Weighing the value of completion nodal dissection for melanoma

Optimal surveillance strategies for patients with stage 1 cutaneous melanoma post primary tumour excision: three systematic reviews and an economic model

BACKGROUND

Malignant melanoma is the fifth most common cancer in the UK, with rates continuing to rise, resulting in considerable burden to patients and the NHS.

OBJECTIVES

The objectives were to evaluate the effectiveness and cost-effectiveness of current and alternative follow-up strategies for stage IA and IB melanoma.

REVIEW METHODS

Three systematic reviews were conducted. (1) The effectiveness of surveillance strategies. Outcomes were detection of new primaries, recurrences, metastases and survival. Risk of bias was assessed using the Cochrane Collaboration's Risk-of-Bias 2.0 tool. (2) Prediction models to stratify by risk of recurrence, metastases and survival. Model performance was assessed by study-reported measures of discrimination (e.g. D-statistic, Harrel's c-statistic), calibration (e.g. the Hosmer-Lemeshow 'goodness-of-fit' test) or overall performance (e.g. Brier score, R ²). Risk of bias was assessed using the Prediction model Risk Of Bias ASsessment Tool (PROBAST). (3) Diagnostic test accuracy of fine-needle biopsy and ultrasonography. Outcomes were detection of new primaries, recurrences, metastases and overall survival. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Review data and data from elsewhere were used to model the cost-effectiveness of alternative surveillance strategies and the value of further research.

RESULTS

(1) The surveillance review included one randomised controlled trial. There was no evidence of a difference in new primary or recurrence detected (risk ratio 0.75, 95% confidence interval 0.43 to 1.31). Risk of bias was considered to be of some concern. Certainty of the evidence was low. (2) Eleven risk prediction models were identified. Discrimination measures were reported for six models, with the area under the operating curve ranging from 0.59 to 0.88. Three models reported calibration measures, with coefficients of ≥ 0.88. Overall performance was reported by two models. In one, the Brier score was slightly better than the American Joint Committee on Cancer scheme score. The other reported an R ² of 0.47 (95% confidence interval 0.45 to 0.49). All studies were judged to have a high risk of bias. (3) The diagnostic test accuracy review identified two studies. One study considered fine-needle biopsy and the other considered ultrasonography. The sensitivity and specificity for fine-needle biopsy were 0.94 (95% confidence interval 0.90 to 0.97) and 0.95 (95% confidence interval 0.90 to 0.97), respectively. For ultrasonography, sensitivity and specificity were 1.00 (95% confidence interval 0.03 to 1.00) and 0.99 (95% confidence interval 0.96 to 0.99), respectively. For the reference standards and flow and timing domains, the risk of bias was rated as being high for both studies. The cost-effectiveness results suggest that, over a lifetime, less intensive surveillance than recommended by the National Institute for Health and Care Excellence might be worthwhile. There was considerable uncertainty. Improving the diagnostic performance of cancer nurse specialists and introducing a risk prediction tool could be promising. Further research on transition probabilities between different stages of melanoma and on improving diagnostic accuracy would be of most value.

LIMITATIONS

Overall, few data of limited quality were available, and these related to earlier versions of the American Joint Committee on Cancer staging. Consequently, there was considerable uncertainty in the economic evaluation.

CONCLUSIONS

Despite adoption of rigorous methods, too few data are available to justify changes to the National Institute for Health and Care Excellence recommendations on surveillance. However, alternative strategies warrant further research, specifically on improving estimates of incidence, progression of recurrent disease; diagnostic accuracy and health-related quality of life; developing and evaluating risk stratification tools; and understanding patient preferences.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018086784.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol 25, No. 64. See the NIHR Journals Library website for further project information.

Complete lymphadenectomy following positive sentinel lymph node biopsy in cutaneous melanoma: a critical review

Cutaneous melanoma is the solid neoplasia with the highest growing incidence among all tumors. It spreads predictably to the lymphatic vessels and sentinel lymph node, and when the latter is affected the prognosis worsens dramatically. Sentinel lymph node biopsy is considered when thickness of the primary tumor exceeds 1mm and/or when there are adverse features in thinner melanomas. When there is nodal metastasis, current evidence in the literature recommends complete lymphadenectomy, although this procedure has its intrinsic risks (i.e., lymphedema and cellulitis), and there are no published clinical trials proving additional overall survival benefits. The current in-depth literature review thus aims to identify patients that will benefit most from the procedure, including those with the highest likelihood of presenting additional affected lymph nodes in the same nodal basin. The authors also discuss techniques for identification of the sentinel lymph node, false-negative rates, and predictive models for lymph node involvement. In conclusion, complete elective lymphadenectomy should always be discussed on a case-by-case basis when metastases are detected in the sentinel lymph node.

Mitotic rate is associated with positive lymph nodes in patients with thin melanomas

BACKGROUND

The American Joint Commission on Cancer will remove mitotic rate from its staging guidelines in 2018.

OBJECTIVE

Using a large nationally representative cohort, we examined the association between mitotic rate and lymph node positivity among thin melanomas.

METHODS

A total of 149,273 thin melanomas in the National Cancer Database were examined for their association of high-risk features of mitotic rate, ulceration, and Breslow depth with lymph node status.

RESULTS

Among 17,204 patients with thin melanomas with data on Breslow depth, ulceration, and mitotic rate who underwent a lymph node biopsy, there was a strong linear relationship between odds of having a positive lymph node and mitotic rate (R² = 0.96, P < .0001, β = 3.31). The odds of having a positive node increased by 19% with each 1-point increase in mitotic rate (odds ratio, 1.19; 95% confidence interval, 1.17-1.21). Cases with negative nodes had a mean mitotic rate of 1.54 plus or minus 2.07 mitoses/mm² compared with 3.30 plus or minus 3.54 mitoses/mm² for those with positive nodes (P < .0001).

LIMITATIONS

The data collected do not allow for survival analyses.

CONCLUSIONS

Mitotic rate was strongly associated with the odds of having a positive lymph node and should continue to be reported on pathology reports.