Screening and patient education for acral melanoma
Frequently missed or misdiagnosed, acral melanoma are more common in patients with darker skin tones (Issue #233, 1,700 words, 8 minutes)
People with darker skin types are less likely to develop melanoma, but they are more likely to develop acral melanoma than White individuals. Dr. Joël Claveau said in a presentation at the 10th annual Skin Spectrum Summit on Oct. 5, 2024, that screening for this type of cancer is essential.
Dr. Claveau is a dermatologist who specializes in diagnosing and treating melanoma and skin cancers. He is an associate professor in the Laval University Department of Medicine. He has been the director of the Melanoma and Skin Cancer Clinic at Le Centre Hospitalier, Hôtel-Dieu de Québec, since 1996.
Because patients with darker skin types are more likely to develop acral lentiginous melanoma than White patients, it is essential that examinations of these patients include the mucous membranes, hands, feet, and nails, he said. For palms and soles, the “ABCDEs of melanoma”—asymmetry, border irregularity, colour variation, diameter, and evolution—can be applied to examination, but nails require a different approach. Physicians should not hesitate to biopsy suspected nail melanoma. Dermoscopy is also a valuable tool for diagnosing acral melanoma.
Physicians should know patients often don't realize they have an acral melanoma, said Dr. Claveau. Melanomas that are hidden, such as between toes, often escape detection by patients. He recommended encouraging patients with dark skin to include their feet in self-examinations. Over time, acral melanomas will lose their pigment and may come to resemble warts. If the lesions are misidentified as warts, patients may undergo cryotherapy, which can worsen and spread acral melanoma.
Patients with thick acral melanomas often have a history of visiting an ulcer clinic and not being correctly diagnosed for years, said Dr. Claveau. By the time the melanoma is diagnosed, the cancer has often metastasized to the lymph nodes or legs. Ulcers should be biopsied if they do not heal normally.
Bottom line: Patients with dark skin are more likely than White patients to develop acral melanoma. These patients may not know how or where to check for signs of acral melanoma. Physicians should include the mucous membranes, hands, feet, and nails in their examinations for these patients and also provide education on how to self-examine. Older acral melanomas may be mistaken for warts or non-cancerous ulcers.
From the literature on melanoma in skin of colour
Shades of evidence: A review of skin colour reporting in melanoma-related randomized controlled trials
Researchers examined the rate of skin colour reporting in randomized controlled trials involving melanoma in the top 10 highest dermatology journals by impact factor over the past four decades.
Investigators characterized studies as positive for reporting skin of colour (SOC) if the demographic data in the results or methods sections included any of the following terms: race, ethnicity, skin of colour, Fitzpatrick scale, sunburn tendency, phototype, skin type, or skin tone.
Out of 76 studies initially identified, only 49 articles met the inclusion criteria. Of these 49 articles, only 24 recorded skin colour data from their demographics (49%). Subgroup analysis showed no statistically significant difference in the rate of reporting between studies grouped by decade (p=0.779) or by study location (p=0.763).
The authors write that the small number of randomized controlled trials related to melanoma in major dermatology journals that included skin of colour in their results has a negative impact on the understanding of this potentially devastating disease.
The risk of ultraviolet exposure for melanoma in Fitzpatrick skin types I-IV: A 20-year systematic review with meta-analysis for sunburns
This study was conducted to determine whether there had been a change in the risk of ultraviolet (UV) exposure with the development of melanoma in Fitzpatrick skin types I-IV based on more recent data over the past 20 years.
Investigators performed a systematic review from Jan. 2002 to Dec. 2021, analyzing UV exposure and melanoma risk in Fitzpatrick type I-IV individuals. Of 19,852 studies, 26 met the inclusion criteria. The data spanned subjects from national and multinational cohorts (United States, Europe, Australia, Asia, and South America).
Twenty studies (77%, 20/26) identified a significant association between UV exposure and melanoma incidence, and sunburn was the most commonly assessed risk factor.
The sunburn studies encompassed 3,417 melanoma cases and found positive significant odds ratios (OR [95% CI]) in 11 out of 13 studies, ranging from 1.23 [1.01-1.49] to 8.48 [4.35-16.54]. Pooled analysis of the risk of melanoma with sunburn history found an unadjusted odds ratio of 1.66 [1.40-1.97] and an adjusted odds ratio of 1.23 [1.04-1.46]. Cumulative sun exposure, measured as the number of hours of sun exposure or calculated UV flux, was the second most common risk factor, encompassing 913 melanomas with positive significant ORs ranging from 1.1 [1.0-1.2] to 5.2 [2.1-12.5]. For other forms of UV exposure, a majority of studies showed an association with UV index (6/9), outdoor leisure activity (3/3) and left-sided laterality (1/1).
The authors conclude that UV exposure should continue to be considered a modifiable risk factor for melanoma in individuals with fairer skin.
Clinical performance of a non-invasive melanoma rule-out test across Fitzpatrick skin types
The authors of this study aimed to assess the performance of a non-invasive rule-out melanoma test across all Fitzpatrick skin types, focusing on negative predictive value in skin types IV to VI.
They explain the rule-out test assesses gene expression of LINC00518 and PRAME and is intended to help augment the detection of melanoma at an early stage while reducing the number of biopsies performed for benign pigmented lesions that simulate melanoma. However, participant cohorts in prior validation studies mainly consisted of samples from individuals with skin types I, II, or III.
Investigators compared test performance metrics for patients with skin types I to III (n=4,152) and IV to VI (n=130) across 73 U.S. clinical practice sites using biopsy results and follow-up information compiled through the DermTech Melanoma Test Registry Protocol. They also calculated performance metrics for a cohort limited to lesions with at least six months of follow-up or biopsy results.
In the full cohort, sensitivity was 0.9429 (66/70), specificity was 0.9086 (3,709/4,082), positive predictive value was 0.1503 (66/439), and negative predictive value was 0.9989 (3709/3713) for skin types I to III. For skin types IV to VI, sensitivity was 1.0 (3/3), specificity was 0.9449 (120/127), positive predictive value was 0.3 (3/10), and negative predictive value was 1.0 (120/120). Three of three melanomas (0.55 mm, 0.40 mm, and melanoma in situ in non–sun-exposed areas on the trunk) in the IV to VI group diagnosed by histopathology were correctly identified as positive with the test. The 95% confidence intervals for the differences in sensitivity, specificity, negative predictive value, and positive predictive value between the two groups included zero, indicating no significant difference in any of the performance metrics.
The subgroup analyses limited to subjects with either a biopsy result or at least six months of follow-up after testing confirmed the results observed in the full cohort.
PODCAST: Skin Cancer Concerns for People of Colour
In a podcast from Weill Cornell Medicine in New York, dermatologist Dr. Andrew Alexis discusses skin cancer prevention and considerations for patients of colour. He shares which ethnicities are more at risk, what skin cancer warning signs are more prevalent in skin of colour and the precautions he recommends to patients of colour.
At the intersection of skin and society
CBC News reports that a new exhibit highlighting the histories of Indigenous and Black people in Treaty One territory will open at the Winnipeg Art Gallery-Qaumajuq in February.
The new exhibit's hope "is for people to be in this room to learn about themselves because we [Indigenous and Black folks] are not a monolith—none of our groups are," said Elliott Walsh, one of two co-curators of the exhibit, in an interview with the news outlet.
Walsh, also known as Nestor Wynrush, is a multidisciplinary artist from Winnipeg with Trinibagonian origins.
Making art "reflective of ourselves is super important," said Walsh.
"Black people have been in Manitoba for well over 100 years, yet our representation [in gallery spaces] is so small."
Among the exhibit pieces that speak to Black history in Winnipeg is a photography collection on loan from the Manitoba Museum to the gallery.
The photographs, taken between 1900 and the 1960s in Winnipeg, document the Menelik Lodge, an organization founded by a Winnipeg union of sleeping car porters to support the Black community with fundraising, education and social activities.
While the WAG-Qaumajuq is home to the largest collection of Inuit art in the world, its permanent collection of more than 28,000 pieces includes fewer than 10 created by Black artists and just 293 by First Nations and Métis artists, according to Katryna Barske, the gallery's public relations officer.
The gallery has selected some of the "well-represented" work in its permanent collection for deaccessioning—the formal process of removing work from a collection—in an effort to diversify its collection. The pieces are being auctioned off, with the proceeds going toward endowment funds to purchase art from underrepresented groups, said Barske.
Walsh said when the opportunity came for him to co-curate the new exhibit, which he describes as a collaborative effort with the artists involved, he was initially reluctant but thought, "Why not help tell a few stories?"
The exhibit will feature about 25 artworks from seven Black artists and six Indigenous artists worldwide. Visitors can expect an immersive experience, with each art piece accompanied by audio descriptions.
Threads of Kin and Belonging has its opening event on Feb. 7 and opens to the public the next day. It runs until Sept. 30.
This week
Feb. 4 is Rosa Parks Day in the U.S.
Feb. 4 is International Day of Human Fraternity
The first full week of February is National Burn Awareness Week in the U.S.
Something to think about in the week ahead . . .
—Ellen Glasgow, U.S. novelist, author of In This Our Life (1873–1945)
Next week
As part of a presentation at the 2024 Indigenous Skin Spectrum Summit in Toronto, Montreal-based dermatologist Dr. Carolyn Jack discusses some challenges in managing atopic dermatitis in remote communities and communicating effectively with Indigenous patients.
Register now for the first Global Indigenous Skin Spectrum Summit in Montreal
Skin Spectrum Weekly readers are invited to register for the first Indigenous Skin Spectrum Global Summit, which will be held in Montreal on April 5, 2025.
The summit will allow attendees to learn more about the unique dermatologic challenges facing Indigenous populations worldwide. Experts worldwide will provide insights on how physicians can support equitable health for these populations.
Summit chair Dr. Rachel Asiniwasis (Regina) leads a world-renowned faculty that includes Dr. Rachel Pugh (Australia), Dr. Carsten Sauer Mikkelson (Denmark), Dr. Monique Mackenzie (New Zealand), Dr. Anna Chacon (Florida), Dr. Dana Slape (Australia), Dr. Carolyn Jack (Montreal), and other thought leaders.
More details on the Global Summit will appear in future editions of Skin Spectrum Weekly.
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