After surgery in April 2012, Kniss kept her diagnosis under wraps. Staying silent was important to her healing, albeit uncharacteristic for her extroverted personality, she said.
This March, she broke her silence at a fundraiser breakfast for the nonprofit Breast Cancer Connections in Palo Alto. The admission shocked people who were close to Kniss. Even her campaign manager did not know, she said.
Now, with actress Angelina Jolie's recent announcement of her preventative double-mastectomy raising awareness of breast cancer, Kniss has decided to speak openly about her own diagnosis and treatment. By coming forward, Kniss said she hopes to encourage women to get screened for the disease.
"This is not about me. It really is about everyone else. I'm one of so many. I feel like my story shouldn't be any more special than anyone else's," she said last Friday.
And she has a straightforward message for women: "Get your damn mammogram every year."
Jolie has a gene mutation, BRCA1, which can cause an eight-fold increase in breast cancer risk. About 5 to 10 percent of breast cancer patients carry a BRCA gene — 10 percent if they are Ashkenazi Jews.
Women with BRCA1 or a second mutation, BRCA2, have a 60 percent chance of developing breast cancer, according to the National Cancer Institute. The risk of breast cancer is about 12 percent for the general population.
About 36 percent of U.S. women with a BRCA mutation chose preventive mastectomies, a study by the Women's College Research Institute in Toronto found.
In addition to breast cancer, BRCA carriers have a 15 to 40 percent chance of developing ovarian cancer, compared to 1.4 percent for the general population, according to the National Cancer Institute.
Kniss does not carry the BRCA gene. But one of her sisters died from breast cancer 10 years ago, she said. Still, that did not raise any red flags.
"The only thing I remember her saying is, 'It's not familial; don't worry about it,'" Kniss said.
The diagnosis came as Kniss was gearing up for her campaign for City Council.
Dr. Diana Guthaner, a Palo Alto radiologist, had asked Kniss to return to her office after a routine mammogram in March 2012.
"She said, 'Liz, come in for a minute. I'm really not liking what I'm seeing,'" Kniss recalled.
"How much are you not liking what you're seeing?" Kniss asked.
"I'm really not liking it at all," she recalled Guthaner said.
The first weekend after the diagnosis, Kniss panicked.
"Does this mean I won't see my grandkids grow up?" she said she asked herself. "I think you're stunned initially for about a week. Then you think, 'I hope I'll survive.'"
Kniss first underwent a lumpectomy on her left breast. Two weeks later, she returned for surgery to remove additional tissue. At the same time, she had a lumpectomy on her right breast. She did not undergo chemotherapy. After a carefully considered second opinion, she decided against radiation treatment, she said.
But whom to tell was one of the most difficult decisions to make, she said. She didn't want to be viewed as the candidate who needs sympathy or the candidate who is sick.
"That was a very hard one. I decided I could handle my disease better if I had a small support group — if it was me handling it. I knew at some level I had to conserve my energy, and I couldn't spend it keeping a lot of people in the loop," she said.
After surgery, Kniss and her husband rented a motel room for three days where they could be anonymous. But she didn't put her life on hold. She viewed the cancer as a distraction that she didn't want to get in the way.
"I remember thinking, 'I have got to get done with this. May is a heavy budget month,'" she said, referring to her prior role as a Santa Clara County supervisor.
Kniss said she plans to help Breast Cancer Connections with fundraising and to spread the word about the importance of screening.
Most oncology organizations prefer women receive an annual mammogram beginning at age 40, said Dr. Allison Kurian, assistant professor of medicine at Stanford University and associate director of the Women's Cancer Genetics Clinic at the Stanford Women's Cancer Center.
Other tests, such as sonograms and magnetic resonance imaging, can refine detection and are helpful for women with dense breast tissue, which can sometimes hide a tumor. On April 1, California's so-called breast-density bill went into effect. The legislation requires medical professionals to notify women if they have dense breasts. The bill was introduced by former state Sen. Joe Simitian.
Frank delaRama, clinical nurse specialist in oncology and genomics at Palo Alto Medical Foundation, said factors such as a family history of breast or ovarian cancer, age at childbearing and lifestyle can be factors for getting the diseases.
Since Jolie's announcement, local organizations are seeing an uptick in concern. DelaRama said women who postponed physician-referred screenings are now calling his department for appointments.
More women have inquired at Breast Cancer Connections about information related to BRCA, said Erika Bell, manager of medical-information services. The nonprofit serves women and men with breast cancer and has a research library, support groups for cancer patients and families, classes, a "buddy" system that pairs patients with cancer survivors and an early screening program for uninsured patients.
Kniss said she hopes the new spotlight on breast cancer will have lasting effects.
She reflected on how a simple screening may be responsible for two very different outcomes between sisters: Kniss is cancer-free, although she will continue her vigilance for the rest of her life. Her sister was diagnosed at age 47 and died at 52.
"I don't think she had mammograms. She thought she had back trouble," Kniss said.