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A Day in the Life of: Dr Tozaki, Breast Cancer Expert

Dr. Mitsuhiro Tozaki, director of the Breast Oncology Department at Sagara Breastopia Healthcare Group, is an expert in diagnostic imaging who works hard every day to raise the quality of breast cancer diagnosis in Japan. Based in Kyushu, southern Japan, the Breastopia Healthcare Group is a pioneer in women’s healthcare, including breast cancer diagnosis and treatment. Most recently, they have been engaged in a new experimental venture. They have opened a satellite clinic in Tokyo, which provides remote diagnostic imaging services. At the satellite clinic, Dr. Tozaki can give his invaluable second opinion and expertise to a total of nearly 2,000 mammograms and ultrasound images transmitted from the hospital in Kyushu.

Dr Tozaki

These remote diagnostic centers have yet to become widespread in Japan. But Dr Tozaki hopes that this kind of effort will expand nationwide. The ability to easily undergo breast exams at a clinic near home, and have the images read by specialists wherever they are in the country, would have major advantages, he said.

The fact is that at about 30%1, the breast exam rate in Japan is very low for an advanced industrial nation. The sheer numbers of both breast cancer cases and deaths are on the rise. What’s more, according to a recent survey2, only 1% of Japanese people are aware of dense breast tissue, a natural variation in breast tissue that can make it harder to detect cancer, despite the fact that 80% of Asian women aged 50 and under have high breast tissue density3. To help improve the situation, Dr. Tozaki joined forces with other doctors and breast cancer survivors to form the nonprofit organization, Breast Cancer Imaging Network (BCIN). While working with outside organizations such as “Are You Dense?” in the United States, Dr. Tozaki’s nonprofit provides accurate information on breast cancer and breast cancer exams while enabling doctors in the field to collaborate on efforts to make diagnosis easier, especially for women with dense breasts.


“Through our BCIN activities, we discovered people who said they didn’t mind their photos and names being used publicly if they could help spread the word on what they’ve experienced,” said Dr. Tozaki. “I was deeply moved by their willingness to disclose such extremely sensitive and private information for the sake of other women around the world.”

Regarding the extremely low level of awareness of dense breast tissue in Japan, Dr. Tozaki added: “Even in America, where disclosure to breast exam patients of their breast tissue density is mandated by law in some states, the awareness rate is only 48%*2. So in a sense, Japan’s 1% awareness rate can be understood in that context. And yet, we are actively putting out information at BCIN, and there are healthcare facilities that have recently begun to distribute printouts to examinees, showing them what kind of breast tissue density they have. Knowledge of dense breast tissue enables a woman to take action on her own initiative. So I want to believe that this is going to spread in Japan.”

“To Japanese women, many of whom have dense breast tissue, I strongly recommend undergoing breast exams,” said Dr Tozaki. “I’m not denying screening by mammography. I’d simply want you to know what type of breast tissue you have since the resulting knowledge enables you to know what action you should take next. To every woman, I would like to suggest taking an active interest in your own health in this way.”



1:  OECD Health Data 2013

2:  GE Healthcare Survy, conduded in June – July 2015, targetting approximately 4,500 people over 18 years of age, in U.S., Brazil, England, Indonesia, Japan, India, China, Australia, Korea

3: Jeffrey A. Tice et at, Ann Intern Med. Mar 4, 2008; 148(5): 337-347