Home Medizin Neue NCCN-Melanom-Richtlinien erfassen sich entwickelnde Best Practices

Neue NCCN-Melanom-Richtlinien erfassen sich entwickelnde Best Practices

von NFI Redaktion

In San Diego, the National Comprehensive Cancer Network (NCCN) has issued new guidelines for cutaneous melanoma, establishing some new practice standards that expand on the American Academy of Dermatology’s (AAD) detailed recommendations from 2016 to 2019.

According to Dr. Susan M. Swetter, Professor of Dermatology and Director of the Pigmented Lesion and Melanoma Program, the new NCCN recommendations are based on evolving science underlying the guidelines, reflecting the latest consensus efforts on defining best practices at Stanford University in California.

Swetter led the committee that developed the latest NCCN guidelines, released on February 12. She also led the working group that developed the 2019 AAD recommendations. The differences between the two primarily reflect evolving evidence and expert opinions over time.

The next AAD guidelines are over a year away

The AAD guidelines are seldom developed and can take years. The next AAD guidelines for cutaneous melanoma are not expected until late 2025 or 2026, Swetter said at the American Academy of Dermatology’s annual meeting on March 8. In contrast, the NCCN guidelines for cutaneous melanoma are frequently revised. The last iteration was released just a year ago.

Many changes in the 2024 NCCN guidelines are more incremental improvements than a radical departure from previous practices. For example, regarding shave biopsies, a new recommendation suggests that any remaining pigment or tumors found at the base of a shave procedure, whether for tumor removal or biopsy, should lead to a deeper punch or elliptical biopsy.

The additional biopsy „should be performed immediately and submitted to the pathologist in a separate container,“ said Swetter.

Furthermore, the biopsy should include a note to the pathologist indicating that the shave sample was transected. She added that the Breslow thickness (the measurement of the depth of the melanoma from the top of the granular layer to the deepest point of the tumor) can accompany each of the two tissue samples submitted to the pathologist.

This update, like most NCCN guidelines, is a Category 2A recommendation. Category 1 recommendations indicate a high level of evidence, such as a multicenter randomized trial. A 2A recommendation is based on non-definitive evidence, but represents a near-unanimous (≥ 85% agreement) expert consensus.

Consensus above 50% is generally required

The NCCN committee, which regularly issues guidelines for cutaneous melanoma, consists of a rotating group of interdisciplinary melanoma specialists. Typically, more than 30 academic institutions nationwide are represented in the group, including patient representatives. Generally, no comment or recommendation is made if the committee cannot achieve at least a majority (≥ 50%) on a particular topic.

Overall, most guidelines, including those issued by the NCCN and AAD, agree, except for the extent of the time delay providing different evidence to consider. The reason to stay current on NCCN recommendations, according to Swetter, is that updates are more frequent, and she noted that they are available for free once a user registers on the NCCN website.

It is important to note that guidelines not only show what further steps can be taken to improve diagnostic accuracy or outcomes, but also what practices can be abandoned to improve the risk-benefit ratio. For example, surgical margins for primary melanomas are becoming smaller as evidence suggests larger margins increase morbidity without improving outcomes.

While Swetter acknowledged that „we still have not identified the narrowest and most effective margins for cutaneous melanomas,“ she cited studies suggesting that margins of 2 cm seem to be sufficient even for advanced T3 and T4 tumors. Prior to the 1970s, margins of 5 cm or more were common.

There are still many unanswered questions regarding optimal margins, but the 2023 NCCN guidelines already call for surgical margins of at least 1 cm and no more than 2 cm for large invasive melanomas when measured clinically around the primary tumor. Swetter said that even smaller margins could be considered „to account for function and/or anatomical location.“

Best Margins for MIS Undefined

As of now, there are no randomized studies determining surgical margins or depth for many melanoma subtypes, including melanoma in situ (MIS). These are the kinds of data that change guidelines once available.

There is a long list of procedures that are commonly performed but for which there are no specific NCCN or other organization guidelines. Numerous examples were presented during the AAD guidelines symposium where Swetter spoke. One example was the diagnosis of cutaneous melanoma at the bedside using non-invasive tests.

Caroline C. Kim, MD, Director of the Melanoma and Pigmented Lesion Program at Tufts University in Boston, described the 2-gene molecular test for assessing a suspected melanoma, stating that this tool based on the presence of the LINC00158 gene and the preferentially expressed antigen in melanoma (PRAME) is only limitedly useful as an aid in making a melanoma diagnosis. However, she said it has a fairly good reliability to rule out melanoma and thus provides the basis to avoid or delay further diagnostic steps such as a biopsy.

Kim stated that the skin biopsy, as stipulated in the guidelines, is still the gold standard, but there are numerous studies indicating that patients who test negative for both LINC00158 and PRAME have a low risk of melanoma. „A double negative result is not 100% effective, but it is high,“ she said, citing several examples where she used the test for patient monitoring instead of invasive tests.

According to Kim, this test is gaining popularity. She cited several surveys indicating increasing clinician use. However, she referred to it as a complementary approach that should be considered within the guidelines. It is an example of an approach that is not yet standard practice but can be helpful when used correctly, she noted.

Swetter and Kim report no relevant financial relationships.

Ted Bosworth is a medical journalist based in New York City.

Related Posts

Adblock Detected

Please support us by disabling your AdBlocker extension from your browsers for our website.