Why are Tamoxifen and Radiation BOTH necessary (for some women)?

Raili

I know I should ask my oncologist.  But it's a Sunday, and she is only in the clinic that I go to once a week, so I won't be able to see her for a while...and time is of the essence, because I'm considering quitting radiation, 10 treatments in.

What I don't understand is why radiation is even so necessary if one is going to take Tamoxifen.  Tamox is a systemic treatment, right?  Which means it treats your entire body, INCLUDING your breasts?  I had successful surgeries that resulted in good margins (not 10mm, but wide enough), and then had a thermogram pre-radiation that showed that my breasts were healthy and functioning well.  So...radiation is designed to kill whatever microscopic cancer cells are still lingering in the breast after surgery... but why wouldn't Tamox be enough to take care of those microscopic cells - assuming they're even there??

MzJ

My doc offered this analogy comparing cancer to a dandelion/weed in your front lawn...the lumpectomy pulled the weed out.....radiation is like a gardener spritzing the specific spot to make sure any root pieces are killed off to help reduce the chance of the weed coming back.... hormone or chemo therapy is another gardener that walks around with a sprayer treating the whole rest of the lawn, backyard and side, to help further reduce the chance of that weed spreading.

Sydney6

Raili - I'm curious as to why you are considering quiting radiation?

Sue

Beesie

Tamoxifen reduces both local and distant recurrence risk.  Radiation reduces local recurrence risk. So whether you need both depends on what your local (in breast) recurrence risk is after surgery and your own personal risk tolerance. 

If you start with a relatively low local recurrence risk post-surgery because of wide margins and a low grade cancer, Tamoxifen alone might be enough to get your risk to an acceptable level. 

If you start with a relatively high local recurrence risk post-surgery, because of small margins and a high grade cancer (and hormone status and age....), then you may need both radiation and Tamoxifen to get your risk to an acceptable level.

Of course, what is an "acceptable" level of recurrence risk depends on your own personal risk tolerance.  Some women can live comfortably with a recurrence risk of 15%.   Other women are fearful with a recurrence risk of 7%.  So in the end, you really do need to talk to your oncologist to understand what your local recurrence risk level would be if you took Tamoxifen only vs. if you had radiation and then took Tamoxifen.  Then you can decide if the benefit from radiation is worth it to you.

pj12

It is my impression that the "standard of care" following lumpectomy is to follow up with radiation. It would be hard to find a doctor who did not want to follow that protocol. When radiation is not an option, mastectomy would be advised. That still does not guarantee radiation would not be indicated if at all possible.

The hormonal drugs are mainly to prevent a metastasis or a new tumor from forming in either breast. 

idaho

Radiation will kill any remaining cancer cells in your breast (and even if you have clear margins you could still have some----example- in the needle track from your biopsy)... Tamoxifen will keep you from forming any new cancer throughout your body.   Tami