A new pocket-sized device may allow doctors to check a woman's breast cancer risk in minutes with just droplets of blood or a sliver of breast tissue, Canadian researchers said on Wednesday.

They said the microchip device can measure levels of the hormone estrogen using far smaller samples than conventional methods, making it possible to quickly screen for breast cancer risk or check to see if breast cancer treatments are working.

The new device is compatible with extremely small samples -- around 1,000 times smaller than the amount needed for conventional analyses, said Aaron Wheeler of the University of Toronto, whose study appears in the journal Science Translational Medicine.

We could replace the invasive techniques of intravenous blood collection and even tissue biopsies with pinpricks of blood, or fine needle aspirates of tissue, Wheeler told a news briefing.

The experimental device advances the notion of a so-called lab on a chip -- a device that shrinks down several lab functions onto a microchip.

Wheeler said other such tools rely on microchannels -- a series of interconnected, enclosed tubes -- but these cannot process tissue because they can clog up.

The method we're reporting here relies on digital microfluid moved across an open surface. Droplets essentially can be made to dance across the surface, Wheeler said.

There are no tubes to clog.

More than 400,000 women die from breast cancer globally every year.

Being able to directly test breast tissue could lead to faster test results, Wheeler said.

Dr. Noha Mousa of the University of Toronto, who worked on the study, said the device could be used to check on the effectiveness of breast cancer drugs called aromatase inhibitors, which block the production of estrogen that can fuel tumors.

They include Pfizer's Aromasin, Novartis' Femara, and AstraZeneca's Arimidex.

About 75 percent of breast cancers are estrogen-receptor-positive, meaning they are fed by estrogen.

This will allow us to monitor how effective that therapy is at reducing estrogen levels, Mousa told the briefing.

It also may help identify new patients who are at risk of developing estrogen-sensitive breast cancers, she said.

Wheeler said the device is still in the research phase. We're looking for funding to work on building a prototype and moving this into commercialization, he said.

We're anticipating within the next five years a product based on this technology will become available.