“No Radiation after a Mastectomy”… and other misconceptions

Laurakay, the info and discussion in this thread may be helpful to you too. 

aces, that's the study that I was referring to.

Until this study came out in 2008, it was very unusual to have radiation recommended after a mastectomy for DCIS if the margins were 1mm or greater.  I saw it a few times on this board for those with smaller margins (0.2mm for example) or negative margins (cancer cells right at the edge of the removed tissue) but very rarely for those with margins of 1mm or more.  I was in that camp (although my 1mm margin was at the skin) so I paid a lot of attention to posts from others who were in that situation.  Quite a few women went for 2nd opinions and I remember one women went for 4 opinions, all at the most highly rated cancer centers.  All said "no" to radiation.

With this new study, there does seem to be a bit of a shift, but this is only one study and there were only 80 patients in the relevant groups (margins <10mm, no radiation) and only 31 who had margins of <2mm.  Because the sample size is so small, it's not possible to know if those with margins of 1mm or greater had a more favorable result (less recurrences) vs. those with smaller or negative margins - all the 31 women with margins of 2mm or less were grouped together.  I would guess that the smaller the margin, the greater the likelihood of recurrence but we just don't have that info yet.  

This uncertainty is why I think a lot of oncologists and radiation oncologists probably are still sticking to their previous recommendation that no radiation is needed for those with 1mm margins.  If their experience is good (i.e. a very low recurrence rate) there is not enough compelling info to change.  But certainly you do fall in what is now a gray area.

Sorry I couldn't be more helpful!

hliu_2001,

My understanding is that if you take Tamoxifen, but for a shorter time than the 5 year regimen, you will get partial benefits - some risk reduction but not the maximum risk reduction.

As for my decision to not take Tamoxifen, I based it on a risk/benefit assessment, as well as my oncologist's recommendation. I was diagnosed with lots of high grade DCIS and a microinvasion of IDC. I had a single mastectomy and an SNB. My lymph nodes were clear.  My oncologist recommended against Tamoxifen for me. His explanation was that with DCIS, even with a microinvasion, after a mastectomy my risk of recurrence is only about 1% - 2%. While Tamoxifen can reduce recurrence risk by about 40%-50%, for me that would be at most a 1% benefit, compared to a 2%-3% risk of serious side effects from Tamoxifen.

There was one other factor that my oncologist wanted me to consider, however, and that was the protection that Tamoxifen would provide to my remaining breast.  He explained that my lifetime risk (to age 90) of getting BC in my remaining breast was about double what it would be for the average woman my age (I was 49 when diagnosed).  That worked out to 22%. The way Tamoxifen works, if you take the full 5 years of therapy, you get full benefit for about 10 years.  After that, studies have shown that the benefit continues, but at a declining rate. In my case, my cancer was ER+ but PR- so I guessed that my benefit would be on the lower side - probably closer to 40% risk reduction rather than 50%.  So doing the math, if I got full benefit for the first 10 years, that would be about a 2% - 2.5% risk reduction over those years.  If I got a 50% benefit for the next 10 years, that would about another 1% risk reduction.  So my total benefit would be a bit less than 4%, which for me was not enough to warrant the risk of serious side effects and the potential quality of life issues.

Here's another way I thought about it.  Of 100 women my age with something like my diagnosis, if none of us take Tamoxifen, 24 of us will get BC again (a recurrence or a new primary). If all of us take Tamoxifen, about 19 of us will get BC anyway. This means that from this whole group, 5 women will benefit from taking Tamoxifen.  I'm not normally a pessimist, but I can't help but think that if I'm unlucky enough to be one of the 24 doomed to get BC again, chances are I'll be unlucky enough to also be one of the 19 who will get BC despite taking Tamoxifen.  I understand and appreciate that a lot of women would look at it differently - and they would take Tamoxifen to ensure that they don't miss out on the chance that they would be one of the 5 who benefits.  But that's not me.  So it's all in how you look at and assess risk.

Having explained all that, I want to emphasize that I do think that Tamoxifen is a great drug - it can reduce the risk of recurrence by about 40%-50% and that benefits a lot of women.  But like most drugs, Tamoxifen comes with side effects and risks.  For Tamoxifen, the risk of serious side effects is about 2%-3% (this can be higher or lower depending on your age and your health history).  Tamoxifen also has a long list of possible "quality of life" side effects.  For someone who has a high risk of recurrence, and particularly, for those who have a high risk of distant recurrence (mets), the risk/benefit equation works out completely differently than it did for me.  For women who have those risks, personally I think taking Tamoxifen is an obvious decision.  But for those of us who have a lower risk, and particularly no risk (or minimal risk) of distant mets, the decision becomes one of personal choice.  How much recurrence risk are you willing to live with?  How much risk reduction is enough to warrant the risk of side effects and the possible discomfort?  The answer to these questions is different for each of us.

Hope that helps.  And here are some websites with info about Tamoxifen, including clinical trial results.  Unfortunately some of the clinical trial result detailed tables that I used are no longer readily available.

http://www.rxlist.com/nolvadex-drug.htm#ad

http://www.drugs.com/pro/tamoxifen.html

http://www.bccancer.bc.ca/HPI/DrugDatabase/DrugIndexPro/Tamoxifen.htm

Bumping to the current list of posts, for those who are newly diagnosed.