Stage I-II melanoma: the value of metastatic work-up

Ultrasound, CT, MRI, or PET-CT for staging and re-staging of adults with cutaneous melanoma

BACKGROUND

Melanoma is one of the most aggressive forms of skin cancer, with the potential to metastasise to other parts of the body via the lymphatic system and the bloodstream. Melanoma accounts for a small percentage of skin cancer cases but is responsible for the majority of skin cancer deaths. Various imaging tests can be used with the aim of detecting metastatic spread of disease following a primary diagnosis of melanoma (primary staging) or on clinical suspicion of disease recurrence (re-staging). Accurate staging is crucial to ensuring that patients are directed to the most appropriate and effective treatment at different points on the clinical pathway. Establishing the comparative accuracy of ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET)-CT imaging for detection of nodal or distant metastases, or both, is critical to understanding if, how, and where on the pathway these tests might be used.

OBJECTIVES

Primary objectivesWe estimated accuracy separately according to the point in the clinical pathway at which imaging tests were used. Our objectives were:• to determine the diagnostic accuracy of ultrasound or PET-CT for detection of nodal metastases before sentinel lymph node biopsy in adults with confirmed cutaneous invasive melanoma; and• to determine the diagnostic accuracy of ultrasound, CT, MRI, or PET-CT for whole body imaging in adults with cutaneous invasive melanoma:○ for detection of any metastasis in adults with a primary diagnosis of melanoma (i.e. primary staging at presentation); and○ for detection of any metastasis in adults undergoing staging of recurrence of melanoma (i.e. re-staging prompted by findings on routine follow-up).We undertook separate analyses according to whether accuracy data were reported per patient or per lesion.Secondary objectivesWe sought to determine the diagnostic accuracy of ultrasound, CT, MRI, or PET-CT for whole body imaging (detection of any metastasis) in mixed or not clearly described populations of adults with cutaneous invasive melanoma.For study participants undergoing primary staging or re-staging (for possible recurrence), and for mixed or unclear populations, our objectives were:• to determine the diagnostic accuracy of ultrasound, CT, MRI, or PET-CT for detection of nodal metastases;• to determine the diagnostic accuracy of ultrasound, CT, MRI, or PET-CT for detection of distant metastases; and• to determine the diagnostic accuracy of ultrasound, CT, MRI, or PET-CT for detection of distant metastases according to metastatic site.

SEARCH METHODS

We undertook a comprehensive search of the following databases from inception up to August 2016: Cochrane Central Register of Controlled Trials; MEDLINE; Embase; CINAHL; CPCI; Zetoc; Science Citation Index; US National Institutes of Health Ongoing Trials Register; NIHR Clinical Research Network Portfolio Database; and the World Health Organization International Clinical Trials Registry Platform. We studied reference lists as well as published systematic review articles.

SELECTION CRITERIA

We included studies of any design that evaluated ultrasound (with or without the use of fine needle aspiration cytology (FNAC)), CT, MRI, or PET-CT for staging of cutaneous melanoma in adults, compared with a reference standard of histological confirmation or imaging with clinical follow-up of at least three months' duration. We excluded studies reporting multiple applications of the same test in more than 10% of study participants.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted all data using a standardised data extraction and quality assessment form (based on the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2)). We estimated accuracy using the bivariate hierarchical method to produce summary sensitivities and specificities with 95% confidence and prediction regions. We undertook analysis of studies allowing direct and indirect comparison between tests. We examined heterogeneity between studies by visually inspecting the forest plots of sensitivity and specificity and summary receiver operating characteristic (ROC) plots. Numbers of identified studies were insufficient to allow formal investigation of potential sources of heterogeneity.

MAIN RESULTS

We included a total of 39 publications reporting on 5204 study participants; 34 studies reporting data per patient included 4980 study participants with 1265 cases of metastatic disease, and seven studies reporting data per lesion included 417 study participants with 1846 potentially metastatic lesions, 1061 of which were confirmed metastases. The risk of bias was low or unclear for all domains apart from participant flow. Concerns regarding applicability of the evidence were high or unclear for almost all domains. Participant selection from mixed or not clearly defined populations and poorly described application and interpretation of index tests were particularly problematic.The accuracy of imaging for detection of regional nodal metastases before sentinel lymph node biopsy (SLNB) was evaluated in 18 studies. In 11 studies (2614 participants; 542 cases), the summary sensitivity of ultrasound alone was 35.4% (95% confidence interval (CI) 17.0% to 59.4%) and specificity was 93.9% (95% CI 86.1% to 97.5%). Combining pre-SLNB ultrasound with FNAC revealed summary sensitivity of 18.0% (95% CI 3.58% to 56.5%) and specificity of 99.8% (95% CI 99.1% to 99.9%) (1164 participants; 259 cases). Four studies demonstrated lower sensitivity (10.2%, 95% CI 4.31% to 22.3%) and specificity (96.5%,95% CI 87.1% to 99.1%) for PET-CT before SLNB (170 participants, 49 cases). When these data are translated to a hypothetical cohort of 1000 people eligible for SLNB, 237 of whom have nodal metastases (median prevalence), the combination of ultrasound with FNAC potentially allows 43 people with nodal metastases to be triaged directly to adjuvant therapy rather than having SLNB first, at a cost of two people with false positive results (who are incorrectly managed). Those with a false negative ultrasound will be identified on subsequent SLNB.Limited test accuracy data were available for whole body imaging via PET-CT for primary staging or re-staging for disease recurrence, and none evaluated MRI. Twenty-four studies evaluated whole body imaging. Six of these studies explored primary staging following a confirmed diagnosis of melanoma (492 participants), three evaluated re-staging of disease following some clinical indication of recurrence (589 participants), and 15 included mixed or not clearly described population groups comprising participants at a number of different points on the clinical pathway and at varying stages of disease (1265 participants). Results for whole body imaging could not be translated to a hypothetical cohort of people due to paucity of data.Most of the studies (6/9) of primary disease or re-staging of disease considered PET-CT, two in comparison to CT alone, and three studies examined the use of ultrasound. No eligible evaluations of MRI in these groups were identified. All studies used histological reference standards combined with follow-up, and two included FNAC for some participants. Observed accuracy for detection of any metastases for PET-CT was higher for re-staging of disease (summary sensitivity from two studies: 92.6%, 95% CI 85.3% to 96.4%; specificity: 89.7%, 95% CI 78.8% to 95.3%; 153 participants; 95 cases) compared to primary staging (sensitivities from individual studies ranged from 30% to 47% and specificities from 73% to 88%), and was more sensitive than CT alone in both population groups, but participant numbers were very small.No conclusions can be drawn regarding routine imaging of the brain via MRI or CT.

AUTHORS' CONCLUSIONS

Review authors found a disappointing lack of evidence on the accuracy of imaging in people with a diagnosis of melanoma at different points on the clinical pathway. Studies were small and often reported data according to the number of lesions rather than the number of study participants. Imaging with ultrasound combined with FNAC before SLNB may identify around one-fifth of those with nodal disease, but confidence intervals are wide and further work is needed to establish cost-effectiveness. Much of the evidence for whole body imaging for primary staging or re-staging of disease is focused on PET-CT, and comparative data with CT or MRI are lacking. Future studies should go beyond diagnostic accuracy and consider the effects of different imaging tests on disease management. The increasing availability of adjuvant therapies for people with melanoma at high risk of disease spread at presentation will have a considerable impact on imaging services, yet evidence for the relative diagnostic accuracy of available tests is limited.

Follow-up in patients with low-risk cutaneous melanoma: is it worth it?

Follow-up examinations in melanoma aim to detect recurrences or secondary melanomas in an early phase of development. Follow-up guidelines that have been developed in many European countries, the USA and Australia show varying recommendations and are controversial, especially in patients with melanomas of 1.0 mm tumor thickness or less. This group contains 50-70% of all melanoma patients and the majority is unlikely to develop recurrences. On the other hand, within this entity, subgroups at higher risk for recurrences can be defined who require a more intense follow-up. This article discusses recommendations for the frequency, duration and costs of follow-up in low-risk melanoma patients. Patient preferences are addressed and a risk-adapted follow-up scheme is proposed.

Preoperative imaging for early-stage cutaneous melanoma: predictors, usage, and utility at a single institution

BACKGROUND

Preoperative imaging for early-stage cutaneous melanoma is not recommended by current guidelines. Our goal was to investigate our institutional usage and utility.

METHODS

Patients with clinically node-negative cutaneous melanoma undergoing surgery with sentinel lymph node biopsy were identified retrospectively. Any melanoma-related imaging after diagnosis and before surgery was considered a staging study.

RESULTS

Five hundred fifteen studies were performed in 409 of 546 (75%) patients. Chest x-rays was performed in 70% and advanced imaging in 14% (computed tomography imaging, magnetic resonance imaging, ultrasound, and positron-emission computed tomography imaging). No metastatic lesions were identified. A Breslow thickness greater than 4 mm (odds ratio = 6.46 vs <1 mm; 95% confidence interval, 2.07 to 20.15) and male sex (odds ratio = 2.62 vs female; 95% confidence interval, 1.26 to 5.46) were associated with an increased likelihood of advanced imaging.

CONCLUSIONS

Preoperative imaging was performed in the majority of patients with node-negative melanoma, with 14% undergoing advanced studies. No metastatic lesions were identified, confirming the limited utility in this setting.

Is detection of melanoma metastasis during surveillance in an early phase of development associated with a survival benefit?

Surveillance schedules in patients with cutaneous melanoma (CM) aim to detect metastatic spread in an early phase of development. Few studies investigated whether detection in an early phase is associated with prolonged survival and whether the observed longer survival times are a mere consequence of detection at an earlier time point (lead time bias). This is a long-term survival analysis of 1969 patients with stage I-III CM documented during 1996-1998 in the frame of a prospective surveillance study. Development of metastatic spread was detected in 112 patients during this period and classified as early phase or advanced phase based on tumor load and operability. The impact of lead time bias on differences in survival probabilities was examined using different statistical approaches. Of 59 patients with metastases detected in an early phase of development, 64.4% died of CM, of 43 patients with advanced phase metastases 86% died (P=0.013). The 10-year overall survival probability was 42.6% for early and 25.6% for advanced phase metastases (P=0.012). This comparison remained significant after adjustment for sojourn time. Multivariate analysis identified detection of early phase metastases (P=0.022) and stage at primary diagnosis (P<0.0001) as independent prognostic factors. In conclusion, this long-term follow-up study showed a factual gain in survival time for the detection of metastasis in an early phase of development beyond lead time bias. The classification of metastasis detected in early and advanced phase may be used in future studies aiming to improve melanoma surveillance.

Costs of the detection of metastases and follow-up examinations in cutaneous melanoma

At present, no universally accepted recommendations exist for cutaneous melanoma follow-up. Various surveillance strategies, some associated with significant cost, others of uncertain value, are routinely used. This study aimed to evaluate of the costs incurred for varied surveillance strategies practiced in Europe and the USA. One thousand nine hundred and sixty-nine cutaneous melanoma patients with stage I-III disease attending the Department of Dermatology, University of Tuebingen for follow-up between 1996 and 1998 participated in the study. Routine surveillance consisted of cutaneous examination, lymph node and abdomen sonography, chest radiograph (CR) and blood tests. The costs incurred were based upon the 2004 German official scale for medical reimbursement and the 2004 Medicare fee reimbursement schedule (USA). The total charges were based on the number of recurrences detected per stage. Recurrences were detected in 1.5% of patients with stage I, 18.0% in stage II, and 68.6% in stage III. Physical examination was the most effective method, detecting 50.0% of recurrences. Lymph node sonography was effective in stage II-III, detecting 13.2% of recurrences; CR and abdominal sonography, detecting 4.5 and 3.4% of recurrences, were deemed beneficial in stage III. Blood tests detected 1.4% of recurrences and were deemed to be ineffective. Computed tomography scans were valuable in clarifying ambiguous findings and helping to detect 22.5% of recurrences (1.9% in stage I, 1.9% in stage II, and 18.6% in stage III). A risk-adapted surveillance strategy for stage I-II including thorough history, physical examination and lymph node sonography but omitting CR, blood work and abdomen sonography, seems appropriate and cost effective.

Imaging in cutaneous melanoma

Cutaneous melanoma (CM) is a common malignancy and imaging, particularly lymphoscintigraphy (LS), positron-emission tomography with 2-fluoro-2-deoxyglucose (FDG-PET), ultrasound, radiography computed tomography (CT) and magnetic resonance imaging have important roles in staging and restaging, surgical guidance, surveillance and assessment of recurrent disease. This review aims to summarize the available data regarding these and other imaging modalities in CM and provide the basis for subsequent formulation of guidelines regarding the use of imaging in CM. PubMed and Medline searches were performed and reference lists from publications were also searched. The published data were reviewed and tabulated. There is level I evidence supporting the use of LS and sentinel lymph node biopsy in nodal staging for CM. There is level III evidence demonstrating the superiority of ultrasound to palpation in the assessment of lymph nodes in CM. There is level IV evidence supporting FDG-PET in American Joint Committee on Cancer stage III/IV and recurrent CM and that FDG-PET/CT may be superior to FDG-PET. Level IV evidence also supports the use of CT in the same group of patients and the role of CT appears to be complementary to FDG-PET. Various imaging modalities, especially LS/sentinel lymph node biopsy and FDG-PET/CT, add incremental information in the management of CM and the various modalities have complementary roles depending on the clinical situation.

Imaging Studies in Patients with Melanoma

The incidence of malignant cutaneous melanoma is rising. Imaging studies represent a major component of the staging work-up and follow-up of melanoma patients and are used to facilitate preoperative planning and intraoperative management. Study benefits are not clear, and evidence does not support any particular protocol for their use. The National Comprehensive Cancer Network's updated guidelines for use of imaging studies in melanoma patients represent a consensus based on lower level evidence, including clinical experience. The utility of individual imaging studies in melanoma patients depends on disease stage. Chest radiography, CT, MRI, lymphoscintigraphy, ultrasonography, PET, and PET/CT have specific roles in patient evaluation. Clinicians must use available evidence to guide decisions regarding which imaging modalities are appropriate for a given indication.

Utility of Computed Tomography and Magnetic Resonance Imaging Staging Before Completion Lymphadenectomy in Patients With Sentinel Lymph Node–Positive Melanoma

Purpose

Although melanoma patients with regional nodal metastases are frequently imaged with computed tomography (CT) and magnetic resonance imaging (MRI) scans, the efficacy of routine radiologic staging in asymptomatic patients with microscopic nodal involvement has not been established. To determine the utility of this approach, we analyzed the incidence of synchronous distant metastases (SDM) detected by CT or MRI of the head, chest, and abdomen in a large group of patients with sentinel lymph node (SLN) –positive melanoma.

Patients and Methods

Positive SLNs were identified in 314 (16.2%) of the 1,934 melanoma patients who underwent sentinel lymphadenectomy at our institution from 1996 to 2003. Within 3 months of sentinel lymphadenectomy, 270 (86.0%) of the 314 SLN-positive patients were radiologically staged. To determine which prognostic factors were associated with SDM, associations between final staging outcomes and clinicopathologic variables, including SLN tumor burden, were analyzed.

Results

CT and/or MRI scans identified lesions that were suspicious for SDM in 23 (8.6%) of the 270 patients who underwent staging. In eight of these patients, further diagnostic studies determined that these abnormalities were benign. The remaining 15 suspicious lesions were percutaneously biopsied (10 negative and five positive), yielding a radiologically detectable SDM rate of 1.9%. Detection of SDM was associated with primary tumor thickness (P = .011), ulceration (P = .018), and SLN tumor burden (P = .018).

Conclusion

These data suggest that the vast majority of asymptomatic patients with a new diagnosis of microscopic SLN-positive melanoma do not harbor radiologically detectable SDM and can proceed to completion lymph node dissection without immediate CT or MRI staging.

Evaluation of staging chest radiographs and serum lactate dehydrogenase for localized melanoma

BACKGROUND

Radiographic and laboratory evaluations are often routinely used in the initial work-up for melanoma.

PURPOSE

To examine the yield of a chest radiograph and serum lactate dehydrogenase (LDH), in the work-up for newly diagnosed localized melanoma.

METHODS

Patients with a new diagnosis of localized invasive melanoma were entered into a prospective database. The status of the chest radiograph, LDH, and sentinel lymph node (SLN) was assessed.

RESULTS

Two-hundred-twenty-four patients were entered into the study and 210 had chest radiograph data for analysis. The true positive chest radiograph rate, defined as the percent of chest radiographs interpreted as "positive or equivocal possibly melanoma related" with subsequent confirmed melanoma metastases, was 0%. The false positive chest radiograph rate, defined as the percent of chest radiographs interpreted as "positive or equivocal possibly melanoma related" with melanoma metastases excluded based on previous or subsequent studies or other known medical conditions, was 7%. Ninety-six patients (melanoma> or =1 mm) had LDH results for analysis. Elevations in LDH were found in 15% and did not lead to detection of occult disease in any patients. Seventy-seven patients underwent SLN biopsy. A positive SLN did not correlate with abnormal chest radiograph or LDH.

CONCLUSION

Low yield, high rate of false-positive tests and lack of significant impact of early detection of metastases on survival argue that chest radiographs and serum lactate dehydrogenase should probably not be accepted into routine clinical practice in patients with clinically localized melanoma in the absence of data supporting their use.

Prospective evaluation of a follow-up schedule in cutaneous melanoma patients: recommendations for an effective follow-up strategy

PURPOSE

To prospectively examine and evaluate the results of follow-up procedures in a large cohort of cutaneous melanoma patients.

PATIENTS AND METHODS

This was a prospective study in 2,008 consecutive patients with stage I to IV cutaneous melanoma from 1996 to 1998 on the yield of stage-appropriate follow-up examinations according to the German guidelines. Documentation of patient and follow-up data comprised patient demography, primary tumor specifics, and any clinical and technical examinations performed. The detection of metastasis was classified as early or late, and the means of their detection and the resulting overall survival probabilities were examined.

RESULTS

A total of 3,800 clinical examinations and 12,398 imaging techniques were documented. Sixty-two second primary melanomas in 46 patients and 233 disease recurrences in 112 patients were detected during this time. In stage I to III disease, physical examination was responsible for the discovery of 50% of all recurrences. In the primary tumor stages, 21% of all recurrences were discovered by lymph node sonography, with the majority being classified as early detection. Forty-eight percent of the recurrences were classified as early detection, and these patients had a significant benefit of overall survival probability.

CONCLUSION

The results of our study suggest that an elaborated follow-up schedule in cutaneous melanoma is suitable for the early detection of second primary melanomas and early recurrences. The intensity of clinical and technical examinations can be reduced during follow-up of patients in the primary tumor stages and may be intensified in locoregional disease. Recommendations for an effective follow-up strategy are outlined.

A rational approach to the follow-up of melanoma patients

There are no generally accepted guidelines for the follow-up of cutaneous melanoma (CM), and there is an ongoing debate about the value of follow-up examinations. Some authors doubt whether early detection has any beneficial effect on patient survival and suggest that it may only prolong the patient's period of suffering from the knowledge of having metastasis. A systematic review of the literature on early detection and resection of CM metastasis shows the following picture: (1) In in-transit metastasis and in regional node metastasis, the tumour volume of the metastatic nodules at the time of diagnosis is prognostically significant. Either the number of nodes involved in regional metastasis or the diameter of the largest node showed prognostic impact in different studies. Therefore, early detection seems to affect the cure rate in this stage of disease. (2) In distant metastasis, surgical resection of all recognisable metastases prolongs survival. This is true as long as only one organ system is involved and particularly if complete resection of all metastases can be achieved. Therefore, early detection contributes to prolongation of survival. We performed a follow-up study in 2008 prospectively documented consecutive patients with stage I-III cutaneous melanoma who presented for follow-up examination at the Department of Dermatology of the University of Tübingen from August 1996 to August 1998. Stage-appropriate follow-up examinations were carried out according to the German Society of Dermatology guidelines. A total of 3,800 clinical examinations and 12,398 imaging techniques were documented: 62 second primary melanomas were detected in 46 patients and 233 disease recurrences in 112 patients during this time. Physical examination was responsible for the discovery of 50% of all recurrences, with the patient initially detecting the metastasis on self-examination in 17% of these cases. Technical examinations were responsible for the detection of the remaining 50%. In the primary tumour stages, 21% of all recurrences were discovered by lymph node sonography, the majority being classified as early detection. Among the recurrences, 48% were classified as early detection, and these patients had a significantly more favourable probability of recurrence-free survival than those with recurrences classified as late detection. The results of our study suggest that a follow-up schedule elaborated for cutaneous melanoma is suitable for the early detection of second primary melanomas and of early recurrences in approximately 5% of patients during a 2-year follow-up period.

Current concepts in the management of patients with melanoma

Melanoma is a significant health problem. Despite public education and free cancer screenings, the incidence and mortality of melanoma continues to rise; however, many currently diagnosed melanomas are thin lesions, suggesting that education and awareness is having an impact. In addition, there are still subsets of patients who need increased surveillance in order to increase their survival. Although large congenital nevi may be precursors of melanoma, small and medium congenital nevi have an insignificant risk for melanoma development. Large congenital nevi, which are axial in location, appear to be more likely to develop melanoma and are associated with melanocytosis and melanoma of the CNS, both of which portend a poor prognosis. Recently, the recommended margins of excision have become more conservative so that many of the surgical defects can be closed primarily. Lymphoscintigraphy and sentinel node biopsy have replaced elective node dissections, thus decreasing the morbidity associated with the surgical management of melanoma. Although controversy still exists as to whether or not sentinel lymph node biopsy alters a patient's prognosis, it has been shown to be a powerful prognostic indicator. Although most melanomas are managed by routine surgical excision, other modalities are sometimes employed. For example, cryosurgery or radiation therapy may be indicated in the frail, elderly individual with a large facial lentigo maligna. Mohs surgery is the treatment of choice for head and neck melanomas and those located in areas where maximum preservation of tissue is required and for desmoplastic and acral lentiginous melanomas. Much more work remains in the area of adjuvant therapy, chemotherapy, and immunotherapy. Dacarbazine remains the drug of choice in disseminated melanoma, but remissions are usually short lived. Interleukin and biochemotherapy has yielded good results but the percentage benefiting is small. Although high dose interferon increases disease-free and overall survival in some patients, it remains a controversial drug which is not easily tolerated. In the new staging system for melanoma, ulceration is second only to Breslow's thickness. In transit (satellite) lesions have also been included in this new system. The new system also recognizes that patients with only microscopic metastatic nodal disease fare better than patients with clinically enlarged metastatic nodes and that it is the number of nodes involved with metastases, not their size, that determines the patient's prognosis. Except for lesions <1mm thick, the Clark's level of invasion has been de-emphasized.

Primary staging and follow-up in melanoma patients--monocenter evaluation of methods, costs and patient survival

In a German cohort of 661 melanoma patients the performance, costs and survival benefits of staging methods (history and physical examination; chest X-ray; ultrasonography of the abdomen; high resolution sonography of the peripheral lymph nodes) were assessed at initial staging and during follow-up of stage I/II+III disease. At initial staging, 74% (23 out of 31) of synchronous metastases were first detected by physical examination followed by sonography of the lymph nodes revealing 16% (5 out of 31). Other imaging methods were less efficient (Chest X-ray: one out of 31; sonography of abdomen: two out of 31). Nearly 24% of all 127 first recurrences and 18% of 73 second recurrences developed in patients not participating in the follow-up programme. In follow-up patients detection of first or second recurrence were attributed to history and physical examination on a routine visit in 47 and 52% recurrences, respectively, and to routine imaging procedures in 21 and 17% of cases, respectively. Lymph node sonography was the most successful technical staging procedure indicating 13% of first relapses, but comprised 24% of total costs of follow-up in stage I/II. Routine imaging comprised nearly 50% of total costs for follow-up in stage I/II and in stage III. The mode of detecting a relapse ('patient vs. doctor-diagnosed' or 'symptomatic vs asymptomatic') did not significantly influence patients overall survival. Taken together, imaging procedures for routine follow-up in stage I/II and stage III melanoma patients were inefficient and not cost-efficient.

Current therapy of cutaneous melanoma

Melanoma is a growing public health problem. Optimal care of the melanoma patient is multidisciplinary, but plastic surgeons and other surgical specialties play a central role in the management of these patients. Although surgery remains the mainstay of therapy for melanoma, several recent clinical studies have helped to clarify the biology of the disease and have changed the patterns of care for patients with melanoma. The advent of lymphatic mapping for interrogation of regional lymph nodes and interferon as the first effective postsurgical adjuvant therapy have had a major impact on the care of melanoma in the United States and elsewhere. This article will review the current clinical approach and therapy for cutaneous melanoma. The diagnosis, prognostic variables, staging evaluation, current surgical and medical treatment, and follow-up guidelines for patients with all stages of melanoma are reviewed. Recent studies, controversies, and directions of future investigational therapies will be discussed.

Prospective study of fluorodeoxyglucose-positron emission tomography imaging of lymph node basins in melanoma patients undergoing sentinel node biopsy

PURPOSE

To prospectively compare positron emission tomography (PET) imaging of regional lymph node basins to sentinel node biopsy (SNB) in patients with American Joint Committee on Cancer (AJCC) stage I, II, and III melanoma localized to the skin.

METHODS

Patients with cutaneous melanoma with Breslow's depth greater than 1 mm (AJCC T2-4N0M0) or localized regional cutaneous recurrence (TxN2bM0) underwent whole-body imaging of glucose metabolism with fluorodeoxyglucose (FDG) PET followed by SNB. PET scans were interpreted in a blinded fashion and compared with histologic analyses of SNB specimens and clinical follow-up examination. Nodal tumor volumes were estimated.

RESULTS

Eighty-nine lymph node basins were evaluated by FDG-PET and SNB in 70 assessable patients. Eighteen patients (25.7%) had lymph node metastases at the time of FDG-PET imaging: 17 proved by SNB (24.3%) and one by follow-up examination (1.4%). Median tumor volume in positive sentinel node basins was 4.3 mm3 (range, 0.07 to 523 mm3). Sensitivity of SNB for detection of occult regional lymph node metastases was 94.4%, specificity was 100%, positive predictive value (PPV) was 100%, and negative predictive value (NPV) was 98.6%. Sensitivity of FDG-PET was 16.7%, specificity was 95.8%, PPV was 50%, and NPV was 81.9%. At a median follow-up duration of 16.6 months, seven patients (10%) developed recurrent disease. PET predicted one recurrence (14.3%) in a node basin missed by SNB.

CONCLUSION

FDG-PET is an insensitive indicator of occult regional lymph node metastases in patients with melanoma because of the minute tumor volumes in this population. FDG-PET does not have a primary role for staging regional nodes in patients with clinically localized melanoma.

Laboratory tests and imaging studies in patients with cutaneous malignant melanoma

Laboratory tests and imaging studies are often ordered for asymptomatic patients with malignant melanomas (MMs) in an effort to detect subclinical metastatic disease. However, their sensitivity and specificity for detecting cryptic metastases are not well established. A review of the literature on laboratory tests and imaging studies for MM metastases was undertaken to address the usefulness of such investigations in asymptomatic patients with MM in AJCC (American Joint Committee on Cancer system of classification) stages I, II, and III. A review of the pertinent literature since 1966 was conducted through MEDLINE, Medica, and Cancerlit. Laboratory tests and imaging studies revealed occult MM metastases in only a small number of the thousands of reported patients with putative AJCC stage I, II, and III MM. However, for those diagnosed with limited metastases, surgical removal with or without immunotherapy, chemotherapy, or radiotherapy can lead to long-term remissions in some patients. For patients with asymptomatic AJCC stage I or II disease, chest roentgenograms (CXR) and blood lactic dehydrogenase (LDH) levels may be obtained at low cost and prove to be of benefit if metastases are identified. For patients with AJCC stage III disease, computed tomographic (CT) scans of the thorax, abdomen, and pelvis (especially when the primary cutaneous site of the melanoma is below the waist) may be considered for detecting metastatic MM. Other tests, such as magnetic resonance imaging (MRI) scans of the brain, may be ordered based on symptoms or physical findings. In the future, technologically improved techniques and newer methods may prove cost-effective for detecting treatable asymptomatic MM metastases. Furthermore, improvement in treatments will also influence the indications for the search for occult MM metastases. At this time there is a need for an international consensus conference on laboratory tests and imaging studies for occult melanoma metastases.

Classification and staging of melanoma

Although a standardized and uniformly accepted cancer staging system is an essential and fundamental requirement to enable meaningful comparisons across patient populations, the sometimes capricious biologic behavior of melanoma makes developing such a staging system particularly difficult. Since the earliest well-documented attempts at classifying patients with cutaneous melanoma were described more than 50 years ago, the identification of increasingly powerful prognostic factors has led to sequential modifications of the cutaneous melanoma staging system. The current AJCC staging system is based on relatively well-established prognostic factors; however, several recent reports have identified additional prognostic factors not included in the current system, and other studies support the re-evaluation of some of the currently employed staging criteria. Some of the more controversial areas include the relevance of level of invasion versus tumor thickness, optimal cutoffs for tumor thickness, importance of ulceration, the grouping of satellites with in-transit metastases, the inclusion of microsatellites and local recurrences as a separate staging criterion, the replacement of size of nodal mass with number of positive nodes, the importance of nodal metastases in more than one nodal basin, and the prognostic significance of distant metastases. Therefore, future modifications of the staging system are anticipated to better incorporate these observations. Stage-specific staging recommendations for the patient with melanoma provide the clinician with a framework to most efficiently assess extent of disease in an era of cost-conscious clinical practice. In the asymptomatic patient with primary melanoma (stage I or II), we recommend a chest roentgenogram and evaluation of alkaline phosphatase and LDH levels; extensive radiologic evaluations are not indicated, because the rate of detection in this population is extremely low. Additional staging information should also be obtained by the technique of lymphatic mapping and sentinel lymphadenectomy. For patients with local-regional disease (stage III, satellites, and local recurrence), a selective approach to imaging studies is warranted. For this patient population, we recommend complete blood count, liver function tests including alkaline phosphatase and LDH, a chest roentgenogram, and a CT scan of the abdomen. Although the yield of these tests, particularly CT of the abdomen, in detecting distant metastases in asymptomatic patients is low, they may identify false-positive abnormalities and provide an important baseline for future studies in this high-risk population. For patients with disease below the waist or in the head and neck region, we recommend CT of the pelvis and CT of the neck, respectively. Additional studies should be done only if clinically indicated. Finally, patients with known systemic disease (stage IV) should be more comprehensively evaluated, because the likelihood of detecting asymptomatic metastases is higher. Accordingly, in addition to the work-up outlined previously for stage III patients, we also perform a CT scan of the chest and MR imaging of the brain; other studies (e.g., bone scan, gastrointestinal series) are performed on the basis of symptoms.

Laboratory tests and imaging studies in patients with cutaneous malignant melanomas: a survey of experienced physicians

BACKGROUND

The presence or absence of metastases is important in determining prognosis and treatment options for patients with malignant melanoma (MM). Laboratory tests and imaging studies are ordered for patients with MMs but without symptoms in an effort to detect occult metastases. However, which laboratory tests and imaging studies to order and how often to reorder them is not well established.

OBJECTIVE

Our purpose was to determine which tests and studies are ordered by physicians with major responsibilities for the care of patients with MM.

METHODS

Physicians were surveyed by questionnaire about the laboratory tests and imaging studies they ordered for MM stages 0, I, II, and III.

RESULTS

Of the 35 physicians queried, 30 (86%) responded to the survey. The majority of physicians order tests as follows: no tests for MM in situ; roentgenography of the chest with or without initial lactic acid dehydrogenase/liver function tests for stages I, II, and III and during follow-up for stages IB, II, and III (more frequently as the Breslow thickness increases); and baseline computed tomographic or magnetic resonance imaging scans of the chest, abdomen/pelvis, and brain for stage III.

CONCLUSION

Although the pattern of ordering examinations was similar for the majority of respondents, there was significant variability among experienced physicians in ordering laboratory tests and imaging studies in the search for occult metastases in patients with asymptomatic MM. The laboratory tests and imaging studies ordered and their frequency depend on the stage of the MM and sometimes on other risk factors.

Computed tomography in evaluation of patients with stage III melanoma

BACKGROUND

Metastatic disease is detected infrequently by computed tomography (CT) in early stage melanoma. The diagnostic yield of routine CT for stage III melanoma is less established, despite extensive use in clinical practice.

METHODS

Charts from 347 asymptomatic patients with stage III melanoma were reviewed. Findings suggestive of metastatic melanoma identified by head or body CT, chest radiography, bone scan, or liver function studies were confirmed histologically or by progression of disease.

RESULTS

Individual CT scans identified 33/788 (4.2%) instances of metastatic melanoma, with 66/788 (8.4%) false positive studies. No metastases were identified among 104 head CT scans. Chest CT had the highest yield in patients with cervical adenopathy (7/35, 20%), and the lowest yield with groin adenopathy (1/50, 2%). Pelvic CT diagnosed metastases in 7/94 (7.4%) patients with groin adenopathy, but no patients with palpable axillary (n = 76) or cervical (n = 21) nodes. Metastatic melanoma was diagnosed in 11/136 (8.1%) patients having complete body CT imaging (chest, abdomen, and pelvis), including six patients (4.4%) identified by CT alone.

CONCLUSIONS

Routine CT in patients with clinical stage III melanoma infrequently identifies metastatic disease. Head CT in the asymptomatic patient, chest CT in patients with groin adenopathy, and pelvic CT in the presence of axillary or cervical adenopathy are not indicated. Selective use of chest CT in patients with cervical adenopathy or pelvic CT in the presence of groin disease may be useful.

Initial assessment of positron emission tomography for detection of nonpalpable regional lymphatic metastases in melanoma

BACKGROUND

The purpose of this pilot study is to determine the feasibility of positron emission tomography with fluorodeoxyglucose (FDG-PET) for detection of nonpalpable regional lymph node metastases in patients with melanoma.

METHODS

Adult patients with histologically proven cutaneous melanoma planned to undergo surgical lymphadenectomy for treatment of nonpalpable subclinical or residual metastatic melanoma in regional lymph node basin(s) participated. Each patient underwent attenuation-corrected PET imaging of the regional lymph node basin(s) with F18 fluorodeoxyglucose (FDG) followed by complete surgical lymphadenectomy. FDG-PET scans were interpreted prospectively by an experienced nuclear medicine physician. FDG-PET scan interpretations and histologic results were then correlated.

RESULTS

Eleven patients underwent 12 FDG-PET scans followed by 12 operations to clear 14 regional lymph node basins. FDG-PET correctly predicted the presence of metastatic melanoma in seven of seven surgical specimens. FDG-PET scans correctly predicted the absence of disease in seven of seven histologically negative node basins. Sensitivity was 1.0; specificity was 1.0.

CONCLUSIONS

This study suggests that increased fluorodeoxyglucose uptake in palpably unremarkable regional lymph node basins in patients with melanoma is highly suggestive of metastatic disease.