Sandra Yates knew.

As soon as she felt the pea-size lump in her breast, she was sure it was cancer. Still, she refused to acknowledge it. She wouldn’t go to the doctor. She didn’t tell anyone. And when Breast Cancer Awareness Month rolled around that fall, she wanted no part of it.

“I would turn down the radio or change the channel on the TV when an ad came on. I was flipping pages in magazines,” she said. “I didn’t want to hear it. I wasn’t trying to put on no pink ribbons. That wasn’t me.”

It would be nearly nine months before she told herself it was time to act. By then, the lump was the size of a small egg. The diagnosis was Stage 3 breast cancer.

Yates, a witty, fiercely independent woman who raised two daughters on her own, doesn’t seem the type to back down from a challenge. Doctors and advocates say the fear that kept her from acting quickly is all too common among black women. It is among the factors that contribute to a disturbing trend: Although they are less likely than white women to get breast cancer, black women are more likely to die from it. The difference in mortality began to emerge in the early 1980s. By 2007, according to the American Cancer Society, even though rates for both groups were going down, death rates were 41 percent higher among African American women than among white women.

Some health-care professionals and advocates contend that the disparate mortality rates argue for a more urgent effort to reach more black women. They are frustrated that, with all of the information available about the importance of early detection and treatment, the statistics remain so dire.

In a survey focusing on African American women by The Washington Post and the Kaiser Family Foundation, 75 percent of black women rated their health as good or excellent, about the same percentage as white women, black men and white men.

Health data, however, tell a different story. Across the country, women of color report higher rates of disease and health problems, are more likely to be uninsured and have had fewer doctor visits for preventive care. A 2009 Kaiser study noted “consistently higher rates of health challenges among black women, ranging from poor health status to chronic illness to obesity and cancer deaths.”

For breast cancer in particular, experts cite some additional factors: Black women often get their diagnoses at later stages and appear to be more susceptible to aggressive tumors. They also have a higher rate than white women of a diagnosis before age 40.

Poverty and racial inequities are the primary factors driving the disparity, according to a study released Wednesday at a breast cancer forum sponsored by the Avon Foundation. The study, which compared mortality rates between black and white women in the nation’s 25 largest cities, states that “nearly five black women die needlessly per day from breast cancer” because they don’t have information about the importance of breast screening and they don’t have access to high quality care. The authors of the study, conducted by Sinai Urban Health Institute and published Wednesday in Cancer Epidemiology, said genetics play only a small role in the disparity.

“Our research shows societal factors — not genetics — are largely to blame for the racial disparity in breast cancer mortality nationwide,” Stephen Whitman director of the institute and lead author of the study, said in a news release. “When a woman believes genetics causes her disease, it breeds a sense of hopelessness and fear.” He said that women can play an active role in reducing their risk, but that the health-care community needs to improve access to quality care for all women, including those who are uninsured or under-insured.

Regina Hampton, a surgeon who specializes in benign and malignant breast disease, works with the Capital Breast Care Center in the District, which serves uninsured women, and runs her own private practice in Prince George’s County, where she sees many women with good health-care coverage.

In both settings, she said, “a lot of women come in at later stages . . . and what I hear from my patients is they’re all afraid.”

Besides the fear that most women have that the disease will rob them of femininity or sexuality, Hampton and others think black women also carry angst stemming from a historically unhealthy relationship between African Americans and a medical system that was inaccessible. Often lacking the money or insurance for preventive care, many black people didn’t seek medical help until they were seriously ill.

Cancer of any kind was viewed by many as certain death, because most of the people they knew who had the disease died. Hampton says some patients still bring up an old myth advising against cancer operations for fear of spreading the disease.

Breast cancer, she said, “is the most treatable female cancer that we have. I think one of the challenges is getting people to realize that the survival rates are very good for breast cancer if you present early. I think that message has not resonated through our community.”

Yates, 53, said that once she got her diagnosis and learned that she could fight the disease and most likely beat it with an aggressive treatment plan, “I felt immediately empowered. Immediately.”

Last week, she completed her treatment. “I am officially a survivor,” said Yates, who lives in Lanham and works for an information technology firm. One of her biggest surprises along the way has been discovering how many friends and acquaintances are breast cancer survivors but never mentioned it.

Until recently, she’d heard only about women who had died from the disease.

“Now, everybody tells me, ‘Oh, yeah, girl, I had my surgery 12 years ago.’

“You hear all these stories from these women who had these awesome, victorious experiences. It’s not easy, but they survived, and they’ve survived for long periods and they’re not telling anyone.”

Yates says she will not keep quiet. “Oh, I tell people. I talk about it.”

‘We deny our pain’

Eleanor Hinton Hoytt, president and chief executive of the Black Women’s Health Imperative, an advocacy group, addresses the disconnect between what black women say and what statistics show about their health in a new book, “Health First! The Black Woman’s Wellness Guide.”

“Black women invariably put on a mask. We deny our pain, grief and sorrows because we want to project an image of what I call being okay to the world and to our families and community,” she said. “We put that veil over what bothers us because so many others depend on us being in good health or being okay.”

Many of the findings of the Post-Kaiser survey support Hinton Hoytt’s assessment. Black women were more likely than white women to report being worried about losing their jobs, not having enough money to pay their bills, being a victim of a violent crime and being discriminated against. They are more often responsible for their elderly relatives’ financial needs and more likely to provide child care for family and friends.

Such demands not only put wear and tear on black women’s bodies but also leave little time and energy for addressing their health needs. Obesity — more common among black women than among white women, or men of either race — “drives a lot of our leading conditions that lead to high mortality,” Hinton Hoytt said. “Fat just squeezes the life out of us.”

Black-oriented radio and cable television networks run public service announcements about diabetes, hypertension, and the dangers of HIV and AIDS. But aside from the month of October, or leading up to major fundraising walks, breast cancer is rarely discussed in media targeted to the black community.

Karen Eubanks Jackson, founder of the Sisters Network, a national organization of African American breast cancer survivors, suggests that black women have not had a prominent role in the breast cancer movement. White women, she said, see themselves depicted in the media as survivors. “They champion each other as survivors. It’s very difficult for an African American woman to open a magazine and see someone saying, ‘I’m a survivor.’ ”

Jackson, an 18-year survivor, said she founded the organization because there was no national voice to speak to the disease’s disproportionate effect on black women. The Sisters Network has chapters in 43 cities and 22 states.

“Stop the Silence” is the organization’s slogan, Jackson said, because “there has been a definite increase in awareness, but the fact is women still are hesitant to speak up, whether to ask questions about the disease itself or to accept the fact that they’ve been diagnosed with it.” Jackson’s group has partnered with Delta Sigma Theta Sorority, a national black women’s organization, on education efforts.

The Susan G. Komen for the Cure foundation has a program and a Web site called the Circle of Promise, which recruits black women to share information about the disease with other black women.

“We think that, like so many things, we value the information of our peers. That’s the philosophy behind the Circle of Promise,” said Susan Brown, director of health education for Komen. About 110,000 women have signed up as “ambassadors” and, armed with facts about screening and treatment, they spread the word in churches, sororities and business groups.

Marc Hurlbert, executive director of the Avon Breast Cancer Crusade, said individual institutions need to coordinate better to make sure that women have access to high-quality breast-health care.

“We think most women want to do the right thing. It’s getting access to it,” Hurlbert said. “And institutions are doing their best to provide quality care, but no one can solve the problem on our own.”

Women in the Washington region who have no insurance and can’t pay for medical care can get free mammograms at the Capital Breast Care Center, which was started by Georgetown’s Lombardi Comprehensive Cancer Center in 2004 with a grant from Avon because of concern about the District’s high mortality rate.

Beth Beck, director of the center, near the Eastern Market Metro station on Pennsylvania Avenue SE, said that the center does about 2,000 mammograms each year and that 10 to 15 percent of the patients have abnormal findings, twice the national average. Almost all of the patients are African Americans or Latinas.

The center visits community health clinics, homeless shelters, and other neighborhood social and services organizations to encourage women to come in for mammograms. They have a van service for women who don’t have transportation. Women who receive a diagnosis of breast cancer are enrolled in Medicaid to cover the cost of their treatment.

Karen Crawford, who lives in the District, had not had a mammogram in more than 10 years, so when the center gave a presentation at her church, a cousin encouraged her to sign up.

Although she is employed, Crawford, 63, said she hasn’t had health insurance since her divorce 13 years ago.

Her mammogram last month turned up a shadow, and, after additional tests, she is awaiting a biopsy. She said she is “hoping for the best.”

‘It was surreal’

Most types of breast cancer are diagnosed based on the presence of cells that have receptors for estrogen, progesterone or a protein that promotes cell growth. None of these receptors are present in triple-negative breast cancer, meaning it can’t be treated with hormones or other drugs that target those specific types of breast cancer. Doctors and researchers do not know why black women are twice as likely as other women to get a diagnosis of triple-negative breast cancer.

The day after her doctor told her she had triple-negative breast cancer, Tiffany Mathis started thinking about arranging her funeral. Later that day, she called a friend who was a lawyer and told her she wanted her to help draw up a will.

Nothing suspicious had shown up on Mathis’s mammogram in January 2011, but six months later, during a self-examination, she found an unusual lump. She didn’t panic because the texture of her breasts is normally lumpy, but she decided to check it out. Her doctor determined that it was a malignant tumor and, after more tests, that she had triple-negative breast cancer.

“It was surreal,” Mathis recalls. “For three days, I was literally trying to plan a funeral.” Her husband and daughter, who researched the disease and told Mathis that most women survive breast cancer, helped her focus instead on a battle plan.

Mathis, 43, whose cancer was discovered in Stage 1, had a lumpectomy last fall. She is undergoing chemotherapy. There is still “a tiny piece of cancer in me,” she said, and doctors believe it can be eliminated with radiation. Her medical team has told her that her prognosis is good.

Lisa A. Newman, a surgical oncologist and professor of surgery at the University of Michigan, is studying whether the higher incidence of triple-negative breast cancer in black women is genetic.

Working closely with a clinic in Ghana, Newman has seen a higher incidence of triple-negative breast cancer, as well as estrogen-receptor-negative cancer, which also shows up more in black women in the United States.

“It’s been remarkable to see that the pattern of breast cancer in this part of Africa really does support our theory that African ancestry in and of itself may be putting us at risk for certain patterns of the disease,” said Newman, who also is director of the Breast Care Clinic at the University of Michigan.

Triple-negative breast cancer is treatable, and early detection is even more important because of its aggressiveness.

After Mathis shared her diagnosis with her circle of girlfriends, one of them confided that she had never had a mammogram. “She’s older than I am and had never had one. So she got one.”

Mathis said it is vitally important that women take ownership of their bodies and their health. Remember, she says, that she discovered the cancerous lump that the mammogram missed. “Knowing yourself and taking charge of your own health is so very important, especially for black women.”

Mathis, who lives in Owings Mills and works for a health-care firm, tapped into the Baltimore chapter of the Sisters Network, which she said has been “a lifesaver and a resource.”

“I feel good,” she said. “It is scary. It’s no joke. I’m not going to downplay it.” But, she added, laughter lightening her voice, it has helped that her husband has “accepted my bald head. So I’m good now.”