Steep declines in fatal cases of lung and breast cancer have led the drop in cancer deaths in the US in the past years, according to data released by the American Cancer Society.

In all, more than a million deaths have been avoided since cancer mortality first began to decline at the start of the 1990s, said the Cancer Statistics 2012 report based on US government health data and statistical models.

But while deaths from four major cancers – lung, colorectum, breast, and prostate – continued to drop in the past decade, other potentially lethal cancers have been on the rise, including throat and mouth cancers linked to human papillomaviruses, a common sexually transmitted disease.

Cancers of the pancreas, liver, thyroid, and kidney and melanoma of the skin have also been mounting over the past 10 years.

Some of those may be tied to the obesity epidemic in the US as well as better early detection practices for certain cancers, the report suggested.

For the most recent four years of the study, 2004-2008, overall cancer incidence rates declined 0.6 per cent per year for men and were stable in women.

Cancer death rates for that period dropped 1.8 per cent per year in men and 1.6 per cent annually in women.

The biggest contributors to the drop in fatalities were lung cancer, which accounted for 40 per cent of the decline in deaths among men and breast cancer, which made up 34 per cent of the fall in deaths among women.