Size difference in tumor between ultrasound and MRI...

Was your ultrasound before or after the biopsy?

I was told that the biopsy can make the tumor look bigger. My biopsy called my tumor 1.3cm, and on the MRI it looked more like 3-4cm. Surgery found 1.8cm. The surgeon said that she does not trust post-biopsy imaging for size. And of course the biopsy wasn't quite accurate either. I think you can't really know until they take it out.

I raised this one with my BC surgeon after my surgery. He advised that an US tends to undersize a tumour. Remember sound waves are being used to estimate the dimensions. Magnetic resonance imaging is a different technology, which results in different sizings (not always accurate again).

Like someone has already said, you won't find out the true size and character of the tumour until it has been removed and tested. It is however quite typical that during this journey we try to make sense of what is happening; with each piece of additional information. The mind is quite literally trying to find homeostasis so that we can live lives that aren't in perpetual trauma. We also start to exhibit survivor characteristics by rationalising our experiences ... it's a good thing to do, just remember that the journey is somewhat unpredictable and getting used to that is in fact the wave that we ride.

Good luck with the next stage and wishing you healing and gentleness.

I can feel my tumor -- before biopsy it was really hard to find - needle core ultrasound measured 1.3 cm. After biopsy it was really easy to find. I mentioned this to the surgeon and she said that it's because the tumor is swollen from the biopsy trauma. I just had my MRI which is a month after the biopsy. The swelling has gone down so I'll be curious what size it measured. Will let you know.

I will echo what others have said, you won't know the exact size until the tumor is removed. My mass on imaging (which didn't show on mammogram or ultrasound, only MRI) was over 2cm. But wonderfully at surgical removal was 1.3 cm

My tumor was HER2 positive and was clearly exploding in growth at the time of diagnosis, but did it really grow from 1.5 cm to 7 cm in two weeks? Note below that in December I had an ultrasound on the 10th and an MRI on the 13th. The ultrasound measured the tumor's largest dimension as 8 mm and the MRI three days later measured it at 1.3 cm. My oncologist did the original MRI in August because he wanted me to qualify for Perjeta. Boy, did I! He looked pretty ashen the next time I saw him. Suddenly I not only qualified for Perjeta, but also radiation! I would say that, in my experience, based on the December imaging, MRI exaggerates.

8/15/18 Biopsy Ultrasound---1.5 x 1 x 1 cm

8/30/18 MRI----------------------7 x 2 x 3.4 cm (!!!!)

11/12/18 Ultrasound-----------1.1 x 0.6 x 0.4 cm

12/10/18 Ultrasound------------0.8 x 0.7 x 0.3 cm

12/13/18 MRI---------------------1.3 cm at largest point (radiologist did not record other 2 measurements)