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The Society of Surgical Oncology's "Five Things Physicians and Patients Should Question" contribution to the recommendations for avoiding unnecessary medical tests, treatments, and procedures advise against routine sentinel lymph node biopsy (SLNB) in clinically node-negative women age 70 or older with early-stage hormone receptor positive, HER2-negative invasive breast cancer. The recommendation is based on clinical trial data showing no effect on overall survival. Despite this, however, approximately 80% of such patients still undergo the procedure, researchers reported.

For the study, Christina Minami, MD, and colleagues interviewed surgical, medical, and radiation breast oncologists throughout North America to find out why the recommendation against SLNB in these patients so often remains unfollowed. The results showed that oncologists believed the decision was more complex than clear-cut, affected by patient comorbidities, age, disease factors, and preferences.

"Although patients' physiologic age and life expectancy were also important decisional factors, almost all participants assessed these subjectively despite knowing that validated tools existed," Minami's group wrote in the abstract presented at the . "Most surgeons perceived the data backing the Choosing Wisely recommendation as weak, although knowledge of specific supporting studies was low. While all participants agreed that SLNB omission does not affect survival, several radiation oncologists expressed anxiety about resultant increased regional recurrence risk."

"While surgeons are aware of the Choosing Wisely recommendation, high SLNB rates in patients eligible for omission may be driven by perceptions of the quality of the supporting data and differing ideas regarding appropriate candidacy for omission," the researchers concluded.

In the following interview, Minami, a breast surgeon at Brigham and Women's Hospital and Harvard Medical School in Boston, discussed the team's findings in more detail.

One interesting finding was the extent to which the sentinel node biopsy decision was subjective for many oncologists. Did this surprise you?

Minami: This wasn't particularly surprising to us; applying trial data to clinical practice is often not as black and white as it may seem, and often, the clinical conversations to omit sentinel lymph node biopsy in this population can be quite nuanced. Many of the factors that the subjects mentioned in their interviews are points that we discuss in our own tumor boards or case conferences.

The doctors you interviewed reported patient preference as a significant factor affecting this decision. In your opinion, to what extent should patient preference play a role here?

Minami: This particular decision can be seen as preference-sensitive given that the overall survival is the same with or without an SLNB, but there is a slight difference in regional recurrence. However, the extent to which preference should play may differ on a case-by-case basis -- for instance, the risk/benefit ratio of SLNB to reduce the small regional recurrence risk could be different in a healthy 75-year-old with a long life expectancy with a larger, higher-grade tumor than a frail 75-year-old with limited life expectancy and a smaller, low-grade tumor.

We're past the age of paternalism in medicine, but what is abundantly clear is that we need to strive for very clear communication and provide guidance to our patients in decisions such as these.

Another of your findings was that physician knowledge of the clinical trials supporting the Choosing Wisely recommendation was low. Why do you think that was?

Minami: One of the fascinating aspects of practicing breast oncology is the velocity at which the literature and practice changes. But that velocity, along with physicians' heavy clinical load, can make it difficult for physicians to stay abreast with all of the current literature.

It can be especially difficult for more general practitioners -- e.g., general surgeons who have to try to stay up to date on literature touching on all general surgery practices, including breast surgery -- to keep their knowledge current, but that can even hold true of specialists at academic centers.

Can you briefly tell us about one of these clinical trials?

Minami: The clinical trial most often cited in the U.S. in support of this practice is the which was actually designed to examine the difference in outcomes in women 70 years and older with clinical T1N0 hormone receptor-positive disease on adjuvant tamoxifen who were randomized to post-lumpectomy radiation versus no radiation.

However, axillary surgery was discouraged in this trial, and 60% of subjects did not undergo axillary surgery. In those women who did not undergo axillary surgery, there was no difference in survival between the two arms, but there was a small (3%) difference in regional recurrence.

Finally, your study also mentions that omitting SLNB had downstream effects on treatment decisions. Can you tell us about this?

Minami: Although the decision to do an SLNB may be seen as one made by the surgeon -- often, before a patient has even seen a medical or radiation oncologist -- the medical and radiation oncologists we interviewed stated that the availability of the pathologic nodal status could change their treatment decision-making. For instance, the SLNB was omitted by the surgeon, but the medical oncologist may feel as if this information is crucial to deciding whether or not to pursue chemotherapy; in these cases, some oncologists said they might request the patient be taken back to the OR, or, alternatively, they would send an Oncotype DX test on the tumor to help them make up their mind.

Similarly, radiation oncologists, without the SLNB information, said they would do more imaging after surgery to try to evaluate whether a patient's lymph nodes appear suspicious or would not offer a patient partial-breast irradiation as an option.

This is thus a decision that can affect all subspecialties involved in a patient's care, and surgeons need to be aware of the possible ramifications of their decision-making.

Read the study here.