Merkel cell carcinoma recurrence risk estimation is improved by integrating factors beyond cancer stage: A multivariable model and web-based calculator

BACKGROUND

Merkel cell carcinoma (MCC) recurs in 40% of patients. In addition to stage, factors known to affect recurrence risk include: sex, immunosuppression, unknown primary status, age, site of primary tumor, and time since diagnosis.

PURPOSE

Create a multivariable model and web-based calculator to predict MCC recurrence risk more accurately than stage alone.

METHODS

Data from 618 patients in a prospective cohort were used in a competing risk regression model to estimate recurrence risk using stage and other factors.

RESULTS

In this multivariable model, the most impactful recurrence risk factors were: American Joint Committee on Cancer stage (P < .001), immunosuppression (hazard ratio 2.05; P < .001), male sex (1.59; P = .003) and unknown primary (0.65; P = .064). Compared to stage alone, the model improved prognostic accuracy (concordance index for 2-year risk, 0.66 vs 0.70; P < .001), and modified estimated recurrence risk by up to 4-fold (18% for low-risk stage IIIA vs 78% for high-risk IIIA over 5 years).

LIMITATIONS

Lack of an external data set for model validation.

CONCLUSION/RELEVANCE

As demonstrated by this multivariable model, accurate recurrence risk prediction requires integration of factors beyond stage. An online calculator based on this model (at merkelcell.org/recur) integrates time since diagnosis and provides new data for optimizing surveillance for MCC patients.

Increased risk of recurrence and disease-specific death following delayed postoperative radiation for Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is often treated with surgery and postoperative radiation therapy (PORT). The optimal time to initiate PORT (Time-to-PORT [ttPORT]) is unknown.

PURPOSE

We assessed if delays in ttPORT were associated with inferior outcomes.

METHODS

Competing risk regression was used to evaluate associations between ttPORT and locoregional recurrence (LRR) for patients with stage I/II MCC in a prospective registry and adjust for covariates. Distant metastasis and death were competing risks.

RESULTS

The cohort included 124 patients with median ttPORT of 41 days (range: 8-125 days). Median follow-up was 55 months. 17 (14%) patients experienced a LRR, 14 (82%) of which arose outside the radiation field. LRR at 5 years was increased for ttPORT >8 weeks vs ≤ 8 weeks, 28.0% vs 9.2%, P = .006. There was an increase in the cumulative incidence of MCC-specific death with increasing ttPORT (HR = 1.14 per 1-week increase, P = .016).

LIMITATIONS

The relatively low number of LRRs limited the extent of our multivariable analyses.

CONCLUSIONS

Delay of PORT was associated with increased LRR, usually beyond the radiation field. This is consistent with the tendency of MCC to spread quickly via lymphatics. Initiation of PORT within 8 weeks was associated with improved locoregional control and MCC-specific survival.

Postoperative Radiation Therapy Is Indicated for "Low-Risk" Pathologic Stage I Merkel Cell Carcinoma of the Head and Neck Region but Not for Other Locations

Purpose

The role of postoperative radiation therapy (PORT) in early stage Merkel cell carcinoma (MCC) is controversial. We analyzed the role of PORT in preventing local recurrences (LR) among patients with low-risk, pathologic stage I MCC based on the location of the primary tumors: head/neck (HN) versus non-HN sites.

Methods and Materials

One hundred forty-seven patients with MCC were identified that had "low risk" disease (pathologic T1 primary tumor, negative microscopic margins, negative pathologic node status, no immunosuppression or prior systemic therapy). LR was defined as tumor recurrence within 2 cm of the primary surgical bed, and its frequency was estimated with the cumulative incidence method.

Results

Seventy-nine patients received PORT (30 HN, 49 non-HN) with a median dose of 50 Gy (range, 8-64 Gy) and 68 patients were treated with surgery alone (30 HN, 38 non-HN). Overall, PORT was associated with a decreased risk of LR (5-year rate: 0% vs 9.5%; P = .004) with 6 LRs observed in the surgery alone group. Although the addition of PORT significantly reduced LR rates among patients with HN MCC (0% vs. 21%; P = .034), no LRs were observed in patients with non-HN MCC managed with surgery alone. There was no significant difference in MCC-specific survival comparing HN versus non-HN groups, with or without PORT.

Conclusions

For low-risk, pathologic stage I MCC of the extremities and trunk, excellent local control rates were achieved with surgery, and PORT is not indicated. However, PORT was associated with a significant reduction in LRs among low-risk MCC of the HN.

Genetic Risk Factors for Early-Onset Merkel Cell Carcinoma

Importance

Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer. Of the patients who develop MCC annually, only 4% are younger than 50 years.

Objective

To identify genetic risk factors for early-onset MCC via genomic sequencing.

Design, Setting, and Participants

The study represents a multicenter collaboration between the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the National Institute of Allergy and Infectious Diseases (NIAID), and the University of Washington. Participants with early-onset and later-onset MCC were prospectively enrolled in an institutional review board-approved study at the University of Washington between January 2003 and May 2019. Unrelated controls were enrolled in the NIAID Centralized Sequencing Program (CSP) between September 2017 and September 2021. Analysis was performed from September 2021 and March 2023. Early-onset MCC was defined as disease occurrence in individuals younger than 50 years. Later-onset MCC was defined as disease occurrence at age 50 years or older. Unrelated controls were evaluated by the NIAID CSP for reasons other than familial cancer syndromes, including immunological, neurological, and psychiatric disorders.

Results

This case-control analysis included 1012 participants: 37 with early-onset MCC, 45 with later-onset MCC, and 930 unrelated controls. Among 37 patients with early-onset MCC, 7 (19%) had well-described variants in genes associated with cancer predisposition. Six patients had variants associated with hereditary cancer syndromes (ATM = 2, BRCA1 = 2, BRCA2 = 1, and TP53 = 1) and 1 patient had a variant associated with immunodeficiency and lymphoma (MAGT1). Compared with 930 unrelated controls, the early-onset MCC cohort was significantly enriched for cancer-predisposing pathogenic or likely pathogenic variants in these 5 genes (odds ratio, 30.35; 95% CI, 8.89-106.30; P < .001). No germline disease variants in these genes were identified in 45 patients with later-onset MCC. Additional variants in DNA repair genes were also identified among patients with MCC.

Conclusions and Relevance

Because variants in certain DNA repair and cancer predisposition genes are associated with early-onset MCC, genetic counseling and testing should be considered for patients presenting at younger than 50 years.

Enhancing immunogenic responses through CDK4/6 and HIF2α inhibition in Merkel cell carcinoma

Approximately 50% of Merkel cell carcinoma (MCC) patients facing this highly aggressive skin cancer initially respond positively to PD-1-based immunotherapy. Nevertheless, the recurrence of MCC post-immunotherapy emphasizes the pressing need for more effective treatments. Recent research has highlighted Cyclin-dependent kinases 4 and 6 (CDK4/6) as pivotal cell cycle regulators gaining prominence in cancer studies. This study reveals that the CDK4/6 inhibitor, palbociclib can enhance PD-L1 gene transcription and surface expression in MCC cells by activating HIF2α. Inhibiting HIF2α with TC-S7009 effectively counteracts palbociclib-induced PD-L1 transcription and significantly intensifies cell death in MCC. Simultaneously, co-targeting CDK4/6 and HIF2α boosts ROS levels while suppressing SLC7A11, a key regulator of cellular redox balance, promoting ferroptosis- a form of immunogenic cell death linked to iron. Considering the rising importance of immunogenic cell death in immunotherapy, this strategy holds promise for improving future MCC treatments, markedly increasing immunogenic cell death various across various MCC cell lines, thus advancing cancer immunotherapy.

Efficacy of Single-Fraction Postoperative Radiotherapy in Resected, Early-Stage Merkel Cell Carcinoma with High-Risk Features

PURPOSE/OBJECTIVE(S)

Merkel cell carcinoma (MCC) is an aggressive skin cancer with a high recurrence risk. Postoperative radiotherapy (PORT) improves the local recurrence rate (LRR) in early-stage MCC with risk factors per NCCN guidelines: primary tumor size > 1cm, head/neck (HN) location, immunosuppression, lymphovascular invasion (LVI), and positive/narrow surgical margins. Conventionally fractionated PORT (C-PORT, ∼50 Gy in 25 fractions) is often recommended for localized MCC with these risk factors; however, some institutions elect observation. Prior studies suggest LRR of ∼20% for stage I/II MCC with high-risk features managed with surgery alone. C-PORT significantly decreases LRR but may cause significant morbidity and financial toxicity. We have previously reported that single fraction (SF)-PORT with 8 Gy achieves high rates of in-field control both in the metastatic and adjuvant settings with minimal morbidity. Here, we present updated long-term outcomes of SF-PORT, offered as an alternative to C-PORT with the hypothesis that it improves LRR relative to observation while minimizing toxicity, for resected stage I/II MCC.

MATERIALS/METHODS

A retrospective, single-institution analysis was completed for stage I/II MCC patients receiving SF-PORT following surgical management. The primary objective was estimating the LRR, defined as recurrence within 2 cm of the primary tumor. Patients with resected, stage I/II MCC with at least one high-risk feature were offered C-PORT as standard of care or SF-PORT as an alternative.

RESULTS

Forty-six patients (median age: 74.5; range 50-96 years) received SF-PORT to the primary tumor site at a median 44 days after wide local excision (85%), shave/excisional biopsy (13%), or Mohs (2%). Fifty-four percent of patients had 1 high-risk feature, 35% had 2, and 11% had 3 or more. HN (74%) was the most common primary site, 26% of tumors were > 1cm, 26% were LVI+, and 15% of patients were immunosuppressed (pathological margin status was often not available). There were no local recurrences (LRR = 0%) at a median follow-up time of 2.3 years. In-field locoregional control was 96% (44/46 patients) with 2 in-field, regional recurrences observed in draining nodal basins of HN primary lesions. There were 2 out-of-field regional nodal recurrences (1 patient with IMS; neither received elective nodal SFRT). Of 9 patients who received elective nodal SF-PORT, 8 did not have a successful sentinel lymph node biopsy. No MCC-specific deaths were observed. The most common side effect was in-field, grade 1 erythema (13%); no side effects > grade 1 (CTCAE v5) were noted.

CONCLUSION

SF-PORT is associated with a very low LRR which has proven durable with long-term follow-up. The LRR for SF-PORT appears lower than historical controls treated with surgery alone for patients with resected, stage I/II MCC with high-risk features.

Real-world clinical outcomes with avelumab in patients with Merkel cell carcinoma treated in the USA: a multicenter chart review study

Background

Merkel cell carcinoma (MCC) is a rare, aggressive, cutaneous neuroendocrine neoplasm with annual incidence rates of 0.13–1.6 cases/100,000/year worldwide as of 2018. Chemotherapy for metastatic MCC (mMCC) has high objective response rates (ORRs), but responses are not durable and overall survival (OS) is poor. Avelumab (anti-programmed death-ligand 1) has demonstrated meaningful survival benefit and durable responses in clinical trials for mMCC. This study investigated real-world clinical outcomes in avelumab-treated patients with advanced (stage IIIB/IV) MCC in US academic medical centers.

Methods

We conducted a retrospective chart review of patients with advanced MCC who initiated avelumab between March 1, 2017, and July 31, 2019, at six US academic centers. Data were requested for eligible patients from index date through December 31, 2020. Descriptive analyses were conducted to assess demographic and clinical characteristics, real-world ORR (rwORR), real-world duration of response, real-world progression-free survival (rwPFS), and OS.

Results

Ninety patients with advanced MCC (82%, stage IV; 18%, stage IIIB) received avelumab. Median follow-up was 20.8 months (95% CI: 19.1 to 24.2). Median age was 68 years (range, 48–83), and the majority of patients were men (58%) and white (93%). The primary tumor was most commonly located on the lower limb (38%), with metastases mostly located in lymph nodes (68%), lung (52%), and viscera (52%). Approximately 42% and 26% of patients had an Eastern Cooperative Oncology Group performance status of 2 and 3, respectively. Seventy-three patients (81%) received avelumab as first-line treatment of advanced MCC, while 17 (19%) received avelumab as second-line or later treatment. The median duration of avelumab treatment was 13.5 months (95% CI: 6.4 to 30.6), with 42% of patients still receiving avelumab by the end of follow-up. Patients with avelumab treatment had an rwORR of 73% (95% CI: 64 to 83), median rwPFS of 24.4 months (95% CI: 8.31 to not estimable (NE)), and median OS of 30.7 months (95% CI: 11.2 to NE).

Conclusions

This real-world study of patients with advanced MCC demonstrated that avelumab treatment resulted in a high response rate with durable responses and prolonged survival. The study findings validate the results demonstrated in prospective clinical trials and other observational studies.

The relationship between circulating tumor DNA with Merkel cell carcinoma tumor burden and detection of recurrence

9566

Background: Merkel cell carcinoma (MCC) is an aggressive skin cancer with a recurrence rate of 40%. Early detection of recurrence can improve outcomes, and effective surveillance is crucial for management of patients with MCC. While Merkel cell polyomavirus (MCPyV) oncoprotein serology is useful in surveillance for MCPyV-positive MCC tumors, patients with MCPyV-negative tumors have no available blood biomarkers and require frequent imaging. This prospective, multicenter study assessed whether circulating tumor DNA (ctDNA) can assess disease burden and detect recurrence regardless of virus status. Methods: A total of 328 blood samples were collected from 125 patients at various time points with a median follow-up of 6 months (range: 0-21 months) between April 2020 to January 2022. Whole-exome sequencing was performed on tumor tissue and matched normal blood to identify a set of somatic, clonal single nucleotide variants, which were tracked in subsequent blood (plasma) samples using a personalized and multiplex PCR-NGS based ctDNA assay (Signatera). Clinically evident disease was defined as MCC noted either by physical exam or by imaging, and molecular evidence of disease was defined as a positive ctDNA test. Surveillance phase began once there was no clinically evident or molecular evidence of disease. Results: Among 125 patients, 47 (38%) had clinically evident MCC and all were found to be ctDNA-positive at the first time point (sensitivity: 100%; 95% CI: 91-100%). Of the 47, 24 were newly diagnosed with MCC and had a median primary tumor size of 2.2 cm (range 0.5-8.5 cm) and a median ctDNA value of 26 mean tumor molecules (MTM)/mL (range: 0.08-1470 MTM/mL). Primary tumor diameter and ctDNA value were strongly correlated (Spearman’s r = 0.81, p < 0.001). Of the 125 patients, 73 (58%) patients were assessed in the surveillance setting and had a total of 152 plasma samples available for longitudinal ctDNA testing. Over this period, 7 ctDNA tests were positive while 145 were negative. After a positive test, 5/7 developed a clinically evident recurrence (4 within 60 days). Of the remaining 2 without clinical recurrence, one had < 60 days of follow-up at time of data analysis. The estimated risk of recurrence, accounting for incomplete follow-up, was 57% within 60 days of a positive ctDNA test (n = 7 tests). In contrast, after a negative ctDNA test (n = 145 tests), the risk of recurrence was 0% within 60 days and 3% between 60-90 days. Conclusions: To our knowledge, this is the largest study to explore ctDNA testing in MCC patients. This study demonstrates that ctDNA testing can detect MCC recurrence early and is a promising clinical surveillance tool regardless of tumor viral status.

Recurrence and Mortality Risk of Merkel Cell Carcinoma by Cancer Stage and Time From Diagnosis

IMPORTANCE

Merkel cell carcinoma (MCC) often behaves aggressively; however, disease-recurrence data are not captured in national databases, and it is unclear what proportion of patients with MCC experience a recurrence (estimates vary from 27%-77%). Stage-specific recurrence data that includes time from diagnosis would provide more precise prognostic information and contribute to risk-appropriate clinical surveillance.

OBJECTIVE

To estimate risk of stage-specific MCC recurrence and mortality over time since diagnosis.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study included 618 patients with MCC who were prospectively enrolled in a Seattle-based data repository between 2003 and 2019. Of these patients, 223 experienced a recurrence of MCC. Data analysis was performed July 2019 to November 2021.

MAIN OUTCOMES AND MEASURES

Stage-specific recurrence and survival, as well as cumulative incidence and Kaplan-Meier analyses.

RESULTS

Among the 618 patients included in the analysis (median [range] age, 69 [11-98] years; 227 [37%] female), the 5-year recurrence rate for MCC was 40%. Risk of recurrence in the first year was high (11% for patients with pathologic stage I, 33% for pathologic stage IIA/IIB, 30% for pathologic stage IIIA, 45% for pathologic stage IIIB, and 58% for pathologic stage IV), with 95% of recurrences occurring within the first 3 years. Median follow-up among living patients was 4.3 years. Beyond stage, 4 factors were associated with increased recurrence risk in univariable analyses: immunosuppression (hazard ratio [HR], 2.4; 95% CI, 1.7-3.3; P < .001), male sex (HR, 1.9; 95% CI, 1.4-2.5; P < .001), known primary lesion among patients with clinically detectable nodal disease (HR, 2.3; 95% CI, 1.4-4.0; P = .001), and older age (HR, 1.1; 95% CI, 1.0-1.3; P = .06 for each 10-year increase). Among 187 deaths in the cohort, 121 (65%) were due to MCC. The MCC-specific survival rate was strongly stage dependent (95% at 5 years for patients with pathologic stage I vs 41% for pathologic stage IV). Among patients presenting with stage I to II MCC, a local recurrence (17 arising within/adjacent to the primary tumor scar) did not appreciably diminish survival compared with patients who had no recurrence (85% vs 88% MCC-specific survival at 5 years).

CONCLUSIONS AND RELEVANCE

In this cohort study, the MCC recurrence rate (approximately 40%) was notably different than that reported for invasive melanoma (approximately 19%), squamous cell carcinoma (approximately 5%-9%), or basal cell carcinoma (approximately 1%-2%) following definitive therapy. Because more than 90% of MCC recurrences arise within 3 years, it is appropriate to adjust surveillance intensity accordingly. Stage- and time-specific recurrence data can assist in appropriately focusing surveillance resources on patients and time intervals in which recurrence risk is highest.

628 Real-world clinical outcomes among patients with advanced Merkel cell carcinoma treated with avelumab in academic medical centers in the United States

Background

Merkel cell carcinoma (MCC) is a rare, aggressive cutaneous neuroendocrine neoplasm with annual incidence rates ranging from 0.13 to 1.6 cases per 100,000 per year.1 Chemotherapy for metastatic MCC (mMCC) has high objective response rates (ORRs), but responses are not durable and overall survival (OS) is poor. In March 2017, avelumab (anti–PD-L1) was approved for the treatment of mMCC and has demonstrated meaningful survival benefit and durable response.2 This study sought to investigate real-world clinical outcomes of avelumab-treated patients with advanced (stage IIIB/IV) MCC in academic medical centers in the United States (US).

Methods

A retrospective chart review study of patients with advanced MCC who initiated avelumab between March 1, 2017, and July 31, 2019 was conducted at 6 US academic medical centers across the 4 US census regions. Eligible patients were followed through December 30, 2020. Descriptive analyses were conducted to assess demographics, clinical characteristics, and outcomes. Kaplan-Meier curves were constructed to illustrate real-world duration of response (rwDOR), real-world progression free survival (rwPFS), OS, and time-to-treatment discontinuation.

Results

Ninety patients with advanced MCC were treated with avelumab, with a median follow-up of 15.0 months (95% CI, 13.1–17.8). Median age was 68 years; the majority were male (58%) and White (93%). During the time of avelumab initiation, 74 patients had stage IV MCC and 16 patients had stage IIIB MCC. Primary tumor was located most commonly on the lower limb (38%), with metastasis primarily to lymph nodes (67%) and lung (52%); 52% of patients had visceral metastases. Approximately 42% and 26% of patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 2 and 3, respectively. Seventy-three patients (81%) received avelumab as first-line treatment of advanced MCC, whereas 17 (19%) received avelumab as second-line or later. Median duration of avelumab treatment was 13.5 months (95% CI, 6.4–30.6); 58% discontinued by the end of follow-up. Patients with avelumab treatment (n=90) had a rwORR of 73% (95% CI, 64–83), median rwPFS of 24.4 months (95% CI, 8.3-not reached [NR]), and median OS of 30.7 months (95% CI, 11.2-NR). Other clinical outcomes by line of avelumab treatment and stage at avelumab initiation are reported in table 1.

Conclusions

This real-world study of patients with advanced MCC treated with avelumab demonstrates high response rate with durable responses and prolonged survival. The study findings are consistent with the efficacy results demonstrated in pivotal clinical trials2 and other recent observational studies.3 4

Acknowledgements

The authors would like to acknowledge all physicians at the respective sites who participated in the data collection process for the study.

References

Müller-Richter UDA, Gesierich A, Kübler AC, Hartmann S, Brands RC. Merkel cell carcinoma of the head and neck: recommendations for diagnostics and treatment. Ann Surg Oncol 2017;24:3430–3437.

D'Angelo SP, Bhatia S, Brohl AS, et al. Avelumab in patients with previously treated metastatic Merkel cell carcinoma: long-term data and biomarker analyses from the single-arm phase 2 JAVELIN Merkel 200 trial. J Immunother Cancer 2020;8:e000674.

Cowey CL, Liu FX, Kim R, et al. Real-world clinical outcomes with first-line avelumab in locally advanced/metastatic Merkel cell carcinoma in the USA: SPEAR-Merkel. Future Oncol 2021;17:2339–2350.

Levy S, Aarts MJB, Eskens FALM, et al. Avelumab for advanced Merkel cell carcinoma in the Netherlands: a real-world cohort. J Immunother Cancer 2020;8:e001076.

Ethics Approval

The study was approved by New England Institutional Review Board.

Abstract 628 Table 1

Clinical outcomes among avelumab-treated patients with advanced MCC by line-of-treatment and stage at avelumab initiation

Folate hydrolase-1 (FOLH1) is a novel target for antibody-based brachytherapy in Merkel cell carcinoma

Backgrounds

Folate Hydrolase‐1 (FOLH1; PSMA) is a type II transmembrane protein, luminally expressed by solid tumour neo‐vasculature. Monoclonal antibody (mAb), J591, is a vehicle for mAb‐based brachytherapy in FOLH1+ cancers. Brachytherapy is a form of radiotherapy that involves placing a radioactive material a short distance from the target tissue (e.g., on the skin or internally); brachytherapy is commonly accomplished with the use of catheters, needles, metal seeds and antibody or small peptide conjugates. Herein, FOLH1 expression in primary (p) and metastatic (m) Merkel cell carcinoma (MCC) is characterized to determine its targeting potential for J591‐brachytherapy.

Materials & Methods

Paraffin sections from pMCC and mMCC were evaluated by immunohistochemistry for FOLH1. Monte Carlo simulation was performed using the physical properties of conjugated radioisotope lutetium‐177. Kaplan–Meier survival curves were calculated based on patient outcome data and FOLH1 expression.

Results

Eighty‐one MCC tumours were evaluated. 67% (54/81) of all cases, 77% (24/31) pMCC and 60% (30/50) mMCC tumours were FOLH1+. Monte Carlo simulation showed highly localized ionizing tracks of electrons emitted from the targeted neo‐vessel. 42% (34/81) of patients with FOLH1+/− MCC had available survival data for analysis. No significant differences in our limited data set were detected based on FOLH1 status (p = 0.4718; p = 0.6470), staining intensity score (p = 0.6966; p = 0.9841) or by grouping staining intensity scores (− and + vs. ++, +++, +++) (p = 0.8022; p = 0.8496) for MCC‐specific survival or recurrence free survival, respectively.

Conclusions

We report the first evidence of prevalent FOLH1 expression within MCC‐associated neo‐vessels, in 60‐77% of patients in a large MCC cohort. Given this data, and the need for alternatives to immune therapies it is appropriate to explore the safety and efficacy of FOLH1‐targeted brachytherapy for MCC.

What's already known about this topic?

We report the first evidence of prevalent folate hydrolase‐1 (FOLH1; also known as prostate‐specific membrane antigen) expression within MCC‐associated neovessels.

What does this study add?

Herein, FOLH1 expression in Merkel cell carcinoma neovasculature is validated, and the therapeutic mechanism of specific, systemic targeting of disseminated disease with antibody‐based brachytherapy, is defined.

Integrative medicine use in patients with cutaneous T-Cell lymphoma: A cross-sectional survey study

OBJECTIVES

To characterize patterns of integrative medicine (IM) use and health-related quality of life (HRQoL) in patients with cutaneous T-cell lymphoma (CTCL).

DESIGN

Cross-sectional, online survey, created in conjunction with the Cutaneous Lymphoma Foundation (CLF).

SETTING

A link to the online survey was posted on the CLF Facebook page and emailed to the CLF listserv; 372 survey responses were received.

MAIN OUTCOME MEASURES

The study outcomes were IM use, cancer symptoms, and HRQoL measured via the Skindex-16 and Functional Assessment of Cancer Therapy-General (FACT-G).

RESULTS

A total of 292 patient responses (66 % female, median age 59y) were included in analysis. 87 % had mycosis fungoides and 12 % had Sézary syndrome. A majority (59 %) of patients reported using IM for their CTCL, with 48 % using IM to treat their disease and 47 % using IM to manage their symptoms. The most commonly used IM were vitamins/minerals (32 %), prayer/meditation (26 %), diet (24 %), and exercise/yoga (22 %). Higher itch scores were reported by patients using IM compared to non-users (31 (IQR 10-62) and 18 (IQR 3-46) respectively; p = 0.002). HRQoL was worse among patients who reported IM use; median Skindex-16 scores were 54 (IQR 28-72) among IM users compared to 33 (IQR 19-57) for non-IM users (p < 0.001).

CONCLUSIONS

IM use is common among patients with CTCL, particularly those with worse itching and worse HRQoL. IM interventions require further study given use by CTCL patients to treat disease and ameliorate symptoms.

Prevalence of sexual harassment and sexual assault from patient to provider among women in dermatology and across specialties

BACKGROUND

Sexual harassment (SH) includes unwelcome sexual advances, requests for sexual favors, and hostile conduct that targets someone based on gender and overlaps with some types of sexual assault (SA). SH/SA in health care can occur between providers or between patient and provider. Most studies of SH in medicine focus on SH perpetrated by one health care provider against another, with very few studies examining SH from patient to provider.

OBJECTIVE

This study aimed to describe the prevalence and impact of SH/SA from patient to provider, with a particular focus on SH/SA experienced by dermatologists and trainees.

METHODS

An anonymous electronic survey was sent to professional listservs and an online forum, which included representatives from multiple institutions, practice settings, and medical specialties. Trainees and dermatologists were targeted particularly.

RESULTS

A total of 330 complete responses were included. In all, 83% of respondents reported experiencing SH from a patient. SH from a patient was more frequently reported by women compared with men (94% vs. 52%; p = .001). Behaviors consistent with SA were experienced by 31% of respondents and were more frequently experienced by women (35% vs. 15%; p = .001). Women were more likely to report that patient-to-provider SH contributed to burnout (33% of women vs. 9% of men; p = .002). Female trainees were significantly more likely to have experienced SH compared with female attendings within the past year (94 of 110 trainees [86%] vs. 83 of 127 attendings [65%]; p = .001). There was no significant difference in the proportion of women reporting ever experiencing SH when comparing dermatology and nondermatology specialties.

LIMITATIONS

The limitations of this study include the relatively small sample size, oversampling of trainees, and a gender-biased sample.

CONCLUSION

Patient-to-provider SH/SA is widespread, particularly among women and trainees, and may have a significant impact on burnout.

Clinical benefit of baseline imaging in Merkel cell carcinoma: Analysis of 584 patients

BACKGROUND

Merkel cell carcinoma (MCC) guidelines derive from melanoma and do not recommend baseline cross-sectional imaging for most patients. However, MCC is more likely to have metastasized at diagnosis than melanoma.

OBJECTIVE

To determine how often baseline imaging identifies clinically occult MCC in patients with newly diagnosed disease with and without palpable nodal involvement.

METHODS

Analysis of 584 patients with MCC with a cutaneous primary tumor, baseline imaging, no evident distant metastases, and sufficient staging data.

RESULTS

Among 492 patients with clinically uninvolved regional nodes, 13.2% had disease upstaged by imaging (8.9% in regional nodes, 4.3% in distant sites). Among 92 patients with clinically involved regional nodes, 10.8% had disease upstaged to distant metastatic disease. Large (>4 cm) and small (<1 cm) primary tumors were both frequently upstaged (29.4% and 7.8%, respectively). Patients who underwent positron emission tomography-computed tomography more often had disease upstaged (16.8% of 352), than those with computed tomography alone (6.9% of 231; P = .0006).

LIMITATIONS

This was a retrospective study.

CONCLUSIONS

In patients with clinically node-negative disease, baseline imaging showed occult metastatic MCC at a higher rate than reported for melanoma (13.2% vs <1%). Although imaging is already recommended for patients with clinically node-positive MCC, these data suggest that baseline imaging is also indicated for patients with clinically node-negative MCC because upstaging is frequent and markedly alters management and prognosis.

Imaging of Merkel Cell Carcinoma: What Imaging Experts Should Know

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous neuroendocrine tumor with a higher mortality rate than melanoma. Approximately 40% of MCC patients have nodal or distant metastasis at initial presentation, and one-third of patients will develop distant metastatic disease over their clinical course. Although MCC is rare, its incidence has been steadily increasing. Furthermore, the immunogenicity of MCC and its diagnostic and therapeutic application have made MCC one of the most rapidly developing topics in dermatology and oncology. Owing to the aggressive and complex nature of MCC, a multidisciplinary approach is necessary for management of this tumor, including dermatologists, surgeons, radiation oncologists, medical oncologists, pathologists, radiologists, and nuclear medicine physicians. Imaging plays a crucial role in diagnosis, planning for surgery or radiation therapy, and assessment of treatment response and surveillance. However, MCC is still not well recognized among radiologists and nuclear medicine physicians, likely owing to its rarity. The purpose of this review is to raise awareness of MCC among imaging experts by describing the epidemiology, pathophysiology, and clinical features of MCC and current clinical management with a focus on the role of imaging. The authors highlight imaging findings characteristic of MCC, as well as the clinical significance of CT, MRI, sentinel lymph node mapping, fluorine 18 fluorodeoxyglucose PET/CT, and other nuclear medicine studies such as bone scintigraphy and somatostatin receptor scintigraphy. ^©RSNA, 2019.

Narrow excision margins are appropriate for Merkel cell carcinoma when combined with adjuvant radiation: Analysis of 188 cases of localized disease and proposed management algorithm

BACKGROUND

Merkel cell carcinoma (MCC) management typically includes surgery with or without adjuvant radiation therapy (aRT). Major challenges include determining surgical margin size and whether aRT is indicated.

OBJECTIVE

To assess the association of aRT, surgical margin size, and MCC local recurrence.

METHODS

Analysis of 188 MCC cases presenting without clinical nodal involvement.

RESULTS

aRT-treated patients tended to have higher-risk tumors (larger diameter, positive microscopic margins, immunosuppression) yet had fewer local recurrences (LRs) than patients treated with surgery only (1% vs 15%; P = .001). For patients who underwent surgery alone, 7 of 35 (20%) treated with narrow margins (defined as ≤1.0 cm) developed LR, whereas 0 of 13 patients treated with surgical margins greater than 1.0 cm developed LR (P = .049). For aRT-treated patients, local control was excellent regardless of surgical margin size; only 1% experienced recurrence in each group (1 of 70 with narrow margins ≤1 cm and 1 of 70 with margins >1 cm; P = .56).

LIMITATIONS

This was a retrospective study.

CONCLUSIONS

Among patients treated with aRT, local control was superb even if significant risk factors were present and margins were narrow. We propose an algorithm for managing primary MCC that integrates risk factors and optimizes local control while minimizing morbidity.

High somatostatin receptor expression and efficacy of somatostatin analogues in patients with metastatic Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive, high-grade, cutaneous neuroendocrine tumour (NET). Agents blocking programmed death 1/programmed death ligand 1 have efficacy in metastatic MCC (mMCC), but half of patients do not derive durable benefit. Somatostatin analogues (SSAs) are commonly used to treat low- and moderate-grade NETs that express somatostatin receptors (SSTRs).

OBJECTIVES

To assess SSTR expression and the efficacy of SSAs in mMCC, a high-grade NET. Methods In this retrospective study of 40 patients with mMCC, SSTR expression was assessed radiologically by somatostatin receptor scintigraphy (SRS; n = 39) and/or immunohistochemically when feasible (n = 9). Nineteen patients (18 had SRS uptake in MCC tumours) were treated with SSA. Disease control was defined as progression-free survival (PFS) of ≥ 120 days after initiation of SSA.

RESULTS

Thirty-three of 39 patients (85%) had some degree (low 52%, moderate 23%, high 10%) of SRS uptake. Of 19 patients treated with SSA, seven had a response-evaluable target lesion; three of these seven patients (43%) experienced disease control, with a median PFS of 237 days (range 152-358). Twelve of 19 patients did not have a response-evaluable lesion due to antecedent radiation; five of these 12 (42%) experienced disease control (median PFS of 429 days, range 143-1757). The degree of SSTR expression (determined by SRS and/or immunohistochemistry) did not correlate significantly with the efficacy endpoints.

CONCLUSIONS

In contrast to other high-grade NETs, mMCC tumours appear frequently to express SSTRs. SSAs can lead to clinically meaningful disease control with minimal side-effects. Targeting of SSTRs using SSA or other novel approaches should be explored further for mMCC.

Patterns of distant metastases in 215 Merkel cell carcinoma patients: Implications for prognosis and surveillance

Approximately one‐third of Merkel cell carcinoma (MCC) patients eventually develop distant metastatic disease. Little is known about whether the location of the primary lesion is predictive of initial distant metastatic site, or if survival likelihood differs depending on the metastatic site. Such data could inform imaging/surveillance practices and improve prognostic accuracy. Multivariate and competing‐risk analyses were performed on a cohort of 215 MCC patients with distant metastases, 31% of whom had two or more initial sites of distant metastasis. At time of initial distant metastasis in the 215 patients, metastatic sites (n = 305) included non‐regional lymph nodes (present in 41% of patients), skin/body wall (25%), liver (23%), bone (21%), pancreas (8%), lung (7%), and brain (5%). Among the 194 patients who presented with MCC limited to local or regional sites (stage I‐III) but who ultimately developed distant metastases, distant progression occurred in 49% by 1 year and in 80% by 2 years following initial diagnosis. Primary MCC locations differed in how likely they were to metastasize to specific organs/sites (P < .001). For example, liver metastases were far more likely from a head/neck primary (43% of 58 patients) versus a lower limb primary (5% of 39 patients; P < .0001). Skin‐only distant metastasis was associated with lower MCC‐specific mortality as compared to metastases in multiple organs/sites (HR 2.7; P = .003), in the liver (HR 2.1; P = .05), or in distant lymph nodes (HR 2.0; P = .045). These data reflect outcomes before PD1‐pathway inhibitor availability, which may positively impact survival. In conclusion, primary MCC location is associated with a pattern of distant spread, which may assist in optimizing surveillance. Because it is linked to survival, the site of initial distant metastasis should be considered when assessing prognosis.

Travel burden associated with rare cancers: The example of Merkel cell carcinoma

Background

There are limited data on the travel burden for cancer patients with rare tumor types, such as Merkel cell carcinoma (MCC).

Objective

The objective of this study was to understand the travel burden of MCC patients.

Methods

This study used data from an MCC registry at the Seattle Cancer Care Alliance (SCCA). All MCC patients enrolled at SCCA with a valid 3‐digit ZIP code were included. Patients were followed up from January 1, 2012 until their last follow‐up, death, or end of data (January 1, 2017). Travel burden was measured by one‐way travel distance to SCCA from each patient's 3‐digit ZIP code. Patient demographics, tumor characteristics, and follow‐up visit were evaluated and stratified by one‐way driving distance of ≤300 and >300 miles.

Results

A total of 391 MCC patients were included (68% men, mean age = 67 years [±SD = ±11 years], 67% residing in the West, and 70% white). At diagnosis, 53% of the patients had Stage III or IV MCC. Mean one‐way distance traveled by patients was 1,137 (median: 813) miles, and 57% of patients traveled >300 miles. Compared to patients who traveled ≤300 miles, those who traveled >300 miles were more likely to be <70 years old (46% vs 65%; P < 0.001), were diagnosed with advanced stage (III or IV) MCC (46% vs 59%; P = 0.01), had shorter follow‐up in the cancer registry (mean: 509 vs 212 days; P < 0.001), and had fewer visits during follow‐up (mean: 5.2 vs 2.5; P < 0.001).

Conclusions

In this single cancer center study, the majority of MCC patients trav‐eled long distances to receive expert care. Longer travel distances appeared to be associated with younger age, a more advanced stage of cancer at study entry and fewer in‐clinic visits, suggesting that travel burden may impact timely and adequate patient care for this rare cancer.

Differential Outcomes Among Immunosuppressed Patients With Merkel Cell Carcinoma: Impact of Immunosuppression Type on Cancer-specific and Overall Survival

OBJECTIVES

Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer with higher incidence among whites, elderly, and immunosuppressed patients. Although immunosuppressed MCC patients are at higher risk of recurrence and MCC-related death, it is unknown whether immunosuppression type is associated with differential outcomes.

MATERIALS AND METHODS

We retrospectively evaluated 89 nonmetastatic MCC patients with a diagnosis of chronic immunosuppression. Immunosuppression was categorized as chronic lymphocytic leukemia (31% of cohort), other hematologic malignancies (18%), solid organ transplant (21%), autoimmune disease (21%), and human immunodeficiency virus acquired deficiency syndrome (8%). Progression-free survival (PFS) and MCC-specific survival (MSS) were estimated with the cumulative incidence function. Overall survival (OS) was estimated by the Kaplan-Meier method.

RESULTS

With a median follow-up of 52 months, 53 deaths occurred (42 from MCC, 7 unknown, and 4 non-MCC). Two-year PFS, MSS, and OS were 30%, 55%, and 52%, respectively. Human immunodeficiency virus/acquired deficiency syndrome and solid organ transplant patients were diagnosed with MCC at a younger age (median 55 and 59 y, respectively) and with more advanced stage disease compared with other immunosuppressed subgroups. PFS did not significantly differ among the 5 immunosuppression subgroups (P=0.30), but significant differences were observed in MSS and OS (both P=0.01). Controlling for potential confounders for OS, including age and stage, immunosuppression type was still significantly associated with risk of death (P=0.01).

CONCLUSIONS

Among immunosuppressed MCC patients, recurrent MCC is the major cause of mortality. The risk of death from MCC differs among immunosuppression types, suggesting important biological differences in host-tumor immune interactions.

Abstract 2518: Folate hydrolase-1 is a novel target for J591-brachytherapy in Merkel cell carcinoma

Folate hydrolase-1 (FOLH1) is a type II transmembrane protein. Oncologically, FOLH1 is upregulated throughout prostate cancer cells; it is also luminally expressed by the neovasculature of most solid tumors but not by normal vessels. J591, a monoclonal antibody (AB), is specific to, and is effectively endocytosed after extracellular binding to, FOLH1. J591 is presently being developed in clinical trials as a vehicle for AB-based brachytherapy in FOLH1+ cancers. Merkel cell carcinoma (MCC) is a rare, neuroendocrine tumor; metastatic (m) MCC is associated with poor survival. We characterized FOLH1 expression in MCC to determine its target potential for J591-brachytherapy. Paraffin sections from primary (p) and mMCC were deparaffinized and rehydrated. Samples were stained with 3E6 (DAKO), a mouse IgG1 monoclonal anti-human FOLH1. Mouse IgG1 (10 ug/mL in 1% bovine serum albumin) was used as an isotype-matched negative control. Anti-CD31 (IgG1) was used as a positive control. Kaplan-Meier survival curves were calculated based on patient outcome data and FOLH1 expression. 81 MCC tumors were evaluated. 67% (54/81) of all cases with 77% (24/31) of pMCC and 60% (30/50) of mMCC tumors demonstrated FOLH1+ neovessels. No cellular staining of tumor cells was identified. 34 patients with FOLH1 +/- MCC were demographically homogeneous in terms of sex, age, immunosuppression status, prior therapies, stage at diagnosis, and local or distant recurrences. No significant differences were detected based on FOLH1 status, in regards to MCC specific survival (P=0.905), or overall survival (P=0.687), as measured from time of diagnosis. FOLH1 is expressed in the majority of pMCC and mMCC cases and is nonprognostic. Our findings support further investigation of targeted therapy with J591-brachytherapy for the management of MCC.

Citation Format: Barbara Meier, Marigdalia K. Ramirez-Fort, Kristina Lachance, Candice D. Church, Sean S. Mahase, Joseph M. Jenrette, Christopher S. Lange, Lars E. French, Paul Nghiem, Neil H. Bander. Folate hydrolase-1 is a novel target for J591-brachytherapy in Merkel cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2518.

Effect of Patient Immune Status on the Efficacy of Radiation Therapy and Recurrence-Free Survival Among 805 Patients With Merkel Cell Carcinoma

PURPOSE

Patients with Merkel cell carcinoma (MCC) with chronic immunosuppression (IS) have worse outcomes, but the mechanisms are not well understood. We hypothesized that these differences may be mediated in part by differential response to treatment, and we evaluated whether radiation therapy (RT) efficacy is altered among IS compared with immune-competent (IC) patients with MCC.

METHODS AND MATERIALS

Among 805 patients with MCC, recurrence-free survival (RFS) and patterns of first recurrence were compared between 89 IS and 716 IC patients with stage I to III MCC treated with curative intent. We used a Fine and Gray's competing risk multivariable analysis to estimate associations with RFS.

RESULTS

IS and IC patients with MCC had similar demographic and disease characteristics. Most (77% IC, 86% IS) were irradiated (median, 50.4 Gy IC, 50.3 Gy IS), although more IS patients were irradiated to the primary site (97% vs 81%). With a median follow-up of 54.4 months, IS patients had inferior RFS (2-year: 30% vs 57%; P < .0001) and higher rates of local recurrence as the first site of relapse (25% vs 12%; P = .0002). The association between RT and RFS differed by immune status (interaction P = .01). Although RT was associated with significantly improved RFS among IC patients (hazard ratio 0.56, 95% confidence interval 0.44-0.72), no difference in RFS was observed with RT among IS patients (hazard ratio 1.49, 95% confidence interval 0.70-3.17).

CONCLUSIONS

Radiation therapy efficacy at current standard RT doses for MCC is impaired among immunosuppressed patients with MCC. Although a strong link between durability of RT response and immune function does not appear to be evident in most cancers, our results may reflect an especially dynamic interaction between immune status and RT efficacy in MCC.

Tumor-Infiltrating Merkel Cell Polyomavirus-Specific T Cells Are Diverse and Associated with Improved Patient Survival

Tumor-infiltrating CD8+ T cells are associated with improved survival of patients with Merkel cell carcinoma (MCC), an aggressive skin cancer causally linked to Merkel cell polyomavirus (MCPyV). However, CD8+ T-cell infiltration is robust in only 4% to 18% of MCC tumors. We characterized the T-cell receptor (TCR) repertoire restricted to one prominent epitope of MCPyV (KLLEIAPNC, "KLL") and assessed whether TCR diversity, tumor infiltration, or T-cell avidity correlated with clinical outcome. HLA-A*02:01/KLL tetramer+ CD8+ T cells from MCC patient peripheral blood mononuclear cells (PBMC) and tumor-infiltrating lymphocytes (TIL) were isolated via flow cytometry. TCRβ (TRB) sequencing was performed on tetramer+ cells from PBMCs or TILs (n = 14) and matched tumors (n = 12). Functional avidity of T-cell clones was determined by IFNγ production. We identified KLL tetramer+ T cells in 14% of PBMC and 21% of TIL from MCC patients. TRB repertoires were strikingly diverse (397 unique TRBs were identified from 12 patients) and mostly private (only one TCRb clonotype shared between two patients). An increased fraction of KLL-specific TIL (>1.9%) was associated with significantly increased MCC-specific survival P = 0.0009). T-cell cloning from four patients identified 42 distinct KLL-specific TCRa/b pairs. T-cell clones from patients with improved MCC-specific outcomes were more avid (P < 0.05) and recognized an HLA-appropriate MCC cell line. T cells specific for a single MCPyV epitope display marked TCR diversity within and between patients. Intratumoral infiltration by MCPyV-specific T cells was associated with significantly improved MCC-specific survival, suggesting that augmenting the number or avidity of virus-specific T cells may have therapeutic benefit. Cancer Immunol Res; 5(2); 137-47. ©2017 AACR.

Polyomavirus-Negative Merkel Cell Carcinoma: A More Aggressive Subtype Based on Analysis of 282 Cases Using Multimodal Tumor Virus Detection

Previous studies have reached conflicting conclusions regarding the proportion of Merkel cell carcinomas (MCCs) that contain the Merkel cell polyomavirus (MCPyV) and the clinical significance of tumor viral status. To address these controversies, we detected MCPyV large T antigen using immunohistochemistry with two distinct antibodies and MCPyV DNA using quantitative PCR. Tumors were called MCPyV-positive if two or more of these three assays indicated presence of this virus. A total of 53 of 282 (19%) MCC tumors in this cohort were virus-negative using this multimodal system. Immunohistochemistry with the CM2B4 antibody had the best overall performance (sensitivity = 0.882, specificity = 0.943) compared with the multimodal classification. Multivariate analysis including age, sex, and immunosuppression showed that, relative to MCC patients with virus-positive tumors, virus-negative MCC patients had significantly increased risk of disease progression (hazard ratio = 1.77, 95% confidence interval = 1.20-2.62) and death from MCC (hazard ratio = 1.85, 95% confidence interval = 1.19-2.89). We confirm that approximately 20% of MCCs are not driven by MCPyV and that such virus-negative MCCs, which can be quite reliably identified by immunohistochemistry using the CM2B4 antibody alone, represent a more aggressive subtype that warrants closer clinical follow-up.