While some research indicates women over 70 with early-stage breast cancer receive limited benefits from post-lumpectomy radiation, other studies demonstrate benefits for all patients, suggesting that radiation is an integral part of breast conservation therapy for women of all ages.
Radiation oncologist John Hayes, Jr., MS, MD, shares his views on the topic, including why the reduced risk of recurrence is clinically significant in this subgroup of patients, particularly as more targeted forms of treatment reduce the complications and inconvenience associated with radiation therapy.
Do you consider post-lumpectomy radiation to be optional for women over the age of 70?
As the CALGB, RTOG, ECOG intergroup randomized trial has demonstrated, it is not heresy to omit radiation in women older than 70 with certain small ER+ breast tumors when tamoxifen is administered for 5 years. However, I think it is necessary for these women to discuss the issues with a radiation oncologist. The preponderance of evidence over the years shows a benefit from radiation in breast conservation therapy.
What criteria do you use to determine which patients can safely omit radiation?
There is no measured way to determine who will benefit from radiation and who will not. A patient – after a discussion of pros and cons, costs, inconveniences and adverse effects of the adjuvant treatment – needs to feel empowered to make this decision for herself. That said, I would feel more comfortable in the omission of radiation in widely excised, small tumors or in women whose prospect of longevity, based on comorbid features, is not good.
While there are 11 randomized trials showing that all patients benefit from radiation following lumpectomy, other studies conclude it may not be necessary for certain patients over the age of 70. What are your thoughts on this conflicting data?
I really do not think that there is much in the way of a conflict. Even the intergroup trial mentioned shows a benefit of radiation therapy depending on how you look at the data. Even in this trial, physicians had to give disheartening news to only 2 women in the radiation arm and to 16 women in the no radiation arm, 6 of whom had mastectomies and 8 lumpectomies followed by radiation. Any recurrence is a very unsettling event for the individual involved, and losing a breast is psychologically traumatic to most women at any age. Obviously, the many women in the denominator of this study who did not have a breast recurrence must tolerate the treatment well.
One study notes a 6-7% reduction in local recurrence for patients who received tamoxifen and radiation compared to those who received tamoxifen alone. Even if this is not statistically significant, can this decrease still be considered clinically significant?
As long as an adjuvant treatment is relatively safe in terms of adverse effects, as this intergroup trial showed, then I think this decrease can still be considered to be clinically significant. If the adjuvant treatment becomes safer, less costly and more convenient, the argument for treatment becomes even stronger.
The same study examined women 70 years of age or older with early, ER positive breast cancer – but what about women over 70 with ER negative breast cancer? Do they benefit from post-lumpectomy radiation?
Local recurrence is a significant problem in this subgroup and these women are not going to benefit in the same way from hormone therapy, therefore, the importance of adjuvant radiation will be greater.
Does the availability of partial breast radiation with a device like SAVI – which minimizes radiation dose, treatment time and side effects – make it more viable to offer post-lumpectomy radiation to women over 70 in order to increase local control?
I believe that partial breast radiation is the right direction to go in for these women as long as it is done by a committed team that includes a breast surgeon, radiation oncologist, dosimetrist and physicist that are knowledgeable and trained in brachytherapy. I believe that time will show APBI to be less costly and more convenient than whole breast radiation in this cohort of favorable prognosis patients with better cosmesis and fewer adverse effects, especially breast pain and fibrosis as perceived by the patient.
The ultimate proof of a better paradigm will be obtained when we see an improvement in breast conservation rates. I believe that any new treatment is going to have hiccups along the way and a learning curve. The brachytherapy community as a whole has learned a lot from the experience with multi-catheter interstitial techniques as well as from the various single entry devices. Some of that experience has been about what not to do and has been learned by way of complications. I have not done APBI using external beam radiation based on innate fears of dose-volume effects. I like the dose control and uniformity of multi-catheter interstitial technique, however, it is more complicated to perform and breast surgeons seem to be put off by all the needles/catheters required to get good coverage. I am pleased with the ease of use of single entry devices vs. multi-catheter interstitial technique.
The SAVI device, in my opinion, has significant dose sculpting advantages over the multi-lumen balloon catheters. It is very common in my experience to have skin or chest wall in close proximity to the brachytherapy device, and I am able to shape the radiation dose much more to my liking with SAVI. In my experience so far, I am impressed with it based on patient tolerance of it in the breast, a paucity of inflammatory changes in the skin while in the breast and a lack of symptomatic seroma formation. As long as it proves to be as effective in preventing recurrences, it is the single-entry device most likely to work to my satisfaction in delivering the dose I want to administer.
Dr. Hayes is a board certified radiation oncologist at Gamma West Cancer Services in Salt Lake City, Utah. He has been performing brachytherapy procedures since 1988 and has performed over 2,000 implants.