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The jury is still out on whether skin cancer screening saves lives
Some say physicians should be screening despite a lack of published recommendations; others await hard evidence.
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In February, the U.S. Preventive Services Task Force — a panel of experts that reviews evidence of efficacy and makes recommendations based on its findings — published an update stating that there is insufficient evidence available to recommend for or against skin cancer screening.
Allan Halpern, MD, chief of the dermatology service at Memorial Sloan-Kettering Cancer Center, said the USPSTF may be right in not formally recommending screening in the general population. However, “there is every reason, intuitively, to think that melanoma screening should be as effective, if not more effective, than any other type of cancer screening since melanoma is something that happens right on the surface of the skin.
“You can see [melanomas] very early, and there’s essentially no risk to the actual screening itself, which is a visual exam. The resulting biopsies are literally skin deep,” Halpern told HemOnc Today.
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Photo courtesy of Memorial Sloan-Kettering Cancer Center |
However, to date, no randomized controlled trials have been conducted on the efficacy of skin cancer screening. Therefore, no data are available to demonstrate the effectiveness of early detection or the benefits on morbidity and mortality. According to the task force, this lack of evidence prevents the calculation of the benefits of screening in the general population.
Some experts said these data may never become available. According to Daniel G. Federman, MD, professor of medicine at Yale University School of Medicine, the large number of patients needed for such a study and the difficulty associated with controlling for skin examinations may prevent a sufficiently large study from being conducted in the United States.
“If I had my druthers, I would hope that well-done studies could answer the question [of whether screening for skin cancer saves lives], but I’m not hopeful that it will ever be done,” Federman said.
HemOnc Today spoke with several experts in the fields of dermatology, epidemiology and internal medicine to determine whether physicians should perform full-body skin examinations despite a lack of data and the USPSTF’s ambiguity on the exam.
Lack of data
More than 1 million new skin cancer cases are diagnosed in the United States each year, according to the American Academy of Dermatology. The detection and treatment of skin cancer, specifically melanoma, before it spreads to lymph nodes affords patients a 99% five-year survival rate. However, the USPSTF found no new evidence to positively prove that screening with whole-body examination in asymptomatic people, either by primary care physicians or self-examination, reduces morbidity and mortality from skin cancer.
One study included in its review, conducted by Marianne Berwick, PhD, MPH, professor and chief in the division of epidemiology at the University of New Mexico, aimed to determine whether skin self-examination was associated with a decrease in lethal melanoma.
The study included 1,199 people with newly diagnosed cutaneous melanoma (n=650) or no disease (n=549). Participants were interviewed regarding skin self-examination. Fifteen percent of participants reported practicing skin self-examination, which was associated with a reduced risk for melanoma incidence (OR=0.66; 95% CI, 0.44-0.99). According to the data, skin self-examination may reduce the risk for advanced disease among patients with melanoma (OR=0.58; 95% CI, 0.31-1.11). However, the researchers noted that further data were needed to confirm the latter finding.
“The reason a [large, randomized] trial has not been conducted is that it is very expensive, and the mortality for melanoma in the United States is about 8,000 to 9,000 per year, which is a lot,” Berwick told HemOnc Today. “Cervical cancer has less mortality, and the amount of money that gets spent on that is amazing. So it’s not bad to do a randomized study, but it will cost $40 million to $50 million. When you start looking at cost-benefit ratio, it’s not clear that it’s going to make a difference.”
Cost may prevent large trials from being conducted, but some experts said the USPSTF’s reliance on this type of trial to provide sufficient evidence may be impractical, especially for a noninvasive intervention such as skin cancer screening.
“It’s important to think about applying standards appropriate to the screening intervention you’re evaluating,” said
Martin A. Weinstock, MD, PhD, professor of dermatology at Brown Medical School and chief of dermatology at the VA Medical Center in Providence, R.I.
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According to Weinstock, full-body skin exam is not as severe as colonoscopy or pap smear; therefore, “the standard of evidence should not be as exacting in order to justify it.”
Until data are available
Despite current recommendations, or lack thereof, some experts acknowledge full-body skin cancer screening as a simple, practical way to reduce skin cancer incidence and mortality. In her time as an attending physician at The University of Texas M.D. Anderson Cancer Center, Ana Mercedes Ciurea, MD, had such a large number of melanomas diagnosed during regular physical exams in patients with no skin complaints that she started a database to track the incidence of melanoma and the types of lesions detected.
“I’m detecting very thin melanomas,” she said. “I hope that I’ll be able to come up with good results because of the patient population that I see compared with an outside practice.”
Based on her findings thus far, Ciurea is in favor of full-body skin examination, and so are some of her colleagues. According to Alan Geller, MPH, RN, senior research scientist and deputy director of the division of public health practice at Harvard School of Public Health, screenings should be conducted, at the very least, in patients at risk for skin cancer.
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People with at least one known risk factor — including alot of moles, atypical moles, family history of skin cancer and multiple sun burns — should definitely be screened by their physician, Geller said. According to data from a retrospective study published in the Archives of Dermatology in August, more melanomas were detected after dermatologist-initiated full-body skin examination compared with exams that stemmed from patient complaints.
The retrospective, analytical case series included 126 patients treated for melanoma at a private dermatology practice; 51 incidences were invasive and 75 were in situ. More than half of all melanomas found (56.3%) were detected by dermatologists and not part of the presenting complaint. Dermatologists found 60% of all melanomas in situ detected. In addition, dermatologists found thinner lesions compared with those detected by patients (0.33 mm vs. 0.55 mm). Increasing melanoma depth was associated with patient detection (OR=2.39), and dermatologist detection was associated with thinner melanomas (OR=0.42).
These data demonstrate a positive association between dermatologist-conducted full-body skin examinations and disease diagnosis, but not all patients see dermatologists; often, PCPs are a patient’s only doctor. According to some experts, this may be problematic due to the inexperience of PCPs in detecting suspicious skin lesions.
Preparing PCPs for diagnosis
In 1999 in the Archives of Family Medicine, Federman and colleagues published a literature review that demonstrated that non-dermatologists did not perform as well as dermatologists when presented with color slides, transparencies or patients with lesions.
Eight studies were included in the review. Federman and colleagues reported that 93% of skin diseases were correctly diagnosed by dermatologists compared with 52% diagnosed by other MDs. In addition, family medicine physicians correctly diagnosed 70% of skin diseases compared with 52% correctly diagnosed by internal medicine physicians.
“Our group and others have shown that non-dermatologists’ acumen with respect to diagnosis and treatment of skin disease is not perfect, and there is room for improvement,” Federman said. “By examining people for skin cancer — if they do — they may miss some cancers or over refer non-lesions to dermatologists, which could worry the patient and potentially drive up the cost of health care.”
This concern is shared by most experts in the field, who recognize the need for additional training in dermatology during and after medical school (see sidebar). Currently, Weinstock, Geller and Halpern are working to determine the best possible training program for melanoma screening among PCPs. The study is funded by the Melanoma Research Alliance.
Given that there are not enough dermatologists to screen the entire population, were that the recommendation, it would be a bonus to have more PCPs capable of skin cancer screening, Halpern said.
“What this study is really designed to do is to formally develop a curriculum that would be both effective and acceptable to the primary care physician community because we recognize that they themselves are under enormous time pressure, both in terms of finding the time to take such a curriculum, as well as actually implementing skin cancer screening in their practices,” he said.
Other steps to reduce mortality
At minimum, most experts recommend screening patients at high-risk for skin cancer. Without formal guidelines or recommendations, one easy way to incorporate screening into current practice would be for physicians to look at the skin while listening to the lungs, Geller said. If PCPs spot atypical skin lesions, they should then refer the patient to a dermatologist.
“All these things can and should happen in the absence of formal screening guidelines,” he said. “If we’re talking about what is good optimal practice for a physician, they should be identifying signs of early disease. If we think of that in terms of cancer, the only cancer which can be detected by clinicians is melanoma.”
Educating patients about melanoma and conveying the importance of skin self-examination may also help reduce mortality rates from skin cancer. Currently, patients find most of the melanomas diagnosed, Halpern said, adding that they are getting better at self skin examination, but can only improve with education from their physician. Family members of patients with melanoma should also be educated about the disease and their risk for developing skin cancer.
“Hopefully most medical oncologists are aware of the importance of life-long melanoma surveillance in melanoma patients because of their known risk for additional primary melanomas,” Halpern said. “But because it is such a teachable moment, using the point of diagnosis of metastatic disease or melanoma to have family members screened is critical.”
Halpern does not recommend genetic testing of family members of patients with melanoma, but instead simple screening for the disease and associated risk factors such as atypical moles.
“All clinicians should always advise patients on prevention and early detection,” Weinstock said. “Particularly for physicians, the early detection is most important because patients generally look to clinicians for advice on early detection of cancer.” – by Stacey L. Adams
For more information:
- Berwick M. Arch Dermatol. 2006;142:1485-1486.
- Berwick M. J Natl Cancer Inst. 1996;88:17-23.
- Chen SC. Arch Dermatol. 2001;137:1627-1634.
- Federman D. Arch Dermatol. 2009;145:926-927.
- Federman D. Arch Fam Med. 1999;8:170-172.
- Skin Cancer Fact Sheet. American Academy of Dermatology website. http://www.aad.org