Skin cancers

Distrust of evidence deters sentinel node biopsy for melanoma


Improving adherence to sentinel node (SN) biopsy guidelines in melanoma requires some breaking down of barriers between the various specialties involved, Australian research suggests.

While current guidelines [link here] recommend that SN biopsy be considered for all patients with melanoma thickness > 1.0 mm or 0.8–1.0 mm with high-risk pathological features, the procedure has been controversial.

According to a study published in Implementation Science Communications [link here], there was also evidence that rates of SN biopsy for melanoma in Australia have been sub-optimal.

“Given that appropriate treatment and management is increasingly dependent on accurate staging, it is important to understand why rates might be low,” the qualitative study said.

The study comprised semi-structured interviews with 25 clinicians or researchers and four consumer representatives. Most clinicians were dermatologists (41%), followed by GPs (17%), surgeons (17%) and medical oncologists (10%).

It found that the key influence on acceptance, adoption and adherence to guideline recommendations was the social and knowledge boundaries that exist between professional groups.

“Almost all key informants talked about how the at times heated and polarised discussion relating to key clinical trial data (Guideline Factors – Quality of Evidence) had impacted on attitudes and beliefs about SN biopsy, and ultimately on uptake of SN biopsy.”

“It was acknowledged that while this debate has at times seemed intense and potentially detrimental to improved patient outcomes, ultimately it has been a driving force in refining evidence and knowledge.”

The study indicated that dermatologists and GPs distrusted the evidence, instead perceiving SN biopsy as overpromoted.

“It’s a procedure that’s promoted strongly by the proceduralists who do it and the enthusiasm for the procedure exceeded the evidence. A lot of the literature was biased and full of spin that suggested a benefit to the surgery that wasn’t supported by the evidence,” a dermatologist said in the study.

“I think just the perception from outside of [the guidelines being chaired by a surgeon] is probably not favourable. So I think probably it would have been ideal to have declared that as a conflict and probably stepped aside from any discussions around sentinel node biopsy,” a second dermatologist said.

Evidence from the interviews was that dermatologists felt they were “being dealt out of melanoma management” and that there was a financial disincentive in referring patients to surgeons for a discussion of SN biopsy.

There was also a recognition that “clinical inertia” certainly existed and that current practice was still based on what clinicians had learnt as trainees.

“It was also suggested that clinicians who were not connected to multidisciplinary teams were more likely to hold out-of-date beliefs about the current role of SN biopsy in melanoma management,” the study said.

The study investigators, including clinicians and researchers from The Daffodil Centre and Melanoma Institute Australia, said that “seemingly entrenched opinions and behaviours” could shift suddenly.

“The introduction of effective adjuvant systemic therapy for the management of melanoma acted as a disruptor, rapidly overturning past hesitancies about the use of SN biopsy, rendering many of the old debates irrelevant and rapidly quickening the pace of uptake of SN biopsy.

“Importantly, medical oncologists acting as expert opinion leaders have played an important role in disrupting the social and knowledge boundaries between the professional groups and communities of practice in melanoma management by highlighting the potential benefits of adjuvant systemic therapy to patients with Stage III melanoma.”

They also noted that “the reluctance to accept and adopt the guidelines may have been in part because of the perception that they had been developed primarily by one group of clinicians (surgeons) yet applied to the clinical practice of several other groups of clinicians (dermatologists and primary care physicians).”

“Any intervention aimed at improving uptake or adherence to SN biopsy recommendations would benefit from a co-design approach to ensure appropriate engagement of key existing and emerging opinion leaders who are familiar with the evidence on which those recommendations are based,” they concluded.

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