Cancers of Unknown Primary Origin: Real-World Clinical Outcomes and Genomic Analysis at the European Institute of Oncology.

BACKGROUND: Cancer of unknown primary origin (CUP) poses a significant challenge due to poor clinical outcomes and limited treatment options. As such, further definition of clinicopathological factors and genomic profile to better adapt treatment strategies is required. METHODS: Medical records were interrogated to retrospectively include CUP with available clinical and genomics data at the European Institute of Oncology. Next-generation sequencing (NGS) included targeted panels. Statistical analyses were conducted with R Software 4.2.2. RESULTS: A total of 44 patients were included. With a median follow-up of 39.46 months (interquartile range [IQR] 35.98-47.41 months), median PFS (mPFS) to first-line regimen was 3.98 months (95% CI 3.22-5.98), with a clinical benefit rate of 26% (95% CI 14%-49%), and disease control rate (DCR) limited to 48.28%. Most patients (26 of 31, 83.87%) received platinum-doublet chemotherapy, with no statistically significant difference between first-line treatment regimens. Median OS (mOS) was 18.8 months (95% CI 12.3-39.9), with a 12-month OS rate of 66% (95% CI 50%-85%). All patients received comprehensive genomic profiling (CGP). For 11 patients, NGS was unsuccessful due to low sample quantity and/or quality. For the remaining, TP53 (n = 16, 48%) and KRAS (n = 10, 30%) represented the most altered (alt) genes. No microsatellite instability was observed (0 of 28), while 6 of 28 (21.43%) tumors carried high TMB (≥10 mutation per megabase). Eight of 33 tumors (24.2%) displayed at least one actionable alteration with potential clinical benefit according to ESCAT. Only 2 of them received targeted therapy matched to genomic alterations, with a combined mPFS of 2.63 months (95% CI 1.84-not evaluable) as third-line regimens. Six patients received anti-PD1/PD-L1 therapy, showing a meaningful mPFS of 13 months (95% CI 2.04-not evaluable). CONCLUSION: CUP exhibits poor prognosis with limited benefits from standard treatment regimens. A significant proportion of CUPs carry actionable alterations, underscoring the importance of genomic profiling to gather additional treatment opportunities. In addition, immunotherapy might represent a valuable treatment option for a subset of CUP. Finally, accurate definition of sequencing methods and platforms is crucial to overcome NGS failures.

[A Patient with Cancer of Unknown Primary Who Responded to Chemotherapy].

Cancer of unknown primary is a class of malignant tumors, histologically identified as metastatic lesions whose primary origin is unknown despite adequate investigations for the primary tumor. Although the prognosis of cancer of unknown primary is generally poor, here, we report our experience with a patient who responded to chemotherapy. The patient was a 78-year-old woman. She had a history of gastric cancer at the age of 76 years. In June of year X-1, she was diagnosed with gastric cancer(tub1>tub2, pT1bN0M0, pStage Ⅰa)and underwent distal gastrectomy. One year after surgery, computed tomography revealed right supraclavicular lymphadenopathy, for which cervical lymphadenectomy was performed. The pathological diagnosis was ductal carcinoma with comedo necrosis and poorly differentiated solid adenocarcinoma that were suggestive of metastases from breast cancer. However, a detailed examination of the mammary glands revealed no mass. Imaging studies led to a diagnosis of cancer of unknown primary. Therefore, chemotherapy, according to the treatment of pancreatic cancer, was planned based on immunostaining, tumor markers, etc. Chemotherapy response evaluation after completing 4 courses demonstrated a partial response; the patient responded to the chemotherapy. We considered that estimating primary lesions from histopathological images, tumor markers, etc., may help determine effective chemotherapy regimens.

[Case of a Patient with Cancer of Unknown Primary in the Poor Prognosis Group Who Had a Experienced a Beneficial Treatment Course].

A 47-year-old woman with general malaise and abdominal pain presented with multiple liver tumors and lymph node metastasis. She was diagnosed with small cell carcinoma on the basis of a lymph node biopsy; however, the primary lesion was not identified. Finally, we diagnosed her with cancer of unknown primary lesion and placed her in the poor prognosis group. Although her general condition was poor, she experienced a relatively good response to treatment for small cell carcinoma.

Comprehensive biomarker diagnostics of unfavorable cancer of unknown primary to identify patients eligible for precision medical therapies.

PURPOSE: Current guidelines recommend combination chemotherapy for treatment of patients with unfavorable cancer of unknown primary (CUP). Biomarker-guided targeted therapies may offer additional benefit. Data on the feasibility and effectiveness of comprehensive genomic biomarker profiling of CUP in a standard clinical practice setting are limited. METHODS: This analysis included 156 patients with confirmed unfavorable CUP diagnosis according to ESMO guidelines, who were treated at the West German Cancer Center, Essen, Germany, from 2015 to 2021. Clinical parameters and outcome data were retrieved from the electronic hospital information system. Genomic biomarker analyses were performed in formalin-fixed paraffin-embedded tumor tissue whenever possible using the QIAseq Multimodal-Pancancer-Panel. RESULTS: Non-squamous histologies, high tumor burden, and age above 60 years associated with poor survival outcome. Tissue availability restricted comprehensive biomarker analyses to 50 patients (32%), reflecting a major limitation in the real-world setting. In those patients a total of 24 potentially actionable alterations were identified in 17 patients (34% of profiled patients, 11% of total population). The most prevalent biomarkers were high tumor mutational burden and BRCA-mutations. CONCLUSION: In a real-world setting precision medicine for patients with CUP is severely restricted by tissue availability, and a limited spectrum of actionable alterations. Progress for patients may require emphasizing the need for sufficient biopsies, and prospective exploration of blood-based biomarker profiling.

Peptide receptor radionuclide therapy (PRRT) in metastatic neuroendocrine tumors of unknown primary (CUP-NETs).

Rationale: Peptide receptor radionuclide therapy (PRRT) for the treatment of neuroendocrine tumors (NETs) has been explored for more than two decades, but there are only limited data on the treatment of NETs of unknown primary site (CUP-NETs). This study aimed to analyze the long-term outcome, efficacy, and safety of PRRT in patients with CUP-NETs. Methods: Patients with pathologically confirmed metastatic CUP-NET who received lutetium-177 (177Lu) and/or yttrium-90 (90Y) labeled somatostatin analogs between March 2001 and March 2019 were retrospectively reviewed; those patients were referred as cCUP-NETs (clinical CUP-NETs). Eighty-one patients had unknown primary tumors even after [68Ga]Ga-SSTR and [18F]FDG PET/CT and were classified as pCUP-NETs (PET CUP-NETs). Treatment response was assessed according to RECIST 1.1 and PERCIST. Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier analysis, and adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 5.0. Results: A total of 575 PRRT cycles were administered to 156 patients (76 men and 80 women) evaluable for analysis: these patients were monitored for a median period of 92.3 mo (range, 4.0-169.1 mo). The disease control rate was 41.4% (43.4%) by RECIST and 40.2% (40.8%) by PERCIST in cCUP-NENs (pCUP-NETs). The objective response rate (ORR) with PRRT was 29.4% and 32.2% in cCUP-NENs and pCUP-NETs, respectively. The median PFS and OS for the entire cohort were 17.4 mo (95% confidence interval [95% CI], 11.4-23.4) and 67.4 mo (95% CI, 47.2-87.2) for all patients, respectively. The median OS for G3 tumors was significantly lower (15 mo) than for patients with G1 NET (85.5 mo), G2 (71.7 mo), and for patients with unknown grade (63.3 mo) NETs (P = 0.186, HR: 10.6, 95% CI: 3.87, 28.97, P = 0.09). PRRT was well tolerated by all patients. During treatment and long-term follow-up, CTCAE grade 3 and grade 4 thrombocytopenia and leukocytopenia were observed in only 3 patients (1.9%); there was no evidence of renal or hepatic toxicity. Conclusion: In a large cohort of patients with advanced CUP-NETs treated with PRRT in a real-world scenario and followed up to 14 years after the commencement, PRRT has demonstrated favorable and clinically significant efficacy and survival with minimal and acceptable side effects. Our results indicate that PRRT is a well-tolerated and effective treatment option for patients with metastatic CUP-NETs expressing somatostatin receptors.

Impact of the Identification of Nonhuman Genetic Signatures in the Diagnosis and Management of Carcinoma of Unknown Primary.

This report presents the case of a 62-year-old woman who was diagnosed in 1999 with stage I cervical carcinoma treated by surgical resection. In 2021, she presented to the emergency department with a complaint of predominantly right-sided lower back pain. A CT scan of the lumbosacral region revealed a bone lesion in the L5 vertebra and retroperitoneal lymphadenopathies suggestive of malignancy. Histology of the L5 vertebra biopsy showed a poorly differentiated carcinoma with an inconclusive immunophenotypic profile. Treatment for carcinoma of unknown primary was started with a combination of carboplatin and paclitaxel every 21 days. A genomic study of the biopsy specimen performed on the FoundationOne CDx platform identified a nonhuman genetic signature compatible with HPV. The presence of HPV 18 DNA in the specimen was confirmed by PCR-reverse dot blot, and the immunophenotypic profile was expanded, revealing strong and diffuse p16 expression, thus corroborating the molecular findings. In view of these findings, the case was reclassified as a recurrence of the cervical adenocarcinoma that had been diagnosed and treated 23 years earlier. Based on the new results, and according to first-line cervical carcinoma protocols, bevacizumab at 15 mg/kg every 21 days was added to her chemotherapy regimen. The identification of HPV DNA sequences by next-generation sequencing facilitated the correct diagnosis and led to a modification of the first-line therapeutic approach.

Local Treatment Efficacy for Single-Area Squamous Cell Carcinoma of the Unknown Primary Site.

The prognosis for cancer of unknown primary site (CUP) is poor, and squamous cell carcinoma of the unknown primary site (SCCUP) is a rare histological type. CUP is often treated with aggressive multimodal treatments, while the treatment of single-area localized CUP remains controversial. We retrospectively reviewed the medical records of patients with CUP. SCCUP in women was classified according to several definitions. Based on the histologic type and site, they were classified into favorable and unfavorable subsets. We further divided SCCUP into two types (single and multiple areas) and reviewed treatment and efficacy. Among the 227 female CUP patients, 36 (15%) had SCCUP. The median age was 59.9 years (range, 31-90 years). Most patients (61.1%) had a good performance status. Of the SCCUP patients, 22 had cancer in a single area, and 14 in multiple areas. Single-area SCCUP was further divided into favorable (16 cases) and unfavorable subsets (6 cases). In the favorable subset, local treatment was predominant, and almost all cases had a good prognosis. Even in the unfavorable subset, local therapy was combined with systemic chemotherapy in only two cases, and four cases showed no recurrences. Local treatment may be effective for single-area SCCUP, even in the unfavorable subset.

Nivolumab and ipilimumab in recurrent or refractory cancer of unknown primary: a phase II trial.

Cancer of unknown primary has a dismal prognosis, especially following failure of platinum-based chemotherapy. 10-20% of patients have a high tumor mutational burden (TMB), which predicts response to immunotherapy in many cancer types. In this prospective, non-randomized, open-label, multicenter Phase II trial (EudraCT 2018-004562-33; NCT04131621), patients relapsed or refractory after platinum-based chemotherapy received nivolumab and ipilimumab following TMBhigh vs. TMBlow stratification. Progression-free survival (PFS) represented the primary endpoint; overall survival (OS), response rates, duration of clinical benefit and safety were the secondary endpoints. The trial was prematurely terminated in March 2021 before reaching the preplanned sample size (n = 194). Among 31 evaluable patients, 16% had a high TMB ( > 12 mutations/Mb). Overall response rate was 16% (95% CI 6-34%), with 7.7% (95% CI 1-25%) vs. 60% (95% CI 15-95%) in TMBlow and TMBhigh, respectively. Although the primary endpoint was not met, high TMB was associated with better median PFS (18.3 vs. 2.4 months) and OS (18.3 vs. 3.6 months). Severe immune-related adverse events were reported in 29% of cases. Assessing on-treatment dynamics of circulating tumor DNA using combined targeted hotspot mutation and shallow whole genome sequencing as part of a predefined exploratory analysis identified patients benefiting from immunotherapy irrespective of initial radiologic response.

Combined Immunotherapy and Tyrosine Kinase Inhibitor Treatment for Metastatic Renal Cell Carcinoma With Unknown Primary Origin: A Report of Two Cases and Literature Review.

BACKGROUND/AIM: Renal cell carcinoma (RCC) of unknown primary origin is rarely identified and accounts for only 5% of cancers of unknown primary origin (CUP). The disease prognosis is typically poor because of no standard and effective therapy. Our review indicated that 23 cases have been reported and treated with conventional chemotherapy or tyrosine-kinase inhibitors alone; accordingly, most patients showed partial response or progression diseases with short survival time. CASE REPORT: Herein, we present two cases of metastatic RCC of unknown primary origin. One case was papillary type and the other was clear cell type. According to the recent clinical trials in patients with metastatic RCC, a combination of immunotherapy and tyrosine-kinase inhibitors exhibited better response than conventional therapy or tyrosine-kinase inhibitors alone. Both present cases accepted a combination treatment with immunotherapy and tyrosine-kinase inhibitor and showed stable diseases. The radiological progression-free time for the case with metastatic papillary RCC was 5 months, and that with clear cell RCC was 6 months until now. CONCLUSION: The combination of immunotherapy and tyrosine-kinase inhibitors is at least as effective as a tyrosine-kinase inhibitor alone, and superior to conventional chemotherapy for treating metastatic RCC of unknown primary origin.

Immunochemotherapy achieved a complete response for metastatic adenocarcinoma of unknown primary based on gene expression profiling: a case report and review of the literature.

Background: Cancer of unknown primary (CUP) is a malignant and aggressive tumor whose primary origin is still unknown despite thorough evaluation. CUP can be life-threatening with a median overall survival of less than 1 year based on empirical chemotherapy. Gene detection technology advances the driver gene detection of malignant tumors and the appropriate precise therapy. Immunotherapy has ushered in a new era in cancer therapy, changing the way advanced tumors, including CUP, are treated. Combined with comprehensive clinical and pathological investigations, molecular analysis of the original tissue and detection of potential driver mutations may provide therapeutic recommendations for CUP. Case presentation: A 52-year-old female was admitted to hospital for dull abdominal pain, with peripancreatic lesions below the caudate lobe of the liver and posterior peritoneal lymph nodes enlargement. Conventional biopsy under endoscopic ultrasonography and laparoscopic biopsy both revealed poorly differentiated adenocarcinoma based on immunohistochemical series. To help identify tumor origin and molecular characteristics, 90-gene expression assay, tumor gene expression profiling with Next-generation sequencing (NGS) method and Immunohistochemical expression of PD-L1 were employed. Although no gastroesophageal lesions discovered by gastroenteroscopy, the 90-gene expression assay yielded a similarity score and prompted the most likely primary site was gastric/esophagus cancer. NGS revealed high TMB (19.3mutations/Mb) but no druggable driver genes identified. The Dako PD-L1 22C3 assay IHC assay for PD-L1 expression revealed a tumor proportion score (TPS) of 35%. Given the presence of negative predictive biomarkers for immunotherapy, including adenomatous polyposis coli (APC) c.646C>T mutation at exon 7 and Janus kinase 1(JAK1), the patient received immunochemotherapy instead of immunotherapy alone. She was successfully treated with nivolumab plus carboplatin and albumin-bound nanoparticle paclitaxel for six cycles and nivolumab maintenance, which achieved a complete response (CR) maintained for 2 years without severe adverse events. Conclusions: This case highlights the value of multidisciplinary diagnosis and individual precision treatment in CUP. Further investigation is needed as an individualized treatment approach combining immunotherapy and chemotherapy based on tumor molecular characteristics and immunotherapy predictors is expected to improve the outcome of CUP therapy.

Feasibility and value of genomic profiling in cancer of unknown primary: real-world evidence from prospective profiling study.

Real-world evidence regarding the value of integrating genomic profiling (GP) in managing cancer of unknown primary (CUP) is limited. We assessed this clinical utility using a prospective trial of 158 patients with CUP (October 2016-September 2019) who underwent GP using next-generation sequencing designed to identify genomic alterations (GAs). Only 61 (38.6%) patients had sufficient tissue for successful profiling. GAs were seen in 55 (90.2%) patients of which GAs with US Food and Drug Administration-approved genomically matched therapy were seen in 25 (40.9%) patients. A change in therapy was recommended and implemented (primary endpoint of the study) in 16 (10.1%) and 4 (2.5%) patients of the entire study cohort, respectively. The most common reason for inability to implement the profiling-guided therapy was worsening of performance status (56.3%). Integrating GP in management of CUP is feasible but challenging because of paucity of tissue and aggressive natural history of the disease and requires innovative precision strategies.

Significance of Distinct Liquid Biopsy Compartments in Evaluating Somatic Mutations for Targeted Therapy Selection in Cancer of Unknown Primary.

PURPOSE: Cancer of unknown primary (CUP) accounts for 2-5% of all cancer diagnoses, wherein standard investigations fail to reveal the original tumor site. Basket trials allocate targeted therapeutics based on actionable somatic mutations, independent of tumor entity. These trials, however, mostly rely on variants identified in tissue biopsies. Since liquid biopsies (LB) represent the overall tumor genomic landscape, they may provide an ideal diagnostic source in CUP patients. To identify the most informative liquid biopsy compartment, we compared the utility of genomic variant analysis for therapy stratification in two LB compartments (circulating cell-free (cf) and extracellular vesicle (ev) DNA). METHODS: CfDNA and evDNA from 23 CUP patients were analyzed using a targeted gene panel covering 151 genes. Identified genetic variants were interpreted regarding diagnostic and therapeutic relevance using the MetaKB knowledgebase. RESULTS: LB revealed a total of 22 somatic mutations in evDNA and/or cfDNA in 11/23 patients. Out of the 22 identified somatic variants, 14 are classified as Tier I druggable somatic variants. Comparison of variants identified in evDNA and cfDNA revealed an overlap of 58% of somatic variants in both LB compartments, whereas over 40% of variants were only found in one or the other compartment. CONCLUSION: We observed substantial overlap between somatic variants identified in evDNA and cfDNA of CUP patients. Nonetheless, interrogation of both LB compartments can potentially increase the rate of druggable alterations, stressing the significance of liquid biopsies for possible primary-independent basket and umbrella trial inclusion.

[New strategies for the treatment of carcinoma of unknown primary].

Carcinoma of unknown primary (CUP) is a kind of metastatic tumor whose primary origin cannot be identified after adequate examination and evaluation. The main treatment modality of CUP is empiric chemotherapy, and the median overall survival time is less than 1 year. Compared with immunohistochemistry, novel method based on gene expression profiling have improved the sensitivity and specificity of CUP detection, but its guiding value for treatment is still controversial. The approval of immune checkpoint inhibitors and pan-cancer antitumor agents has improved the prognosis of patients with CUP, and targeted therapy and immunotherapy based on specific molecular characteristics are the main directions of future research. Given the high heterogeneity and unique clinicopathological characteristics of CUP, "basket trial" is more suitable for clinical trial design in CUP.

A case of refractory pelvic squamous cell carcinoma of unknown primary that responded to nivolumab.

Cancer of unknown primary (CUP) is a heterogeneous group of metastatic tumors with a usually unfavorable prognosis. A 33-year-old female was diagnosed with pelvic squamous cell carcinoma of unknown primary. The tumor was p16-positive, suggesting that it was human papillomavirus (HPV)-related. The tumor progressed for 4 months after concurrent chemoradiotherapy (initial treatment) and was refractory to paclitaxel plus carboplatin (second-line therapy). Liquid-based cancer genomic profiling identified five pathogenic variants, including Neurofibromin1 (NF1) (p.T1690Mfs*5); however, due to the lack of domestic clinical trials, the patient could not receive genome-based molecular-target therapies. Simultaneously, nivolumab was administered to the patient post its approval in Japan for CUP. The tumor responded to nivolumab, accompanied by decreased levels of tumor markers. NF1 mutations and HPV-related carcinogenesis may be associated with a favorable response to nivolumab treatment. It may therefore serve as a potential treatment against cancers of unknown primaries.

Immune and genomic biomarkers of immunotherapy response in cancer of unknown primary.

BACKGROUND: Cancer of unknown primary (CUP) is a heterogeneous group of metastatic cancers where a primary tissue of origin (TOO) is uncertain. Most patients with CUP have limited treatment options and poor survival outcomes. Immune checkpoint inhibitors (ICIs) can be efficacious in some patients with CUP, but the optimal predictive biomarkers are unknown. We therefore assessed immune and genomic biomarkers as well as predicted TOO in patients with CUP, including a subset treated with ICIs. METHODS: Patients with CUP were subject to gene-expression profiling (GEP) and DNA panel sequencing. Immune and stromal-related gene expression was explored by NanoString, including genes associated with immunotherapy response (IR) in other solid malignancies. ICI responsive cancer types were assigned based on Food and Drug Administration-approved indications, and either detection of a latent primary tumor or the TOO was suspected based on genomics informed pathology review. Tumor mutation burden (TMB) and gene mutations were also assessed. RESULTS: A total of 219 patients with CUP were included, 215 assessed for TOO in a previous study, with the majority (163) receiving both RNA and DNA tests. Of GEP profiled cases, 33% (59/175) had a high IR gene-expression score. Of the DNA sequenced cases, 16% (32/203) had high TMB (>10 mutations/Mb), including two with mismatch repair deficiency. Low correlation was observed between TMB and an IR score (R=0.26, p<0.001). Among 110 CUPs with a latent primary or suspected TOO, 47% (52/110) belonged to ICI-responsive cancer types. More than half of the CUPs had at least one feature that may predict ICI response (high IR score, high TMB, ICI-responsive cancer type). Among patients with CUP treated with ICIs, 8/28 (29%) responded (2 complete responses and 6 partial responses). Among non-responders, 9 had stable and 11 had progressive disease. All responders had a high IR score (7/8) and/or high TMB (3/8), while most (5/8) belonged to ICI-responsive cancer types. These features were detected at a lower frequency in non-responders and mostly in patients with stable disease. CONCLUSIONS: A significant fraction of CUP tumors had genomic features previously associated with ICI response. High IR score was the most sensitive predictive feature of ICI response, warranting evaluation in a larger patient series.

Melanuria in a patient with BRAF-mutant metastatic melanoma of unknown primary: Insights on the pathophysiology, differential diagnosis, prognosis, and treatment.

Melanuria is the dark brown discoloration of the urine and an uncommon manifestation in patients with melanoma. It is an ominous sign, usually indicating widespread disease. In this article, through an illustrative case, we discuss the pathophysiological, clinical, and prognostic characteristics of melanuria in melanoma. Moreover, we aim to provide the available data for the prompt diagnosis and treatment of patients presenting with melanuria. We present the case of a 47-year-old man presenting with melanuria and diffure melanosis cutis, who was eventually diagnosed with a BRAF-mutated metastatic melanoma of unknown primary. The patient was started on a BRAF and MEK inhibitor, but he had a rapid disease progression and succumbed to the disease. There is only a limited number of case reports of melanoma patients with melanuria receiving targeted therapies or immune checkpoint inhibitors. In these reports, variable treatment responses have been described. In view of the increasing significance of targeted therapies and immunotherapy for melanoma, more cases are needed to improve our understanding on the prognostic significance of melanuria in the era of novel therapies for melanoma.

Complete genomic characterization in patients with cancer of unknown primary origin in routine diagnostics.

BACKGROUND: In ∼3%-5% of patients with metastatic disease, tumor origin remains unknown despite modern imaging techniques and extensive pathology work-up. With long diagnostic delays and limited and ineffective therapy options, the clinical outcome of patients with cancer of unknown primary (CUP) remains poor. Large-scale genome sequencing studies have revealed that tumor types can be predicted based on distinct patterns of somatic variants and other genomic characteristics. Moreover, actionable genomic events are present in almost half of CUP patients. This study investigated the clinical value of whole genome sequencing (WGS) in terms of primary tumor identification and detection of actionable events, in the routine diagnostic work-up of CUP patients. PATIENTS AND METHODS: A WGS-based tumor type 'cancer of unknown primary prediction algorithm' (CUPPA) was developed based on previously described principles and validated on a large pan-cancer WGS database of metastatic cancer patients (>4000 samples) and 254 independent patients, respectively. We assessed the clinical value of this prediction algorithm as part of routine WGS-based diagnostic work-up for 72 CUP patients. RESULTS: CUPPA correctly predicted the primary tumor type in 78% of samples in the independent validation cohort (194/254 patients). High-confidence predictions (>95% precision) were obtained for 162/254 patients (64%). When integrated in the diagnostic work-up of CUP patients, CUPPA could identify a primary tumor type for 49/72 patients (68%). Most common diagnoses included non-small-cell lung (n = 7), gastroesophageal (n = 4), pancreatic (n = 4), and colorectal cancer (n = 3). Actionable events with matched therapy options in clinical trials were identified in 47% of patients. CONCLUSIONS: Genome-based tumor type prediction can predict cancer diagnoses with high accuracy when integrated in the routine diagnostic work-up of patients with metastatic cancer. With identification of the primary tumor type in the majority of patients and detection of actionable events, WGS is a valuable diagnostic tool for patients with CUP.

Rhabdomyosarcoma with unknown primary tumor site: A report from European pediatric Soft tissue sarcoma Study Group (EpSSG).

BACKGROUND: Rhabdomyosarcoma (RMS) is an aggressive malignancy, and 20% of children present with metastases at diagnosis. Patients presenting with disseminated disease very occasionally have no clear evidence of a primary tumor mass. As these patients have rarely been investigated, we report on a series of patients with RMS and unknown primary tumor site registered in the Metastatic (MTS) RMS 2008 protocol (October 2008 to December 2016) coordinated by the European pediatric Soft tissue sarcoma Study Group. METHODS: Patients were administered nine cycles of induction chemotherapy, and 48 weeks of maintenance chemotherapy. Surgery and/or radiotherapy were planned after the first assessment of tumor response, and implemented after six cycles of chemotherapy. If feasible, radiotherapy to all sites of metastasis was recommended. RESULTS: We identified 10 patients with RMS and unknown primary site, most of them adolescents (median age 15.8 years, range: 4.6-20.4). Nine had fusion-positive alveolar RMS. Multiple organ involvement was identified in seven patients, two only had bone marrow disease, and one only had leptomeningeal dissemination. All patients were given chemotherapy, four were irradiated, and none had surgery. Three patients underwent allogeneic bone marrow transplantation. At the time of this analysis, only two patients are alive in complete remission: one had received radiotherapy; and one had a bone marrow transplant. CONCLUSIONS: RMS with unknown primary tumor occurs mainly in adolescents and is typically fusion-positive alveolar. Radiotherapy may be important, but survival is poor and patients should be offered enrollment in investigational trials.

A multicentre retrospective study comparing site-specific treatment with empiric treatment for unfavourable subset of cancer of unknown primary site.

BACKGROUND: Patients with cancer of unknown primary site are divided into two distinct groups, favourable and unfavourable subsets. For the unfavourable subset, empiric treatment or site-specific treatment is recommended, but limited knowledge exists about the efficacy of site-specific treatment compared with empiric treatment in clinical practice. METHODS: In this multicentre retrospective study, we reviewed the medical records of patients with cancer of unknown primary site treated with chemotherapy (or chemoradiotherapy) as first-line treatment from eight institutions during 2006-18. We investigated the workup modality and categorized the patients into favourable and unfavourable subsets, which were further divided into site-specific and empiric treatment groups. Site-specific treatment is defined as a standard chemotherapy for an estimated primary site. We examined the efficacy in the favourable and unfavourable subsets and performed multivariable analysis for estimating the overall survival in the unfavourable subset. RESULTS: Of 177 patients with cancer of unknown primary site, 33 and 144 were categorized into favourable and unfavourable subsets, respectively. In the unfavourable subset, 84 patients (58.3%) received empiric therapy, and 60 patients (41.7%) received site-specific treatment. Median overall survival was 10.0 and 10.1 months in site-specific and empiric treatment groups, respectively, with no significant difference (hazard ratio 1.01, 95% confidence interval 0.70-1.45, P = 0.95). Multivariable analysis revealed performance status, number of metastatic sites and hypoalbuminaemia as independent prognostic factors for overall survival in the unfavourable subset. CONCLUSIONS: Overall survival in site-specific and empiric treatment groups was similar in the unfavourable cancer of unknown primary site subset in this study. Further research is needed to prolong overall survival in patients in the unfavourable cancer of unknown primary site subset.