"Like you did something bad, you know, because it took up residence in your anus?" she said.
Cross said doctors later told her the cancer was likely linked to HPV, a sexually transmitted disease, and the same strain had caused her husband Tom Mahoney's throat cancer in 2009. "I've read a lot of cancer survivor stories, and many people, women especially, were too embarrassed to say what kind of cancer they had", the actress said. "Anus, anus, anus!" she said with a laugh.
"I'm feeling back to normal though it's a new normal", she said.
According to the CDC, HPV causes more than 90% of anal cancers, and can spread from one person to another through sex or just by skin-to-skin contact.
She says she is recovering well and hopes that sharing her story will encourage others to speak to their doctor if they believe they have symptoms of anal cancer.
"I would be like working all day".
Mahoney was diagnosed with throat cancer three years after their 2006 wedding.
According to the American Cancer Society, about 8,300 people are expected to be diagnosed in 2019 and that almost 1,300 will die.
But the types of HPV that most commonly cause cancer can be prevented by a vaccine, which Marcia is now encouraging people to get.
As a parent, Cross was relieved to learn early immunization can protect the next generation.
"I was so not thinking anything was wrong because I didn't have any symptoms, and she gave me an exam and came around and said, 'Well, I just want you to know, whatever it is it's curable.' It was like - what?!"
Cross told CBS she planned to vaccinate her 12-year-old twin daughters Eden and Savannah against HPV later this month.
She was referred to a colon and rectal surgeon and, after two biopsies, she was diagnosed with anal cancer.
'I don't think I'll ever take it for granted.
Cross, who charmed audiences as perfectionist Bree Van de Kamp in Desperate Housewives, underwent six weeks of radiation therapy and two weeks of chemotherapy. She chose to speak openly about her experience so others will hopefully be less embarrassed about the disease and get a rectal exam, which is how she learned of her cancer. It's great what my body can do!