In situand invasive melanoma in a high-risk, New Zealand, population: A population-based study

Practitioner characteristics, diagnostic accuracy metrics and discovering-individual with respect to 637 melanomas documented by 27 general practitioners on the Skin Cancer Audit Research Database

BACKGROUND AND OBJECTIVE

Knowledge of accuracy for melanoma diagnosis and melanoma discovering-individual in primary care is limited. We describe general practitioner (GP) characteristics and analyse defined diagnostic accuracy metrics for GPs in the current study comparing this with a previous study for GPs common to both, and we analyse the individual first discovering each melanoma as a lesion of concern.

METHODS

The characteristics and diagnostic accuracy of 27 Australasian GPs documenting 637 melanomas on the Skin Cancer Audit Research Database (SCARD) in 2013 were described and analysed. The number needed to treat (NNT) and percentage of melanomas that were in situ (percentage in situ) were analysed as surrogates for specificity and sensitivity, respectively. The discovering-individual was analysed according to patient age and sex and lesion Breslow thickness.

RESULTS

The average NNT and percentage in situ were 5.73% and 65.07%, respectively. For 21 GPs in both a 2008-2010 study and the current study, the NNT was 10.78 and 5.56, respectively (p = 0.0037). A consistent trend of decreasing NNT and increasing percentage in situ through increasingly subspecialised GP categories did not reach statistical significance. NNT trended high at ages and sites for which melanoma was rare. While the patient or family member was more likely to discover thick melanomas and melanomas in patients under 40 years, GPs discovered 73.9% of the melanomas as lesions of concern.

CONCLUSIONS

GPs were the discovering-individuals for the majority of melanomas in the current study and their accuracy metrics compared favourably with published figures for dermatologists and GPs.

The risk of subsequent invasive melanoma after a primary in situ or invasive melanoma in a high incidence country (New Zealand)

Background

Patients with invasive melanoma are at increased risk of developing subsequent invasive melanoma, but the risks for those with primary in situ melanoma are unclear.

Objectives

To assess and compare the cumulative risk of subsequent invasive melanoma after primary invasive or in situ melanoma. To estimate the standardized incidence ratio (SIR) of subsequent invasive melanoma compared to population incidence in both cohorts.

Methods

Patients with a first diagnosis of melanoma (invasive or in situ) between 2001 and 2017 were identified from the New Zealand national cancer registry, and any subsequent invasive melanoma during follow-up to the end of 2017 identified. Cumulative risk of subsequent invasive melanoma was estimated by Kaplan-Meier analysis separately for primary invasive and in situ cohorts. Risk of subsequent invasive melanoma was assessed using Cox proportional hazard models. SIR was assessed, allowing for age, sex, ethnicity, year of diagnosis and follow up time.

Results

Among 33 284 primary invasive and 27 978 primary in situ melanoma patients, median follow up time was 5.5 and 5.7 years, respectively. A subsequent invasive melanoma developed in 1777 (5%) of the invasive and 1469 (5%) of the in situ cohort, with the same median interval (2.5 years) from initial to first subsequent lesion in both cohorts. The cumulative incidence of subsequent invasive melanoma at 5 years was similar in the two cohorts (invasive 4.2%, in situ 3.8%); the cumulative incidence increased linearly over time in both cohorts. The risk of subsequent invasive melanoma was marginally higher for primary invasive compared to in situ melanoma after adjustment for age, sex, ethnicity and body site of the initial lesion (hazard ratio 1.11, 95% CI 1.02-1.21). Compared to population incidence, the SIR of invasive melanoma was 4.6 (95% CI 4.3-4.9) for the primary invasive and 4 (95% CI 3.7-4.2) for the primary in situ melanoma cohorts.

Conclusions

The risk of subsequent invasive melanoma is similar whether patients present with in situ or invasive melanoma. Thus follow-up surveillance for new lesions should be similar, although patients with invasive melanoma require more surveillance for recurrence.

Characteristics, treatment and outcomes of 589 melanoma patients documented by 27 general practitioners on the Skin Cancer Audit Research Database

BACKGROUND AND OBJECTIVE

General practitioners manage more melanomas than dermatologists or surgeons in Australia. Previously undescribed, the management and outcomes of melanoma patients treated by multiple Australasian general practitioners are examined.

METHODS

The characteristics, management and outcomes of 589 melanoma patients, managed by 27 Australasian general practitioners and documented on the Skin Cancer Audit Research Database (SCARD), were analysed.

RESULTS

Most patients (58.9%) were males with mean age at diagnosis of 62.7 years (range 18-96), and most melanomas were in situ or thin-invasive. Patients aged under 40 years had fewer melanomas, but a higher proportion (the majority) were invasive, compared with older patients (P < 0.0001). Most (55.9%) melanomas were diagnosed following elliptical excision biopsy, the rate of unintended involved margins being eightfold higher for shave biopsies. Wide re-excision was performed by the treating general practitioner for most (74.9%) melanomas, with thick melanomas preferentially referred to surgeons. The average Breslow thickness of invasive melanomas re-excised by general practitioners was 0.67 mm compared with 1.99 mm for those referred to other specialists (P < 0.0001). Of 205 patients with invasive melanoma, 14 progressed to metastatic disease, 50% of these being associated with nodular melanoma. Nine patients progressed to melanoma-specific death. The 5-year survival rate for patients with invasive melanoma was 95.2% (95% CI: 91.2-98.5%).

CONCLUSIONS

Diagnostic and therapeutic management of a series of melanoma patients by Australasian general practitioners were closely aligned with current guidelines and 5-year survival with respect to invasive melanoma was at least as favourable as national population-based metrics.

Melanoma sentinel lymph node biopsy and completion lymph node dissection: A regional hospital experience

Completion lymph node dissection (CLND) following positive sentinel lymph node biopsy (SLNB) for cutaneous melanoma is a topic of controversy. The second Multicenter Selective Lymphadenectomy Trial (MSLT-II) suggested no survival benefit with CLND over observation amongst patients with a positive SLNB. The findings of the MSLT-II may have limited applicability to our high-risk population where nodal ultrasound and non-surgical melanoma treatment is rationed. In this regional, retrospective study, we reviewed primary melanoma, SLNB and CLND histopathological reports in the Bay of Plenty District Health Board (BOPDHB) across a 10-year period. The primary outcomes measured were size of sentinel lymph node metastases and non-sentinel node (NSN) positivity on CLND for patients with a positive SLNB. In the 157 SLNB identified, the mean sentinel lymph node metastatic deposit size was larger in BOPDHB compared with MSLT-II (3.53 vs 1.07/1.11mm). A greater proportion of BOPDHB patients (54.8%) had metastatic deposits larger than 1mm compared with MSLT-II (33.2/34.5%) and the rate of NSN involvement on CLND was also higher (23.8% vs 11.5%). These findings indicate that the BOPDHB is a high-risk population for nodal melanoma metastases. Forgoing CLND in the context of a positive SLNB may place these patients at risk.

Characteristics of 637 melanomas documented by 27 general practitioners on the Skin Cancer Audit Research Database

BACKGROUND AND OBJECTIVE

Most melanomas (including melanomas in situ), in Australasia, are treated by general practitioners (GPs). Previously undescribed, the characteristics of a series of melanomas treated by multiple GPs are examined.

PATIENTS AND METHODS

Six hundred and thirty-seven melanomas treated by 27 Australasian GPs during 2013 and documented on the Skin Cancer Audit Research Database (SCARD) were analysed by anatomical site, subtype, Breslow thickness, diameter, associated naevi and linked adverse outcomes.

RESULTS

Most melanomas (59.7%) were on males, mean age at diagnosis being 62.7 years (range 18-96). Most (65.0%) were in situ, with a high incidence of lentiginous melanoma (LM) (38.8%) and 32% were naevus associated. Most LM (86.4%) were in situ, compared to 55% of superficial spreading melanoma (SSM) (P < 0.0001). There was male predominance on the head, neck and trunk and female predominance on extremities. There was no significant association between Breslow thickness and diameter, with small melanomas as likely to be thick as large melanomas, and melanomas ≤3 mm diameter, on average, more likely to be invasive than larger melanomas. There was a positive correlation between age and both melanoma diameter and Breslow thickness. Seven cases progressed to melanoma-specific death: Five nodular melanoma (NM) and two SSM, one of which was thin (Breslow thickness 0.5 mm).

CONCLUSIONS

A large series of melanomas treated by Australasian GPs were predominantly in situ, with a high proportion of LM subtype. With implications for GP training, NM linked to death was over-represented and there was a novel finding that older patients had larger diameter melanomas.

Lentiginous melanoma (lentigo maligna and lentigo maligna melanoma) in Australia: clinicopathological characteristics, management and recurrence rates after 10-year follow-up at a tertiary centre

BACKGROUND

Lentiginous melanoma or lentigo maligna is a slow-growing type of melanoma frequently arising in sun-damaged skin and often first diagnosed in the elderly. Few studies report long-term follow-up.

OBJECTIVES

To define characteristics of lentiginous melanoma in situ (LM) and invasive lentiginous melanoma (LMM) in Australian patients managed at a tertiary centre and describe local recurrence or treatment failure rates after long-term follow-up.

METHODS

Retrospective single-centre study of LM/LMM patients evaluated between January 2005 and March 2007. Medical and photographic records were reviewed.

RESULTS

One hundred two patients were included, with a total of 117 lesions (70 LM and 47 LMM). Seventy-nine were new primary LM/LMM, and 38 were recurrences. Primary cases were mostly pigmented (71%), while 77% of recurrent cases were partially pigmented/light brown or amelanotic. The margins were clinically ill-defined in the majority of cases (64% of primary cases and 94% of recurrent cases). Dermoscopy of the primary LM/LMM showed either classic 'common' melanoma features (33%) or classic LM/LMM features (41%), while 95% of recurrent cases had no features for melanoma or LM/LMM. Primary cases that were initially excised (113, 97%) had mean histopathological clear margins of 4.9 mm (range 0.1-22 mm). The median follow-up time was 7.5 years (95% CI 5.2-10.0) with more than 10-year follow-up in 32% and 5-10 years in 24% of patients. There were 44 (38%) recurrences over the entire follow-up period. Half of the patients who recurred did so within the first 3.8 years after the first treatment.

CONCLUSION

LM/LMM often recur late and are clinically subtle; therefore, careful monitoring and long-term follow-up are required.

E-referrals and teledermatoscopy grading for melanoma: a successful model of care

BACKGROUND/OBJECTIVES

An e-referral system was developed at a tertiary care hospital in Auckland, New Zealand in 2014 for suspected cutaneous malignancy. E-referrals include patient information, a description of the lesion(s), biopsy results and/or attached photograph(s). Experienced surgical oncologists prioritised the referrals and selected a management option or referred them for a teledermatoscopy opinion. Our aim was to review the efficacy of e-referrals for improving diagnostic accuracy for melanoma.

METHODS

Referrals received in 2016 including images and categorisation as confirmed, likely or suspected melanoma by the triage specialist were evaluated. Concordance of the pathological diagnosis with the triage diagnosis and teledermatoscopy diagnosis was determined for each referral.

RESULTS

809 of 3470 e-referrals for skin cancer were categorised as confirmed, likely or suspected melanoma. 230 (28.4%) of these included a referral histopathology confirming melanoma/melanoma in situ. Of the remaining 579 referrals, 315 were sent for urgent diagnostic excision and 264 were referred for teledermatoscopy. 120 of the 315 sent for urgent excision were confirmed as melanoma (53) or melanoma in situ (67) on histopathology: a positive predictive value (PPV) of 38.1% and number needed to excise (NNE) of 2.6. Less than 10% of referrals triaged for teledermatoscopy were confirmed as melanoma (24/264). Almost half of all referrals (374/809, 45.6%) included melanoma/melanoma in situ. The melanoma: melanoma in situ ratio was 1: 1.18.

CONCLUSIONS

The e-referral and teledermatoscopy service for suspected melanoma has proven fewer unnecessary excisions of benign lesions than previously reported.

The steadily growing problem of lentigo maligna and lentigo maligna melanoma in Australia: Population-based data on diagnosis and management

BACKGROUND/OBJECTIVES

There are limited population-based data documenting the incidence and management of lentigo maligna (LM) and invasive lentigo maligna melanoma (LMM). We report the data on occurrence and management of LM and LMM in an Australian population.

METHODS

Prospective collection of incidence and clinician-reported management of melanoma in situ (MIS; n = 450, capped) and localised invasive melanoma (n = 3251) notified to the New South Wales Cancer Registry over 12-months in 2006-2007.

RESULTS

The estimated annual incidence of all MIS was 27.0 per 100 000 (LM 12.2, non-LM MIS 5.9 and unclassified MIS 9.0). Patients with LM or LMM were on average approximately 10 years older than those with other melanoma subtypes (P < 0.001). The head and neck was the location of 59% of LM, 44% of LMM and <20% of other melanoma subtypes (P < 0.001). The majority of LM and LMM were treated only by specialists. Diagnostic partial biopsies were more frequent for LM and LMM than for other melanoma subtypes, and primary care physicians were more likely than specialists to do a punch partial biopsy than a shave biopsy. The reported median definitive excision margin for LM was 5.0 mm compared with 7.2 mm for non-LM MIS (P = 0.001).

CONCLUSIONS

In this Australian population, LM was twice as frequent as other types of MIS. Improved strategies for diagnosis and management are required.