Letrozole for 10 years? Some research results (also relevant for Survivorship)

Hullo all. I'm sorry if this is a bit technical but I find any actual research-based information is worth trying to understand these days, even though a lot of it makes my eyes glaze over but of late I am persisting -  here's why.

After mastectomy and radiation for a very large mixed invasive and in-situ DCIS with multiple affected nodes (9/20) I was put on Letrozole. I did not have chemo due to several other health issues and age (72 at the time). The oncologist wanted me to take the chemo in spite of the risks (especially my Long QT syndrome, a heart dis-rhythmia which AC-T is not good for) and when I stuck to my guns he said it would be imperative that I do not go off the Letrozole as I would be relying on it almost completely to control recurrence. I chose Femara because of the common finding in the UK that there are fewer side effects on it, no evidence one way or the other on this but it seems sensible enough even though it is more expensive.

So it is now almost twelve months I have been on it and slowly but surely I have been noticing side effects creeping up and getting worse. Let me say at once that I have found it very tolerable up to now. Some mornings the body aches so it is hard to get out of bed, the hands are stiff, shoulders and neck often bad especially at night, interrupted sleep, all that. But now my hands are cramping up, legs cramp at night, aching shoulders worse, and mood swings and a state of generalised crossness/anger is making me wonder who I am. I know compared to so many others I have been lucky. But at my age, you have to think about what you are going to do with "the rest of your life".

So I have been in the research zone lately looking for the scientific basis and validated studies on which so many of our medical treatments and recommendations are based. Because I can feel my general state of well-being getting steadily worse I have, like many of us on this forum, been wondering whether the quality of life on the AI drugs is worth the reduced risk. I know a lot of women are going off their AIs altogether, or looking at trying Tamoxifen instead. 

So when I came across this research study, I thought I should let everyone know about it. The short results of this study are very encouraging for those on Letrozole for the extension after five years. But It is also quite encouraging for those who stop the AI after the first five years. The study (published 2016)  included 1,918 women diagnosed with early-stage, hormone-receptor-positive breast cancer.  The women were aged 60-72 years. All the women had been treated with surgery and 5 years of Femara or another aromatase inhibitor and none of the women had had a recurrence. Presumably any who had had a recurrence were not included in the study but this very important issue is not addressed. It is also not clear whether or not they had been treated with chemotherapy of one sort or another. I am trying to contact the study authors to see if I can find out more.

This same group of women were then divided into two, one group continuing to take letrozole (Femara) and the other given an identical placebo. After a median follow-up of 6.3 years, there were 165 events involving disease recurrence or the occurrence of contralateral breast cancer (67 with letrozole and 98 with placebo) and 200 deaths (100 in each group). The 5-year disease-free survival rate was 95% (95% confidence interval [CI], 93 to 96) with letrozole and 91% (95% CI; 89 to 93) with placebo.
Presumably the 200 deaths had not been related to their BC. 

While it is horrible to see that those 165 had developed further cancer, it is still statistically-speaking not a great many. It does suggest that Femara (or other AI) is very effective over the ten years frame for those who have got to five years without recurrence. But even for those who were not taking it, 91% still had no recurrence.

I found this very reassuring.  Even if you decide you've had enough after five years, there's still a very good chance that you will be fine for another five. Of course there's no knowing whether or not you will be in the group who DO develop recurrences: we need a study of that group to see if there is anything specific to them. For instance, does the number of affected lymph nodes play a clear part in predicting who will or won't be in the 10%? Does the use of chemo of one sort or another make a significant difference?

What we really need is much better statistics on what happens to those who go off Letrozole before the first five yeas is up. And one statistic I really want to find: how many who have surgery, radiation and Letrozole (or Tamoxifen) do in fact get to the five years with no recurrence?  If anyone has come across research reports specifically on that point, could you put the references up? 

Reference: The research was published online on June 5, 2016 by the New England Journal of Medicine and presented at the 2016 American Society of Clinical Oncology Annual Meeting on June 6, 2016:

• Read “Extending Aromatase-Inhibitor Adjuvant Therapy to 10 Years,” in the New England Journal of Medicine
• Read the abstract of “Patient-reported outcomes from MA.17R: A randomized trial of extending adjuvant letrozole for 5 years after completing an initial 5 years of aromatase inhibitor therapy alone or preceded by tamoxifen in postmenopausal women with early-stage breast cancer.” presented at the ASCO Annual Meeting

I don't know if this will make any real difference to my thinking about staying on Letrozole. Obviously the continuing effects on mood, bones, cholesterol etc. need to be taken into account. But it's heartening to think even if one goes off it after five years there is still a good chance you'll see another five. 

Cheers to all, hope you have a great Saturday in your various places and time-zones,

Annski.