American deaths from cancer dropped 27% overall from 1991 to 2016, and racial disparities are slowly narrowing, according to a major new report from the American Cancer Society.

Yes, but: This isn't the same for all Americans or the case for all cancers. The gap in the success rate is widening between socioeconomic groups, particularly in preventable cancers. And deaths from some cancers, mostly related to obesity, continue to rise.

The good news:

There were roughly 2.6 million fewer cancer deaths over that 25-year period than would have happened if the peak rates in 1991 had remained the same, Rebecca Siegel, report author and ACS' strategic director of surveillance information services, tells Axios.

The 4 major cancers — lung, breast, prostate and colorectal — all show declines. (Lung cancer deaths have decreased since 1991, but the Axios chart above shows an overall increase since 1970 due to the majority of women smokers picking up the habit later than men.)

The declines in the 4 cancers are mainly due to less smoking and advances in early detection and treatment, Siegel says.

The racial disparity is lessening. Black people had death rates 33% higher than white people in 1993, but that gap dropped to 14% in 2016.

Survival rates for most cancers have improved, except for lung and pancreatic cancers, which tend to be diagnosed at a more advanced stage.

The bad news:

Cancer remained the second leading cause of death in the U.S in 2016.

The socioeconomic gap in cancer mortality is growing, Siegel says. For example, poor women have twice as many deaths from cervical cancer than affluent women — and this is mostly preventable. Lung and liver cancer mortality also is more than 40% higher in poor men compared to affluent men.

"Poor people have less access to quality health care. Not only are they unable to get systematic screenings, but treatment options are oftentimes not the highest quality."

— Rebecca Siegel

Incidence rates have increased for melanoma and cancers of the liver, thyroid, uterine corpus and pancreas — and some of this has been linked to the obesity epidemic, Siegel adds.

Prostate cancer deaths, which had been dropping, have recently flattened.

Of note: The impacts of the Affordable Care Act on prevention and treatment and the HPV vaccine on cervical cancer rates are not yet included in these statistics. "Death from cervical cancers is very preventable. [And yet,] almost 10 women per week in their 20s and 30s died from cervical cancer in 2016," Siegel says.

The bottom line: If disadvantaged groups could have better access to regular screenings and better treatments, cancer deaths would continue to decline for all Americans, Siegel says. "Many of these deaths are unnecessary."