The efficacy of immune checkpoint blockade for melanoma in-transit with or without nodal metastases - A multicenter cohort study

Isolated Limb Infusion or Perfusion as First-Line Versus Second-Line Therapy for In-Transit Metastatic Melanoma

BACKGROUND

In-transit metastases (ITM) develops in 10% of patients with high-risk melanoma. Isolated limb infusion and perfusion (ILI/ILP) are well-established therapies for ITM, but the ideal line of therapy has not been defined. This study compared ILI/ILP as first- versus second-line therapy.

METHODS

An international multi-institution retrospective study reviewed patients with unresectable ITM who underwent ILI/ILP from 2006 to 2023.

RESULTS

The study was comprised of 364 patients (55% female) with a median age of 71 years. Of the 364 patients, 329 (90%) were treated with ILI/ILP as first-line therapy, and 35 (10%) were treated with ILI/ILP as second-line therapy. The median follow-up period was 3 years. Lower-extremity disease was present in 85% (n = 310) of the patients. The best response for ILI/ILP as any line of therapy was 54% complete response (CR), 29 % partial response (PR), 8.2% stable disease (SD), and 9.1% progressive disease (PD). The CR/PR/SD/PD rates for first- versus second-line therapy were respectively 55%/ 29%/ 7.5%/ 8.2% versus 41%/ 26%/ 15%/ 18% (P = 0.09). As first-line therapy, ILI/ILP was associated with a significantly higher overall response rate (ORR) of 84% versus 68% (odds ratio [OR], 2.9; 95% confidence interval [CI], 1.2-6.9; P = 0.02). The comparison showed no statistical difference in median in-field progression-free survival (PFS) (10.8 vs. 8.1 months; P = 0.2), out-of-field PFS (13.5 vs. 15.3 months; P = 0.4), or overall survival (OS) (4.1 vs. 4.5 years; P = 0.7).

CONCLUSION

For patients with unresectable melanoma ITM, ILI/ILP either as first- or second-line therapy provides high overall response rates. Although first-line therapy had a higher ORR, this did not translate to a difference in in-field PFS, indicating that ILI/ILP is indeed an effective salvage therapy also as second-line therapy.

Identification of Predictive Factors for the Development of In-Transit Metastasis in Patients with Melanoma

BACKGROUND

In patients with melanoma, in-transit metastasis (ITM) can develop. This study aimed to identify the risk for a first recurrence of ITM and associated predictive clinical factors in a large international cohort of patients with melanoma.

METHODS

Patients with primary cutaneous melanoma who underwent wide local excision (WLE) and sentinel lymph node biopsy (SLNB) were identified from the Sentinel Lymph Node Working Group (SLNWG) database between January 1993 and February 2023. Predictive factors for first recurrence of ITM were analyzed.

RESULTS

The study enrolled 7860 patients, and the median follow-up time was 47.1 months (interquartile range [IQR], 19.0-95.0 months). The risk for the development of ITM as a first recurrence was 4.12% (95% confidence interval [CI], 3.63-4.66%) at 5 years. The median time to first ITM recurrence was 15 months (IQR, 7.0-30.0 months). Significant clinicopathologic factors independently associated with an increased risk of ITM in multivariable analysis were increasing Breslow thickness (hazard ratio [HR], 1.37; 95% CI, 1.30-1.43; p < 0.0001), lower-extremity versus trunk melanoma (HR, 2.49; 95% CI, 1.86-3.32; p < 0.0001), increasing age (HR, 1.03; 95% CI, 1.02-1.04; p < 0.0001), number of positive sentinel lymph nodes (SLNs: 1 vs. 0 [HR, 2.24; 95% CI, 1.66-3.01; p < 0.0001] and 2 vs. 0 [HR, 2.37; 95% CI, 1.45-3.88; p = 0.0006]), and presence of vascular invasion (HR, 1.79; 95% CI, 1.21-2.64; p = 0.0035).

CONCLUSION

The independent risk factors for the development of ITM identified in a large international cohort of melanoma patients were Breslow thickness, lower-extremity melanoma, older age, number of positive SLNs, and presence of vascular invasion.

A comparison of isolated limb infusion/perfusion, immune checkpoint inhibitors, and intralesional therapy as first-line treatment for patients with melanoma in-transit metastases

BACKGROUND

Isolated limb infusion and perfusion (ILI/ILP) has been a mainstay treatment for unresectable melanoma in-transit metastases (ITM), but increased use of immune checkpoint inhibitors (ICI) and intralesional therapy (talimogene laherparepvec [TVEC]) introduced several different management options. This study compares first-line ILI/ILP, ICI, and TVEC.

METHODS

Retrospective review from 12 international institutions included patients treated from 1990 to 2022 with first-line ILI/ILP, ICI, or TVEC for unresectable melanoma ITM.

RESULTS

A total of 551 patients were treated, with ILI/ILP (n = 356), ICI (n = 125), and TVEC (n = 70) with median follow-up of 5.5 years. Tumor burden was highest with ILI/ILP and lowest with TVEC (p = .002). Breslow thickness was lowest with TVEC (p = .007). TVEC was mostly used in stage IIIB disease versus IIIC for ILI/ILP and ICI (p = .01). Using ICI as the reference category, TVEC had the highest odds of a complete response (CR) (odds ratio, 1.96; p = .029) and a longer local progression-free survival (PFS) (hazard ratio [HR], 0.40; p = .003). ILI/ILP had shorter local PFS (HR, 1.72; p = .012), PFS (HR, 1.79; p < .001), distant metastasis-free survival (DMFS) (HR, 1.75; p = .014), overall survival (HR, 1.82; p = .009), and melanoma-specific survival (HR, 2.29; p = .004). Stage IIIB disease had longer DMFS (HR, 0.24; p < .001) compared to IIIC/D.

CONCLUSIONS

TVEC as first-line therapy for unresectable melanoma ITM was associated with superior CR rates and local PFS. Notably, TVEC was used in patients with a lower Breslow thickness, disease stage, and tumor burden. Therefore, when compared to ILI/ILP and ICI, TVEC should be considered as first-line therapy for unresectable stage IIIB melanoma ITM with minimal tumor burden and lower Breslow thickness.

Treatment strategies with electrochemotherapy for limb in-transit melanoma: Real-world outcomes from a European, retrospective, cohort study

BACKGROUND

This study analysed treatment strategies with electrochemotherapy (ECT) in melanoma with limb in-transit metastases (ITM).

METHODS

We audited AJCC v.8 stage IIIB-IIID patients treated across 22 centres (2006-2020) within the International Network for Sharing Practices of ECT (InspECT).

RESULTS

452 patients were included, 58 % pre-treated (93 % had lower limb ITM, 44 % had ≤10 metastases [median size 1.5 cm]. Treatment strategies included first-line ECT (n = 145, 32 %), ECT with concurrent locoregional/systemic treatment (n = 163, 36 %), and salvage ECT (n = 144, 32 %). The objective response rate was 63 % (complete response [CR], 24 %), increasing to 74 % (CR, 39 %) following retreatment (median two ECT, range 1-8). CR rate in treatment-naïve and pre-treated patients was 50 % vs 32 % (p < 0.001). Bleomycin de-escalation was associated with lower CR (p = 0.004). Small tumour number and size, hexagonal electrode, retreatment, and post-ECT skin ulceration predicted response in multivariable analysis. At a median follow-up of 61 months, local and locoregional recurrence occurred in 55 % and 81 % of patients. Median local progression-free, new lesions-free, and regional recurrence-free survival were 32.9, 6.9, and 7.7 months. Grade-3 toxicity was 15 %. Concurrent treatment and CR correlated with improved regional control and survival. Concomitant checkpoint inhibition did not impact toxicity or survival outcomes. The median overall survival was 5.7 years.

CONCLUSIONS

Among patients with low-burden limb-only ITM, standard-dose bleomycin ECT results in durable local response. Treatment naivety, low tumour volume, hexagonal electrode application, retreatment, and post-ECT ulceration predict response. CR and concurrent treatment correlate with improved regional control and survival outcomes. Combination with checkpoint inhibitors is safe but lacks conclusive support.

Therapeutic Treatment Options for In-Transit Metastases from Melanoma

In-transit metastases (ITM) in melanoma present a significant therapeutic challenge due to their advanced stage and complex clinical nature. From traditional management with surgical resection, ITM treatment has evolved with the advent of systemic therapies such as immune checkpoint inhibitors and targeted therapies, which have markedly improved survival outcomes. This study aims to review and highlight the efficacy of both systemic and locoregional treatment approaches for ITM. Methods include a comprehensive review of clinical studies examining the impact of treatments like immune checkpoint inhibitors, targeted therapies, Isolated Limb Perfusion, and electrochemotherapy. The results indicate that combining systemic therapies with locoregional treatments enhances both local disease control and overall survival rates. The introduction of modern immunotherapies has not diminished the effectiveness of locoregional therapies but rather improved patient outcomes when used in conjunction. The conclusions emphasize that a multidisciplinary approach integrating systemic and locoregional therapies offers a promising strategy for optimizing the management of ITM in melanoma patients. This integrated treatment model not only improves survival rates but also enhances the quality of life for patients, suggesting a shift in standard care practices toward more comprehensive therapeutic regimens.

Isolated hyperthermic perfusions for cutaneous melanoma in-transit metastasis of the limb and uveal melanoma metastasis to the liver

Patients with cutaneous melanoma can develop in-transit metastases (ITM), most often localized to limbs. For patients with uveal melanoma that develop metastatic disease, the overall majority develop isolated liver metastases. For these types of metastases, regional cancer therapies have evolved as effective treatments. Isolated limb perfusion (ILP), isolated limb infusion (ILI), isolated hepatic perfusion (IHP) and percutaneous hepatic perfusion (PHP) achieve a high local concentration of chemotherapy with minimal systemic exposure. This review discusses the mechanism and available literature on locoregional treatment modalities in the era of modern immunotherapy.

The effect of a single dose of nivolumab prior to isolated limb perfusion for patients with in-transit melanoma metastases: An interim analysis of a phase Ib/II randomized double-blind placebo-controlled trial (NivoILP trial)

OBJECTIVE

ILP has shown to achieve high response rates in patients with melanoma ITM. Possibly there is a synergistic mechanism of action of ILP and anti-PD1. The aim of this trial was to investigate the safety and efficacy of adding a single dose of systemic anti-PD1 to isolated limb perfusion (ILP) for patients with melanoma in-transit metastases (ITM).

METHODS

In this placebo controlled double-blind phase Ib/II trial, patients with melanoma ITM were randomized 1:1 to either a single systemic dose of nivolumab or placebo one day prior to ILP. The primary endpoint was complete response (CR) rate at three months, and safety in terms of incidence and severity of adverse events (AEs).

RESULTS

A total of 20 patients were included. AEs of any grade occurred in 90% of patients in the nivolumab arm and in 80% in the placebo arm within three months after ILP. Grade 3 AEs were reported in 40% and 30% respectively, most commonly related to wound infection, wound dehiscence, or skin necrosis. There were no grade 4 or 5 AEs reported. The CR rate was 75% in the nivolumab arm and 60% in the placebo arm. The 1-year local progression-free rate was 86% in the nivolumab arm and 67% in the placebo arm. The 1-year OS was 100% in both arms.

CONCLUSION

For patients with melanoma ITM, the addition of a single systemic dose of nivolumab the day before ILP is considered safe and feasible with promising efficacy. Accrual will continue in a phase 2 trial.

Isolated Limb Perfusion and Immunotherapy in the Treatment of In-Transit Melanoma Metastases: Is It a Real Synergy?

BACKGROUND

Isolated limb hyperthermic-antiblastic perfusion (ILP) was the most effective local treatment for advanced in-transit melanoma, but the advent of modern effective immunotherapy (IT), such as immune checkpoint inhibitors, has changed the treatment landscape.

METHODS

This study evaluated the role of the association between ILP and IT in the treatment of locally advanced unresectable melanoma, particularly in relation to modern systemic therapies. We analyzed 187 consecutive patients who were treated with ILP (melphalan or melphalan associated with TNF-alpha) for advanced melanoma at the Veneto Institute of Oncology of Padua (Italy) and the Padua University Hospital (Italy) between June 1989 and September 2021. Overall survival (OS), disease-specific survival (DSS), local disease-free survival (local DFS) and distant disease-free survival (distant DFS) were evaluated. Local toxicity was classified according to the Wieberdink scale and surgical complications according to the Clavien-Dindo classification. Response to locoregional therapy was evaluated during follow-up according to the RECIST 1.1 criteria (Response Evaluation Criteria in Solid Tumor).

RESULTS

A total of 99 patients were treated with ILP and 88 with IT + ILP. The overall response rate was 67% in both groups. At 36 months, OS was 43% in the ILP group and 61% in the ILP + IT group (p = 0.02); DSS was 43% in the ILP group and 64% in the ILP + IT group (p = 0.02); local DFS was the 37% in ILP group and 53% in the ILP + IT group (p = 0.04); and distant DFS was 33% in the ILP group and 35% in the ILP + IT group (p = 0.40). Adjusting for age and lymph node involvement, receiving ILP + IT was associated with improved OS (p = 0.01) and DSS (p = 0.007) but not local DFS (p = 0.13) and distant DFS (p = 0.21).

CONCLUSIONS

Our findings confirm the synergy between ILP and IT. ILP remains a valuable loco-regional treatment option in the era of effective systemic treatments. Further studies are needed to establish the optimal combination of loco-regional and systemic treatments and address the best timing of this combination to obtain the highest local response rate.

Understanding the Tumor Microenvironment in Melanoma Patients with In-Transit Metastases and Its Impacts on Immune Checkpoint Immunotherapy Responses

Melanoma is the leading cause of global skin cancer-related death and currently ranks as the third most commonly diagnosed cancer in Australia. Melanoma patients with in-transit metastases (ITM), a type of locoregional metastasis located close to the primary tumor site, exhibit a high likelihood of further disease progression and poor survival outcomes. Immunotherapies, particularly immune checkpoint inhibitors (ICI), have demonstrated remarkable efficacy in ITM patients with reduced occurrence of further metastases and prolonged survival. The major challenge of immunotherapeutic efficacy lies in the limited understanding of melanoma and ITM biology, hindering our ability to identify patients who likely respond to ICIs effectively. In this review, we provided an overview of melanoma and ITM disease. We outlined the key ICI therapies and the critical immune features associated with therapy response or resistance. Lastly, we dissected the underlying biological components, including the cellular compositions and their communication networks within the tumor compartment, to enhance our understanding of the interactions between immunotherapy and melanoma, providing insights for future investigation and the development of drug targets and predictive biomarkers.

KIF4A functions as a diagnostic and prognostic biomarker and regulates tumor immune microenvironment in skin cutaneous melanoma

BACKGROUND

KIF4A is upregulated in various malignancies and serves as an independent risk factor. However, its function in skin cutaneous melanoma (SKCM) and the regulation of the immunological environment remains unknown.

METHODS

We first explored the mRNA and protein levels of KIF4A in SKCM through public databases. Then, the co-expressed genes with KIF4A in SKCM and their functional enrichment analysis were performed. Moreover, the clinical value, relationship with immune infiltration and tumor microenvironment (TME), as well as the correlation between KIF4A and immunomodulators were evaluated. In addition, we validated the function of KIF4A by in vitro experiments such as CCK-8 assay, clone formation and wound healing assay.

RESULTS

Our data reveal that the mRNA and protein levels of KIF4A are highly expressed in SKCM. Moreover, functional enrichment analysis of the top 50 co-expressed genes with KIF4A showed significant association with organelle fission, tubulin binding and immune processes. KIF4A can distinguish SKCM from normal tissue and predict a poorer prognosis. A negative association was observed between KIF4A and TME, and KIF4A exhibited a negative correlation with most immunomodulators. Additionally, the knockdown of KIF4A inhibited the proliferation and migration ability of A375 cells.

CONCLUSIONS

Our findings suggest that KIF4A promotes the progression of SKCM and is negatively associated with immune infiltration and immunomodulators, which indicates a poor prognosis.

Isolated Limb Infusion as First, Second, or Third or Later-Line Therapy for Metastatic In-Transit Melanoma

BACKGROUND

Ten percent of patients with melanoma develop in-transit metastases (ITM). Isolated limb infusion (ILI) is a well-established therapy for unresectable ITM on the extremities, but the ideal sequencing/line of therapy of ILI has not been defined. This study evaluates ILI as first-line, second-line, or third or later-line therapy.

METHODS

A retrospective review included all patients with unresectable ITM who underwent ILI from 2006-2023.

RESULTS

A total of 130 patients were identified, 61% female, median age of 71 (31-89) years. Median follow-up was 37.5 months. ILI was first-line therapy in 80% (n = 104), second-line in 15% (n = 19), and third or later-line in 5.4% (n = 7). Overall response rate (ORR) and complete response (CR) rates for ILI as any line of therapy were 74% and 41%, respectively. ORR for ILI as first, second, or third or later-line therapy were 78%, 63%, and 57%, respectively. CR rates for ILI as first, second, or third or later-line therapy were 42%, 37%, and 43%, respectively. There were no significant differences in ORR, progression-free survival (PFS), overall survival, or disease-free survival between therapy lines. Median PFS for ILI as first, second, or third or later-line therapy were 6.9, 5.4, and 18 months, respectively.

CONCLUSION

Patients responded well to ILI, whether or not they received previous therapies for unresectable ITM. First-line ILI appears to have a better ORR than later lines of ILI. Although sample size limited statistical significance, there was a 21% improvement in ORR when ILI was used as first-line vs third-line therapy, which is clinically meaningful. ILI is effective for unresectable melanoma ITM and can be used as salvage therapy.

The Diagnosis and Management of Cutaneous Metastases from Melanoma

Melanoma is one of the deadliest skin tumors, accounting for almost 90% of skin cancer mortality. Although immune therapy and targeted therapy have dramatically changed the prognosis of metastatic melanoma, many patients experience disease progression despite the currently available new treatments. Skin metastases from melanoma represent a relatively common event as first sign of advanced disease or a sign of recurrence. Skin metastases are usually asymptomatic, although in advanced stages, they can present with ulceration, bleeding, and superinfection; furthermore, they can cause symptoms related to compression on nearby tissues. Treatments vary from simple surgery resections to topical or intralesional local injections, or a combination of these techniques with the most recent systemic immune or target therapies. New research and studies should focus on the pathogenesis and molecular mechanisms of the cutaneous metastases of melanoma in order to shed light on the mechanisms underlying the different behavior and prognoses of different patients.

A safety review of recently approved and late-stage trial treatments for metastatic melanoma: systemic and regional therapies

INTRODUCTION

Advanced melanoma accounts for the majority of skin cancer-associated deaths. Over the past 15 years, there has been a dramatic change in the treatment options and prognosis for patients with advanced melanoma secondary to the development of novel systemic immunotherapies (IO) and targeted therapies. In addition to these novel systemic therapies, regional therapies (intralesional and perfusional) also continue to play a major role in the management of these patients.

AREAS COVERED

In this article, we review recent updates in the management of advanced melanoma via Medline (PubMed) and Google Scholar, including recently published trials in the metastatic, adjuvant, and neoadjuvant settings. We also review recently published trials for regional therapies and discuss future directions in the management of patients with advanced melanoma.

EXPERT OPINION

A significant portion of patients with advanced melanoma will develop recurrent or progressive disease following treatment with IO or targeted therapy. Therefore, identifying not only the appropriate therapeutic agent but also the sequence and duration of treatment is pivotal for these patients.

European e-Delphi process to define expert consensus on electrochemotherapy treatment indications, procedural aspects, and quality indicators in melanoma

BACKGROUND

Skin metastases are an important co-morbidity in melanoma. Despite broad adoption, electrochemotherapy implementation is hindered by a lack of treatment indications, uncertainty regarding procedural aspects, and the absence of quality indicators. An expert consensus may harmonize the approach among centres and facilitate comparison with other therapies.

METHODS

An interdisciplinary panel was recruited for a three-round e-Delphi survey. A literature-based 113-item questionnaire was proposed to 160 professionals from 53 European centres. Participants rated each item for relevance and degree of agreement on a five-point Likert scale, and received anonymous controlled feedback to allow revision. The items that reached concordant agreement in two successive iterations were included in the final consensus list. In the third round, quality indicator benchmarks were defined using a real-time Delphi method.

RESULTS

The initial working group included 122 respondents, of whom 100 (82 per cent) completed the first round, thus qualifying for inclusion in the expert panel (49 surgeons, 29 dermatologists, 15 medical oncologists, three radiotherapists, two nurse specialists, two clinician scientists). The completion rate was 97 per cent (97 of 100) and 93 per cent (90 of 97) in the second and third rounds respectively. The final consensus list included 54 statements with benchmarks (treatment indications, (37); procedural aspects, (1); quality indicators, (16)).

CONCLUSION

An expert panel achieved consensus on the use of electrochemotherapy in melanoma, with a core set of statements providing general direction to electrochemotherapy users to refine indications, align clinical practices, and promote quality assurance programmes and local audits. The residual controversial topics set future research priorities to improve patient care.

Chemotherapy in Cutaneous Melanoma: Is There Still a Role?

Purpose of Review

In the preceding decade, the management of metastatic cutaneous melanoma has been revolutionised with the development of highly effective therapies including immune checkpoint inhibitors (specifically CTLA-4 and PD-1 inhibitors) and targeted therapies (BRAF and MEK inhibitors). The role of chemotherapy in the contemporary management of melanoma is undefined.

Recent Findings

Extended analyses highlight substantially improved 5-year survival rates of approximately 50% in patients with metastatic melanoma treated with first-line therapies. However, most patients will progress on these first-line treatments. Sequencing of chemotherapy following failure of targeted and immunotherapies is associated with low objective response rates and short progression-free survival, and thus, meaningful benefits to patients are minimal.

Summary

Chemotherapy has limited utility in the contemporary management of cutaneous melanoma (with a few exceptions, discussed herein) and should not be the standard treatment sequence following failure of first-line therapies. Instead, enrolment onto clinical trials should be standard-of-care in these patients.

Effects of the Introduction of Modern Immunotherapy on the Outcome of Isolated Limb Perfusion for Melanoma In-Transit Metastases

Isolated limb perfusion (ILP) is an effective locoregional treatment for melanoma in-transit metastasis, but the advent of modern effective immunotherapy, such as ICI (immune checkpoint inhibitors), has changed the treatment landscape. The primary aims of this study were to compare the characteristics of the patient population receiving ILP before and after the introduction of modern systemic treatments and to assess if outcomes after ILP were influenced by previous immunotherapy treatment. A single-centre analysis of patients that underwent ILP for melanoma in-transit metastasis between 2010 and 2021 was conducted, with patients grouped and compared by treatment time period: pre-ICI era (2010-2014) and ICI era (2017-2021). 218 patients were included. Patients undergoing ILP in the ICI era were slightly older (median age 73 vs. 68 years) compared to the pre-ICI era, with no other difference found. The overall response rate (ORR) was 83% vs. 84% and the complete response (CR) rate was 52% vs. 47% for the pre-ICI era and the ICI era, respectively. For patients that had received and failed immunotherapy prior to ILP (n = 20), the ORR was 75% and the CR rate was 50%. Melanoma-specific survival has improved, with a 3-year survival rate of 54% in the pre-ICI era vs. 86% in the ICI era. The patient population undergoing ILP for in-transit melanoma is largely unchanged in the current era of effective systemic treatments. Response rates have not decreased, and prior ICI treatment did not affect response rates, making ILP still a valid treatment option for this patient group.

Tumor Burden and Health-Related Quality of Life in Patients with Melanoma In-Transit Metastases

BACKGROUND

Few studies have investigated the health-related quality of life (HRQOL) in patients with melanoma in-transit metastases (ITM). The aim was to investigate the association between tumor burden and HRQOL, including disparities pertaining to sex and age, in treatment-naïve patients with ITM.

METHODS

Functional Assessment of Cancer Therapy-Melanoma (FACT-M) questionnaire was used to assess HRQOL Pairwise comparisons using t-tests between clinical cutoffs are presented and multiple linear regression analysis showing the unique associations of gender, age, number of tumors, tumor size, presence of lymph node metastases, and tumor localization.

RESULTS

A total of 95 patients, 47% females and 53% males (median age 72 years) were included between 2012 and 2021. Women scored significantly lower on emotional well-being (p = 0.038) and lower on FACT-M (p = 0.058). Patients who had ≥10 tumors scored significantly lower on FACT-M (p = 0.015), emotional- and functional well-being (p = 0.04, p = 0.004, respectively), melanoma scale (p = 0.005), and FACT-G (p = 0.027). There was no significant difference in HRQOL depending on age, size of tumors, localization, or presence of lymph node metastases.

CONCLUSION

For patients with melanoma ITMs, the female sex and higher tumor burden (i.e., number of tumors) were significantly correlated with lower HRQOL. However, these findings do not fully explain HRQOL for this patient population, and future research should consider the possibility that there are specific questions for patients with ITM where current instruments might fail to measure their discomfort to the full extent.