Unraveling molecular signatures in rare bone tumors and navigating the cancer pathway landscapes for targeted therapeutics

Rare cancers (RCs), which account for over 20% of cancer cases, face significant research and treatment challenges due to their limited prevalence. This results in suboptimal outcomes compared to more common malignancies. Rare bone tumors (RBTs) constitute 5-10% of rare cancer cases and pose unique diagnostic complexities. The therapeutic potential of anti-cancer drugs for RBTs remains largely unexplored. Identifying molecular alterations in cancer-related genes and their associated pathways is essential for precision medicine in RBTs. Small molecule inhibitors and monoclonal antibodies targeting specific RBT-associated proteins show promise. Ongoing clinical trials aim to define RBT biomarkers, subtypes, and optimal treatment contexts, including combination therapies and immunotherapeutic agents. This review addresses the challenges in diagnosing, treating, and studying RBTs, shedding light on the current state of RBT biomarkers, potential therapeutic targets, and promising inhibitors. Rare cancers demand attention and innovative solutions to improve clinical outcomes.

Management of patients with rare adult solid cancers: objectives and evaluation of European reference networks (ERN) EURACAN

About 500,000 patients with rare adult solid cancers (RASC) are diagnosed yearly in Europe. Delays and unequal quality of management impact negatively their survival. Since 2017, European reference networks (ERN) aim to improve the quality of care of patients with rare disease. The steering committee of EURACAN, including physicians, researchers and patients review here the previous actions, present objectives of the ERN EURACAN dedicated to RASC. EURACAN promoted management in reference centres, and equal implementation of excellence and innovation in Europe and developed 22 clinical practice guidelines (CPGs). Additionally, fourteen information brochures translated in 24 EU languages were developed in collaboration with patient advocacy groups (ePAGs) and seventeen training session were organized. Nevertheless, connections to national networks in the 26 participating countries (106 centres), simplification of cross-border healthcare, international multidisciplinary tumour boards, registries and monitoring of the quality of care are still required. In this Health Policy, evaluation criteria of the performances of the network and of health care providers are proposed.

Twelve years after: The french national network on rare head and neck tumours (REFCOR)

BACKGROUND

Rare cancers constitute less than 10% of head and neck cancers and lack sufficient evidence for standardized care. The French Rare Head and Neck Cancer Expert Network (REFCOR) as established a national database to collect data on these rare cancers. This study aims to describe patient and tumour characteristics in this database.

METHODS

Prospective data collection was conducted across multiple centers. Survival analyses were performed using Kaplan Meier method and Log Rank test. Odds ratios were used for comparing proportions.

RESULTS

A total of 7208 patients were included over a period of 10 years. The most frequent histologies were: Not Otherwise Specified (NOS) adenocarcinoma 13 %, adenoid cystic carcinoma 12 %, squamous cell carcinoma of rare locations 10 %, mucoepidermoid carcinoma 9 %, intestinal-type adenocarcinoma (8 %). Tumours were located in sinonasal area (38 %); salivary glands (32 %); oral cavity / oropharynx / nasopharynx (16 %); larynx / hypopharynx (3 %); ears (1 %); others (3 %). Tumours were predominantly classified as T4 (23 %), N0 (54 %), and M0 (62 %). Primary treatment approach involved tumour resection (78 %) and / or radiotherapy (63 %). Patients with salivary gland cancers exhibited better 5-year overall survival (OS) rates (p < 0.05), and lower recurrence rates compared to patients with sinonasal, laryngeal/ hypopharyngeal cancers. No significant differences were observed in the other comparisons. Acinar cell carcinoma demonstrated the best OS while mucous melanoma had the poorest prognosis.

CONCLUSION

Melanoma, carcinoma NOS, and sinonasal undifferenciated carcinoma still have poor prognoses. Efforts are being made, including training and guidelines, to expand network coverage (REFCOR, EURACAN), improve data collection and contribute to personalized therapies.

Dabrafenib and trametinib administration in patients with BRAF V600E/R or non-V600 BRAF mutated advanced solid tumours (BELIEVE, NCCH1901): a multicentre, open-label, and single-arm phase II trial

Background

BRAF V600 mutations are common in melanoma, thyroid, and non-small-cell lung cancers. Despite dabrafenib and trametinib being standard treatments for certain cancers, their efficacy across various solid tumours remains unelucidated. The BELIEVE trial assessed the efficacy of dabrafenib and trametinib in solid tumours with BRAF V600E/R or non-V600 BRAF mutations.

Methods

Between October 1, 2019, and June 2022, at least 50 patients with measurable and seven without measurable diseases examined were enrolled in a subcohort of the BELIEVE trial (NCCH1901, jRCTs031190104). BRAF mutated solid tumour cases other than BRAF V600E mutated colorectal cancer, melanoma, and non-small cell lung cancer cases were included. Patients with solid tumours received dabrafenib (150 mg) twice daily and trametinib (2 mg) once daily until disease progression or intolerable toxicity was observed. The primary endpoint was overall response rate (ORR), and secondary endpoints included progression-free survival (PFS), 6-month PFS, and overall survival (OS). Bayesian analysis was performed using a prior distribution with a 30% expected response rate [Beta (0.6, 1.4)].

Findings

Fourty-seven patients with measurable disease, mainly with the BRAF V600E mutation (94%), and three others with non-V600E BRAF mutations (V600R, G466A, and N486_P490del) were enrolled. The primary sites included the thyroid gland, central nervous system, liver, bile ducts, colorectum, and pancreas. The confirmed ORR was 28.0%; the expected value of posterior distribution [Beta (14.6, 37.4)] was 28.1%, although the primary endpoint was achieved, not exceeding an unexpectedly high response rate of 60% obtained using Bayesian analysis. The disease control rate (DCR) was 84.0%. The median PFS was 6.5 months (95% confidence interval [CI]; 4.2-7.2 months, 87.8% at 6 months). Responses were observed across seven tumour types. Median OS was 9.7 months (95% CI, 7.5-12.2 months). Additional patients without measurable diseases had a median PFS of 4.5 months. Adverse events (AEs) were consistent with previous reports, with 45.6% of patients experiencing grade ≥3 AEs.

Interpretation

This study reported promising efficacy against BRAF V600-mutant tumours. Dabrafenib and trametinib would offer a new therapeutic option for rare cancers, such as high-grade gliomas, biliary tract cancer, and thyroid cancer.

Funding

This study was funded by the Japan Agency for Medical Research and Development (22ck0106622h0003) and a Health and Labour Sciences Research Grant (19EA1008).

The organization of care in pediatric radiotherapy across SIOP Europe affiliated centers: A multicenter survey in the framework of the 'Joint Action on Rare Cancers' project

BACKGROUND/PURPOSE

To reduce inequalities among SIOPE-affiliated countries, standard and optional levels to deliver 'Good Clinical Practice' compliant treatment in pediatric radiation oncology have been published. The aim of this project was to map the availability of pediatric radiotherapy resources across SIOPE-affiliated radiotherapy departments.

MATERIALS/METHODS

An online survey with 34 questions was distributed to 246 radiotherapy departments across 35 SIOPE-affiliated countries. In addition to demographic data, 15 general items related to the organization of the radiotherapy process, and 10 radiotherapy-specific items were defined. For each of the 25 items, sum scores were calculated per center and country. Mann-Whitney U tests were used to analyze associations.

RESULTS

Between March-June 2019, 121 departments (49 %) out of 31 countries (89 %) completed the survey. At center level, involvement of core disciplines in tumor boards (28 %), and integration of dedicated pediatric radiation therapy technologists (24 %) are limited, while rare & complex brachytherapy procedures are performed in many centers (23 %). For general and radiotherapy-specific items respectively, a relevant variation of sum scores was observed across countries (Δgeneral: ≤10 points; ΔRT_specific: ≤5 points) and among centers within a country (Δgeneral: ≤9 points; ΔRT_specific: ≤6 points). Sum scores for general and radiotherapy-specific items were higher in countries with a high-income (p < 0.01) and higher health development index (p < 0.01). A larger annual number of irradiated pediatric patients was associated with higher sum scores for general items (p < 0.01).

CONCLUSION

This survey demonstrates the disparities in organization of pediatric radiotherapy departments between SIOPE-affiliated countries and centers within the same country. Investment is needed to reduce inequalities in pediatric radiotherapy care.

Establishment and characterization of a patient-derived solitary fibrous tumor/hemangiopericytoma cell line model

Solitary fibrous tumor/Hemangiopericytoma (SFT/HPC) is a rare subtype of soft tissue sarcoma harboring NAB2-STAT6 gene fusions. Mechanistic studies and therapeutic development on SFT/HPC are impeded by scarcity and lack of system models. In this study, we established and characterized a novel SFT/HPC patient-derived cell line (PDC), SFT-S1, and screened for potential drug candidates that could be repurposed for the treatment of SFT/HPC. Immunohistochemistry profiles of the PDC was consistent with the patient's tumor sample (CD99+/CD34+/desmin-). RNA sequencing, followed by Sanger sequencing confirmed the pathognomonic NAB2exon3-STAT6exon18 fusion in both the PDC and the original tumor. Transcriptomic data showed strong enrichment for oncogenic pathways (epithelial-mesenchymal transition, FGF, EGR1 and TGFβ signaling pathways) in the tumor. Whole genome sequencing identified potentially pathogenic somatic variants such as MAGEA10 and ABCA2. Among a panel of 14 targeted agents screened, dasatinib was identified to be the most potent small molecule inhibitor against the PDC (IC50, 473 nM), followed by osimertinib (IC50, 730 nM) and sunitinib (IC50, 1765 nM). Methylation profiling of the tumor suggests that this specific variant of SFT/HPC could lead to genome-wide hypomethylation. In conclusion, we established a novel PDC model of SFT/HPC with comprehensive characterization of its genomic, epigenomic and transcriptomic landscape, which can facilitate future preclinical studies of SFT/HPC, such as in vitro drug screening and in vivo drug testing.

Sclerosing Epithelioid Fibrosarcoma (SEF) versus Low Grade Fibromyxoid Sarcoma (LGFMS): Presentation and outcome in the nationwide NETSARC+ series of 330 patients over 13 years

Sclerosing Epithelioid Fibrosarcoma (SEF) and Low Grade Fibromyxoid Sarcoma (LGFMS) are ultrarare sarcomas sharing common translocations whose natural history are not well known. We report on the nationwide exhaustive series of 330 patients with SEF or LGFMS in NETSARC+ since 2010.

PATIENTS AND METHODS

NETSARC (netsarc.org) is a network of 26 reference sarcoma centers with specialized multidisciplinary tumor boards (MDTB). Since 2010, (i) pathological review has been mandatory for sarcoma,and (ii) tumour/patients' characteristics have been collected in the NETSARC+ nationwide database. The characteristics of patients with SEF and LGFMS and their outcome are compared.

RESULTS

35/73 (48%) and 125/257(49%) of patients with SEF and LGFMS were female. More visceral, bone and trunk primary sites were observed in SEF (p < 0.001). 30% of SEF vs 4% of LGFMS patients had metastasis at diagnosis (p < 0.0001). Median size of the primary tumor was 51 mm (range 10-90) for LGFMS vs 80 (20-320) for SEF (p < 0.001). Median age for LGFMS patients was 12 years younger than that of SEF patients (43 [range 4-98] vs 55 [range 10-91], p < 0.001). Neoadjuvant treatment was more often given to SEF (16% vs 9%, p = 0.05). More patients with LGFMS were operated first in reference centers (51% vs 26%, p < 0.001). The R0 rate on the operative specimen was 41% in LGFMS vs 16% in SEF (p < 0.001). Median event-free survival (EFS) of patients with SEF and LGFMS were 32 vs 136 months (p < 0.0001). The median overall survival (OS) was not reached. Fifty-months OS was 93% vs 81% for LGFMS vs SEF (p = 0.05). Median OS was 77 months after first relapse, similar for SEF and LGFMS. In multivariate analysis, age, tumor size, metastasis at diagnosis were independent prognostic factors for OS in LGFMS.

CONCLUSIONS

Although sharing close molecular alterations, SEF and LGFMS have a different natural history, clinical presentation and outcome, with a higher risk of metastatic relapse in SEF. Survival after relapse is longer than with other sarcomas, and similar for SEF and LGFMS.

Role of radiotherapy in the management of rare gynaecological cancers

There are a large number of gynaecological cancers with rare histologies, for which the available data are limited and usually retrospective. Because of their rarity and poor prognosis, the management of these cancers must be centralized in expert centres, for both histological diagnosis and treatment. With the exception of sarcomas, most endometrial or cervical cancers with rare histologies respond to the same radiation treatment modalities than cancers with more common histologies, although there are some specificities regarding treatments such as neuroendocrine carcinomas (chemotherapy with platinum and etoposide, major role of surgery). For localized or locally advanced ovarian cancer, external beam radiotherapy has a role in the management of hypercalcaemic small cell carcinoma of the ovary. This article summarizes the current role of external beam radiotherapy and brachytherapy in the management of cancers of the uterine cervix, uterine corpus and ovaries, with rare or very rare histologies, and with localized or locally advanced stages.

Multi-omic profiling and real time ex vivo modelling of imatinib-resistant dermatofibrosarcoma protuberans with fibrosarcomatous transformation

Dermatofibrosarcoma protuberans (DFSP) is a rare and indolent cutaneous sarcoma, with the risk of aggressive fibro-sarcomatous transformation. Limited effective options are available for un-resectable or metastatic DFSP beyond targeting the oncogenic PDGF pathway with imatinib therapy. We established a patient-derived xenograft (PDX) and cell line model (designated MDFSP-S1) of imatinib-resistant DFSP with fibro-sarcomatous transformation. Whole genome sequencing identified high-level amplification at chromosomes 17 and 22, whilst homozygous deep deletion was demonstrated at chromosome 9 (CDKN2A, CDKN2B, MTAP). RNA sequencing followed by Sanger sequencing confirmed the pathognomonic COL1A1-PDGFB t (17;22) rearrangement in the original tumour, PDX and cell line model. Immunohistochemistry profiles of the PDX model were consistent with the patient's tumour sample (CD34 + /MIB1 + /SOX10- ). Gene set enrichment analysis highlighted top-scoring Hallmark gene sets in several oncogenic signalling pathways, including potentially targetable MTORC1 signalling and angiogenesis pathways. Antiangiogenic agents (sunitinib, regorafenib, pazopanib, axitinib) and the third-generation irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor osimertinib exhibited modest anti-proliferative activity in the cell line, with IC50 values between 1 and 10 µM at 72 h. No significant activity was observed with imatinib, palbociclib, everolimus, olaparib, gefitinib and erlotinib (IC50 all > 10 µM). In conclusion, we established MDFSP-S1, a new PDX and cell line model of imatinib-resistant DFSP with fibro-sarcomatous transformation.

Epithelioid hemangio-endothelioma (EHE) in NETSARC: The nationwide series of 267 patients over 12 years

EPITHELIOID HEMANGIOENDOTHELIOMA

A NATIONWIDE STUDY: Epithelioid hemangioendothelioma (EHE) is an ultrarare sarcoma whose natural history and treatment is not well defined. We report on the presentation and outcome of 267 patients with EHE in the NETSARC+ network since 2010 in France.

PATIENTS AND METHODS

NETSARC (netsarc.org) is a network of 26 reference sarcoma centres with specialised multidisciplinary tumour boards (MDTB), funded by the French National Cancer Institute (NCI), Institut National du Cancer (INCA). Since 2010, presentation to an MDTB and second pathological review are mandatory for sarcoma patients. Patients' characteristics are collected in a nationwide database regularly monitored with stable incidence since 2013. The characteristics of patients with EHE at diagnosis are presented as well as progression-free survival (PFS), overall survival (OS), and outcome under treatment.

RESULTS

Two hundred and sixty-seven patients with EHE were included in the NETSARC+ database since 2010. Median age in the series was 51 (range 10-90) years, 58% were women. Median tumour size was 37 mm (4-220). Forty-eight percent, 42%, and 10% were visceral, soft parts, or bone primaries. The most frequent sites were liver (28%), lung (13%). 40% were reported to have systemic (i.e. multifocal or metastatic disease) at diagnosis. With a median follow-up of 20 months, OS and PFS rates at 24 months were 82% and 67%, with 10-year projected OS and PFS of 62% and 21% respectively. Male and M+ patients at diagnosis had a significantly worse OS, but not PFS. Local treatment was associated with a favourable survival in localised but not in patients with advanced stage at diagnosis. For 23 patients receiving medical treatment, PFS and OS were 50.2% and 33.2% at 60 months were respectively.

CONCLUSIONS

EHE is a frequently metastatic sarcoma at diagnosis with a unique natural history. This study shows in a nationwide series over 12 years that most patients progressed but are still alive at 10 years, both in localised and metastatic stages.

Targeting homologous recombination deficiency in uterine leiomyosarcoma

BACKGROUND

Uterine leiomyosarcoma (uLMS) is a rare and aggressive gynaecological malignancy, with individuals with advanced uLMS having a five-year survival of < 10%. Mutations in the homologous recombination (HR) DNA repair pathway have been observed in ~ 10% of uLMS cases, with reports of some individuals benefiting from poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi) therapy, which targets this DNA repair defect. In this report, we screened individuals with uLMS, accrued nationally, for mutations in the HR repair pathway and explored new approaches to therapeutic targeting.

METHODS

A cohort of 58 individuals with uLMS were screened for HR Deficiency (HRD) using whole genome sequencing (WGS), whole exome sequencing (WES) or NGS panel testing. Individuals identified to have HRD uLMS were offered PARPi therapy and clinical outcome details collected. Patient-derived xenografts (PDX) were generated for therapeutic targeting.

RESULTS

All 13 uLMS samples analysed by WGS had a dominant COSMIC mutational signature 3; 11 of these had high genome-wide loss of heterozygosity (LOH) (> 0.2) but only two samples had a CHORD score > 50%, one of which had a homozygous pathogenic alteration in an HR gene (deletion in BRCA2). A further three samples harboured homozygous HRD alterations (all deletions in BRCA2), detected by WES or panel sequencing, with 5/58 (9%) individuals having HRD uLMS. All five individuals gained access to PARPi therapy. Two of three individuals with mature clinical follow up achieved a complete response or durable partial response (PR) with the subsequent addition of platinum to PARPi upon minor progression during initial PR on PARPi. Corresponding PDX responses were most rapid, complete and sustained with the PARP1-specific PARPi, AZD5305, compared with either olaparib alone or olaparib plus cisplatin, even in a paired sample of a BRCA2-deleted PDX, derived following PARPi therapy in the patient, which had developed PARPi-resistance mutations in PRKDC, encoding DNA-PKcs.

CONCLUSIONS

Our work demonstrates the value of identifying HRD for therapeutic targeting by PARPi and platinum in individuals with the aggressive rare malignancy, uLMS and suggests that individuals with HRD uLMS should be included in trials of PARP1-specific PARPi.

Epidemiology of rare cancers in India and South Asian countries - remembering the forgotten

Background

Rare cancers (RCs) are challenging to manage and are "forgotten cancers" though they collectively constitute a significant proportion of all cancers (∼20%). As a first step towards streamlining care, there is an unmet need to map the epidemiology of RCs in South Asian Association for Regional Collaboration (SAARC) countries.

Methods

The authors collected data from 30 Population-Based Cancer Registries (PBCR) of India and the published national registries of Nepal, Bhutan and Sri Lanka (SL) and compared them with the standard RARECAREnet RC list.

Findings

With the standard definition of crude incidence rates (CR) ≤6/100,0000 per population, 67.5%, 68.3%, 62.3% and 37% of all incident cancers qualify as RCs in India, Bhutan, Nepal and SL, respectively. An arbitrary cut-off CR ≤3 appears more appropriate with 43%, 39.5%, 51.8% and 17.2% of cancers identified as RCs, respectively, due to the lower cancer incidence.There are similarities and notable differences between the RC lists of the SAARC region with that of the European RC list. Oral cavity cancers are rare in Europe, while pancreas, rectum, urinary bladder and melanomas are common. In addition, uterine, colon and prostatic cancers are rare in India, Nepal and Bhutan. In SL, thyroid cancer is common. There are gender-related and regional differences in RC trends in the SAARC countries.

Interpretation

There is an unmet need in SAARC nations to capture epidemiological nuances in rare cancers. Understanding the unique issues in the developing world may guide policymakers to adopt appropriate measures to improve RC care and tailor public health interventions.

Funding

None.

Clinicopathological features, genetic alterations, and BRCA1 promoter methylation in Japanese male patients with breast cancer

PURPOSE

Male breast cancer (MBC) is a rare cancer accounting for only 1% of all male cancers and is, therefore, poorly studied. We aimed to characterize the subtypes of MBC in Japanese patients based on genetic profiling, the presence of tumor-infiltrating cells, and the expression of immunohistochemical markers.

METHODS

This retrospective study included 103 patients with MBC diagnosed between January 2009 and December 2019 at various hospitals in Japan. Clinicopathological patient characteristics were obtained from medical records, and formalin-fixed paraffin-embedded tissue specimens were analyzed for histological markers, mutations of 126 genes, BRCA1 methylation, and stromal tumor-infiltrating lymphocytes.

RESULTS

The median patient age was 71 (range 31-92) years. T1-stage tumors were the most frequent (47.6%), and most were node negative (77.7%). The majority of tumors were positive for estrogen receptor (98.1%), progesterone receptor (95.1%), and androgen receptor (96.1%), and BRCA2 was the most frequently mutated gene (12.6%). The most common treatment was surgery (99.0%), either total mastectomy (91.1%) or partial mastectomy (7.0%). Survival analysis showed a 5-year recurrence-free survival rate of 64.4% (95% confidence interval [CI] 46.7-88.8) and a 5-year overall survival rate of 54.3% (95% CI 24.1-100.0).

CONCLUSION

Japanese MBC is characterized by a high rate of hormonal receptor positivity and BRCA2 somatic mutation. Due to the observed clinicopathological differences in MBC between the Western countries and Japan, further prospective studies are needed to evaluate the most suitable treatment strategies.

Patient-driven research: Initial results from a prospective health-related quality of life study performed at the request of patients living with hairy cell leukemia

A diagnosis of leukemia can have a profound effect on patients' health-related quality of life (HRQoL), however this has not been measured prospectively in patients with hairy cell leukemia (HCL). At the request of patients living with HCL who had identified this gap in knowledge about the disease, we conducted a longitudinal study of HRQoL among patients enrolled in the HCL Patient Data Registry (PDR). From September 1, 2018 to September 1, 2020, 165 patients were enrolled in the study and completed the baseline survey. The Functional Assessment of Cancer Therapy - Leukemia (FACT-Leu) was used to measure patients' HRQoL. Results show that newly diagnosed HCL patients reported the lowest HRQoL, followed by patients in relapse and those on "watch and wait." Factors associated with higher (better) FACT-Leu total scores in the multivariable analysis included older age, higher social support, and greater physical activity. These same factors were associated with lower levels of fatigue. In rare diseases where it is difficult to perform large prospective studies, patient/researcher collaborations are critical for the identification of studies that are of importance to patients and their families in order to maximize the benefits of the research and improve the lives of patients living with HCL.

The gap between rare and common cancers still exists: Results from a population-based study in the Netherlands

INTRODUCTION

Epidemiological discrepancies exist between rare and common cancers. The aim of this population-based study was to compare rare versus common adult solid cancers in the Netherlands, by providing incidence, prevalence and survival rates, evaluating trends in survival and comparing individual entities within domains and families.

METHODS

All adult patients with malignant solid cancers in the Netherlands between 1995 and 2019 were identified from the Netherlands Cancer Registry. Data on patient, tumour and treatment characteristics were collected, and relative survival and survival trends were analysed.

RESULTS

A total of 170,628 patients with rare adult solid cancers and 806,023 patients with common adult solid cancers were included. Rare cancers accounted for 18% of all cancer diagnoses (mean incidence), and 15% of the total ten-year cancer prevalence during 2010-2019. Overall 5-year survival was worse for rare cancers than for common cancers (52.0% versus 68.7%). Between 1995-1999 and 2015-2019, 5-year survival rates for rare cancers increased to a lesser extent (from 46.2% to 52.6%, i.e. 6.4%) than for common cancers (56.9%-70.1%, i.e. 13.2%), and for most rare cancer domains compared to common cancer domains. The majority of rare cancer entities did not show an improvement in 5-year survival. Differences for individual entities between domains and families were found.

CONCLUSION

Differences in survival between rare and common cancers indicate major challenges for rare cancer care and emphasise that improvement is highly needed. Observed inequalities need to be overcome by investing in early diagnosis, novel therapies, scientific research and in establishing centres of expertise.

Pembrolizumab in Patients with Refractory Cutaneous Squamous Cell Carcinoma: A Phase II Trial

INTRODUCTION

Patients with advanced cutaneous squamous cell carcinoma (CSCC) have a poor prognosis. Blocking the PD-1-PD-L1 axis has shown promising activity in this patient population. We assessed the safety and antitumor activity of PD-1 inhibitor pembrolizumab in patients with refractory advanced CSCC.

METHODS

This was a prespecified subgroup analysis of patients with advanced CSCC who enrolled in an open-label, phase II clinical trial for pembrolizumab in patients with refractory rare cancers during 2016-2018. Patients received pembrolizumab 200 mg intravenously every 21 days until progressive disease, unacceptable adverse event, or completion of 24 months of treatment. The primary endpoint was nonprogression rate (NPR) at 27 weeks; secondary endpoints included safety, objective response rate (ORR) per irRECIST, clinical benefit rate (CBR), progression-free survival, and overall survival.

RESULTS

Twenty patients with refractory CSCC enrolled; 19 were evaluable for efficacy. Median follow-up time was 44.1 months. The NPR at 27 weeks was 37% (95% CI 0.16-0.62). Three patients had a complete response (CR), three had a partial response, and one had stable disease, for an ORR of 32% and a CBR of 37%; median duration of response was 27.3 months. All three patients with a CR remained free of recurrence at the time of writing. Severe treatment-related adverse events (grade ≥ 3) occurred in 10% of patients (2/20). PD-L1 expression was not correlated with response to pembrolizumab.

CONCLUSION

A long-term follow-up confirms pembrolizumab's antitumor activity and safety profile in patients with refractory CSCC. Patients with a CR may experience cure.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02721732, Registered March 29, 2016.

The emerging landscape of immune checkpoint inhibitor based clinical trials in adults with advanced rare tumors

"Rare cancers" are a diverse collection of cancers that collectively account for approximately 20% of all adult cancers in the United States. Their rarity has caused an underrepresentation of these cancers in preclinical research and clinical trials, leading to fewer (and often no) treatment options for patients backed by robust clinical evidence. The recent advent of immune checkpoint inhibitors (ICIs) into the oncologist's armamentarium, while revolutionizing the treatment of many common cancers, has also started to make gradual inroads into the treatment of certain rare cancers. One reason is that the efficacy of ICIs depends more on factors intrinsic to the tumor cells and the tumor microenvironment and less on tumor histology. Recent years have seen ICI approvals in many rare cancers, and many trials are being designed using ICIs as single agents or in combination. In this commentary, we present an overview of the emerging role of ICIs in some rare cancers.

Determinants of the access to remote specialised services provided by national sarcoma reference centres

Background

Spatial inequalities in cancer management have been evidenced by studies reporting lower quality of care or/and lower survival for patients living in remote or socially deprived areas. NETSARC+ is a national reference network implemented to improve the outcome of sarcoma patients in France since 2010, providing remote access to specialized diagnosis and Multidisciplinary Tumour Board (MTB). The IGéAS research program aims to assess the potential of this innovative organization, with remote management of cancers including rare tumours, to go through geographical barriers usually impeding the optimal management of cancer patients.

Methods

Using the nationwide NETSARC+ databases, the individual, clinical and geographical determinants of the access to sarcoma-specialized diagnosis and MTB were analysed. The IGéAS cohort (n = 20,590) includes all patients living in France with first sarcoma diagnosis between 2011 and 2014. Early access was defined as specialised review performed before 30 days of sampling and as first sarcoma MTB discussion performed before the first surgery.

Results

Some clinical populations are at highest risk of initial management without access to sarcoma specialized services, such as patients with non-GIST visceral sarcoma for diagnosis [OR 1.96, 95% CI 1.78 to 2.15] and MTB discussion [OR 3.56, 95% CI 3.16 to 4.01]. Social deprivation of the municipality is not associated with early access on NETSARC+ remote services. The quintile of patients furthest away from reference centres have lower chances of early access to specialized diagnosis [OR 1.18, 95% CI 1.06 to 1.31] and MTB discussion [OR 1.24, 95% CI 1.10 to 1.40] but this influence of the distance is slight in comparison with clinical factors and previous studies on the access to cancer-specialized facilities.

Conclusions

In the context of national organization driven by reference network, distance to reference centres slightly alters the early access to sarcoma specialized services and social deprivation has no impact on it. The reference networks’ organization, designed to improve the access to specialized services and the quality of cancer management, can be considered as an interesting device to reduce social and spatial inequalities in cancer management. The potential of this organization must be confirmed by further studies, including survival analysis.

A Phase II Study of Durvalumab in Combination with Tremelimumab in Patients with Rare Cancers

LESSONS LEARNED

Disease control with signals of response were demonstrated, which should lead to future validating clinical trials using checkpoint inhibitors in this underserved rare malignancy population. Although the study of single types of rare cancers is practically challenging, clinical trial designs that aggregate such patients into cohorts treated similarly are feasible, even in the community setting.

BACKGROUND

Patients with rare cancers are an underserved population with limited access to clinical trials aside from phase I trials in the refractory setting. Treatment of these patients is often based on collections of anecdotes and small denominator review articles. Despite broad evidence of efficacy of combined immune checkpoint blockade across multiple tumor types, patients with rare tumors have not been afforded the opportunity for these therapies.

METHODS

A phase II, investigator-initiated, single institution trial using durvalumab (1,500 mg every [Q]4 weeks × 13) and tremelimumab (75 mg Q4 weeks × 7, then Q12 weeks × 2) is reported. The population included 50 patients with advanced rare solid tumors (incidence <6/100,000 per year). The phase II dose and safety profile were defined in prior phase I trials. All patients had exhausted standard therapy options and all had received at least one prior line of systemic therapy (n = 49) unless a standard treatment option did not exist (n = 1).

RESULTS

A complete response was demonstrated in one patient with anal cancer. Striking partial responses were seen in four patients. Prolonged disease stability was noted in 18 patients. Thirteen patients experienced disease progression. Patients were considered unevaluable if unable to initiate therapy (n = 6) or unable to complete two cycles of therapy (n = 8). In all cases, patients were unevaluable because of clinical deterioration. The toxicity profile paralleled prior published studies. Toxicities were manageable and without new signals. There were two events of grade 4 immune-mediated hepatitis and one death from pneumonitis.

CONCLUSION

This single-cohort basket trial demonstrated clinical activity from combined checkpoint blockade in 23 of the 36 evaluable patients. Patients with rare cancers, not eligible for immunotherapy via conventional clinical trial mechanisms, should be considered for this therapy through compassionate use, further clinical trials, and national registry programs.

Kaposi sarcoma incidence, survival and trends: Data from the information network on rare cancers in Europe (RARECAREnet)

BACKGROUND

This study provides updated information on Kaposi sarcoma (KS) in Europe during 1995-2007 from the RARECARENet project.

METHODS

Data comes from 59 population-based cancer registries in 22 countries. KS was defined as ICD-O-3 morphology code 9140 combined with any topography code. Crude and age-adjusted incidence rates and relative survival for years of diagnosis 2000-2007 and with trends during 1995-2007 were calculated overall, by age and by country.

RESULTS

The crude annual incidence rate was 0.28 per 100,000 and age-adjusted incidence was 0.23 per 100,000; incidence increased with age, from 0.18/100,000 at age 0-44 to 0.25/100,000 at age 45-64 and 0.69/100,000 at age 65 and over. Age-adjusted incidence in males was more than four times that in females. Portugal, which had the highest incidence of AIDS in Europe, had by far the highest incidence of KS at age 0-44, 1.44/100,000, more than four times the rate in any other country. Incidence among males in Europe aged 0-44 fell significantly between 1995-1998 and 1999-2002, followed by a significant increase in 2003-2007. Younger patients, with predominantly AIDS-related KS, formerly had a worse prognosis, but since 1999-2001 5-year relative survival increased for patients aged under 65, and by 2005-2007 was 83-86 % for all three age groups 0-44, 45-64, and 65 and over.

CONCLUSION

Survival and quality of life for the increasing number of people in Europe affected by KS should improve further following the development of evidence-based guidelines for its management. Population-based cancer registries will continue to play a vital role in monitoring the burden of KS and improvements in its outcome.

Rare cancers are not rare in Asia as well: The rare cancer burden in East Asia

INTRODUCTION

Epidemiologic information on rare cancers is scarce outside of the Western countries. The project "surveillance of rare cancers in Asia" (RARECAREnet Asia) provides, for the first time, the burden of rare cancers in some Asian countries based on the latest list.

OBJECTIVES

1) to assess whether the European list of rare cancers fits the Asian setting and 2) to compare the incidences of rare cancers between Europe and Asian countries.

MATERIAL AND METHODS

Population-based cancer registry data on patients diagnosed from 2011 to 2015 in Japan, Korea, and Taiwan and patients diagnosed from 2000 to 2007 in 94 European registries were analysed. The incidences for all cancers were calculated; they were then grouped into several tiers and families according to the rare cancer list, and whether cancers rare was examined.

RESULTS

Rare cancer counts according to the list in the observed population were 196 in Japan, 203 in Korea, 198 in Taiwan, and 198 in the EU. The proportions of rare in overall incidence were 16.3% in Japan, 23.7% in Korea, 24.2% in Taiwan, and 22.2% in the EU. The numbers of newly diagnosed rare cancer cases in 2015 were 140,188 in Japan, 52,071 in Korea, and 24,147 in Taiwan.

CONCLUSION

Most rare cancers in Europe were also rare in the Asian countries considered. The observed differences were due to well-known risk factors. The European definition and list of rare cancers appear to reflect well cancer incidence in East Asia.

Rare cancers in Canada, 2006-2016: A population-based surveillance report and comparison of different methods for classifying rare cancers

BACKGROUND

The cumulative burden from rare cancers has not been adequately explored in Canada. This analysis aims to characterize the occurrence of rare cancers among Canadians and estimate the probability of being diagnosed with a rare cancer among cancer patients with different demographic characteristics.

METHODS

The Canadian Cancer Registry was used for this analysis. Cancer types were classified in three ways: using the SEER site recode scheme; by histology group; and by site/histology group. The age-standardized incidence rate (ASIR) and 95 % confidence intervals (CI) for each cancer type was estimated for diagnoses from 2006 to 2016. Two ASIR thresholds were used to classify cancers as rare:6/100,000/year and 15/100,000/year. Log-binomial regression was used to estimate the adjusted probability of having a rare cancer among those with cancer by age, sex and geographic region.

RESULTS

Using the 6/100,000/year threshold, the incidence proportion (IP) of rare cancers ranged from 9.7 %(95 %CI:9.6,9.7 %)-17.0 %(95 %CI:16.9,17.0 %), and ranged from 19.2 %(95 %CI:19.1,19.3 %)-52.5 %(95 %CI:52.0,53.0 %) using the <15/100,000/year threshold. The adjusted probability of being diagnosed with a rare cancer was highest among those aged ≤19 years. There was higher concordance in estimates of the burden of rare cancers across methods to classify cancer types when the lower incidence rate threshold was used to define rare cancers.

INTERPRETATION

This analysis yielded evidence that rare cancers comprise a substantial proportion of annual cancer diagnoses among Canadians. Findings from this analysis point to using a lower incidence rate threshold, to generate estimates of the burden of rare cancers that are robust to different cancer classification schemes.

Sample size calculation in randomised phase II selection trials using a margin of practical equivalence

Background

In rare cancers or subtypes of common cancers, a comparison of multiple promising treatments may be required. The selected treatment can then be assessed against the standard of care (if it exists) or used as a backbone for combinations with new, possibly targeted, agents. There could be different experimental therapies or different doses of the same therapy, and either can be done in combination with standard treatments. A ’pick-the-winner’ design is often used, which focuses on efficacy to select the most promising treatment. However, a treatment with a slightly lower efficacy compared to another treatment may actually be preferred if it has a better toxicity or quality of life profile, is easier to administer, or cheaper.

Methods

By pre-defining a margin of practical equivalence in order to calculate the sample size, a more flexible assessment can be made of whether the treatments have very different effects or are sufficiently close so that other factors can be used to choose between them. Using exact binomial probabilities, we calculated the sample size for two- and three-arm randomised selection trials including a margin of practical equivalence with a variety of input parameters.

Results

We explain conceptually the margin of practical equivalence in this paper, and provide a free user-friendly web application to calculate the required sample size for a variety of input parameters.

Conclusion

The web application should help promote the randomised selection design with a margin of practical equivalence, which provides greater flexibility than the ’pick-the-winner’ approach in assessing the results of selection trials.

Renal Neuroendocrine Neoplasms: A Single-center Experience

BACKGROUND

Primary neuroendocrine neoplasms (NENs) of the kidney are exceedingly rare malignancies and the available literature is very limited. The natural history and response to treatments is not well characterized. We aimed to describe the presenting features, demographics, tumor characteristics, and treatment outcomes of patients with renal NENs.

PATIENTS AND METHODS

We performed a retrospective analysis of all Mayo Clinic patient records with a tissue diagnosis of a primary renal NEN. Baseline patient and surgical pathologic features and treatment modalities were collected. Time to recurrence after resection and overall survival (OS) were estimated using with survival analysis. Surveillance, Epidemiology, and End Results data were used to estimate the population-wide incidence and OS.

RESULTS

A total of 17 patients were included in the present study, with a median follow-up of 62.8 months. Distant metastasis was present in 29% at diagnosis, with 76% experiencing distant metastasis at any point; 24% had a horseshoe kidney. Of the 17 patients, 14 had undergone surgical resection with no evidence of disease postoperatively. Ten of these patients had documented recurrence. The median time to recurrence was 18 months (95% confidence interval, 9-46 months). Only 1 of the 10 patients showed a radiographic response to systemic therapy. Of 9 patients, 4 had stable disease with somatostatin analogs. The median OS was 143 months (95% confidence interval, 50-143 months).

CONCLUSIONS

Renal NENs are rare malignancies affecting mostly middle-age patients, with distant metastasis being common. Approximately one half of patients experience stable disease with somatostatin analogs. The OS usually exceeds 5 years.

The European study on centralisation of childhood cancer treatment

BACKGROUND

It is generally agreed to centralise treatment of childhood cancers (CCs). We analysed (1) the degree of centralisation of CCs in European countries and 2) the relations between centralisation and survival.

PATIENTS AND METHODS

The analysis comprised 4415 CCs, diagnosed between 2000 and 2007 and followed up to the end of 2013, from Belgium, Bulgaria, Finland, Ireland, the Netherlands and Slovenia. All these countries had national population-based cancer registries and were able to provide information on diagnosis, treatment, treatment hospitals, and survival. Each case was then classified according to whether the patient was treated in a high- or a low-volume hospital among those providing CC treatment. A Cox proportional hazard model was used to calculate the relation between volume category and five-year survival, adjusting by age, sex and diagnostic group.

RESULTS

The number of hospitals providing treatment for CCs ranged from six (Slovenia) to slightly more than 40 (the Netherlands and Belgium). We identified a single higher volume hospital in Ireland and in Slovenia, treating 80% and 97% of cases, respectively, and three to five major hospitals in the other countries, treating between 65% and 93% of cases. Outcome was significantly better when primary treatment was given in high-volume hospitals compared to low-volume hospitals for central nervous system tumours (relative risk [RR] = 0.71), haematologic tumours (RR = 0.74) and for all CC combined (RR = 0.83).

CONCLUSION

Treatment centralisation is associated with survival benefits and should be further strengthened in these countries. New plans for centralisation should include ongoing evaluation.

An Examination of Lymph Node Sampling as a Predictor of Survival in Resected Node-Negative Small Bowel Adenocarcinoma: a SEER Database Analysis

BACKGROUND

Small bowel adenocarcinoma (SBA) is a rare disease. Current recommendations are largely extrapolated from the colorectal literature. For node-negative (N -ve) cases, optimally stratifying cases into high or low risk, may help define optimal management. The objective of this analysis was to determine the importance of lymph node sampling for prognostication and to define what number of lymph nodes sampled is adequate.

METHODS

Cases of non-metastatic SBA with complete staging, pathologic, and demographic information were selected from the SEER database and SAS 9.4 software was used. Variables included age, gender, race, grade, TNM staging, and number of lymph nodes were examined. Comparisons were made between N -ve and N +ve cases. Survival analysis using N -ve cases was performed to characterize the impact of nodal sampling on survival and to determine which nodal cut-offs best predict survival.

RESULTS

A total of 523 cases from 2004 to 2014 were included in this analysis. Statistically significant differences identified included the median number of nodes sampled between the N -ve and N +ve groups, and the distribution of T stage and grade. Survival analysis in the N -ve cases demonstrated that the strongest predictor of survival was sampling of 16 or more lymph nodes.

CONCLUSION

In this analysis, lymph node sampling was shown to be the most important pathologic predictor of survival in cases of N -ve SBA. Replicating these findings in a secondary dataset and determining whether a clinical benefit of adjuvant chemotherapy exists for SBA patients with inadequate sampling are both important next steps.

The Role of Precision Medicine in the Diagnosis and Treatment of Patients with Rare Cancers

Rare cancers pose unique challenges for patients and their physicians arising from a lack of information regarding the best therapeutic options. Very often, a lack of clinical trial data leads physicians to choose treatments based on small case series or case reports. Precision medicine based on genomic analysis of tumors may allow for selection of better treatments with greater efficacy and less toxicity. Physicians are increasingly using genetics to identify patients at high risk for certain cancers to allow for early detection or prophylactic interventions. Genomics can be used to inform prognosis and more accurately establish a diagnosis. Genomic analysis may also expose therapeutic targets for which drugs are currently available and approved for use in other cancers. Notable successes in the treatment of previously refractory cancers have resulted. New more advanced sequencing technologies, tools for interpretation, and an increasing array of targeted drugs offer additional hope, but challenges remain.

Survival of adults with cancers of bone or soft tissue in Europe-Report from the EUROCARE-5 study

BACKGROUND

Five-year relative survival (RS) of adults with bone and soft-tissue cancers in Europe was still <60% by 1995-1999. There was large geographical survival variability, mainly for bone tumours, and survival decreased with increasing age at diagnosis.

METHODS

Data from 87 population-based cancer registries in 29 countries, extracted from the EUROCARE-5 database, were used to provide updated estimates of survival and describe trends in survival of adults with cancers of these sites across Europe. We calculated 5-year RS for patients diagnosed in 2000-2007. We estimated 5-year RS by the period approach to assess changes in survival between 1999-2001, 2002-2004 and 2005-2007, and provide reliable predictions for recently diagnosed patients.

RESULTS

Five-year RS was 60% for adults diagnosed with soft-tissue cancer in 2000-2007 and 53% for those with bone cancer. RS declined with increasing age at diagnosis, especially for bone cancer. Survival from bone cancer varied widely between European regions, from 63 to 62% in Northern and Central Europe to 39% in Eastern Europe. Inter-regional variation was much less for soft-tissue cancer. For both site groupings, there was little evidence of change in five-year RS up to 2002-2004, followed by increases of 3-4% during 2005-2007.

CONCLUSIONS

Outcomes for adults with bone and soft-tissue cancer in Europe began to improve around 2005; new therapeutic developments are expected to result in further progress. Survival improvements already achieved must be brought more fully to elderly patients and those in Eastern Europe. European Reference Networks on rare cancers will have a vital role in future progress.

Networking in rare cancers: What was done, what's next

Rare cancers represent approximately one fourth of all cancers. Despite being a heterogeneous group of diseases, they share similar problems including lack of expertise, issues in quality of care, discrepancies in outcome and limitations in research. Traditionally, centralization of rare cancer patients to dedicated reference centres has been recommended to ensure expertise, multidisciplinarity and access to innovation. However, centralization entails health migration, rationing of resources and a potential failure in routine care. By ensuring appropriate care to all patients regardless the point of access, networking seems the most appropriate answer to the problem of rare cancers. The launch of the Joint Action on Rare Cancers as well as the recent establishment of the European Reference Networks represent for the first time a concrete opportunity to make networking a reality and ultimately reduce disparities and improve outcome in these diseases.

Identification of Driver Mutations in Rare Cancers: The Role of SMARCA4 in Small Cell Carcinoma of the Ovary, Hypercalcemic Type (SCCOHT)

Cancer is a complex genetic disease that can arise through the stepwise accumulation of mutations in oncogenes and tumor suppressor genes in a variety of different tissues. While the varied landscapes of mutations driving common cancer types such as lung, breast, and colorectal cancer have been comprehensively charted, the genetic underpinnings of many rare cancers remain poorly defined. Study of rare cancers faces unique methodological challenges, but collaborative enterprises that incorporate next generation sequencing, reach across disciplines (i.e., pathology, genetic epidemiology, genomics, functional biology, and preclinical modeling), engage advocacy groups, tumor registries, and clinical specialists are adding increasing resolution to the genomic landscapes of rare cancers. Here we describe the approaches and methods used to identify SMARCA4 mutations, which drive development of the rare ovarian cancer, small cell carcinoma of the ovary, hypercalcemic type (SCCOHT), and point to the broader relevance of this paradigm for future research in rare cancers.

Treatment challenges in and outside a specialist network setting: Pancreatic neuroendocrine tumours

Pancreatic Neuroendocrine Neoplasms comprise a group of rare tumours with special biology, an often indolent behaviour and particular diagnostic and therapeutic requirements. The specialized biochemical tests and radiological investigations, the complexity of surgical options and the variety of medical treatments that require individual tailoring, mandate a multidisciplinary approach that can be optimally achieved through an organized network. The present study describes currents concepts in the management of these tumours as well as an insight into the challenges of delivering the pathway in and outside a Network.

Conducting non-commercial international clinical trials: the ICR-CTSU experience

BACKGROUND

Academic clinical trials play a fundamental role in the development of new treatments, the repurposing of existing treatments and in addressing areas of unmet clinical need. With cancer treatments increasingly targeted at molecular subtypes, and with priority placed on developing new treatments for rare tumour types, the need for international trial participation to access sufficient patient numbers for successful trial conduct is growing. However, lack of harmonisation of international legal, ethical and financial systems can make this challenging and the cost and effort of conducting trials internationally can be considered prohibitive, particularly where the sample size is comparatively small.

METHODS

The Institute of Cancer Research - Clinical Trials and Statistics Unit (ICR-CTSU) is a UK-based academic clinical trials unit that specialises in the design, conduct and analysis of clinical trials of cancer treatments with an expanding portfolio of trials in molecular subtypes of breast and urological cancers and in other rare cancer types. Implementing appropriate mechanisms to enable international participation has therefore been imperative. In this article, we explain how we have approached the challenges involved and describe examples of successful international trial conduct, achieved through robust collaborations with academic and industry partners.

CONCLUSION

Conducting academic trials internationally is challenging but can and should be achieved through appropriate governance mechanisms and strong collaborations.

Epidemiology of rare cancers and inequalities in oncologic outcomes

Rare cancers epidemiology is better known compared to the other rare diseases. Thanks to the long history of the European population-based cancer registries and to the EUROCARE huge database, the burden of rare cancers has been estimated the European (EU28) population. A considerable fraction of all cancers is represented by rare cancers (24%). They are a heterogeneous group of diseases, but they share similar problems: uncertainty of diagnosis, lack of therapies, poor research opportunities, difficulties in clinical trials, lack of expertise and of centres of reference. This paper analyses the major epidemiological indicators of frequency (incidence and prevalence) and outcome (5-year survival) of all rare cancers combined and of selected rare cancers that will be in depth treated in this monographic issue. Source of the results is the RARECAREnet search tool, a database publicly available. Disparities both in incidence and survival, and consequently in prevalence of rare cancers were reported across European countries. Major differences were shown in outcome: 5-year relative survival for all rare cancers together, adjusted by age and case-mix, varied from 55% or more (Italy, Germany, Belgium and Iceland) and less than 40% (Bulgaria, Lithuania and Slovakia). Similarly, for all the analyzed rare cancers, a large survival gap was observed between the Eastern and the Nordic and Central European regions. Dramatic geographical variations were assessed for curable cancers like testicular and non epithelial ovarian cancers. Geographical difference in the annual age-adjusted incidence rates for all rare cancers together varied between >140 per 100,000 (Italy, Scotland, France, Germany, and Switzerland) and <100 (Finland, Portugal, Malta, and Poland). Prevalence, the major indicator of public health resources needs, was about 7-8 times larger than incidence. Most of rare cancers require complex surgical treatment, thus a multidisciplinary approach is essential and treatment should be provided in centres of expertise and/or in networks including expert centres. Networking is the most appropriate answer to the issues pertaining to rare cancers. Actually, in Europe, an opportunity to improve outcome and reduce disparities is provided by the creation of the European Reference Networks for rare diseases (ERNs). The Joint Action of rare cancers (JARC) is a major European initiative aimed to support the mission of the ERNs. The role of population based cancer registries still remains crucial to describe rare cancers management and outcome in the real word and to evaluate progresses made at the country and at the European level.

Translational applications of microRNAs in cancer, and therapeutic implications

The search for targeted novel therapies for cancer is ongoing. MicroRNAs (miRNAs) display a number of characteristics making them an attractive and realisable option. In this review, we explore these applications, ranging from diagnostics, prognostics, disease surveillance, to being a primary therapy or a tool to sensitise patients to treatment modalities such as chemotherapy and radiotherapy. We take a particular perspective towards miRNAs and their impact on rare cancers. Advancement in the delivery of miRNAs, from viral vectors and liposomal delivery to nanoparticle based, has led to a number of pre-clinical and clinical applications for microRNA cancer therapeutics. This is promising, especially in the setting of rare cancers.

Clinical trial designs for rare diseases: studies developed and discussed by the International Rare Cancers Initiative

BACKGROUND

The past three decades have seen rapid improvements in the diagnosis and treatment of most cancers and the most important contributor has been research. Progress in rare cancers has been slower, not least because of the challenges of undertaking research.

SETTINGS

The International Rare Cancers Initiative (IRCI) is a partnership which aims to stimulate and facilitate the development of international clinical trials for patients with rare cancers. It is focused on interventional--usually randomized--clinical trials with the clear goal of improving outcomes for patients. The key challenges are organisational and methodological. A multi-disciplinary workshop to review the methods used in ICRI portfolio trials was held in Amsterdam in September 2013. Other as-yet unrealised methods were also discussed.

RESULTS

The IRCI trials are each presented to exemplify possible approaches to designing credible trials in rare cancers. Researchers may consider these for use in future trials and understand the choices made for each design.

INTERPRETATION

Trials can be designed using a wide array of possibilities. There is no 'one size fits all' solution. In order to make progress in the rare diseases, decisions to change practice will have to be based on less direct evidence from clinical trials than in more common diseases.

[Rare cancers and new radiotherapy techniques]

Rare cancers represent about a quarter of all cancers diagnosed in Europe, and their incidence is increasing. Meanwhile, scientific advances provide techniques, which become more and more sophisticated in the domain of radiotherapy. Treatment options for radiotherapy rare cancers are increasing, but are not yet evaluated. The question of the appropriateness of treatment by modern radiotherapy techniques in rare cancers remains. There are a lot of cases reported in the literature for treating rare cancers by modern technology. These techniques are often used when anatomical and dosimetric constraints do not achieve optimal treatment by surgery or standard radiotherapy. In contrast, standard radiotherapy techniques also provide good results in terms of overall survival and tolerance. They are also less expensive and less complex in terms of dosimetry. The establishment of specialized centers in rare cancers seems essential to evaluate the appropriateness of the use of modern techniques in these cases. Currently, data from the literature does not provide an answer to this question.

Descriptive epidemiology of Kaposi sarcoma in Europe. Report from the RARECARE project

Kaposi sarcoma (KS) is a virus-related malignancy which most frequently arises in skin, though visceral sites can also be involved. Infection with Kaposi sarcoma herpes virus (KSHV or HHV-8) is required for development of KS. Nowadays, most cases worldwide occur in persons who are immunosuppressed, usually because of HIV infection or as a result of therapy to combat rejection of a transplanted organ, but classic Kaposi sarcoma is predominantly a disease of the elderly without apparent immunosuppression. We analyzed 2667 KS incident cases diagnosed during 1995-2002 and registered by 75 population-based European cancer registries contributing to the RARECARE project. Total crude and age-standardized incidence rate was 0.3 per 100,000 per year with an estimated 1642 new cases per year in the EU27 countries. Age-standardized incidence rate was 0.8 per 100,000 in Southern Europe but below 0.3 per 100,000 in all other regions. The elevated rate in southern Europe was attributable to a combination of classic Kaposi sarcoma in some Mediterranean countries and the relatively high incidence of AIDS in several countries. Five-year relative survival for 2000-2002 by the period method was 75%. More than 10,000 persons were estimated to be alive in Europe at the beginning of 2008 with a past diagnosis of KS. The aetiological link with suppressed immunity means that many people alive following diagnosis of KS suffer comorbidity from a pre-existing condition. While KS is a rare cancer, it has a relatively good prognosis and so the number of people affected by it is quite large. Thus it provides a notable example of the importance of networking in diagnosis, therapy and research for rare cancers.

The burden of rare cancer in Japan: application of the RARECARE definition

BACKGROUND

Despite the fact that rare cancer is a new target of cancer control in Japan, the incidence of rare cancers is unknown and there is no generally accepted definition of rare cancers in this country. With the aim of calculating incidences of rare cancers in Japan, we therefore adopted a definition and classification of rare cancers that had been published in the European Union (EU) in 2011.

METHODS

Using incidence data between 1998 and 2007 submitted by 12 of population based cancer registries in Japan that met our quality criteria and drawing on the EU definition (incidence <6 per 100,000 per year), we estimated the incidences of 845 combinations of tumor sites and histological groups and thus identified the cancers that are rare in Japan.

RESULTS

After identifying 193 combinations of tumor sites and histological groups that fit our criteria for rare cancers, we estimated their incidence to be about 75 per 100,000, which corresponds to about 94,800 new diagnoses in 2012 or approximately 15% of all cancer diagnoses. The categorization of rare and common cancers was almost the same in Japan as in EU.

CONCLUSIONS

The present study provides an indication of the size of the rare cancer burden in Japan and epidemiological information to explore this. We are expecting further discussion based on our results with stakeholders in order to construct a Japanese definition of rare cancers.