate cancers, with some struck by more than one type, officials said.

That’s up from 1,822 victims in January 2014.

“You see an alarming increase,” said Dr. Michael Crane, medical director of the WTC Health Program at Mount Sinai Hospital.

“It’s been steady for at least the last year and a half — we’re seeing new people here being certified for cancer 10 to 15 times week. That’s every week. ” Crane told The Post.

The program now monitors more than 48,000 cops, hardhats, volunteer firefighters, utility workers and others who toiled at Ground Zero. The FDNY has its own 9/11 health program with 16,000 members.

In all, at least 1,140 have died, officials said.

The feds have listed more than 50 types of cancer believed to be related to the toxic smoke and dust of 9/11. Those afflicted may seek payments from the 9/11 ­Victim Compensation Fund.

Veteran firefighter Ray Pfeifer, 58, has advanced kidney cancer that has spread through his body.

“I’m a lucky guy,” Pfeifer told The Post. “I’ve had 15 years with my kids after 9/11, and I’m still here with Stage 4 cancer.”

He has undergone 11 surgeries, including a kidney removal, hip, femur and knee replacement and radiation for a brain tumor.

On the morning of Sept. 11, 2001, Pfeifer had the day off and was golfing with buddies when the planes hit. He rushed downtown to join the frantic dig for survivors and stayed nine days straight, sleeping on a rig.

All 12 of his fellow Bravest assigned to Engine 40/Ladder 35 on the Upper West Side were among the 343 firefighters killed when the towers collapsed. Pfeifer stayed eight months to search for remains.

The ex-athlete brushed off his “World Trade Center cough” and “a little shortness of breath,” but in 2009 he felt pain in his hip and doctors found a baseball-sized tumor. He kept working as a chief’s aide, but a chemotherapy-caused heart attack forced him to retire in 2014.

He now visits Memorial Sloan Kettering Cancer Center every two weeks: “I see cops and firemen there. It’s not unheard of to see five to 10 people who worked on the pile getting treated for cancer.”

Cancer was the last thing on the mind of an 18-year-old girl who had just moved into a dorm at Pace University downtown to start her freshman year. On 9/11, she heard a loud boom, felt the building rattle and saw shards of glass flying from the Trade Center.

Nicole, who asked that her last name not be printed, went home to Long Island covered in white dust and resumed classes about a week later: “Everybody was reporting it was safe.”

At age 31, Nicole was married and giving birth to a son by C-section, when the doctor noticed an orange marmalade-like goop. She was diagnosed with a rare appendix cancer.

She underwent a hysterectomy, removal of other organs and a chemo bath in her abdominal cavity. Before the surgery, she and her husband froze four embryos. They’re now seeking a surrogate gestational mother.

“This disease didn’t kill me, but it robbed me of the ability to give birth to any more children, which has been the most devastating piece of it,” she said.

The city Health Department said Friday it plans to publish a new report on cancer among 9/11 workers and survivors in September.

So far, scientists have found five cancers hitting the 9/11 community at a significantly higher rate than expected in the normal population — prostate, thyroid, leukemia, lymphoma and multiple myeloma.