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Five-Millimeter Margins Suitable for Low-Risk Melanoma Excisions

– Larger margins may be preferable in higher-risk cases, researchers note


Patients with melanoma in situ (MIS) whose lesions were surgically excised using 5-mm margins experienced almost no cancer recurrence, a recent study in found.

The single-center study affirmed the effectiveness of more conservative margin sizes in lower-risk patients and body sites, although researchers acknowledged that riskier cases often require larger margin sizes.

A total of 351 MIS lesions were identified for the study; each eligible case included a documented 5-mm excisional margin and more than five years of site-specific follow-up.

Ultimately, 348 (99.1%) of the included lesions did not recur; there was local recurrence but no metastasis with the other three lesions (0.9%).

The study was led by a team of Australian dermatologists and researchers. The following paper excerpts have been edited for length and clarity.

What issues led to this investigation?

Incidence of melanoma has risen globally over the past three decades. This includes a 9.5% annual increase in Australia in the diagnosis of MIS.

Traditionally, the recommended margin size for MIS excision has been 5-mm. However, there has been uncertainty regarding the optimal excision margin for MIS, with guidelines ranging between 5-10 mm. In addition, studies have suggested that up to 18 mm may be required for MIS in some cases.

The current study sought to further examine the utility of 5-mm margins for excision of small MIS on low-risk sites.

What did the investigators discover?

Researchers found a low rate of recurrence among the 289 patients with MIS whose data were included in the analysis.

Most of the lesions included in the investigation were small; 274 lesions (78.1%) were less than 10 mm long and 312 (88.9%) were less than 10 mm wide.

What might these findings mean for dermatologists?

Recent literature has suggested that substantially wider excisional margins than 5 mm may be required for larger lesions and lesions in higher-risk areas like the head or neck. Nevertheless, the authors of this study concluded that a conservative 5-mm margin is likely to be suitable for smaller-sized lesions on lower-risk body sites.

What are the report's bottom-line messages?

The study demonstrated a 0.9% recurrence rate achieved with a conservative 5-mm excisional margin. Researchers concluded that using a 5-millimeter excisional margin for MIS lesions of smaller size (<10 mm) may reduce morbidity and cost associated with treatment without compromising outcomes.

The current literature suggests that substantially wider excision margins may be required for larger lesions and lesions in high-risk areas like the head and neck. Therefore, the current study findings may not generalize to these.

No study author disclosed any relevant financial relationship with industry.

Primary Source

JAMA Dermatology

Source Reference:

AAD Publications Corner

AAD Publications Corner