Gut Microbiome in Patients With Early-Stage and Late-Stage Melanoma

Importance

The gut microbiome modulates the immune system and responses to immunotherapy in patients with late-stage melanoma. It is unknown whether fecal microbiota profiles differ between healthy individuals and patients with melanoma or if microbiota profiles differ among patients with different stages of melanoma. Defining gut microbiota profiles in individuals without melanoma and those with early-stage and late-stage melanoma may reveal features associated with disease progression.

Objective

To characterize and compare gut microbiota profiles between healthy volunteers and patients with melanoma and between patients with early-stage and late-stage melanoma.

Design, Setting, and Participants

This single-site case-control study took place at an academic comprehensive cancer center. Fecal samples were collected from systemic treatment-naive patients with stage I to IV melanoma from June 1, 2015, to January 31, 2019, and from healthy volunteers from June 1, 2021, to January 31, 2022. Patients were followed up for disease recurrence until November 30, 2021.

Main Outcomes and Measures

Fecal microbiota was profiled by 16S ribosomal RNA sequencing. Clinical and pathologic characteristics, treatment, and disease recurrence were extracted from electronic medical records. Fecal microbiome diversity, taxonomic profiles and inferred functional profiles were compared between groups.

Results

A total of 228 participants were enrolled (126 men [55.3%]; median age, 59 [range, 21-90] years), including 49 volunteers without melanoma, 38 patients with early-stage melanoma (29 with stage I or melanoma in situ and 9 with stage II), and 141 with late-stage melanoma (66 with stage III and 75 with stage IV). Community differences were observed between patients with melanoma and volunteers. Patients with melanoma had a higher relative abundance of Fusobacterium compared with controls on univariate analysis (0.19% vs 0.003%; P < .001), but this association was attenuated when adjusted for covariates (log2 fold change of 5.18 vs controls; P = .09). Microbiomes were distinct between patients with early-stage and late-stage melanoma. Early-stage melanoma had a higher alpha diversity (Inverse Simpson Index 14.6 [IQR, 9.8-23.0] vs 10.8 [IQR, 7.2-16.8]; P = .003), and a higher abundance of the genus Roseburia on univariate analysis (2.4% vs 1.2%; P < .001) though statistical significance was lost with covariate adjustment (log2 fold change of 0.86 vs controls; P = .13). Multiple functional pathways were differentially enriched between groups. No associations were observed between the microbial taxa and disease recurrence in patients with stage III melanoma treated with adjuvant immunotherapy.

Conclusions and Relevance

The findings of this case-control study suggest that fecal microbiota profiles were significantly different among patients with melanoma and controls and between patients with early-stage and late-stage melanoma. Prospective investigations of the gut microbiome and changes that occur with disease progression may identify future microbial targets for intervention.

Changes In Outcomes And Factors Associated With Survival In Melanoma Patients With Brain Metastases

BACKGROUD

Treatment options for patients with melanoma brain metastasis (MBM) have changed significantly in the last decade. Few studies have evaluated changes in outcomes and factors associated with survival in MBM patients over time. The aim of this study is to evaluate changes in clinical features and overall survival (OS) for MBM patients.

METHODS

Patients diagnosed with MBMs from 1/1/2009-12/31/2013 (Prior Era; PE) and 1/1/2014-12/31/2018 (Current Era; CE) at The University of Texas MD Anderson Cancer Center were included in this retrospective analysis. The primary outcome measure was OS. Log-rank test assessed differences between groups; multivariable analyses were performed with Cox proportional hazards models and recursive partitioning analysis (RPA).

RESULTS

791 MBM patients (PE, n=332; CE, n=459) were included in analysis. Median OS from MBM diagnosis was 10.3 months (95% CI, 8.9 - 12.4) and improved in the CE versus PE (14.4 vs. 10.3 months, P < .001). Elevated serum LDH was the only factor associated with worse OS in both PE and CE patients. Factors associated with survival in CE MBM patients included patient age, primary tumor Breslow thickness, prior immunotherapy, leptomeningeal disease (LMD), symptomatic MBMs, and whole brain radiation therapy (WBRT). Several factors associated with OS in the PE were not significant in the CE. RPA demonstrated that elevated serum LDH and prior immunotherapy treatment are the most important determinants of survival in CE MBM patients.

CONCLUSIONS

OS and factors associated with OS have changed for MBM patients. This information can inform contemporary patient management and clinical investigations.

Dietary fiber and probiotics influence the gut microbiome and melanoma immunotherapy response

Gut bacteria modulate the response to immune checkpoint blockade (ICB) treatment in cancer, but the effect of diet and supplements on this interaction is not well studied. We assessed fecal microbiota profiles, dietary habits, and commercially available probiotic supplement use in melanoma patients and performed parallel preclinical studies. Higher dietary fiber was associated with significantly improved progression-free survival in 128 patients on ICB, with the most pronounced benefit observed in patients with sufficient dietary fiber intake and no probiotic use. Findings were recapitulated in preclinical models, which demonstrated impaired treatment response to anti–programmed cell death 1 (anti–PD-1)–based therapy in mice receiving a low-fiber diet or probiotics, with a lower frequency of interferon-γ–positive cytotoxic T cells in the tumor microenvironment. Together, these data have clinical implications for patients receiving ICB for cancer.

Predictors of overall survival (OS) in patients (pts) with melanoma brain metastasis (MBM) in the modern era

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Background: The management and OS of pts with metastatic melanoma have improved due to new systemic therapies. However, relatively little is known about the use of these treatments (tx) and their association with OS in pts with MBMs. We reviewed a large cohort of MBM pts to assess how pt demographics, disease characteristics, and MBM tx impact OS in the current era. Methods: Under an institutional review board-approved protocol, retrospective data were curated and analyzed from pts diagnosed with, and received tx for, MBM from 2014 to 2018 at the MD Anderson Cancer Center (MDA). Pts diagnosed with uveal or mucosal melanoma or other cancers were excluded. Pt demographics; timing and features of initial melanoma dx; timing and features of initial MBM dx; prior, initial and subsequent tx; and OS were collected. OS was determined from MBM dx to last clinical follow-up (FU). Pts alive at last FU were censored. The Kaplan-Meier method and log-rank test were used to estimate OS and to assess univariate group differences, respectively. Multivariable (MV) associations of OS with variables of interest were investigated with Cox proportional hazards models. Initial treatment of MBM was assessed as a time-varying covariate. All statistical tests used a significance level of 5%. Results: A total of 401 MBM pts were identified. The median age at MBM dx was 61; 67% were male and 46% had a BRAF V600 mutation. At MBM diagnosis dx, most (70%) pts were asymptomatic; 70% had concurrent uncontrolled extracranial disease; 36% had elevated serum LDH. Prior tx included immunotherapy (IMT) for 39% and targeted therapy (TTX) for 17%. The median number of MBMs was 2; 31% had > 3 MBMs. Median largest MBM diameter was 1.0 cm, 9% had MBM > 3.0 cm, and 5% had concurrent leptomeningeal disease (LMD). Tx received after MBM dx included stereotactic radiosurgery (SRS; 53% as initial tx for MBM, 67% at any time after MBM dx), whole brain radiation therapy (WBRT; 16%, 35%), craniotomy (12%, 19%), IMT (37%, 74%), and/or TTX (22%, 40%). 31% received steroids during initial MBM tx. At a median FU of 13.4 (0.0 - 82.8) months (mos), the median OS was 15.1 mos, and 1- and 2-year OS rates were 56% and 40%. Notably, gender, time to MBM dx, and BRAF status were not associated with OS (univariate analysis). On MV analysis, clinical features associated with worse OS included increased age, increased primary tumor thickness, elevated LDH, > 3 MBMs, +LMD, +symptoms, and prior tx with IMT. Among tx used at any time after MBM dx, WBRT (HR 1.9, 95% CI 1.5-2.5) was associated with worse OS; SRS (HR 0.7, 95% CI 0.5-0.8) and IMT (HR 0.6, 95% CI 0.5-0.8) were associated with improved OS. Conclusions: In one of the largest cohorts of MBM pts described to date, OS has improved in MBM pts in the current era. Prognostic factors for OS include pt age, primary tumor and MBM features, prior tx, and tx for MBM. Additional analyses to assess the interaction of tx, disease features, and OS will be presented.

Gut microbiome modulates response to anti-PD-1 immunotherapy in melanoma patients

Preclinical mouse models suggest that the gut microbiome modulates tumor response to checkpoint blockade immunotherapy; however, this has not been well-characterized in human cancer patients. Here we examined the oral and gut microbiome of melanoma patients undergoing anti-programmed cell death 1 protein (PD-1) immunotherapy (n = 112). Significant differences were observed in the diversity and composition of the patient gut microbiome of responders versus nonresponders. Analysis of patient fecal microbiome samples (n = 43, 30 responders, 13 nonresponders) showed significantly higher alpha diversity (P < 0.01) and relative abundance of bacteria of the Ruminococcaceae family (P < 0.01) in responding patients. Metagenomic studies revealed functional differences in gut bacteria in responders, including enrichment of anabolic pathways. Immune profiling suggested enhanced systemic and antitumor immunity in responding patients with a favorable gut microbiome as well as in germ-free mice receiving fecal transplants from responding patients. Together, these data have important implications for the treatment of melanoma patients with immune checkpoint inhibitors.

Erratum to: A case report of Grover's disease from immunotherapy-a skin toxicity induced by inhibition of CTLA-4 but not PD-1

[This corrects the article DOI: 10.1186/s40425-016-0157-6.].