Melanoma Diagnosis Without Biopsy
Overview
Alternatives to photographic surveillance in the diagnosis of melanoma are increasingly used in dermatology practice. Traditional surveillance is done in place of photographic surveillance in the diagnosis of melanoma.
This retrospective study featured melanomas which were diagnosed by three different dermatologists who have had private practice of over seven years.
Patients involved in this study went through a full skin exam using dermoscopy. Suspicious lesions were cut out and taken for biopsy.
Serial digital dermoscopic imaging (SDDI) and total body photography (TBP) were not utilized in the study. Records were kept of the patient’s demographic information, location of melanoma, subtype and thickness of melanoma, technique used in biopsy and diagnosis of keratinocyte cancer during the same visit.
In situ to invasive type melanoma ratio was calculated as the primary endpoint. Risk factors for melanoma were appropriately recorded for randomly selected patients who were 69 in number.
In a total of 579 hospital visits, 492 patients were given a diagnosis of 615 melanomas. Of this, 505 (82%) of the melanomas were in situ. 4.6:1 was the in situ to invasive ratio.
In situ melanomas were either lentiginous/ lentigo maligna (43.3%), or superficial spreading melanomas (41.6%).
85.5% of the invasive melanomas had a <0.8mm Breslow thickness, 9.1% had a 0.8-1 mm Breslow thickness and 5.5% had a >1 mm Breslow thickness.
Invasive melanomas were either lentigo maligna melanoma (24.3%), or superficial spreading melanomas (59.5%).
Shave procedures were used to diagnose 48.4% of melanomas. In the presence of known risk factors, 43% of patients had a previous melanoma history while 25% were termed as very high risk.
Biopsy was used to diagnose keratinocyte carcinoma at 26.1% of hospital visits. Studies which utilized SDDI and TBP gave reports of 0.59:1 to 2.27:1 as the in situ to invasive ratio.
High in situ to invasive ratios were observed with traditional melanoma surveillance associated with biopsy of suspicious lesions. Whereas, lower in situ to invasive ratios were seen in studies which utilized photographic surveillance of melanoma.
Introduction
Melanoma
Melanoma is cancer originating from the skin cells, particularly the melanocytes. The melanocytes are skin cells responsible for producing melanin, which is a skin pigment that determines a person’s complexion. The more melanin a person possesses, the darker the shade of the person’s skin, while the less melanin a person possesses, the lighter the shade of the person’s skin.
Melanomas are seen to be caused by exposure to ultraviolet radiation. Other factors that have been linked to melanomas include a family history of melanomas, having pale skin, presence of multiple moles on the skin etc.
Detecting melanoma early is aimed at reducing mortality and morbidity from the condition.
Traditional Melanoma Surveillance
Traditional methods of melanoma surveillance comprise a thorough skin exam via dermoscopy, loupe magnification and biopsy of suspicious skin lesions.
Photographic Surveillance of Melanoma
Photographic techniques like SDDI and TBP have been demonstrated to enhance the detection of melanoma, and also reduce the need for non-malignant excisions.
In addition to TBP, 3D imaging techniques have been developed that combine TBP with dermoscopic imaging.
Various studies carried out on TBP and SDDI surveillance techniques in recent times did not make use of the traditional surveillance method as a control group to give a comparison between the two techniques. None of these studies have also reported an improvement in survival.
From two published systematic reviews on TBP in melanoma diagnosis, Ji-Xiu et al. reported that the ability to estimate the extra benefits of TBP beyond the possible reduction in the number needed to biopsy (NNB) is precluded by the lack of controlled studies.
Hornung et al. also came to a conclusion that a greater number of in situ lesions and melanomas which had lower Breslow thickness were identified by TBP compared to the other groups.
Early melanoma excision before its invasiveness proffers the best chance for cure with a low rate of morbidity and at a lower cost. The in situ to invasive lesion ratio and the proportion of melanomas which are high risk ( >1 mm Breslow thickness) were used to measure the outcome of studies which employed photographic surveillance.
Studies which utilized TBP and SDDI demonstrated a 0.58:1 to 2.17:1 in situ to invasive lesion ratio with about 8.2% high risk melanomas having >1 mm Breslow thickness.
Methods
A retrospective study was carried out in Queensland over the space of 6 years from 1st of January 2012 to 31st of December 2018 to assess the histopathological diagnosis of melanoma by three different dermatologists in their private practice.
Every patient included in this study went through a full skin exam using dermoscopy and loupe magnification.
Suspicious lesions were cut out and taken for biopsy.
Photographic surveillance methods; total body photography (TBP) and serial digital dermoscopic imaging (SDDI) were not utilized.
Records of the patient’s demographic information, pathological melanoma subtype, Breslow thickness, location of melanoma, biopsy technique used and presence of other skin cancers seen at biopsy were taken.
69 patients who were randomized documented their risk factors for melanoma and last time a skin examination was carried out.
Statistical Analysis
Results from this study were largely descriptive and reported in percentages or numbers for variables which are categorical, standard deviation (SD) or mean for variables that are continuous and distributed normally, and inter quartile range (IQR) or median for variables that are continuous and not distributed normally.
Results
In 579 dermatology clinic visits, 615 diagnoses of melanoma were given to 492 patients.
Patients included in this study had a mean age of 63 (with a standard deviation of 13) at first visit. Most of these patients (55.7%) were males.
Most (83.7%) patients had just one melanoma during the study period, 12.2% of patients had two melanomas, while 4% of patients had three or more melanomas during the study period.
98 patients (19.9%) were seen to have a minimum of one invasive skin melanoma.
An in situ to invasive lesion ratio of 4.59:1 were seen in 615 melanomas. 18% (110) of the melanomas were invasive while 82% (505) of the melanomas were in situ.
Out of the 505 in situ melanomas, 41.6% (210) of them were superficial spreading melanomas (SSM) and 43.4% (219) of them were lentiginous type or lentigo maligna.
Out of the 110 invasive melanomas, 1.8% (2) of them were desmoplastic melanomas, 2.7% (3) of them were nodular melanomas, 24.3% (27) of them were lentigo maligna melanoma, while 59.5% (66) were superficial spreading melanomas.
85.5% (94) of the invasive melanomas had a <0.8 mm Breslow thickness, 9.1% (10) melanomas had a Breslow thickness of 0.8-1 mm, and 5.5% (6) melanomas had a Breslow thickness of >1 mm.
0.98% of all melanomas encountered in this study had a Breslow thickness >1 mm. Of these melanomas with >1 mm Breslow thickness, two were superficial spreading melanomas, two were lentigo maligna melanomas (LMM) while two were desmoplastic melanomas.
Procedures for diagnosis were grouped into shave excision or partial biopsy and elliptical excision.
52.3% (264 out of 505) of the in situ melanomas were diagnosed using elliptical excision.
52.7% (58 out of 110) of invasive melanomas were diagnosed using the shave excision.
Following diagnosis, two (0.3%) melanomas out of 615 were revised upwards on the basis of their depth of invasion. The two melanomas were diagnosed using a shave biopsy procedure.
The first melanoma, which was a desmoplastic melanoma, was upgraded to stage II from stage I disease.
The second melanoma, which was an amelanotic melanoma, was upgraded to stage I from stage 0 disease.
Melanomas was seen more frequently on the upper limb, the shoulder and the trunk.
Discussion
Surveillance of melanoma is aimed at reducing morbidity and mortality associated with melanoma.
In ideal situations, all analyses on the surveillance of melanoma would estimate the survival outcomes. This however, needs extensive data collection over a prolonged period of time, and as such is rarely achieved.
Many recent studies of SDDI and TBP have measured efficacy of the technique by using the number of melanomas seen, and the in situ to invasive ratios.
In situ melanomas are relatively benign and pose a negligible threat to a patient’s life.
In the study, 681 invasive melanomas with Breslow thickness of <0.76 mm were recorded to cause metastatic disease in 4.8% of the patients after follow-up for a mean duration of 3-6 years.
Whiteman demonstrated that thin melanomas with Breslow thickness of <1 mm made up 68% of all melanomas, and 23% of deaths in Queensland. This goes on to emphasize the need for early diagnosis of melanoma.
This study demonstrated a lower in situ to invasive melanoma ratio compared to those seen in several other studies which utilized TBP and SDDI.
Conclusion
Based on reports obtained from this study, it is seen that there were higher in situ to invasive ratios and lesser thick invasive melanomas using traditional surveillance by full skin exam and biopsy of suspicious lesions compared to TBP and SDDI.
Delay of melanoma excision due to photographic surveillance has a risk of the melanoma advancing from a low to high risk group.
The safety comparison between TBP and SDDI and traditional melanoma surveillance is not clear, and can only be obtained by conducting a prospective, controlled and randomized trial. Parameters such as patient mortality, welfare and cost effectiveness should be measured.
However, to date, there is no proven survival benefit of using TBP and SDDI for melanoma surveillance.
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