Opinion Community Voice Breast Cancer

Benefit of Radiotherapy in Older Women with Early Stage Breast Cancer

Breast2For some older women with early stage, ER+ breast cancer, radiotherapy after lumpectomy may not be necessary. But some women 70 years or older may benefit, and it’s worth at least meeting a radiation oncologist for a consultation after breast-preserving surgery.

The CALGB 9343 trial randomized 636 women ≥ 70 with clinical stage T1-2 N0, ER+ breast cancer who underwent lumpectomy with negative margin to either tamoxifen and radiation or tamoxifen alone. At median of 12.6 years follow up, radiation was found to decrease the 10-year risk of local recurrence from 10% to 2%. However, radiation didn’t decrease the risk of death from breast cancer or subsequent mastectomy.

So why would a radiation oncologist give adjuvant radiotherapy for women above age 70 with early stage, ER+ breast cancer? Here are at least three reasons:

1. Not taking tamoxifen as planned. Women in the CALBG 9343 trial may have been more compliant with taking hormone therapy. Up to 50% of women in clinical practice don’t end up completing tamoxifen as recommended. It’s possible that contributes to a higher mastectomy rate outside of a clinical trial. A SEER analysis of >7,000 women who met CALBG 9343 criteria found that leaving out radiation had a significantly higher 10-year risk of subsequent mastectomy, 6.3% vs. 3.2%, regardless of grade. In this study, women didn’t benefit at age 75 or higher, with grade 1-2 histology and pathologically negative nodes (Figure 1).

2.  More aggressive features. There are other risk factors not addressed by CALGB 9343 and are independently associated with increased risk of recurrence. In two retrospective studies from the United Kingdom and the Netherlands, lymphovascular space invasion (LVSI) was identified as an independent prognostic factor for overall survival and disease free survival. Higher histologic grade also may be associated with worse overall survival.

3.  Personal preference. Some women opt for aggressive treatment for personal reasons. Many women want to do all they can to minimize the risk of their cancer recurring. Even with a balanced presentation of the risks and benefits of adding radiation to tamoxifen, some women will choose treatment to lessen anxiety related to recurrence risk by feeling they have done ‘everything I can.’

 

One way to individualize risk

M.D. Anderson developed a nomogram to predict 5- and 10- year mastectomy free survival. The nomogram includes age, race, tumor size, ER status, and nodal status (although the CALBG did not include women with positive nodes). For women who are uncertain and want more personalized risk assessment, this nomogram has been adapted as an online user-friendly tool available on their website.

Some older women with early stage, ER+/N0 breast cancer may still benefit from radiation. Counseling patients regarding the level of risk should be individualized to the patient’s known risk factors, life expectancy, compliance, and goals of care. That means seeing a radiation oncologist!

 

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  • Shane Dempsey

    4th reason: purely to reduce the risk of local recurrence rate – recurrent breast cancer in the elderly is not a nice outcome, and in the study reported RT will reduce local recurrence in 8 out of 100 women

  • Agree. The CALGB 9343 did demonstrate a statistically significant benfit in ipsilateral local recurrence. Some would argue that’s not a “good enough” reason to offer radiation to these women. But many women want to worry as little as possible about a recurrence, and would opt for radiation just for that purpose.

  • Simul Parikh

    Miriam – I liked the post. Nice work. I have another question, and maybe the data is out there. If you take the cost of Tam with and without RT, I wonder what the QALY value would be. I.e. What is the economic value of avoiding a local recurrence, even if it doesn’t improve survival? With changes upcoming, it seems important to know if this is cost-effective. Currently, the NCCN says that omitting RT is an option, but not the top option, and I think most clinicians lean that way. You’re right – we need to see them and help them with that decision.

    Finally, in these women, I offer the RT in the trial (50 Gy), no RT, and then the sweetener deal – hypofx with Canadian. Almost all choose that last option, like Goldilocks 🙂

  • Thanks, and thanks for your comment!

    I agree cost-effectiveness is an important consideration. A recent JNCI study in March 2014 reported cost-effectiveness for these women who met critera for CALGB critera; however the study was performed using SEER data.

    Do you offer hypofractionation to women with high grade histology? Some radiation oncologists don’t. The ASTRO guidelines hedges on this issue and the panel ultimately refrained from advising against it.

  • Simul Parikh

    Generally no, but the numbers against it were small in Canadian trial and ad hoc analysis. START trials didn’t show a difference

  • Richard Simcock

    Things just got more interesting….

    You may have seen that yesterday that the Lancet published the 5 year results of the PRIME 2 study.

    http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045%2814%2971221-5/abstract

    This study builds on previous ‘no radiotherapy’ studies by reducing the age for entry (to 65), increasing the T stage (to include tumours up to 3cm) and some Grade 3s (as long as no LVI). The study shows that local recurrences at 5 years ARE higher if you don’t have radiotherapy.

    They are higher – but they are not high.

    The excess local recurrence risk for radiotherapy avoidance in this group is approx 3%. Therefore the Numbers Needed to Treat (NNT) to avoid a breast recurrence at 5 years is about 33. In the UK where we give 15# of RT for adjuvant breast this translates to just short of 500 fractions to prevent one (surgically salvageable) breast recurrence. For those of you still delivering 25 fractions (why oh why??) it’s over a whopping 800 fractions.

    Imagine getting in your car and driving to a cancer centre, parking, checking in, waiting your turn, going in, being set up and treated and then going home. Now imagine doing this EVERY DAY for 2 and a half years and you have visualised the patient burden of preventing a SINGLE local recurrence (and that doesn’t include the work done by radiotherapy staff). You have not yet prevented one single death.

    It’s time to stop overtreating. What we do is good – that doesn’t mean it’s always good to do it.