An interesting finding was published in the May 3 online edition of the Journal of the National Cancer Institute: If a woman had a normal screening mammogram last year but then is diagnosed with breast cancer before she goes for her next screening mammogram 12 months later, then her disease will likely be more aggressive than if it’s one that is detected during her next routine annual mammogram.
This type of cancer finding is referred to as an interval cancer and unfortunately it can and usually does have a worse prognosis than the majority of breast cancers diagnosed. It is important, however, to note that there are two types of interval cancers.
- With a true interval cancer, no breast cancer had been detectable on the previous mammogram.
- A missed interval breast cancer, on the other hand, means that a tumor had indeed been visible on the last mammogram but it went undetected, either because of a technical error, such as a poor-quality mammogram image, or because the radiologist misinterpreted what he or she saw there. (Sadly, this does happen.)
An interval cancer = a more advanced stage
It’s probably no surprise to learn that, by the time an interval cancer is discovered (whether true or missed), it is more likely to be at a higher grade of disease than a tumor detected during a routine annual screening. Interval cancers are also more likely to be hormone-receptor negative, which is a bad thing, since their growth rate is less likely to be boosted by exposure to the naturally occurring hormones estrogen and progesterone. This means that the growth of interval cancers cannot be slowed by using hormonal therapy to lower estrogen and progesterone levels in the body. Hormone-receptor-negative tumors, therefore, may be harder to control since doctors don’t have the option of using hormonal therapy drugs for treatment.
What can you do to avoid having this happen to you?
Sometimes nothing–some interval cancers are purely a case of fate dealing a woman a bad hand. But the fact that interval tumors also occur because they get missed due to human error highlights a question we all must answer: What kind of routine yearly mammogram have you been getting these past few years?
At the risk of repeating myself
Please make sure that:
- You are getting digital mammograms, because digital images provide a more accurate image of your breast tissue.
- Your films are always read by a specialist–that is, a breast-imaging radiologistwho exclusively reads mammograms and breast ultrasounds.