"Your 16-year-old son, and knowing there's a potential for really the worst to happen is just devastating," said Don Grussing, Grant's father.
Grant needed surgery.
"If you are able to remove the lymph nodes completely you have the opportunity to stop cancer in its tracks," said urologist Dr. Viraj Master, Emory University School of Medicine in Atlanta.
Traditionally, removing lymph nodes from the thigh and groin area meant an 8 to 10-inch incision and a 50-percent risk of complications.
"The enormity of the risk of the procedure is based in the fact that it's a large incision in an area that's prone to infection," said Dr. Keith Delman.
Dr. Delman helped develop a new approach. Instead of one big incision, he makes three half-inch incisions in the thigh. He fills the leg with air then goes under the skin to remove the lymph nodes, staying clear of vital structures.
"There's no one else in the world who has done this approach for melanoma," said Dr. Master.
Grant jumped back into competitive swimming less than a month after surgery. And so far, tests show he's cancer-free.
"I'm good to go, 100 percent," said Grant.
The new lymph node surgery was modified at Emory University, where doctors have performed more than 40 of the procedures so far. So far, the procedure has shown a significant reduction in complications like infection and leg swelling compared to the standard open procedure.