About 24 hours after she was admitted, Siejo learned she had stage 3 colon cancer, which soon grew beyond her colon and progressed to stage 4 cancer. When initial chemotherapy and radiation failed, her doctors told her the cancer was inoperable and that she should go home, get her affairs in order and prepare for death.
But another doctor at the University of Virginia was willing to do the surgery, and it was successful. Siejo still takes chemotherapy pills, but she's a 12-year colon cancer survivor.
Wearing her blue colon cancer awareness T-shirt, the 51-year-old Siejo stood with other volunteers outside the inflatable colon to raise awareness.
"We have a voice," she said. "We should use it."
Andrea Kramer, 51, is another colon cancer survivor who was diagnosed before she reached age 50.
"I was experiencing symptoms, but I didn't know they were colorectal symptoms," she said. "I was probably experiencing problems way too long when I went to the doctor."
When the symptoms became unbearable, Kramer went to a doctor and was diagnosed with stage 3 cancer -- an advanced case, but it hadn't yet metastasized to her lungs or liver.
"I was lucky in that regard," she said. "There's no doubt I was embarrassed, and I wish that I hadn't been embarrassed. It would have meant a diagnosis a lot earlier and a lot greater chance of making it."
Berlin said that early detection has actually decreased the number of colorectal cancer deaths in the United States over the years. Two out of three people diagnosed with colon cancer now survive, and survival chances are even greater if it's caught early. More than 90 percent of stage 1 colon cancer patients are cured, Berlin said.
Kramer underwent surgery, radiation and two rounds of chemotherapy, but before she was cancer-free. During one of her sleepless nights before she was cured, Kramer found Fight Colon Cancer on the Internet and decided to participate. She's now on its board.
"If I had known about symptoms, I could have gotten to a doctor much earlier with a much less aggressive form of cancer," she said. "It's important that people stop the silence."
ABC Tweet Chat on Colon Cancer
Please join ABC News chief health and medical correspondent Dr. Richard Besser and ABC talk show host Katie Couric for a tweet chat today at 2:30 p.m. ET about diagnosis, treatment and prevention of colon cancer. You can share your story and get advice from experts at the Centers for Disease Control and Prevention, the National Institutes of Health, the American Cancer Society and others. Click here to learn how you can join in three easy steps.