by Shawn Allen, MD
Melanoma is by far the deadliest form of skin cancer (causing more than 75 percent of all skin cancer deaths) and a major public health concern. The American Cancer Society estimates that about 68,720 new melanomas will be diagnosed in the US during 2009, resulting in about 8,650 deaths, almost one per hour.1 The disease is currently the sixth most common cancer in the US and the number one cancer in young adults aged 25-29.2
Early detection of melanoma can significantly reduce both morbidity and mortality. The risk of dying from the disease, in fact, is directly related to the depth of the cancer, which is directly related to the amount of time it has been growing unnoticed. Hence, earlier detection leads to thinner cancers and saves lives. Fortunately, unlike most other cancers, skin cancers present on the skin and are most often readily visible to the patient and the examiner. Patient skin self-examination (SSE), physician-directed total-body skin exams (TBSE), and patient education are the keys to early detection.
Despite the obvious common sense conclusion that these strategies save lives, in February 2009 the United States Preventative Services Task Force (USPSTF) published a recommendation guideline stating that “current evidence is insufficient to assess the balance of benefits and harms of using a whole-body skin examination by a primary care clinician or patient skin self-examination for the early detection of cutaneous melanoma, basal cell cancer, or squamous cell skin cancer in the adult general population.”3 Although this statement assumes a fairly neutral position, it has unfortunately led to some inappropriate conclusions questioning the value of skin cancer screenings for the public.
Behind the Times
It is important to note that the USPSTF position is severely weakened by being based solely on a review of studies from 1999 to 2005, thereby omitting several important studies from the past four years, many clearly showing the benefits of SSE and TBSE.3
Although a large randomized case-controlled study evaluating skin cancer screening in the general population would help to show the benefits of TBSE, a study of this type may be too cumbersome to be a realistic option and is not currently available. It would be not just clinically naïve but unethical for clinicians to refrain from supporting TBSE, SSE and public skin cancer screenings until such a study is available. Fortunately, valuable research already exists demonstrating that SSE and TBSE can help to detect melanoma at earlier stages, reducing morbidity and mortality.
Patients Often Detect Their Own Melanomas
Clinical experience and clinical studies show that patients play an important role in detection of their own melanomas. Brady, et al prospectively evaluated 471 newly diagnosed melanoma patients between 1995 and 1998 and found that up to 57 percent were able to detect their own melanomas by SSE.4 We see similar findings in our clinics, as many patients present with a chief complaint of a changing or new mole that is subsequently diagnosed as melanoma. It is thus critical that we educate our patients and the public about SSE, which can be a first line of defense.
Other studies demonstrate that increased public awareness results in patients presenting with thinner self-detected melanomas. For example, in the largest population-based study of melanoma patients in Queensland, Australia, results showed that for patients performing SSE, melanomas had a more favorable depth distribution (i.e., thinner tumors) than melanomas detected incidentally.5 Another study showed that SSE performers are generally diagnosed with thinner melanomas than nonperformers (0.77 mm vs. 0.95 mm).6 Finally, SSE and the corresponding earlier detection of thinner melanomas have been reported to reduce mortality by as much as 63 percent.7
Patients Don’t Regularly Perform SSE
Although the data demonstrate that patient education and SSE lead to earlier diagnosis and decreased mortality, only a minority of at-risk individuals actually perform SSE. An Italian study showed that only 28.1 percent of patients who developed melanoma performed SSE regularly.8 Another study of 190 university students in the US found that only 33.2 percent had performed SSE, with only 5.8 percent of individuals checking their entire body.9 These are concerning statistics, especially considering that melanoma is being diagnosed in young adults at an alarming rate. As less than one third of our patients may be performing SSE, it is critical for early detection that TBSE be regularly performed by a highly trained physician in all patients at risk for melanoma.
Physicians Detect Melanomas Earlier
Multiple studies indicate that physicians are more likely to detect melanomas at a thinner stage compared with non-physicians. Carli, et al found that 80.6 percent of physician-detected melanomas were clinically thin (<0.75 mm), compared with 61.9 percent of melanomas detected by laypersons. Mean melanoma thickness was 0.68 mm in physician-detected melanomas vs. 0.90 mm in non-physician-detected melanomas.8 Further studies have shown an even more significant difference in thickness between physician-detected melanomas and those detected by patients (0.23 mm vs 0.9 mm).10 In addition, Swetter, et al found that melanomas discovered by a physician were thinner (median depth, 0.60 mm) than melanomas discovered by a patient’s spouse or partner (median depth, 0.98 mm) and much thinner than those found by patients themselves (median depth, 1.43 mm).11 (See Table 1 below.)6,10,11
Most recently, in a telephone survey of 3,762 eligible melanoma cases and 3,824 eligible controls, Aitken, et al found that whole-body clinical skin examination in the three years before diagnosis was associated with a 14 percent lower risk of being diagnosed with a thick melanoma (>.75 mm) than those who had not been examined. Patients’ risk was reduced by 7 percent of being diagnosed with a melanoma 0.76-1.49 mm, by 17 percent for melanomas 1.50-2.99 mm, and by 40 percent for melanomas ≥ 3 mm. This is perhaps the strongest evidence to date that whole-body clinical skin examination reduces the incidence of thick melanomas, and suggests that TBSE screening would significantly reduce melanoma mortality.12
The Lawrence Livermore Experiment
A study conducted on workers at the Lawrence Livermore Laboratory from 1984 to 1996 showed that a program combining education, SSE, and physician screening could be especially effective at reducing the thickness of detected melanomas.13 With an employee population ranging from 8,056 to 9,250 from year to year, the thickness and crude incidence of melanomas detected during three phases of increasing melanoma surveillance were studied: 1) a “preawareness” period, preceding any education about skin cancer; 2) an early awareness phase, with some initial education or forewarning about increased melanoma risk, and 3) a screening program phase, combining fuller education about skin cancer, encouragement to practice regular SSE, and directed TBSE screening. Employees practicing SSE who found a suggestive lesion, or employees who reported having 5 or more moles greater than or equal to 5 mm in diameter or a single mole greater than or equal to 18 mm in diameter, were offered a full-body screening exam.
The results were notable. Crude incidence of melanomas thicker than 0.75 mm decreased from 22.1 cases per 100,000 employees in the first phase to 15.13 cases in the second phase to only 4.62 cases in the third. Whereas the expected number of melanoma deaths according to the National Death Index during the screening phase was calculated to be 3.39, no eligible melanoma deaths occurred among Livermore employees during the screening period.
Impact of Earlier Detection
Thinner melanomas are at an earlier clinical stage, leading to less morbidity and mortality. According to the guidelines of the American Joint Committee on Cancer, tumor depth is one of the most important factors in staging. In fact, based on tumor thickness alone, a patient may be upstaged from stage 0 to stage 2B. While stage 0 melanomas have an average 5-year survival rate of 100 percent and stage 1A tumors 95 percent, 5-year survival for stage 2B drops to 63-67 percent and stage 4 decreases to 7-19 percent. Early detection of thinner melanomas and the corresponding lower chance of metastasis have a significant impact on both morbidity and mortality.
The 2009 National Comprehensive Cancer Network Guidelines in oncology recommend different management strategies for thinner melanomas than for thicker melanomas. The former require narrower margins, less extensive and expensive imaging studies, and fewer invasive procedures such as sentinel lymph node biopsies. Hence, melanomas detected earlier result in less morbidity and mortality as well as lower costs for the patient and/or third-party payers. Therefore, any efforts leading to earlier melanoma detection, such as SSE and TBSE, play a critical role in saving lives, minimizing surgical morbidity, and decreasing health care costs.
Screening for Melanoma Is Essential
Taken together, these studies show that SSE and TBSE provide the best opportunity for detecting melanoma at its earliest stages. Both are simple, straightforward techniques involving little expense compared to screening tests for other cancers. Highly trained dermatologists are ideally suited for performing TBSE, as they have the knowledge required to differentiate the varying signs and symptoms of different skin cancers and noncancerous lesions. TBSE also helps to pinpoint more clinically subtle melanomas such as amelanotic and desmoplastic types, which do not adhere to the usual ABCDE signs of melanoma and thus would probably be missed by patient self-examination. During a TBSE, a physician should be sure to look for unusual presentations of melanoma, and should examine areas that escape the patient’s field of view, including the scalp and soles of the feet. Patients’ visits for TBSE are also the ideal time to educate them about the signs and symptoms of melanoma and to train them in how to perform a thorough SSE with the aid of items such as handheld mirrors, hair combs and hair-dryers, and informational brochures.
Signs and Symptoms of Melanoma
Whether a skin examination is performed by a physician or a patient, the examiner must be aware of the cardinal features of melanoma. The mnemonic ABCDE (Asymmetry, Border irregularity, Color variation, Diameter >6 mm, Evolving) is useful in recognizing common features of a possible melanoma. Although the ABCD’s have been described since the 1980s, the more recently added “E” for evolving lesions is also important, because melanomas may be changing in other ways — e.g., becoming elevated, painful or ulcerated, itching, burning, or bleeding.
A good extra rule of thumb is that if a lesion is drawing attention to itself, the physician should pay attention; moles that look different than others on the body may be of concern, even if they don’t strictly display ABCDE signs. Some clinicians now refer to such out-of-place or unusual moles as “outliers” or “ugly ducklings.” For patients with moles “too numerous to count,” an overall initial scan looking for such outliers should help focus on any suspect lesions.
Educating patients about the ABCDE’s of melanoma and the “ugly duckling” sign — teaching them what to look for and how — can assist both the physician and the pa- tient in detecting a melanoma early in its development.
Who Should Screen for Melanoma
Dermatologists ideally should take the lead in screening for melanoma. A three- year residency with intense study in the evaluation and management of skin cancers and other skin diseases provides the necessary background training for a physician to become an expert in early detection. Although the USPSTF currently maintains there is not enough evidence to support TBSE by primary care physicians (PCPs), it is important to note that this group did not consider screenings by dermatologists in their analysis. Nonetheless, PCPs also must continue to play a role in examining their patients’ skin, because a well-trained PCP, as a front-line physician, can be extremely helpful in cases where a concerned patient presents for a TBSE. When the patient asks about a specific lesion, if there is any suspicion it may be a cancer, he or she can be referred to a highly trained dermatologist, assuming one is locally available.
Unfortunately, patients who present to a doctor’s office are often unaware of an existing melanoma on their skin. In the August 2009 issue of Archives of Dermatology, Kantor and Kantor showed that most melanomas detected in a general dermatology practice setting were found as a result of dermatologist-initiated TBSE, not directed by a specific patient complaint. Overall, 56.3 percent of melanomas were found by the dermatologist and were not part of the presenting complaint. The investigators also found that detection initiated by the dermatologist was significantly associated with thinner melanomas (<1.0mm).14
Again, this is strong evidence that TBSE by dermatologists leads to earlier detection of new melanomas.
Routine screening examinations and tests are currently recommended by the American Cancer Society (ACS) for breast, colon and rectal, cervical, uterine and prostate cancers. The ACS also advocates exams for thyroid, oral cavity, skin, lymph node, testicular, and ovarian cancers as a standard part of screening for people age 20 and older. However, the National Cancer Institute guidelines for periodic skin cancer examinations are inconsistent. Moreover, the recent USPSTF recommendation statement adheres to this lack of consensus, specifically with respect to TBSE by a PCP and SSE by patients. Despite this lack of official consensus, it is clear based on both clinical studies and common sense that TBSE and SSE play a critical role in early detection of melanoma, a potentially deadly skin cancer when discovered at later stages.
Finding a cancer early leads to better patient outcomes. For example, some forms of breast cancer, if found early, may respond to a tissue-sparing lumpectomy procedure with or without adjuvant radiation. This can be lifesaving with minimal morbidity, as opposed to what may result with later detection — spread to regional lymph nodes or distant organs, requiring radical mastectomies and extensive adjuvant therapy. Similarly, prostate cancer screenings can also lead to early detection of malignancies, some of which may need no intervention, depending on the Gleason score, the cancer type, and the patient’s age. These well-accepted cancer screenings are widely viewed as relatively simple, routinely performed, rather inexpensive, and of great value to the public. However, when compared to a TBSE, breast and prostate cancer screenings are far more invasive and expensive, and carry higher risks.
Unfortunately, the recent USPSTF position statement on TBSE and SSE has created some confusion. However, the latest medical literature together with common sense strongly supports physicians who perform TBSE and advise regular SSE for their patients. The USPSTF should consider reviewing the more current literature and revising their position in the near future.
Dr. Allen is the Director and Founder, Dermatology Specialists of Boulder, PC Assistant Clinical Professor, Department of Dermatology, University of Colorado School of Medicine.
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Published on November 17, 2011