This Sunday we mark the 15-year anniversary of the 9/11 terrorist attacks that killed nearly 3,000 people.

Many of those who responded to Ground Zero at the World Trade Center in Manhattan on that fateful day and for months afterward continue to struggle with health issues — and many are developing new illnesses even after all these years.

Since 2003, the World Trade Center Health Program at the Rutgers University Environmental and Occupational Health Sciences Institute has been treating and monitoring thousands of responders for a variety of conditions and diseases.

“The earliest health problems we saw were the asthmas, the sinusitis, the upper and lower respiratory problems, then we went on to see gastro-reflux and sleep apnea. But these days we’re seeing a growing number of patients developing different types of cancer,” said Iris Udasin, the program’s medical director.

According to Udasin, most cancers take at least four years to develop, while others can take 10 to 20 years.

In addition to lung cancers, they are now treating an increasing number of blood cancer cases, leukemias and lymphomas, prostate cancers, as well as other types of cancer considered rare and unusual.

“In addition to treating patients for cancer, respiratory and gastro-intestinal issues, we have an awful lot of mental-health issues in our patients, post traumatic stress, depression,” she said.

The center currently cares for a total of 1,340 patients, with more than 200 being treated for various cancers, which were added to the list of illnesses covered by the Zadroga Act, which funds WTC workers’ health care and was extended for 75 years by Congress in December.

Udasin, who has testified twice before Congress to ask for continued funding for various health programs for 9/11 responders, said she keeps in touch with many patients, and will attend a funeral this weekend for one man who recently died of cancer.

“I feel blessed that I’m able to do something and am able to take care of people. But at the same time I feel like I know entirely too much about which place you should go to for which kind of cancer,” she said. “The good news is we have a lot of people who are doing very well, who have survived their cancer, but for those who die, I feel like I wish I could have done more.”

Udasin added she feels thankful for the bravery and courage displayed by those who responded during the terror attacks.

“If we didn’t have committed people, police officers, firefighters and rescue workers, where would we be? These people deserve the best medical are we can offer, I feel blessed to be able to help them,” she said.

Contact reporter David Matthau at David.Matthau@townsquaremedia.com.