Because scans aren't ever 100%. The 100% thing holds true for most medical science. The reasons are many and varied. Sometimes too small, breast tissue too dense, tumours hidden behind other tumours/structures, what tissue makes up the tumour etc etc. 

Sometimes other tumours are only found once they go in there and root around. The long and the short of it, CT/MRI/X rays don't always pick up issues.

My uncle had pancratic cancer and nothing ever showed up on any scan. The tumour was only picked up when they put a camera down into his stomach and beyond.

In that case how do I stop this nagging feeling that the other breast might not be safe? They found lumps in there and said they were harmless cysts but I can't get it out of my head. Also I asked the breast nurse if the tumour had been masked by the DCIS and she said no? Could they have suspected something all along and just not told me?

Thankyou for your reply, I really appreciate it.

Sure i had this conversation last week with someone. In laymen terms, If the patient is deemed to be of sound mind and is 16 or over (I'm sure it's 16), doctors are legally obliged to tell the patient what they are testing for, the results of those tests, and anything else relating to those tests if the patient asks. For example, if asked, doctors/nurses will tell you what all the bloods they are taking are for. such as liver panel, hormones etc etc.

For any procedure or test to take place, they need your consent. Even a simple *** test. As such, you have the right to  ask why they are doing those tests as it allows you to make an informed choice.

Unless there was human error involved somewhere, or poor communication, i highly doubt they would keep anything like that from you.

That said, trying to get straight answers from some hospitals is akin to pulling teeth at times. But having a tumour would constitute as an important part of information that needs to be disclosed to you, the patient. 

Hi.  Sorry to read you have had such a difficult time.  Unfortunately sometimes things can be missed in scans.  I was diagnosed with grade 1 IDC after a routine mammogram showed calcifications.  Days before my planned surgery for a lumpectomy I was phoned by a radiologist and told further areas had been found and my surgery was cancelled.  It had been missed.  I was back at square one with more biopsies and waiting.  It was the worst time through the whole experience.  After more DCIS was found I went on to have a mastectomy. 

I was concerned because in all my previous mammograms for the past 5 years I had been recalled each time.  I was certain something was wrong, but each time they sent me on my merry way.  
 

I'd had a mammogram only 2 years ago, again recalled, and they did more pictures, but was told I was ok.  When I went in to have a cyst drained last December they discovered the calcifications.  In my mind they must have been on the mammogram 2 years ago but they were all quite defensive and said not.  They did say that I have very dense breasts and it's hard to see and that since my last mammogram they had installed more accurate scanners in the breast clinic (this didn't really reassure me)!

In the end I asked for a second opinion to have all my mammograms re-read at a different hospital.  My impression was that my request wasn't welcome but that they would arrange it for me and they did.  It confirmed both areas of BC.  Unfortunately I also know someone whose MRI was misread and ended up having a mastectomy when a lumpectomy only should have been done.  So unfortunately mistakes do happen even though images are double read.  I would say to anyone to ask for a second opinion if they have any niggling doubts.

I'm so sorry that you have had all that stress, it just makes things harder.  The way I coped when they found my second area was just to be relieved that despite causing more worry, they had found it and I could move on with my treatment plan.  It's the unknown that is worse and at least you now know what you are dealing with and can move forward.

Wishing you all the best.  You will get through this and get to the other side.  Take each day at a time.

Mary

Thankyou so much for your reply Mary. I appreciate you sharing your experience. I am trying so hard to feel lucky that it has all been found and treated, maybe that will just take a bit of time. 

may i please ask what area of the country you are in as I also am a missed diagnosis HER2 positive

Wales

thank you i am in yorkshire the hospital has admitted negligence and i am dealing with legal proceedings 

That's just what you need, added stress!! I hope you get on ok. Have you started treatment now then?