Reevaluating the Utility of Liver Biopsies in Patients With Melanoma

TL;DR

This study investigates whether liver biopsies can be avoided in some melanoma patients with new liver lesions, based on clinical suspicion and patient history.

Contribution

The study identifies factors like lesion number and confounding cancers that may influence the need for liver biopsies in melanoma patients.

Findings

77.6% of patients with new liver lesions and a melanoma history had confirmed metastatic melanoma on biopsy.

Patients with confounding cancers were significantly less likely to have melanoma-positive biopsy results.

Solitary liver lesions were significantly less likely to be melanoma-positive compared to multiple lesions.

Abstract

Introduction

This study explores whether some patients with a prior melanoma diagnosis and new liver lesions can be presumed to have metastatic melanoma based on clinical suspicion alone, thereby avoiding the need for liver biopsies. The goal is to enable earlier treatment while reducing the risks, costs, and delays associated with invasive biopsy procedures.

Methods

This retrospective cohort study reviewed patients with a history of melanoma who underwent ultrasound- or CT-guided liver biopsies between 2014 and 2023. Patients biopsied for liver toxicity assessment, treatment response, or who underwent only fine-needle aspiration were excluded. Chart review captured biopsy outcomes, metastatic history, presence of solitary or multiple liver lesions, and the presence of confounding cancers (any history of non-melanoma malignancy at the time of biopsy). Statistical analysis included Fisher’s exact test and binomial CIs.

Results

Among 143 patients, 111 (77.6%) had positive biopsy results for melanoma (95% CI: 69.9%-84.2%). Of the 76 with a known history of metastatic melanoma, 63 (82.9%) had positive biopsy results, although this association was not statistically significant (p=0.114). The presence of confounding cancer was significantly associated with melanoma-negative biopsy results (p=6.50×10-⁷), with an odds ratio of 0.106 (95% CI (0.038, 0.281)), indicating a markedly lower likelihood of melanoma metastasis in patients with another known malignancy. Solitary versus multiple lesions were also associated with biopsy outcome. Patients with solitary lesions had significantly lower odds of a melanoma-positive biopsy compared to those with multiple lesions (odds ratio=0.32; 95% CI (0.123, 0.837); p=0.015).

Conclusion

The majority of patients with suspected liver metastases were confirmed to have metastatic melanoma on biopsy, suggesting that clinical suspicion may often be accurate in patients with a history of melanoma. Although a known history of metastatic melanoma did not reach statistical significance, the trend may still be clinically relevant. Lesion number was also associated with biopsy outcome, with solitary lesions significantly less likely to yield melanoma-positive results. In contrast, the presence of a confounding cancer significantly reduced the odds of a melanoma-positive biopsy, underscoring the importance of comprehensive oncologic history in diagnostic decision-making. These findings support consideration of a more selective approach to liver biopsy in melanoma patients, but biopsy remains essential in many scenarios. Validation in larger cohorts is needed before clinical practice changes can be made.