The Importance of Early Detection of Melanoma, Physician and Self-Examination

Important factors in early diagnosis of melanoma

In order for the clinician to make a clinical diagnosis of a possible melanoma, he/she must have a high index of suspicion for melanoma and a thorough knowledge of:

• ▪

  the clinical features of early melanomas ( Chapter 24 )

• ▪

  the clinical features of common pigmented lesions that must be differentiated from melanoma

• ▪

  the characteristics and clinical features of variants of clinically atypical melanocytic nevi (i.e. dysplastic nevi) which may be more commonly seen in association with a higher risk for and/or together with melanoma ( Chapters 22 and 23 )

• ▪

  other factors that increase the risk for a patient developing melanoma: e.g. personal and/or family history of melanoma, history of other non-melanoma skin cancer, presence of dysplastic nevi, presence of many (>100) melanocytic nevi, intermittent sun exposure and sunburn history, history of tanning-booth exposure, especially in childhood/adolescence, red/blonde hair, light eyes, fair complexion, freckling, etc ( Chapters 5 and 6 ).

Clinical characteristics of early melanoma

In 1985, recognizing the critical need to educate physicians and the lay public to recognize melanoma in its early clinical presentation, our group at New York University devised the ABCD acronym ( A symmetry, B order irregularity, C olor variegation, D iameter >6 mm).

That study demonstrated that most early melanomas demonstrate the following features:

• ▪

  A symmetry – they generally cannot be easily divided in half and have one half look like the other ( Fig. 25.1 ).

  

• ▪

  B order irregularity – the borders of most early melanomas are irregularly shaped ( Fig. 25.2 ).

  

• ▪

  C olor variability – most early melanomas have a play in color ranging from subtle nuances of tans and browns, to areas of black, and, more rarely, red, white (regression) and blue (deeper pigment) ( Fig. 25.3 ). Keep in mind, most amelanotic melanomas will lack the play in color usually seen in pigmented melanomas. Sometimes, however, there may be some subtle pigmentation within the lesion which helps the observer in making a diagnosis.

  

• ▪

  D iameter – most early melanomas when they are clinically readily identified are >6 mm in diameter ( Fig. 25.4 ).

  

It is important to remember that all melanomas have a microscopic origin of one or more neoplastic melanocytes. For this reason, there is a stage in the early evolution of melanoma where one or more of the ABCD criteria may be lacking. The most common missing criterion will be the D, in that a few melanomas will have diameters 6 mm or less. Therefore, a good clue to an otherwise atypical pigmented lesion is remembering that malignant neoplasms change over time. Even in a smaller lesion, a change in diameter over time in the presence of other clinically atypical features should arouse the observer's index of suspicion.

The ABCD criteria were intended as a simple tool that could be implemented in daily life, a mnemonic ‘as easy as ABC’, to alert both the layperson and healthcare professionals to the clinical features of early melanoma. Based on our experience evaluating patients in the Melanoma Cooperative Group at New York University School of Medicine, we found that asymmetry, border irregularity, and color variegation were consistently associated with lesion diameter greater than 6 mm in early melanoma lesions. These observations led to the addition of D to the A, B and C criteria. Recent studies have reconfirmed that this diameter guideline of larger than 6 mm remains a useful parameter for clinical diagnosis.

The ABCDs were intended to help describe a subset of melanomas, namely early, thin tumors that might otherwise be confused with benign pigmented lesions. Therefore, both elevated and ulcerated lesions were excluded in the initial analysis because we sought to elucidate features of early melanoma. Pigmented skin lesions that were ulcerated without a history of antecedent trauma would have already been highly suspicious for advanced melanoma and would have required biopsy regardless of other features. Also, it should be emphasized that the criteria were developed to assist non-dermatologists in differentiating common moles from cancer and were not meant to provide a comprehensive template for the recognition of all melanomas.

The ABCD criteria have subsequently been verified in multiple studies documenting their diagnostic accuracy in clinical practice. The sensitivity and specificity of these criteria vary when used singly or in combination: sensitivity ranges from 57% to 90% and specificity from 59% to 90%. Barnhill et al. investigated interobserver variability and reported moderate but statistically significant agreement in most clinical features, including irregular borders and multiple colors, among four physician evaluators, and interrater reliability and objectivity for these criteria has been demonstrated by others. The combination of reliable sensitivity and specificity in addition to adequate interobserver concordance in the application of the ABCD criteria supports the ongoing utility of this screening instrument in clinical medicine.

The importance of lesion evolution as a cardinal feature of cutaneous melanoma is also well supported. The need to recognize lesion change in our acronym was met by our revising the ABCDs through the addition of ‘E’ for ‘ E volving’. This substantially enhanced the ability of physicians and laypersons to recognize melanomas at earlier stages. ‘E’ for Evolving is especially important for the diagnosis of nodular melanomas, which frequently present as smaller lesions that are at more advanced stages (i.e. thicker tumors) where early recognition is even more critical. The ABCDE is a simple, succinct, and memorable tool, which has been demonstrated to effectively educate the public, the non-dermatologist as well as the dermatology medical community about the key features of melanoma including lesion change.

These now well-known parameters of Asymmetry, Border irregularity, Color variegation, Diameter greater than 6 mm and Evolving have been used worldwide by groups such as the American Cancer Society, American Academy of Dermatology, and others, and have been featured in the lay press to provide simple parameters for evaluation and identification of pigmented lesions that may need to be further examined. It should be noted that not all melanomas have all five ABCDE features. It is the combination of features (e.g. ABC, A+C, and the like) that render cutaneous lesions most suspicious for early melanoma.

Other melanoma early diagnosis paradigms have been developed to enhance early diagnosis. The most recognized of these is the Glasgow seven-point checklist that includes three major criteria (change in size, shape, color) and four minor criteria (sensory change, diameter of 7 mm or greater, inflammation, crusting or bleeding). The Glasgow checklist has been less widely adopted than the ABCDE criteria possibly due to its greater complexity. The ‘ugly duckling’ sign is another clinical approach, in which a pigmented lesion that ‘looks different than all of its neighbors’ may be suspicious for melanoma. This sign has been shown to be sensitive for melanoma detection, even for non-dermatologists.

The clinically diagnostic features of early malignant melanoma are relatively similar regardless of anatomic site, despite current hypotheses that melanoma from different body sites may have different etiologies.

The clinician must keep in mind that while the clinical features of early melanoma to be described are generally present in most lesions, there are exceptions that need to be recognized.

The early clinical diagnosis of melanoma has its basis not only in the clinical appearance of the lesion (physical examination), but also in the history and symptomatology. Change in a pre-existing melanocytic lesion or the development of a new pigmented lesion later in life (after the age of 40) are also important features which should alert the patient to seek medical care, and the physician to use his or her skills and ancillary technologies to rule out the possibility of a melanoma. Other clinically suspicious signs seen in pigmented lesions that are suggestive for melanoma are illustrated in Table 25.2 .