Original Contribution
Preoperative Measurement of Thickness of Cutaneous Melanoma Using High-Resolution 20 MHz Ultrasound Imaging: A Monocenter Prospective Study and Systematic Review of the Literature

https://doi.org/10.1016/j.ultrasmedbio.2009.03.018Get rights and content

Abstract

Histologic measurement of the thickness of melanoma is a major prognostic factor and governs the size of the surgical excision (1cm for melanomas less than 1 mm thick, 2 cm for melanomas thicker than 2 mm and 3 cm beyond 4 mm). To determine whether high-resolution ultrasound can be used to predict surgical margins and, thus, to operate on patients in a single procedure avoiding further re-excision, we performed a systematic review of studies published from January 1987 to June 2007 and a prospective study. The systematic review selected 14 studies comparing histologic and ultrasound measurements and showing correlation coefficients generally greater than 0.9. Data available from 7 of the 14 studies (total 869 patients) showed predictive values of adequate margins in at least 72% of lesions using preoperative measurement of ultrasound thickness. The prospective study included 31 patients referred with a primary melanoma from March 2005 to March 2007. Ultrasound measurement of thickness was possible except for thin melanomas (<0.4 mm) in areas with marked photoaging, in the plantar zone, and in the case of very thick melanomas exceeding the explored depth (7.6 mm). The average thickness was 1.96 mm measured by ultrasound (SD: 2.15) and 1.95 mm by histology (SD: 2.62) and the Bland and Altman graph showed moderate agreement between ultrasound and histology. Limits of agreement were estimated at –1.4 and +1.8, corresponding to relative limits of agreement of –40 to +80%. Ultrasound predicted appropriate margins (1, 2 or 3 cm wide according to sonometric thickness) in 26 of the 31 subjects (84%, 95% CI 66–95). Preoperative high-resolution ultrasound is a noninvasive examination that can help in choosing appropriate surgical margins and should reduce the need of partial or excisional biopsy before surgery, and the need for further re-excision. (E-mail: [email protected])

Introduction

The maximum thickness of a melanoma is a major factor prognostic of metastatic dissemination and governs the size of surgical margins. The National Institutes of Health (NIH) consensus recommends a 5 mm margin for all in situ melanomas but this can be inadequate in a large percentage of cases, especially lesions occurring on the head and neck or hands and feet (Cook 2003). According to both French and British Consensus reports (Négrier et al. 2005; Roberts et al. 2002), a margin of 0.5 cm is necessary for in situ melanomas except on the face and a margin of 1 cm is necessary for tumors of 1 mm thickness or less and for in situ melanomas on the face. Although the impact on overall survival has not been demonstrated, wider resections are recommended for melanomas thicker than 1 mm to decrease the risks of local recurrence (Lens et al. 2002). Thus, the recommended margins are 1 to 2 cm for tumors between 1.01 and 2 mm, 2 cm for tumors between 2.01 and 4 mm and 3 cm for tumors thicker than 4 mm (Négrier et al. 2005; Roberts et al. 2002). According to these recommendations, when a pigmented lesion is suspected of being a melanoma on clinical examination, excisional biopsy is usually recommended with a margin of 2–3 mm. If the histologic examination confirms the diagnosis of melanoma, surgical removal is then carried out with margins depending on the maximum thickness measured with a micrometer on the histology slide (Breslow et al. 1970).

Noninvasive preoperative measurement of the maximum depth of a melanoma would be valuable, permitting choice of appropriate surgical margins. The traditional ultrasound equipment used for medical imaging operating at 7.5 MHz does not allow sufficiently precise measurement because the resolution is inadequate (Ulrich et al. 1999). As several studies have previously shown that ultrasound examination using 20 MHz allowed preoperative assessment of melanoma thickness that correlated well with histologic measurement (Hoffmann et al. 1992, 1999; Dummer et al., 1995, Tacke et al., 1995, Lassau et al., 1999, Serrone et al., 2002), our main aim was to check whether the use of 20 MHz ultrasound imaging made it possible to measure melanoma thickness in a sufficiently precise way to choose the appropriate surgical margin. We, therefore, carried out a prospective study comparing histologic and ultrasound thicknesses in a consecutive series of subjects referred with primary cutaneous melanoma not previously removed surgically and we performed a systematic review of the literature to analyze the causes of error and to determine the impact of preoperative ultrasound imaging on the surgical management of melanoma.

Section snippets

Subject selection criteria

From March 2005 to March 2007, all the patients referred to our department for suspected cutaneous melanoma that had not been removed surgically were offered cutaneous ultrasound imaging before surgical removal. The study was approved by the local ethics committee.

The inclusion criteria included suspected primary cutaneous melanoma following clinical and dermatoscopic examination or proven melanoma following partial biopsy providing the pathology diagnosis of in situ or invasive cutaneous

Subjects

Two hundred seven new patients with melanoma were referred in this 2-year period. However 176 lesions had been excised before referral. Thirty-one lesions from 31 subjects (10 women, 21 men, mean age 64 years, range 35–85 years) were included. Thirteen lesions were on the trunk, two on the upper limbs, eight on the lower limbs, seven on the face and one in the genital area. Two lesions from two subjects were excluded, corresponding to dysplastic nevus after histologic examination.

Ultrasound imaging

All 31 lesions

Discussion

The systematic review showed a strong correlation between sonometric and histometric thickness of melanoma lesions in the 14 studies selected. However, the methodology used was based on the calculation of the correlation coefficient. As previously reported (Tacke et al., 1995, Pellacani and Seidenari, 2003, Gambichler et al., 2007), we used the Bland and Altman graph, which is more appropriate to demonstrate agreement of measurements of tumor thickness with the two techniques. Despite a

Conclusion

High-resolution ultrasound imaging offers the advantage of real-time examination of the entire lesion in a few minutes to determine echoic appearance and maximum depth of a pigmented lesion and to help in the differential diagnosis between pigmented basal cell carcinoma or seborrheic keratosis and melanoma. However, it adds little to clinical examination to distinguish an atypical benign pigmented nevus from true melanoma. Ultrasound cannot replace biopsy when it is necessary and we emphasize

References (38)

  • J. Cook

    Surgical margins for resection of primary cutaneous melanoma

    Clin Dermatol

    (2003)
  • W. Dummer et al.

    Preoperative characterization of pigmented skin lesions by epiluminescence microscopy and high-frequency ultrasound

    Arch Dermatol

    (1995)
  • B.D. Fornage et al.

    Imaging of the skin with 20-MHz US

    Radiology

    (1993)
  • T. Gambichler et al.

    Preoperative ultrasonic assessment of thin melanocytic skin lesions using a 100-MHz ultrasound transducer: A comparative study

    Dermatol Surg

    (2007)
  • C.J. Gannon et al.

    Accuracy of lymphatic mapping and sentinel lymph node biopsy after previous wide local excision in patients with primary melanoma

    Cancer

    (2006)
  • G. Gassenmaier et al.

    Wertigkeit der hochauflösenden sonographie für die bestimmung des vertikalent beim malignen melanom der haut

    Hautarzt

    (1990)
  • K. Hoffmann et al.

    Stellenwert der 20-MHz-sonographie des malignen melanoms und pigmentierter läsionen in der routinediagnostik

    Ultraschall Med

    (1999)
  • K. Hoffmann et al.

    Malignant melanoma in 20-MHz B scan sonography

    Dermatology

    (1992)
  • S.S. Jejurikar et al.

    Immediate, optimal reconstruction of facial lentigo maligna and melanoma following total peripheral margin control

    Plast Reconstr Surg

    (2007)
  • Cited by (75)

    View all citing articles on Scopus
    View full text