Abstract
Assuming that 40,000 women are affected by breast cancer annually in Japan, and approximately 10% of those cancers are noninvasive cancers, 36,000 women will have invasive cancers. If these invasive cancers are detected early when as small as 2cm or less and are properly treated, annual breast cancer mortality might be 3,600, since the ten-year survival rate is 90%. However, actual breast cancer death accounts for over 10,000 yearly. My plan for reducing breast cancer death by using ultrasonography screening is as follows :
1) Since almost all invasive breast cancers form a tumor, which is easily detected by ultrasonography, experienced sonographers can detect tumors as small as 0.5cm in the size. When a tumor is 1cm in diameter, it occupies four times the area of a 0.5cm tumor. Therefore ultrasonography capable to detect much less than 2cm, even in screening system, for example as small as 1cm in diameter.
2) Ultrasonography is expected to detect noninvasive cancers as well. Approximately 35% of noninvasive ductal cancers form a tumor such as an intracystic tumor or a solid tumor. Such tumors are easily detected by ultrasonography. Other tumors form a flat hypoechoic image, and these are the commonest type, accounting for about 40% of all noninvasive cancers. Sonographers must be trained to recognize this type for increasing the detection rate of noninvasive ductal cancer dramatically.
In summary, effort toward detection of tumors of 1cm in diameter, and of flat hypoechoic image, by ultrasonography is the key to decreasing the rate of breast cancer death.
