Cancers of unknown primary site: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Exploration of genes related to the development of cancer of unknown primary

The biological basis of the development of cancer of unknown primary (CUP) remains largely unknown, with no evidence of whether a common biological basis exists at present. Our previous multicenter clinical study predicted the primary site of CUP for site‑specific therapy. Concomitantly with the study, a microarray analysis of tumor mRNA samples obtained from 60 participants of the study with CUP was performed, and a gene expression profile specific to CUP was constructed. Several of the genes identified as being upregulated/downregulated in CUP could potentially be clinically useful common biomarkers of CUP. In the present study, to identify genes that may be more closely related to the development of CUP (characterized by its metastatic potential) among the upregulated genes, cell‑based small interfering RNA screening was performed in vitro, and two genes, protein kinase DNA‑activated catalytic subunit (PRKDC) and proteasome subunit β type‑4 (PSMB4), were identified to be possibly involved in the metastatic ability of CUP, since knockdown of these genes resulted in reduced migration of A549 cells. These genes were further knocked down in A549 cells using short hairpin RNAs (shRNAs) and the cells were implanted into the footpad of mice. Marked suppression of the metastatic ability of implanted cells from the footpad to the popliteal lymph node (LN) was observed in cells transfected with the shRNAs for PRKDC and PSMB4. In addition, bortezomib, a proteasome inhibitor, markedly reduced the ability of cells implanted into the footpad to metastasize to the LNs, as well as cell growth at the metastatic site, compared with vehicle or NU7447 (inhibitor of PRKDC). These findings indicated that proteasomal function activation augmented the metastatic ability of malignant CUP cells.

Tumor diagnosis recharacterization enabled by comprehensive genomic profiling to guide precision medicine strategy

Comprehensive genomic profiling (CGP) via next-generation sequencing is standard clinical practice for advanced and metastatic cancers in the U.S. and can help identify clinically actionable alterations in patients who may benefit from targeted therapies. CGP can also complement clinicopathological findings and in certain cases, may lead to diagnostic recharacterization resulting in more precise therapeutic strategies. Here, we highlight examples where molecular findings resulted in tumor re-evaluation and subsequent recharacterization. Twenty-eight cases where CGP results were inconsistent with initial pathological diagnosis and clinical presentation were selected for secondary clinicopathological review to explore alternative diagnostic explanations more consistent with the genomic results. Genomic profiling identified clinically actionable and prognostic variants leading to more accurate therapeutic recommendations based on the updated diagnoses highlighting the value of CGP beyond biomarker detection for therapy selection and supporting its complementary use in diagnostic confirmation to unveil opportunities for precision medicine strategies.

Mucinous adenocarcinoma in the axilla of undetermined origin

Mucinous adenocarcinoma (MAC), accounts for ⁓1% of all cancer diagnoses. We present a case of a 75-year-old male who, after presenting for an elective inguinal hernia repair, disclosed concerns for a new lesion in his right axilla which was removed at the same time. Investigations revealed a MAC of unclear origin, with immunohistochemistry suggesting either a breast or primary cutaneous mucinous adenocarcinoma (PCMC). The patient was asymptomatic with an otherwise normal examination. Extensive investigations failed to identify any primary source. Axillary node clearance was performed, resulting in 0/9 positive nodes. After multi-disciplinary team discussion, this patient (who remains asymptomatic) will be kept under close clinical surveillance, with yearly computerized tomography scans. To our knowledge, minimal presentations have been reported in the literature. Thus, our case report is a unique addition of an atypical presentation of PCMC in the axilla.

Skeletal Muscle Density as a Predictor of Prognosis and Physical Reserve in Patients with Cancer of Unknown Primary

Introduction: The Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) is widely used to assess patient status but relies on subjective judgment and may not fully reflect their physical reserve. While studies have shown that skeletal muscle quality and quantity are associated with patient prognosis, their role in cancers of unknown primary (CUP) remains unclear. Therefore, this study aimed to investigate whether computed tomography (CT)-based skeletal muscle indicators reflect physical reserve and their prognostic value in patients with CUP. Methods: This study enrolled 184 patients with CUP, comprising both inpatients and outpatients, who were diagnosed at Seoul St. Mary's Hospital between 1 January 2008, and 30 June 2024. Overall survival (OS) was evaluated using the Kaplan-Meier method and analyzed using the log-rank test. Univariate and multivariate analyses were performed using Cox proportional hazard models. Statistical significance was defined as p < 0.05. Correlation analyses were conducted to evaluate the relationships between skeletal muscle density (SMD), skeletal muscle index (SMI), and other prognostic factors. Results: SMD was positively correlated with SMI and negatively correlated with age, neutrophil-to-lymphocyte ratio, Charlson Comorbidity Index (CCI), and ECOG-PS. Jonckheere's trend test revealed that SMD decreased significantly as CCI and ECOG-PS increased (p < 0.001), indicating that a higher comorbidity burden and poorer performance status were associated with lower SMD. Both ECOG-PS and SMD were identified as prognostic factors in the univariate analysis of survival; however, only SMD demonstrated statistical significance regarding prognostic value in the multivariate analysis (p = 0.004) Conclusions: SMD, as a measure of muscle quality, demonstrates superior prognostic value compared to the subjective ECOG-PS and may serve as a reliable objective tool for assessing physical reserve in patients with CUP.

Case Report: Personalized diagnosis and treatment strategies for three cases of cancer of unknown primary based on molecular testing techniques

Cancer of unknown primary (CUP) is a malignancy characterized by metastatic disease at diagnosis with an unidentified primary site, accounting for 3-5% of all cancers. Despite significant advancements in cancer diagnosis and treatment in recent years, CUP management has been challenging due to its complexity and heterogeneity; therefore, its prognosis remains poor. This report presents three cases of CUP. The first case involved a 59-year-old female whose abdominal metastatic cancer was identified to be originating from a primary cervical cancer using a 90-gene panel; the disease was controlled with targeted immunotherapy. The second case was a 56-year-old male with cervical lymph node metastatic cancer; genetic testing suggested renal cancer as the primary site, and dual-targeted therapy resulted in approximately 28% tumor reduction. The third case involved a 71-year-old female with subcutaneous metastatic cancer, which was confirmed by genetic profiling to be related to breast cancer; she achieved stable disease after chemotherapy. Diagnosis and treatment of these three CUP cases demonstrated that molecular testing could significantly improve treatment outcomes and extend patient survival. Precision medicine based on molecular detection has shown substantial value in identifying the primary site of CUP, developing personalized treatment plans, and managing the disease. However, treatment costs and patient compliance remain challenging, necessitating further research to optimize both diagnostic and therapeutic strategies.

Solving unknown primary cancer with earlier diagnosis - the SUPER-ED trial: study protocol for a stepped-wedge cluster randomised controlled trial to support earlier diagnosis for people presenting with malignancy of undefined primary origin

BACKGROUND

People with malignancy of undefined primary origin (MUO) have a poor prognosis and may undergo a protracted diagnostic workup causing patient distress and high cancer related costs. Not having a primary diagnosis limits timely site-specific treatment and access to precision medicine. There is a need to improve the diagnostic process, and healthcare delivery and support for these patients. This trial aims to implement and evaluate an optimal model of care for people presenting with MUO to reduce time to diagnosis, improve patient experiences and reduce healthcare costs.

METHODS/DESIGN

This is a pragmatic stepped-wedge cluster randomised trial comparing a control phase of standard practice with an intervention phase. Patient inclusion criteria are: 1) age 18 years or older, 2) presenting with suspected metastatic malignancy without an obvious primary site on imaging, 3) clinically appropriate to undergo diagnostic work-up and 4) able to provide written or verbal consent. The intervention is a new model of care comprising four key components: standardised diagnostic workup, dedicated cancer care coordinators, virtual multidisciplinary meetings and a website resource for patients, carers and clinicians. The primary endpoint is the time to completion of minimum diagnostic workup. Secondary outcomes are whether the type of tumour is diagnosed, clinical trial participation, referral to palliative care, patient-reported physical, social and mental health, patient-reported understanding and uncertainty. Implementation outcomes include acceptability, feasibility, fidelity and adoption and health care use and costs. Intervention implementation will be supported using clinical leadership, education and reinforcement. Patients who consent to having their data collected will receive the model of care active at the site at the time of recruitment. Patients will complete a patient-reported outcomes questionnaire four months after study enrolment. A health economic analysis will be included. Across 15 hospitals, a total sample size of 240 is planned.

DISCUSSION

There is a lack of intervention research for people presenting with MUO. The stepped-wedge design seeks to mitigate the potential challenge of enrolling people with a poor prognosis and high symptom burden in trials. This research will generate important evidence with scalability for future research at trial completion.

TRIAL REGISTRATION

ACTRN12622001504707.

Hepatocyte nuclear factor 4α as a sensitive marker for uterine endocervical adenocarcinomas and their precursors

CONTEXT

Hepatocyte nuclear factor (HNF)-4α is a marker of gastrointestinal tumor differentiation; however, its expression in endocervical tumors remains unclear.

OBJECTIVE

We aimed to assess the utility of HNF4α expression as a marker for endocervical adenocarcinomas (ECAs) and adenocarcinoma in situs (AISs), and to establish a minimal panel for distinguishing them from nonneoplastic endocervical glandular lesions and metastases.

DESIGN

HNF4α expression was analyzed immunohistochemically (positive, H-score ≥10) in 323 tissue samples: 57 endocervical neoplasms including 35 glandular neoplasms and 22 squamous neoplasms, 144 nonneoplastic endocervical lesions, and 122 tumors from other organs. The panel for distinguishing endocervical glandular neoplasms from nonneoplastic glands and from metastases comprised HNF4α, p16, CDX2, and SATB2; staining was assessed.

RESULTS

HNF4α was expressed significantly in ECAs and AISs, both HPV-independent and -associated types, but not in nonneoplastic glandular and squamous lesions (p < 0.05). The immunohistochemical detection sensitivity and specificity for endocervical ECA and AIS were 77% and 95%, respectively. For AIS alone, these were 79% and 94%, and for ECA alone, 75% and 94%, respectively. Either HNF4α(+) or p16(+) or double positive identified endocervical gland and squamous neoplasms (sensitivity, 96%; specificity, 76%). HNF4α(+) and SATB2(-) and CDX2(-) profiles suggested ECAs (sensitivity, 69%; specificity, 88%). HNF4α(+) and SATB2(+) or CDX2(+) profiles suggested adenocarcinomas of the gastrointestinal or genital tract (sensitivity, 81%; specificity, 88%).

CONCLUSIONS

HNF4α is a promising marker for detecting both HPV-independent and -associated ECAs and AIS with high accuracy. Its combination with p16, CDX2, and SATB2 has potential use in diagnostic panels.

Advances in machine learning for tumour classification in cancer of unknown primary: A mini-review

Cancers of unknown primary (CUP) are a heterogeneous group of aggressive metastatic cancers where standardised diagnostic techniques fail to identify the organ where it originated, resulting in a poor prognosis and resistance to treatment. Recent advances in large-scale sequencing techniques have enabled the identification of mutational signatures specific to particular tumour subtypes, even from liquid biopsy samples such as blood. This breakthrough paves the way for the development of new cost-effective diagnostic strategies. This mini-review explores recent advancements in Machine Learning (ML) and its application to tumour classification methods for CUP patients, identifying its weaknesses and strengths when classifying the tumour type. In the era of multi-omics, integrating several sources of information (e.g., imaging, molecular biomarkers, and family history) requires important theoretical advancements: increasing the dimensionality of the problem can result in lowering the predictive accuracy and robustness when data is scarce. Here, we review and discuss different architectures and strategies for incorporating cutting-edge machine learning into CUP diagnosis, aiming to bridge the gap between theory and clinical practice.

Evolution in the diagnosis and treatment of carcinoma of unknown primary: a multicenter Canadian analysis

BACKGROUND

Guidelines for the management of patients with cancer of unknown primary (CUP), who have metastatic disease without an identified primary tumor site, have evolved. We sought to describe the diagnostic work-up and outcomes of patients with CUP in Canada over the last decade. We also sought to identify factors associated with improved prognosis in CUP, including primary tumor site identification, identification of "favorable subtypes," and concordance with published guidelines.

METHODS

With ethics board approval, patients with histologically confirmed CUP between 2012 and 2021 in 3 Canadian cancer centers were reviewed and clinicopathological variables retrospectively collected. The primary endpoint was to describe significant trends in CUP diagnosis and management over the decade using linear regression models. Univariable (UVA) and multivariable (MVA) logistic regression analyses identified variables correlated with primary site identification and overall survival (OS). Kaplan-Meier curves with the log-rank test were used to compare OS outcomes.

RESULTS

In total, 907 patients were included, with a median follow-up of 5.1 months. There was an increase in both 5-year survival and identification of primary tumors over the decade. Diagnostic tests including next-generation sequencing were independently associated with primary site identification on UVA. However, primary site identification was not found to be predictive of survival; instead, patients with "favorable subtypes" of CUP had significantly longer OS.

CONCLUSIONS

Survival in patients with CUP in Canada has been increasing over the last decade. Identifying the primary site does not influence survival, and efforts should be focused on discovering novel "favorable subtypes" which have superior outcomes.

The combination of p16 and Rb expression pattern is helpful to predict high-risk HPV infection and the primary site in lymph node metastases of squamous cell carcinoma

Identifying the primary site of metastatic squamous cell carcinoma in lymph nodes can be challenging. An immunohistochemistry (IHC) analysis recently revealed that high-risk human papillomavirus (HR-HPV)-associated oropharyngeal squamous cell carcinomas (OPSCCs) typically show overexpression of p16 protein and a partial loss pattern of Rb. Nevertheless, the status of these markers in metastatic lesions is still unclear. In this study, we examined p16 and Rb expression status by IHC and transcriptionally active HR-HPV infection by mRNA in situ hybridization in paired primary and metastatic SCC lesions. A total of 50 patients with OPSCCs (n=17), hypopharyngeal SCCs (n=16), laryngeal SCCs (n=6), or uterine cervical SCCs (n=11) were enrolled. HR-HPV and p16 were positive in 21/50 (42 %) and 23/50 (46 %) patients, respectively. Primary and metastatic lesions showed concordant results for those three markers in individual patients. Among the p16-positive patients (n=23), HPV-positive cases typically showed a partial loss of Rb (n=20) and, rarely, a complete loss of Rb (n=1), whereas HPV-negative cases showed preserved Rb expression (n=2). All 27 p16-negative cases lacked HPV infection, while preserved expression and complete loss of Rb were observed in 26 and 1 of the p16-negative cases, respectively. Compared to standalone p16, the combination of p16 overexpression and Rb-partial/complete loss showed equally excellent sensitivity and negative predictive value (each 100 %) as well as improved specificity (100 % versus 93.1 %) and positive predictive value (100 % versus 91.3 %). Our results suggest that combining p16 and Rb expression patterns may be helpful in screening for HR-HPV infection in metastatic lymph nodes and in estimating the primary site of SCC.

PD-L1 expression associates with favorable survival of patients with cancer of unknown primary (CUP) not treated with checkpoint inhibitors

PURPOSE

Cancer of unknown primary (CUP) is a heterogeneous entity with limited overall survival (OS) in most patients. Prognostic biomarkers are needed, particularly for treatment stratification. We investigated the impact of programmed death-ligand 1 (PD-L1) expression as prognostic marker in immunotherapy-naïve CUP patients.

METHODS

Clinical data from patients with confirmed CUP diagnosis according to ESMO guidelines, treated at the West German Cancer Center, Essen from 2015 to 2021, were analyzed. Patients treated with checkpoint inhibitors were excluded. PD-L1 expression was assessed in tumor tissues following established guidelines.

RESULTS

Of a cohort of 132 patients, 62 patients, including 30 patients with prognostically unfavorable CUP, met inclusion criteria and were evaluable for PD-L1 expression. Comparing PD-L1 Tumor Proportional Score (TPS) and Combined Positive Score (CPS) revealed almost complete concordance (96.2 %). Patients with PD-L1-positive CUP (TPS ≥1 %; n = 36; 58 %) had superior overall survival (median not reached) as compared to patients with PD-L1-negative CUP (median 14 months, 95 %CI 10.0-18.0; HR 0.3, p < 0.001). The benefit of PD-L1 positivity (n = 12; 40 %) was maintained in the unfavorable CUP subgroup (median 20 months, 95 %CI 3.0-37.0 versus 10 months, 95 %CI 3.1-16.9; HR 0.4, p = 0.032). In PD-L1-positive CUP there was a positive correlation between the level of PD-L1 expression and survival (TPS ≥50 %: median survival not reached, HR 0.1; TPS 1 to 49 %: OS: 77 months, HR 0.4).

CONCLUSION

PD-L1 expression associates with favorable survival in checkpoint inhibitor-naïve CUP patients. This implies a role of cancer immunity in CUP biology and may nominate PD-L1 for patient stratification in further studies and clinical care.

Molecularly guided therapy versus chemotherapy after disease control in unfavourable cancer of unknown primary (CUPISCO): an open-label, randomised, phase 2 study

BACKGROUND

Patients with unfavourable subset cancer of unknown primary (CUP) have a poor prognosis when treated with standard platinum-based chemotherapy. Whether first-line treatment guided by comprehensive genomic profiling (CGP) can improve outcomes is unknown. The CUPISCO trial was designed to inform a molecularly guided treatment strategy to improve outcomes over standard platinum-based chemotherapy in patients with newly diagnosed, unfavourable, non-squamous CUP. The aim of the trial was to compare the efficacy and safety of molecularly guided therapy (MGT) versus standard platinum-based chemotherapy in these patients. This was to determine whether the inclusion of CGP in the initial diagnostic work-up leads to improved outcomes over the current standard of care. We herein report the primary analysis.

METHODS

CUPISCO was a phase 2, prospective, randomised, open-label, active-controlled, multicentre trial done at 159 sites in 34 countries outside the USA. Patients with central eligibility review-confirmed disease (acceptable histologies included adenocarcinoma and poorly differentiated carcinoma) and an Eastern Cooperative Oncology Group performance status of 0 or 1, evaluated by CGP, who reached disease control after three cycles of standard first-line platinum-based chemotherapy were randomly assigned 3:1 via a block-stratified randomisation procedure to MGT versus chemotherapy continuation for at least three further cycles. The primary endpoint was investigator-assessed progression-free survival in the intention-to-treat population. The study is registered with ClinicalTrials.gov, NCT03498521, and follow-up is ongoing.

FINDINGS

From July 10, 2018, to Dec 9, 2022, 636 (42%) of 1505 screened patients were enrolled. Median follow-up in the treatment period was 24·1 months (IQR 11·6-35·6). Of 438 patients who reached disease control after induction chemotherapy, 436 were randomly assigned: 326 (75%) to the MGT group and 110 (25%) to the chemotherapy group. Median progression-free survival in the intention-to-treat population was 6·1 months (95% CI 4·7-6·5) in the MGT group versus 4·4 months (4·1-5·6) in the chemotherapy group (hazard ratio 0·72 [95% CI 0·56-0·92]; p=0·0079). Related adverse event rates per 100-patient-years at risk were generally similar or lower with MGT versus chemotherapy.

INTERPRETATION

In patients with previously untreated, unfavourable, non-squamous CUP who reached disease control after induction chemotherapy, CGP with subsequent MGTs resulted in longer progression-free survival than standard platinum-based chemotherapy. On the basis of these results, we recommend that CGP is performed at initial diagnosis in patients with unfavourable CUP.

FUNDING

F Hoffmann-La Roche.

A Fast, Affordable, and Minimally Invasive Diagnostic Test for Cancer of Unknown Primary Using DNA Methylation Profiling

Currently, we cannot provide a conclusive diagnosis for 3% to 5% of people who are confronted with cancer. These patients have cancer of unknown primary (CUP), ie, a metastasized cancer for which the tissue of origin cannot be determined. Studies have shown that the DNA methylation profile is a unique "fingerprint" that can be used to classify tumors. Here we used cell-free reduced representation bisulfite sequencing (cfRRBS), a technique that allows us to identify the methylation profile starting from minimal amounts of highly fragmented DNA, for CUP diagnosis on formalin-fixed paraffin-embedded (FFPE) tissue and liquid biopsies. We collected 80 primary tumor FFPE samples covering 16 tumor entities together with 15 healthy plasma samples to use as a custom cfRRBS reference data set. Entity-specific methylation regions are defined for each entity to build a classifier based on nonnegative least squares deconvolution. This classification framework was tested on 30 FFPE, 19 plasma, and 40 pleural and peritoneal effusion samples of both known metastatic tumors and clinical CUPs for which pathological investigation finally resulted in a cancer diagnosis. Using this framework, 27 of 30 FFPE (all CUPs) and 16 of 19 plasma samples (10/13 CUPs) obtained an accurate diagnosis, with a minimal DNA input of 400 pg. Diagnosis of the 40 pleural and peritoneal effusion samples is possible in 9 of 27 samples with negative/inconclusive cytology (6/13 CUPs), showing that cell-free DNA (cfDNA) methylation profiling could complement routine cytologic analysis. However, a low "cfDNA - high-molecular weight DNA ratio" has a considerable impact on the prediction accuracy. Moreover, the accuracy improves significantly if the predicted tumor percentage is >7%. This proof-of-concept study shows the feasibility of using DNA methylation profiling on FFPE and liquid biopsy samples such as blood, ascites, and pleural effusions in a fast and affordable way. Our novel RRBS-based technique requires minimal DNA input, can be performed in <1 week, and is highly adaptable to specific diagnostic problems as we only use 5 FFPE references per tumor entity. We believe that cfRRBS methylation profiling could be a valuable addition to the pathologist's toolbox in the diagnosis of CUPs.

A Case of Carcinoma Metastasis of Unknown Primary Mimicking Spondylodiscitis in an HIV+ Patient

In this case report, a case of carcinoma metastasis of unknown primary mimicking spondylodiscitis in a patient with acquired immunodeficiency syndrome (AIDS) is presented. A 50-year-old AIDS patient presented with a history of mechanical falls from his own level one month ago and leg weakness for the last three days. Spinal magnetic resonance imaging (MRI) revealed a compression fracture of the T4 vertebral body, spinal cord compression, and pathology compatible with spondylodiscitis. Posterior decompression and fusion were performed, and the patient benefited. The preoperative ASIA score was C, and the postoperative ASIA score was D. The sample taken from the lesion for pathology showed carcinoma metastasis. Tumor markers and whole-body computed tomography (CT) and MRI results did not support primary malignancy. Positron emission tomography was planned for further evaluation but could not be performed due to the poor general condition of the patient. During follow-up, the patient died of sepsis due to an intensive care unit infection. As new cases of carcinoma metastasis mimicking spondylodiscitis in AIDS patients are added to the literature, we will have more information about the diagnosis and treatment process.

Peripheral lymphadenopathy of unknown origin in adults: a diagnostic approach emphasizing the malignancy hypothesis

The term lymphadenopathy refers to an abnormality in size, consistency or morphological aspect of one or several lymph nodes. Although lymphadenopathies are commonly observed in everyday clinical practice, the difficulty of differentiating benign and malignant disease may delay therapeutic approaches. The present review aims to update diagnostic algorithms in different clinical situations based on the currently available literature. A literature review was performed to assess current knowledge of and to update the diagnostic approach. A short clinical vignette was used as an example of a typical clinical presentation. This case of metastatic lymphadenopathy with incomplete patient history demonstrates how misleading such lymphadenopathy may be, leading to a delayed diagnosis and even a fatal outcome. Any lymphadenopathy persisting for more than 2 weeks should be considered suspicious and deserves further investigation. Precise clinical examination, meticulous history-taking and a search for associated symptomatology are still cornerstones for diagnosing the origin of the condition. The next diagnostic step depends on the anatomical region and the specific patient's situation. Imaging starts with ultrasound, while computed tomography (CT) and magnetic resonance imaging (MRI) allow assessment of the surrounding structures. If the diagnosis remains uncertain, tissue sampling and histological analyses should be performed. Except for head and neck loco-regional lymphadenopathy, there are no methodical guidelines for persistent lymphadenopathy. The present review clarifies several confusing and complex situations. The accuracy of fine needle aspiration cytology could be increased by using core needle biopsy with immunocytologic and flow cytometric methods. Notably, except in the head and neck area, open biopsy remains the best option when lymphoma is suspected or when inconclusive results of previous fine needle aspiration cytology or core needle biopsy are obtained. The incidence of malignant lymphadenopathy varies with its location and the various diagnostic strategies. In metastatic lymphadenopathy of unknown primary origin, European Society for Medical Oncology (ESMO) guidelines and modern methods like next-generation sequencing (NGS) may help to manage such complex cases.

Programmed death-ligand 1 expression in carcinoma of unknown primary

We examined the expression of programmed death-ligand 1 (PD-L1) in carcinoma of unknown primary (CUP) and its potential implications. Tissue microarrays were constructed for 72 CUP cases (histologic subtypes: 22 adenocarcinoma, 15 poorly differentiated carcinoma, 19 squamous cell carcinoma, and 14 undifferentiated carcinoma; clinical subtype: favorable type 17 [23.6%], unfavorable type 55 [76.4%]), with immunohistochemical staining performed for PD-L1 (22C3, SP142, SP263, and 28 - 8), CK7, and CK20 to determine the association between staining results and clinicopathological parameters. In CUP, the PD-L1 positivity rate was 5.6-48.6% (tumor cells [TC] or tumor proportion score [TPS]: 5.6-36.1%, immune cell score [IC]: 8.3-48.6%, combined positive score [CPS]: 16.7%) using different cutoff values for 22C3 (TPS ≥ 1%, CPS ≥ 10), SP142 (TC ≥ 50%, IC ≥ 10%), SP263, and 28 - 8 (TC and IC ≥ 1%). PD-L1 SP142 TC and PD-L1 SP263 IC showed the lowest (5.6%) and highest (48.6%) positivity rates, respectively. The PD-L1 positivity rate did not significantly differ based on the histologic subtype, clinical subtype, or CK7/CK20 across clones. Considering TC κ ≥ 1%, TC κ ≥ 50%, IC κ ≥ 1%, and IC κ ≥ 10%, the PD-L1 positivity rate was TC = 4.2-36.1% and IC = 9.7-48.6%; the overall agreement between antibodies ranged from 69.4 to 93.1%, showing fair or better agreement (κ ≥ 0.21). In CUP, PD-L1 positivity varied depending on antibodies and scoring systems, with no difference observed according to histologic or clinical subtypes.

Prediction of tumor origin in cancers of unknown primary origin with cytology-based deep learning

Cancer of unknown primary (CUP) site poses diagnostic challenges due to its elusive nature. Many cases of CUP manifest as pleural and peritoneal serous effusions. Leveraging cytological images from 57,220 cases at four tertiary hospitals, we developed a deep-learning method for tumor origin differentiation using cytological histology (TORCH) that can identify malignancy and predict tumor origin in both hydrothorax and ascites. We examined its performance on three internal (n = 12,799) and two external (n = 14,538) testing sets. In both internal and external testing sets, TORCH achieved area under the receiver operating curve values ranging from 0.953 to 0.991 for cancer diagnosis and 0.953 to 0.979 for tumor origin localization. TORCH accurately predicted primary tumor origins, with a top-1 accuracy of 82.6% and top-3 accuracy of 98.9%. Compared with results derived from pathologists, TORCH showed better prediction efficacy (1.677 versus 1.265, P < 0.001), enhancing junior pathologists' diagnostic scores significantly (1.326 versus 1.101, P < 0.001). Patients with CUP whose initial treatment protocol was concordant with TORCH-predicted origins had better overall survival than those who were administrated discordant treatment (27 versus 17 months, P = 0.006). Our study underscores the potential of TORCH as a valuable ancillary tool in clinical practice, although further validation in randomized trials is warranted.

Utility of 18F-FDG PET/CT in Treatment Strategies for Patients With Cancer of Unknown Primary: A Single-Center, Retrospective Change-in-Management Study

Background

Cancer of unknown primary (CUP) is difficult to diagnose and classify clinically, and the disease develops rapidly. Therefore, the primary tumor detected in patients with CUP plays a profound role in the diagnosis and treatment of patients. The search for the primary tumor of CUP is also one of the indications for 18F-fluoro-2-deoxyglucose-positron emission tomography and computed tomography (FDG-PET/CT). Our objective was to evaluate the role of 18F-FDG PET/CT imaging in primary tumor detection and treatment formulation in patients with CUP.

Methods

Sixty-two patients with CUP were selected from a database consisting of 18 802 cases in the Jiangsu Cancer Hospital PET/CT center from May 18, 2016 to November 18, 2022. Clinical data and changes in treatment strategies before and after PET/CT were collected.

Results

A total of 42 primary tumors (42/62, 67.7%) were identified by PET/CT examination. The tumor staging of patients before conventional PET/CT imaging (such as CT/magnetic resonance imaging [MRI]/US) and after PET/CT did not change in 28 patients (28/62, 45.2%), whereas for 34 patients (34/62, 54.8%), tumor staging changed. Forty-five patients (45/62, 72.6%) had not developed treatment plans before PET/CT examination, but treatment plans were clarified after PET/CT examination. Thirteen patients (13/62, 21.0%) underwent changes in treatments before and after PET/CT examination. Among the 20 patients (20/62, 32.3%) whose primary tumors were not detected, 16 patients (16/20, 80.0%) had no treatment plans before PET/CT and the treatment plans were defined after PET/CT, 3 patients (3/20, 15.0%) changed the treatment plans before and after PET/CT, and 1 patient (1/20, 5.0%) did not change the treatment plan.

Conclusions

The 18F-FDG PET/CT plays an important role in the detection and staging of primary tumors in patients with CUP. The PET/CT findings can not only help clinicians develop appropriate treatment plans for patients with CUP but also serve as an effective approach to improve real-life treatment strategies for these patients.

Utility of Bone Scan in Evaluating Patients with Clinically Indeterminate Diagnosis of Cancer in a Low-resource Practice

CONTEXT

A major indication for referrals for bone scans (BS) to establish or exclude skeletal metastases. Few patients are referred with clinically indeterminate diagnosis or cancer of unknown primary (CUP), to search for bony metastases or primary tumor.

AIMS

This study aimed to assess the usefulness or otherwise for BS in such instances.

SETTINGS AND DESIGN

A retrospective cross-sectional study of BS performed for CUP and indeterminate diagnosis from 2012 to 2016 in the nuclear medicine unit of a tertiary teaching hospital.

SUBJECTS AND METHODS

The study involved reviews of technetium-99m diphosphonate BS for patients with CUP. BSs were reported by nuclear physicians as normal, normal variants, suspicious for metastases or as malignant, and with solitary or multiple skeletal metastases.

STATISTICAL ANALYSIS USED

Data were analyzed using SPSS version 21 for descriptive analysis. Continuous data were displayed as means along with their standard deviation; categorical data were tabulated as frequencies and percentages.

RESULTS

Of 2156 BS, 42 (0.02%) were eligible. Patients were aged 27-86 years, mainly in the sixth and seventh decades of life. Bone metastases were identified in 14 (33%) of these patients, whereas 17 BS (40%) were normal, BS appeared equivocal in 10 (23.8%).

CONCLUSIONS

Single-photon emission computed tomography/computed tomography availability would resolve the clinical dilemma in patients with equivocal and apparently normal BS.

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.

Bone metastatic cancer of unknown primary at initial presentation

INTRODUCTION

Cancer of unknown primary (CUP) is a challenging malignancy. The purpose of this study was to investigate the clinical characteristics and prognosis of bone metastatic CUP using the population-based Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

From the SEER database, we identified 1908 patients with bone metastatic CUP at initial presentation between 2010 and 2018. Histology was subdivided following International Classification of Diseases for Oncology codes as Adenocarcinoma, Squamous cell, Neuroendocrine, or Carcinoma not otherwise specified (NOS). Cox proportional hazard modeling was applied using factors of age, sex, ethnicity, histological subtype, and therapeutic intervention.

RESULTS

Among the 1908 patients, histology was Neuroendocrine in 240 patients, Squamous cell in 201 patients, Adenocarcinoma in 810 patients and NOS in 657 patients. In each subtype, patients tended to be predominantly male and white. Chemotherapy was introduced for 28% of patients and radiation for 34% in the entire cohort. Survival in patients with bone metastatic CUP was unfavorable, with a median survival of 2 months. Among the histological subtypes, Adenocarcinoma showed shorter survival than the other groups. In addition, treatment interventions such as chemotherapy and radiation therapy prolonged survival, particularly for Squamous cell, Adenocarcinoma and NOS, but not for Neuroendocrine.

DISCUSSION

Bone metastatic CUP showed extremely poor prognosis, but treatment interventions such as chemotherapy and radiation generally offered survival benefits. Further randomized clinical research is needed to confirm the present results.

Biomarkers of systemic inflammation provide additional prognostic stratification in cancers of unknown primary

BACKGROUND

Biomarkers of systemic inflammation have been shown to predict outcomes in patients with cancer of unknown primary (CUP). We sought to validate these findings in patients with confirmed CUP (cCUP) and explore their role alongside existing clinicopathological prognostic categories.

PATIENTS AND METHODS

CUP oncologist from across the United Kingdom were invited to include patients with cCUP referred to their local CUP multidisciplinary team. Patient demographics, clinical, pathological and outcome data were recorded and analysed.

RESULTS

Data were available for 548 patients from four CUP services. 23% (n = 124) of patients met clinicopathological criteria for favourable-risk cCUP. On multivariate analysis c-reactive protein (CRP) (p < 0.001) and the Scottish Inflammatory Prognostic Score (SIPS: combining albumin and neutrophil count) (p < 0.001) were independently predictive of survival. CRP and SIPS effectively stratified survival in patients with both favourable-risk and poor-risk cCUP based on clinicopathological features.

CONCLUSIONS

Biomarkers of systemic inflammation are reliable prognostic factors in patients with cCUP, regardless of clinicopathological subgroup. We recommend that CRP or SIPS are incorporated into routine clinical assessments of patients with cCUP as a tool to aid investigation and/or treatment decision-making across all groups. Established clinicopathological factors can then be used to inform management pathways and specific systemic anticancer therapy selection.

Rare axillary cancer of unknown primary originating from the breast of a 64‑year‑old male patient: A case report and literature review

Cancers of unknown primary (CUPs) are a heterogeneous group of tumors characterized by a difficult diagnosis. The primitive tumor remains unknown, whereas metastases are the most common manifestation. Occult male breast cancers are very rare types of CUPs. The present study describes the case of a 64-year-old man affected by a CUP of presumed mammary origin. The aim of the article and the present review was to focus on their management. To the best of our knowledge, only thirteen cases have been reported in the literature. Because no specific guidelines are available, various approaches have been applied, influencing the treatment and the prognosis of patients with CUP.

New techniques to identify the tissue of origin for cancer of unknown primary in the era of precision medicine: progress and challenges

Despite a standardized diagnostic examination, cancer of unknown primary (CUP) is a rare metastatic malignancy with an unidentified tissue of origin (TOO). Patients diagnosed with CUP are typically treated with empiric chemotherapy, although their prognosis is worse than those with metastatic cancer of a known origin. TOO identification of CUP has been employed in precision medicine, and subsequent site-specific therapy is clinically helpful. For example, molecular profiling, including genomic profiling, gene expression profiling, epigenetics and proteins, has facilitated TOO identification. Moreover, machine learning has improved identification accuracy, and non-invasive methods, such as liquid biopsy and image omics, are gaining momentum. However, the heterogeneity in prediction accuracy, sample requirements and technical fundamentals among the various techniques is noteworthy. Accordingly, we systematically reviewed the development and limitations of novel TOO identification methods, compared their pros and cons and assessed their potential clinical usefulness. Our study may help patients shift from empirical to customized care and improve their prognoses.

Inguinal nodal metastatic squamous cell carcinoma of unknown primary (CUP) detected 7 years before the diagnosis of vulvar squamous cell carcinoma: A case report

OBJECTIVE

Metastatic squamous cell carcinoma (SCC) of inguinal lymph node region with unknown origin is a rare condition. A patient was diagnosed to have vulvar SCC 7 years after the initial diagnosis of inguinal nodal metastatic SCC of unknown primary.

CASE REPORT

A 59-year-old woman with metastatic SCC of unknown origin in the right inguinal lymph node underwent tumor resection and no evidence of residual disease or possible tumor origin was detected after the surgery and a comprehensive work-up. Seven years later, she was diagnosed to have invasive right vulvar SCC with right pelvic lymph node metastasis. We performed a series of tests to evaluate the relationship between these two events.

CONCLUSION

According to our investigation, the possible relationship between the two events could not be ruled out. This case emphasizes the possibility of late recurrence and the importance of long-term follow up for patients with isolated nodal CUP.

Sequential PET/CT and pathological biomarker crosstalk predict response to PD-1 blockers alone or combined with sunitinib in propensity score-matched cohorts of cancer of unknown primary treatment

INTRODUCTION

The efficacy of immune checkpoint inhibitors (ICIs), including toripalimab and pembrolizumab, has not been confirmed in the treatment of cancer of unknown primary (CUP), which has a very poor prognosis. Combined with anti-angiogenic therapies, ICIs are hypothesized to be effective in prolonging overall survival. The study aims to give evidence on the treatment effects of sunitinib combined with ICIs, find pathological biomarkers associated with changes in volumetric 18F FDG PET/CT parameters, and investigate inner associations among these markers associated with response on PET/CT.

METHODS

The study recruited patients receiving combined treatment (ICIs + sunitinib), compared the effects of combined treatment with those of separate treatment and age-matched negative controls, and analyzed propensity score-matched (PSM) pairs. Markers associated with survival were identified, and their inner associations were tested using structural equation modeling.

RESULTS

A total of 292 patients were enrolled in the final analysis, with 53 patients receiving combined treatment. Survival analysis demonstrated significantly prolonged survival in either combined or separate treatment, with the combined arm showing better response when PSM-paired using pre-treatment whole-body PET/CT parameters. The angiogenic markers KDR and VEGF mediate the PD-1 blockade impact on volumetric value changes in positive and negative manners.

CONCLUSION

The anti-angiogenic agent sunitinib may potentiate PD-1 blockade by diminishing angiogenesis or its downstream effects. The combined separate treatment increased the survival of CUP patients, and the responses could be evaluated using volumetric PET/CT parameters.

Magnetic resonance-based imaging biopsy with signatures including topological Betti number features for prediction of primary brain metastatic sites

This study incorporated topology Betti number (BN) features into the prediction of primary sites of brain metastases and the construction of magnetic resonance-based imaging biopsy (MRB) models. The significant features of the MRB model were selected from those obtained from gray-scale and three-dimensional wavelet-filtered images, BN and inverted BN (iBN) maps, and clinical variables (age and gender). The primary sites were predicted as either lung cancer or other cancers using MRB models, which were built using seven machine learning methods with significant features chosen by three feature selection methods followed by a combination strategy. Our study dealt with a dataset with relatively smaller brain metastases, which included effective diameters greater than 2 mm, with metastases ranging from 2 to 9 mm accounting for 17% of the dataset. The MRB models were trained by T1-weighted contrast-enhanced images of 494 metastases chosen from 247 patients and applied to 115 metastases from 62 test patients. The most feasible model attained an area under the receiver operating characteristic curve (AUC) of 0.763 for the test patients when using a signature including features of BN and iBN maps, gray-scale and wavelet-filtered images, and clinical variables. The AUCs of the model were 0.744 for non-small cell lung cancer and 0.861 for small cell lung cancer. The results suggest that the BN signature boosted the performance of MRB for the identification of primary sites of brain metastases including small tumors.

Cancer metastasis under the magnifying glass of epigenetics and epitranscriptomics

Most of the cancer-associated mortality and morbidity can be attributed to metastasis. The role of epigenetic and epitranscriptomic alterations in cancer origin and progression has been extensively demonstrated during the last years. Both regulations share similar mechanisms driven by DNA or RNA modifiers, namely writers, readers, and erasers; enzymes responsible of respectively introducing, recognizing, or removing the epigenetic or epitranscriptomic modifications. Epigenetic regulation is achieved by DNA methylation, histone modifications, non-coding RNAs, chromatin accessibility, and enhancer reprogramming. In parallel, regulation at RNA level, named epitranscriptomic, is driven by a wide diversity of chemical modifications in mostly all RNA molecules. These two-layer regulatory mechanisms are finely controlled in normal tissue, and dysregulations are associated with every hallmark of human cancer. In this review, we provide an overview of the current state of knowledge regarding epigenetic and epitranscriptomic alterations governing tumor metastasis, and compare pathways regulated at DNA or RNA levels to shed light on a possible epi-crosstalk in cancer metastasis. A deeper understanding on these mechanisms could have important clinical implications for the prevention of advanced malignancies and the management of the disseminated diseases. Additionally, as these epi-alterations can potentially be reversed by small molecules or inhibitors against epi-modifiers, novel therapeutic alternatives could be envisioned.

Carcinoma of unknown primary (CUP): an update for histopathologists

Carcinoma of unknown primary (CUP) is a heterogeneous group of metastatic cancers in which the site of origin is not identifiable. These carcinomas have a poor outcome due to their late presentation with metastatic disease, difficulty in identifying the origin and delay in treatment. The aim of the pathologist is to broadly classify and subtype the cancer and, where possible, to confirm the likely primary site as this information best predicts patient outcome and guides treatment. In this review, we provide histopathologists with diagnostic practice points which contribute to identifying the primary origin in such cases. We present the current clinical evaluation and management from the point of view of the oncologist. We discuss the role of the pathologist in the diagnostic pathway including the control of pre-analytical conditions, assessment of sample adequacy, diagnosis of cancer including diagnostic pitfalls, and evaluation of prognostic and predictive markers. An integrated diagnostic report is ideal in cases of CUP, with results discussed at a forum such as a molecular tumour board and matched with targeted treatment. This highly specialized evolving area ultimately leads to personalized oncology and potentially improved outcomes for patients.

Baseline mutational profiles of patients with carcinoma of unknown primary origin enrolled in the CUPISCO study

BACKGROUND

Patients with unfavorable carcinoma of unknown primary origin (CUP) have an extremely poor prognosis of ∼1 year or less, stressing the need for more tailored treatments, which are currently being tested in clinical trials. CUPISCO (NCT03498521) was a phase II randomized study of targeted therapy/cancer immunotherapy versus platinum-based chemotherapy in patients with previously untreated, unfavorable CUP, defined as per the European Society for Medical Oncology guidelines. We present a preliminary, descriptive molecular analysis of 464 patients with stringently diagnosed, unfavorable CUP enrolled in the CUPISCO study.

MATERIALS AND METHODS

Genomic profiling was carried out on formalin-fixed, paraffin-embedded tissue to detect genomic alterations and assess tumor mutational burden and microsatellite instability.

RESULTS

Overall, ∼32% of patients carried a potentially targetable genomic alteration, including PIK3CA, FGFR2, ERBB2, BRAFV600E, EGFR, MET, NTRK1, ROS1, and ALK. Using hierarchical clustering of co-mutational profiles, 10 clusters were identified with specific genomic alteration co-occurrences, with some mirroring defined tumor entities.

CONCLUSIONS

Results reveal the molecular heterogeneity of patients with unfavorable CUP and suggest that genomic profiling may be used as part of informed decision-making to identify the potential primary tumor and targeted treatment options. Whether stringently diagnosed patients with unfavorable CUP benefit from targeted therapies in a similar manner to those with matched known primaries will be a key learning from CUPISCO.

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.

Modified study designs to expand treatment options in personalised oncology: a multistakeholder view

Personalised oncology, whereby patients are given therapies based on their molecular tumour profile, is rapidly becoming an essential part of optimal clinical care, at least partly facilitated by recent advances in next-generation sequencing-based technology using liquid- and tissue-based biopsies. Consequently, clinical trials have shifted in approach, from traditional studies evaluating cytotoxic chemotherapy in largely histology-based populations to modified, biomarker-driven studies (e.g. basket, umbrella, platform) of molecularly guided therapies and cancer immunotherapies in selected patient subsets. Such modified study designs may assess, within the same trial structure, multiple cancer types and treatments, and should incorporate a multistakeholder perspective. This is key to generating complementary, fit-for-purpose and timely evidence for molecularly guided therapies that can be used as proof-of-concept to inform further study designs, lead to approval by regulatory authorities and be used as confirmation of clinical benefit for health technology assessment bodies. In general, the future of cancer clinical trials requires a framework for the application of innovative technologies and dynamic design methodologies, in order to efficiently transform scientific discoveries into clinical utility. Next-generation, modified studies that involve the joint efforts of all key stakeholders will offer individualised strategies that ultimately contribute to globalised knowledge and collective learning. In this review, we outline the background and purpose of such modified study designs and detail key aspects from a multistakeholder perspective. We also provide methodological considerations for designing the studies and highlight how insights from already-ongoing studies may address current challenges and opportunities in the era of personalised oncology.

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.

Rapid progressive spontaneous hemothorax caused by carcinoma of unknown primary: A very rare case

We present a very rare case of spontaneous hemothorax which was caused by carcinoma of unknown primary. To the best of our knowledge, there are no other such cases reported worldwide. The patient was 72-year-old male who was referred to our department for massive hemothorax. We undertook surgical treatment for haemostasis, and found multiple tumours which led to the diagnosis of carcinoma of unknown primary as the cause of haemorrhage. The tumours increased and grew rapidly after surgery and hemothorax progressed despite our treatment. The patient died from disseminated intravascular coagulation caused by continuous bleeding on postoperative day 19.

Next-generation sequencing in dermatology

Over the past decade, Next-Generation Sequencing (NGS) has advanced our understanding, diagnosis, and management of several areas within dermatology. NGS has emerged as a powerful tool for diagnosing genetic diseases of the skin, improving upon traditional PCR-based techniques limited by significant genetic heterogeneity associated with these disorders. Epidermolysis bullosa and ichthyosis are two of the most extensively studied genetic diseases of the skin, with a well-characterized spectrum of genetic changes occurring in these conditions. NGS has also played a critical role in expanding the mutational landscape of cutaneous squamous cell carcinoma, enhancing our understanding of its molecular pathogenesis. Similarly, genetic testing has greatly benefited melanoma diagnosis and treatment, primarily due to the high prevalence of BRAF hot spot mutations and other well-characterized genetic alterations. Additionally, NGS provides a valuable tool for measuring tumor mutational burden, which can aid in management of melanoma. Lastly, NGS demonstrates promise in improving the sensitivity of diagnosing cutaneous T-cell lymphoma. This article provides a comprehensive summary of NGS applications in the diagnosis and management of genodermatoses, cutaneous squamous cell carcinoma, melanoma, and cutaneous T-cell lymphoma, highlighting the impact of NGS on the field of dermatology.

Primary Retroperitoneal Carcinomas: New Insights into Pathogenesis and Clinical Management in Comparison with Ovarian Carcinomas and Carcinoma of Unknown Primary

Primary retroperitoneal carcinomas are very rare tumors. Their pathogenesis remains unknown but may be associated with that of ovarian carcinomas, considering the similarity in morphology and gender preference. Although metaplasia of coelomic epithelium is the most widely accepted theory, the pathogenesis of retroperitoneal carcinomas may differ by histologic subtype, like ovarian carcinomas. Mucinous carcinoma, which develops in both women and men, may originate in both primordial germ cells and Walthard cell nests that may be derived from the fallopian tube. Serous carcinomas may be associated with endosalpingiosis, the presence of fallopian tube-like epithelium outside the fallopian tube, and a remnant Müllerian tract. Endometrioid and clear cell carcinomas appear to be associated with extraovarian endometriosis. Additionally, both carcinomas in the retroperitoneal lymph nodes may be metastatic diseases from endometrial and/or renal cell cancer that regress spontaneously (carcinoma of unknown primary). Retroperitoneal carcinomas are difficult to diagnose, as they have no characteristic symptoms and signs. Surgery is the cornerstone of treatment, but the necessity of chemotherapy may depend on histological subtype. Further studies are necessary, in particular studies on endosalpingiosis, as endosalpingiosis is a poorly understood condition, although it is associated with the development of both serous and mucinous carcinomas.

DNA methylation profiling to determine the primary sites of metastatic cancers using formalin-fixed paraffin-embedded tissues

Identifying the primary site of metastatic cancer is critical to guiding the subsequent treatment. Approximately 3-9% of metastatic patients are diagnosed with cancer of unknown primary sites (CUP) even after a comprehensive diagnostic workup. However, a widely accepted molecular test is still not available. Here, we report a method that applies formalin-fixed, paraffin-embedded tissues to construct reduced representation bisulfite sequencing libraries (FFPE-RRBS). We then generate and systematically evaluate 28 molecular classifiers, built on four DNA methylation scoring methods and seven machine learning approaches, using the RRBS library dataset of 498 fresh-frozen tumor tissues from primary cancer patients. Among these classifiers, the beta value-based linear support vector (BELIVE) performs the best, achieving overall accuracies of 81-93% for identifying the primary sites in 215 metastatic patients using top-k predictions (k = 1, 2, 3). Coincidentally, BELIVE also successfully predicts the tissue of origin in 81-93% of CUP patients (n = 68).

Development and Validation of a Radiomics Nomogram for Liver Metastases Originating from Gastric and Colorectal Cancer

The origin of metastatic liver tumours (arising from gastric or colorectal sources) is closely linked to treatment choices and survival prospects. However, in some instances, the primary lesion remains elusive even after an exhaustive diagnostic investigation. Consequently, we have devised and validated a radiomics nomogram for ascertaining the primary origin of liver metastases stemming from gastric cancer (GCLMs) and colorectal cancer (CCLMs). This retrospective study encompassed patients diagnosed with either GCLMs or CCLMs, comprising a total of 277 GCLM cases and 278 CCLM cases. Radiomic characteristics were derived from venous phase computed tomography (CT) scans, and a radiomics signature (RS) was computed. Multivariable regression analysis demonstrated that gender (OR = 3.457; 95% CI: 2.102-5.684; p < 0.001), haemoglobin levels (OR = 0.976; 95% CI: 0.967-0.986; p < 0.001), carcinoembryonic antigen (CEA) levels (OR = 0.500; 95% CI: 0.307-0.814; p = 0.005), and RS (OR = 2.147; 95% CI: 1.127-4.091; p = 0.020) exhibited independent associations with GCLMs as compared to CCLMs. The nomogram, combining RS with clinical variables, demonstrated strong discriminatory power in both the training (AUC = 0.71) and validation (AUC = 0.78) cohorts. The calibration curve, decision curve analysis, and clinical impact curves revealed the clinical utility of this nomogram and substantiated its enhanced diagnostic performance.

Cancer of unknown primary eventually diagnosed as poorly differentiated prostate cancer: a case report

BACKGROUND

Prostate cancer has been well known to have a high prevalence among middle-aged and older men, with high incidence of metastases to the bone-the main metastatic site. However, prostate cancer among those less than 50 years of age is extremely rare, and neck swelling is seldom the initial symptom.

CASE PRESENTATION

We herein report case of a 47-year-old Japanese male with poorly differentiated prostate cancer that had been initially diagnosed as a cancer of unknown primary with multiple lymph node and bone metastases before reaching a definitive diagnosis. The patient has been started on endocrine therapy and is currently alive without progression.

DISCUSSION AND CONCLUSION

When locating the primary lesion in men with cancer of unknown primary, it is important to consider the possibility of prostate cancer, confirm serum prostate-specific antigen levels, and perform local prostate evaluation.

Cancer of unknown primary (CUP) through the lens of precision oncology: a single institution perspective

PURPOSE

For patients with cancer of unknown primary (CUP), treatment options are limited. Precision oncology, the interplay of comprehensive genomic profiling (CGP) and targeted therapies, aims to offer additional treatment options to patients with advanced and hard-to-treat cancers. We aimed to highlight the use of a molecular tumor board (MTB) in the therapeutic management of CUP patients.

METHODS

In this single-center observational study, CUP patients, presented to the MTB of the Comprehensive Cancer Center Munich LMU, a tertiary care center, were analyzed retrospectively. Descriptive statistics were applied to describe relevant findings.

RESULTS

Between June 2016 and February 2022, 61 patients with unfavorable CUP were presented to the MTB, detected clinically relevant variants in 74% (45/61) of patients, of which 64% (29/45) led to therapeutic recommendation. In four out of 29 patients (14%), the treatment recommendations were implemented, unfortunately without resulting in clinical benefit. Reasons for not following the therapeutic recommendation were mainly caused by the physicians' choice of another therapy (9/25, 36%), especially in the context of worsening of general condition, lost to follow-up (7/25, 28%) and death (6/25, 24%).

CONCLUSION

CGP and subsequent presentation to a molecular tumor board led to a high rate of therapeutic recommendations in patients with CUP. Recommendations were only implemented at a low rate; however, late GCP diagnostic and, respectively, MTB referral were found more frequent for the patients with implemented treatment. This contrast underscores the need for early implementation of CGP into the management of CUP patients.

2-[18F]FDG-PET/CT in Cancer of Unknown Primary Tumor-A Retrospective Register-Based Cohort Study

We investigated the impact of 2-[18F]FDG-PET/CT on detection rate (DR) of the primary tumor and survival in patients with suspected cancer of unknown primary tumor (CUP), comparing it to the conventional diagnostic imaging method, CT. Patients who received a tentative CUP diagnosis at Odense University Hospital from 2014-2017 were included. Patients receiving a 2-[18F]FDG-PET/CT were assigned to the 2-[18F]FDG-PET/CT group and patients receiving a CT only to the CT group. DR was calculated as the proportion of true positive findings of 2-[18F]FDG-PET/CT and CT scans, separately, using biopsy of the primary tumor, autopsy, or clinical decision as reference standard. Survival analyses included Kaplan-Meier estimates and Cox proportional hazards regression adjusted for age, sex, treatment, and propensity score. We included 193 patients. Of these, 159 were in the 2-[18F]FDG-PET/CT group and 34 were in the CT group. DR was 36.5% in the 2-[18F]FDG-PET/CT group and 17.6% in the CT group, respectively (p = 0.012). Median survival was 7.4 (95% CI 0.4-98.7) months in the 2-[18F]FDG-PET/CT group and 3.8 (95% CI 0.2-98.1) in the CT group. Survival analysis showed a crude hazard ratio of 0.63 (p = 0.024) and an adjusted hazard ratio of 0.68 (p = 0.087) for the 2-[18F]FDG-PET/CT group compared with CT. This study found a significantly higher DR of the primary tumor in suspected CUP patients using 2-[18F]FDG-PET/CT compared with patients receiving only CT, with possible immense clinical importance. No significant difference in survival was found, although a possible tendency towards longer survival in the 2-[18F]FDG-PET/CT group was observed.

Diagnostic Approaches for Neuroendocrine Neoplasms of Unknown Primary (NEN-UPs) and Their Prognostic Relevance-A Retrospective, Long-Term Single-Center Experience

Neuroendocrine neoplasms (NENs) represent a rare and heterogenous group of tumors with predominantly gastroenteropancreatic or pulmonary origin. Despite numerous diagnostic efforts, the primary tumor site remains unknown in up to 20% of the patients diagnosed with NEN. In this subgroup of NEN patients, a standard diagnostic algorithm has not yet been integrated into clinical routine. Of note, an undetermined primary tumor site in NENs is associated with an impaired clinical outcome by at least "formally" limiting treatment options exclusively approved for NENs of a certain histological origin. In this retrospective study, a patient cohort of 113 patients initially diagnosed with NEN of unknown primary (NEN-UP) was analyzed. In 13 patients (11.5%) a primary tumor site could be identified subsequently, amongst others, by performing somatostatin receptor (SSTR)-PET-based imaging, which was irrespective of the initial clinical or demographic features. Diagnostic work-up and therapeutic regimens did not differ significantly between patients with an identified or unidentified primary tumor site; only a detailed immunohistochemical assessment providing additional information on the tumor origin proved to be significantly associated with the detection of a primary tumor site. Our study revealed that a profound diagnostic work-up, particularly including SSTR-PET-based imaging, leads to additional treatment options, finally resulting in significantly improved clinical outcomes for patients with NEN-UPs.

Machine learning for genetics-based classification and treatment response prediction in cancer of unknown primary

Cancer of unknown primary (CUP) is a type of cancer that cannot be traced back to its primary site and accounts for 3-5% of all cancers. Established targeted therapies are lacking for CUP, leading to generally poor outcomes. We developed OncoNPC, a machine-learning classifier trained on targeted next-generation sequencing (NGS) data from 36,445 tumors across 22 cancer types from three institutions. Oncology NGS-based primary cancer-type classifier (OncoNPC) achieved a weighted F1 score of 0.942 for high confidence predictions ([Formula: see text]) on held-out tumor samples, which made up 65.2% of all the held-out samples. When applied to 971 CUP tumors collected at the Dana-Farber Cancer Institute, OncoNPC predicted primary cancer types with high confidence in 41.2% of the tumors. OncoNPC also identified CUP subgroups with significantly higher polygenic germline risk for the predicted cancer types and with significantly different survival outcomes. Notably, patients with CUP who received first palliative intent treatments concordant with their OncoNPC-predicted cancers had significantly better outcomes (hazard ratio (HR) = 0.348; 95% confidence interval (CI) = 0.210-0.570; P = [Formula: see text]). Furthermore, OncoNPC enabled a 2.2-fold increase in patients with CUP who could have received genomically guided therapies. OncoNPC thus provides evidence of distinct CUP subgroups and offers the potential for clinical decision support for managing patients with CUP.

Six-year experience of Australia's first dedicated cancer of unknown primary clinic

BACKGROUND

Diagnosis and management of cancers of unknown primary (CUP) remain challenging. This study examines the referral patterns, management and outcomes of patients referred to Australia's first dedicated CUP clinic.

METHODS

Retrospective medical record review was conducted for patients seen at the Peter MacCallum Cancer Centre CUP clinic between July 2014 and August 2020. Overall survival (OS) was analysed for patients with a CUP diagnosis where treatment information was available.

RESULTS

Of 361 patients referred, fewer than half had completed diagnostic work-up at the time of referral. A diagnosis of CUP was established in 137 (38%), malignancy other than CUP in 177 (49%) and benign pathology in 36 (10%) patients. Genomic testing was successfully completed in 62% of patients with initial provisional CUP and impacted management in 32% by identifying a tissue of origin or actionable genomic alteration. The use of site-specific, targeted therapy or immunotherapy was independently associated with longer OS compared to empirical chemotherapy.

CONCLUSION

Our specialised CUP clinic facilitated diagnostic work-up among patients with suspected malignancy and provided access to genomic testing and clinical trials for patients with a CUP diagnosis, all of which are important to improve outcomes in this patient population.

Case Report: Combined pembrolizumab, 5-fluorouracil, and cisplatin therapy were remarkably effective in p16-positive squamous cell carcinoma of unknown primary

Background

Cancer of unknown primary (CUP) is a malignant tumor without a known primary lesion with a frequency of 3-5%. It can be divided into favorable and unfavorable prognosis subsets. While recommended treatments are available for the former group, there is no established treatment for the latter. Here, we report the effective treatment of a 32-year-old woman with p16-positive squamous cell CUP with pembrolizumab plus 5-fluorouracil and cisplatin therapy.

Case presentation

A 32-year-old woman presented with metastatic lesions in the liver, lung, bone, cervical region, abdominal region, and pelvic lymph nodes. She was diagnosed with p16-positive squamous cell carcinoma of unknown primary origin. The patient received pembrolizumab plus 5-fluorouracil and cisplatin therapy, which markedly reduced the metastasis and improved her Eastern Cooperative Oncology Group performance status after two courses.

Conclusion

This case report highlights the potential of pembrolizumab plus 5-fluorouracil and cisplatin therapy for treating CUP with an unfavorable prognosis. p16 positivity is worth examining for squamous cell carcinoma of unknown primary origin, and if present, this therapy should be considered a promising treatment option.

Validation of a Transcriptome-Based Assay for Classifying Cancers of Unknown Primary Origin

INTRODUCTION

Cancers assume a variety of distinct histologies, and may originate from a myriad of sites including solid organs, hematopoietic cells, and connective tissue. Clinical decision-making based on consensus guidelines such as the National Comprehensive Cancer Network (NCCN) is often predicated on a specific histologic and anatomic diagnosis, supported by clinical features and pathologist interpretation of morphology and immunohistochemical (IHC) staining patterns. However, in patients with nonspecific morphologic and IHC findings-in addition to ambiguous clinical presentations such as recurrence versus new primary-a definitive diagnosis may not be possible, resulting in the patient being categorized as having a cancer of unknown primary (CUP). Therapeutic options and clinical outcomes are poor for patients with CUP, with a median survival of 8-11 months.

METHODS

Here, we describe and validate the Tempus Tumor Origin (Tempus TO) assay, an RNA-sequencing-based machine learning classifier capable of discriminating between 68 clinically relevant cancer subtypes. Model accuracy was assessed using primary and/or metastatic samples with known subtype.

RESULTS

We show that the Tempus TO model is 91% accurate when assessed on both a retrospectively held out cohort and a set of samples sequenced after model freeze that collectively contained 9210 total samples with known diagnoses. When evaluated on a cohort of CUPs, the model recapitulated established associations between genomic alterations and cancer subtype.

DISCUSSION

Combining diagnostic prediction tests (e.g., Tempus TO) with sequencing-based variant reporting (e.g., Tempus xT) may expand therapeutic options for patients with cancers of unknown primary or uncertain histology.

Histopathological Evaluation and Molecular Diagnostic Tests for Peritoneal Metastases with Unknown Primary Site-a Review

Cancer of unknown primary (CUP) is a well-studied entity with guidelines available for the management of patients with CUP. The peritoneum represents one of the metastatic sites in CUP, and peritoneal metastases (PM) could present as CUP. PM of unknown origin remains a poorly studied clinical entity. There is only one series of 15 cases, one population-based study, and few other case reports on this subject. Studies on CUP, in general, cover some common tumour histological types like adenocarcinomas and squamous carcinomas. Some of these tumours may have a good prognosis though majority have high-grade disease with a poor long-term outcome. Some of the histological tumour types commonly seen in the clinical scenario of PM like mucinous carcinoma have not been studied. In this review, we divide PM into five histological types-adenocarcinomas, serous carcinomas, mucinous carcinomas, sarcomas and other rare varieties. We provide algorithms to identify the primary tumour site using immunohistochemistry when imaging, and endoscopy fails to establish the primary tumour site. The role of molecular diagnostic tests for PM or unknown origin is also discussed. Current literature on site-specific systemic therapy based on gene expression profiling does not show a clear benefit of this approach over empirical systemic therapies.

[Cancer of unknown primary-The new ESMO guidelines]

BACKGROUND

The European Society of Medical Oncology (ESMO) recently published extensively revised guidelines on cancer of unknown primary (CUP). The new version contains the following relevant amendments: with respect to diagnostics of CUP, the current guidelines aim for a more precise and standardized definition of CUP by establishing diagnostic algorithms. Recommendations for molecular diagnostics of cancer tissue have also been implemented. With respect to CUP classification, the favorable category has been revised. A carcinoma with immunohistochemistry typical for renal cell carcinoma (renal-like CUP) was introduced in the new definition of favorable subtypes, for which a specific treatment is indicated. Based on a newly defined oligometastatic situation a subgroup with localized cancer potentially curatively treatable with surgery and/or radiotherapy was introduced into the CUP classification. With respect to treatment of CUP, the current guidelines present options beyond empirical chemotherapy, which is still the standard of care treatment, and pinpoint indications and predictive biomarkers for targeted and immune checkpoint inhibitor treatment.

RELEVANT UPDATES

The European Society of Medical Oncology (ESMO) recently published extensively revised guidelines on the CUP syndrome. The new version contains the following relevant amendments: the current guidelines aim for a more precise and standardized definition of CUP by establishing diagnostic algorithms with respect to the diagnostics of CUP syndrome. Recommendations for molecular diagnostics of cancer tissue have also been implemented. The classification of the CUP syndrome has also been revised. A carcinoma with immunohistochemistry typical for renal cell carcinoma (renal-like CUP) was introduced in the new definition of favorable subtypes, for which a specific treatment is indicated. Based on a newly defined oligometastatic situation a local potentially curatively treatable with surgery and/or radiotherapy subgroup was introduced into the CUP classification. With respect to treatment of the CUP syndrome, the current guidelines present options beyond empirical chemotherapy, which is still the gold standard treatment, and pinpoint indications and predictive biomarkers for targeted and immune checkpoint inhibitor treatment.

SCHLUSSFOLGERUNG

The aim of this review is to present the current state of diagnostics, classification and treatment of CUP syndrome, with a focus on recent developments and revisions implemented in the current ESMO guidelines.

Clinical outcomes of patients diagnosed with cancer of unknown primary or malignancy of undefined primary origin who were referred to a regional cancer center

BACKGROUND

A regional cancer hospital has been identified to be crucial in the management of malignancies of undefined primary origin (MUO) and cancer of unknown primary (CUP). This hospital primarily consists of oncologists with expertise in CUP, pathologists, and interventional radiologists. Early consultation or referral of MUO and CUP to a cancer hospital is deemed important.

METHODS

This study retrospectively collected and analyzed the clinical, pathological, and outcome data of all patients (n = 407) referred to the Aichi Cancer Center Hospital (ACCH) in Japan over an 8-year period.

RESULTS

In total, 30% of patients were referred for a second opinion. Among 285 patients, 13% had non-neoplastic disease or confirmed primary site and 76% had confirmed CUP (cCUP), with 29% of cCUP being identified as favorable risk. In 155 patients with unfavorable-risk CUP, 73% had primary sites predicted by immunohistochemistry (IHC) and distribution of metastatic sites, whereas 66% of them received site-specific therapies based on the predicted primary sites. The median overall survival (OS) was found to be poor in patients with MUO (1 month) and provisional CUP (6 months). In addition, the median OS of 206 patients with cCUP treated at the ACCH was 16 months (favorable risk, 27 months; unfavorable risk, 12 months). No significant difference was noted in OS between patients with non-predictable and predictable primary-sites (13 vs 12 months, p = 0.411).

CONCLUSION

The outcome of patients with unfavorable-risk CUP remains to be poor. Site-specific therapy based on IHC is not recommended for all patients with unfavorable-risk CUP.

[Peritoneal carcinomatosis secondary to CUP syndrome : Diagnosis and indications for multimodal treatment]

CLINICAL PROBLEM

Peritoneal carcinomatosis secondary to cancer of unknown primary (CUP) syndrome is a rare entity for which there are no uniform treatment recommendations or guidelines. The median survival time is 3 months.

DIAGNOSIS

Computed tomography (CT), magnetic resonance imaging (MRI), and ¹⁸F‑FDG positron emission tomography (PET)/CT are valid imaging modalities for the detection of peritoneal carcinomatosis. The sensitivity of all techniques is highest for large, macronodular peritoneal carcinomatosis manifestations. A limitation of all imaging techniques is limited and small-nodular peritoneal carcinomatosis. Also, peritoneal metastasis in the small bowel mesentery or diaphragmatic domes can only be visualized with low sensitivity. Therefore, exploratory laparoscopy should be considered as the next diagnostic step. In half of these cases an unnecessary laparotomy can be avoided, because the laparoscopy revealed diffuse, small-nodule involvement of the small bowel wall and thus an irresectable situation.

TREATMENT

In selected patients, performing complete cytoreduction followed by hyperthermic intra-abdominal chemotherapy (HIPEC) is a good therapeutic option. Therefore, the identification of the extent of peritoneal tumor manifestation as accurately as possible is important for the definition of the increasingly complex oncological therapy strategies.