For Carlos Morera, the only symptom of oral cancer was a small lump beneath his jaw when shaving.

With a history of cancer, he knew that a swollen lymph node or a painless lump in the neck was among the most common symptoms of oral cancer.

“My first reaction was fear,” says Carlos. “I had undergone surgery for thyroid cancer the year before and was told the cancer was gone.”

His ENT told him not to worry but recommended...