Chicago is making “remarkable” progress in a longstanding battle to improve public health—by closing the “mortality” gap between black and white women diagnosed with breast cancer.

According to a new study published by Cancer Cause & Control, an international journal of studies of cancer in human populations, Chicago made the “most progress” among nine major cities with the nation’s largest black populations in reducing “racial disparities in breast cancer mortality.”

Over the four year period ending in 2013, the mortality rate from breast cancer among black women in Chicago dropped by 13.9 percent. The gap between black and white women narrowed by more than 20 percent during the same period.

Even with the improvement, African-American women in Chicago have a breast cancer mortality rate that’s 50 percent higher than non-Hispanic white women with similar rates of diagnosis.

The persistent gap has been blamed on “structural inequities” that lead poor women, many of them minorities, to receive lower-quality mammograms or none at all. The later the diagnosis, the lower the chance of survival.

“To show progress in this area is dramatic and remarkable. We’re very pleased,” Chicago Health Commissioner Dr. Julie Morita said Wednesday.

“However, we’re never satisfied when there’s a disparity that remains. So we’ll continue our efforts to close that [gap] and also to continue the progress we’re making with breast cancer among all woman—not just African-Americans.”

To chip away at the racial gap, the Health Department is investing $700,000 in “community partners” charged with bolstering “comprehensive breast health services” for African-American women and others who have faced “historical obstacles to access.”

Those partners include: Cook County Health and Hospital System; Rush University Medical Center; Miles Square Health Center; Metropolitan Chicago Breast Cancer Task Force; Sinai Health System and Centro Comunitario Juan Diego.

Those organizations are increasing breast cancer screenings and ensuring that high-risk, medically underserved women receive high-quality follow-up treatment.

“Early diagnosis helps improve the outcome. So making sure mammography services are available so people can be screened, raising awareness so people know they should get screened are really important. Making sure that individuals are connected to services that are convenient and high-quality is also really important,” Morita said.

“We have to make sure that those individuals who are diagnosed actually get connected to appropriate care and treatment as well. So we’re taking it a step further.”

Dr. Patricia Robinson, a breast oncologist at Loyola University Medical Center, said improving care to under-served populations, providing higher-quality machines in smaller hospitals and educating patients about “mammogram screening adherence” and “personal risk relative to family history” can only go so far.

“If you look beyond the city of Chicago in why there is a disparity in outcomes between African-Americans and other patient populations, it is because our tumor biology may be a little different,” Robinson said.

“African-American women are more likely to present with triple-negative breast cancers. They’re more likely to present with more aggressive, higher-grade lymph node- positive breast cancers. And prognostically, those women are more likely to go on to develop metastatic disease.”

Four years ago, Chicago expanded a program that provides free mammograms to uninsured women – by nearly 1,500 patients – despite a state funding cutoff triggered by alleged mismanagement.

The decision to absorb the $300,000 state cut and bankroll a $200,000 expansion at nearly shuttered Roseland Community Hospital was aimed at saving lives through early diagnosis.

At the time, Roseland and the surrounding communities of Beverly, Washington Heights and Auburn Gresham had Chicago’s four highest rates of premature death from breast cancer.

“This is . . . an attempt to address the disparities that exist in health care services,” Mayor Rahm Emanuel told a news conference on that day at Roseland Community Hospital.

“It’s all about access. It is one of the few cancers in which, if you diagnose it early enough, you can actually deal with it.”

Then-Health Commissioner Dr. Bechara Choucair said then that Roseland Community had a “top-notch” mammography machine, even though the financially strapped hospital came close to closing its doors.

“Women in these neighborhoods who have breast cancer are dying at a younger age than the rest of the city. And we know how we can resolve this – by making sure that more women are getting screened,” Choucair said then.

Earlier that same year, the state cut off funding for the city’s mammography program amid allegations that the Health Department was having unqualified people diagnose women with abnormal mammograms and taking too long to refer them for follow-up exams.