After four years, the researchers reported, there was no difference among the groups.
The researchers reported their results in a recent issue of Science magazine.
They also stand a greater risk of Type 2 diabetes, researchers reported last week.
The researchers then reported this as a success, when in fact the original test had failed.
Some researchers report the cancer is also less common in women who eat a lot of vegetables, but more studies are needed.
Maybe not, researchers report in the current issue of the journal Chest.
The benefits extended, on average, at least 11 years after surgery, the researchers reported.
Several researchers report similar results in particular sectors, though they have not shown the complete picture.
Last week, researchers in London reported that the disease might also have a genetic cause.
Some researchers have reported no benefits, but at least one recent study paints a more positive picture.