There's something remarkable happening with cancer

Here's the bad news: more than 1.6 million new cancer cases and about 600,000 cancer deaths are expected to happen in the US in 2016, according to a report by the American Cancer Society.

But here's the good news: The overall rate of cancer deaths fell by 23% between 1991 and 2012. By its calculation, that's about 1.7 million deaths averted over that 21-year timespan.

The ACS's annual report, which lays out cancer predictions for the year while also analyzing the rates of cancer over the past few decades, was published Thursday.

Because that overall downward trend can be a little tricky, here are some of the biggest trends based on specific cancer types in the report.

• Lung, breast, prostate, and colorectal cancer death rates dropped the most significantly over the past two decades: Lung by 38%, breast by 36%, and prostate and colorectal each down 50% overall.
• On the prevention side, ACS attributed the decrease in cancer-death rates to reduced smoking habits, combined with better cancer prevention, earlier detection and treatment.
• However, while the drops in death rates for lung, breast, prostate, and colorectal cancers are promising, cancer death rates for liver, pancreas, and uterine corpus cancers are still increasing, so this overall drop doesn't extend across the board.
• Brain cancer is now the leading cause of cancer death in children under 19. That's in part because treatments for the previous leader, leukemia, have gotten a lot better, the ACS wrote.

The takeaway: That 23% drop over a 20-year period is promising, but looking past that number shows that there's more that still needs to be done.