Open-label phase II study of the efficacy of nivolumab for cancer of unknown primary

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.

Advancements in Diagnostics and Therapeutics for Cancer of Unknown Primary in the Era of Precision Medicine

Cancer of unknown primary (CUP), a set of histologically confirmed metastases that cannot be identified or traced back to its primary despite comprehensive investigations, accounts for 2-5% of all malignancies. CUP is the fourth leading cause of cancer-related deaths worldwide, with a median overall survival (OS) of 3-16 months. CUP has long been challenging to diagnose principally due to the occult properties of primary site. In the current era of molecular diagnostics, advancements in methodologies based on cytology, histology, gene expression profiling (GEP), and genomic and epigenomic analysis have greatly improved the diagnostic accuracy of CUP, surpassing 90%. Our center conducted the world's first phase III trial and demonstrated improved progression-free survival and favorable OS by GEP-guided site-specific treatment of CUP, setting the foundation of site-specific treatment in first-line management for CUP. In this review, we detailed the epidemiology, etiology, pathogenesis, as well as the histologic, genetic, and clinical characteristics of CUP. We also provided an overview of the advancements in the diagnostics and therapeutics of CUP over the past 50 years. Moving forward, we propose optimizing diagnostic modalities and exploring further-line treatment regimens as two focus areas for future studies on CUP.

Evaluation of Efficacy of Neoadjuvant Immunochemotherapy for Cervical Metastatic Squamous Cell Carcinoma of Unknown Primary

PURPOSE

This study aims to evaluate the antitumor activity of neoadjuvant immunochemotherapy in patients with cervical metastatic squamous cell carcinoma of unknown primary (CMSCCUP), providing a new idea for its treatment.

METHOD

We retrospectively examined the medical records from Sun Yat-sen University Cancer Center to identify patients with CMSCCUP from July 2020 to November 2023. CMSCCUP's diagnoses are based on the results of biopsy and imaging examination. All patients received PD-1 inhibitors combined with chemotherapy: paclitaxel (Albumin-bound) 260 mg/m2 and cisplatin 60 mg/m2 every 3 weeks for two or more cycles as their initial treatment. Clinical response after neoadjuvant immunochemotherapy was assessed using Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1. Surgery, radiotherapy, or chemoradiotherapy was performed subsequently based on the imaging evaluation results. Outcomes included overall survival (OS) and disease-free survival (DFS).

RESULT

After neoadjuvant immunochemotherapy, the objective response rate (ORR) was 84.2%; complete response (CR), partial response (PR), and stable disease (SD) were 36.8%, 47.4%, and 15.8%, respectively. Of the 9 patients (42.9%) who underwent surgery after neoadjuvant immunochemotherapy, 7 (77.8%) achieved pathological complete response (pCR). No severe treatment-related adverse events occurred. The most common treatment-related adverse events were Grade 1-2 fatigue (11/14, 78.6%), decreased appetite (11/15, 73.3%), and increased aspartate transaminase (12/20, 60.0%). One (1/20, 5.0%) patient experienced Grade 3 anemia. The 2-year overall survival (OS) and 2-year disease-free survival (DFS) rates were 94.4% and 89.4%, respectively.

CONCLUSION

Neoadjuvant immunochemotherapy showed favorable efficacies, anticipated outcomes, and tolerable toxicity for patients with CMSCCUP. More clinical practice and clinical studies are still needed to confirm further.

Cancer of Unknown Primary Presenting with Chylothorax

A 56-year-old man presented to our hospital with dyspnea on exertion for two months. Bilateral pleural effusions were found, and a close examination revealed a chylothorax, including adenocarcinoma. The primary tumor could not be identified by systemic examination. Therefore, the patient was diagnosed with cancer of unknown primary (CUP) presenting with chylothorax. Chemotherapy was administered for CUP, and thoracentesis, pleurodesis, ascites puncture, and nutritional therapy were performed for chylothorax and chylous ascites. Although drainage frequency and tumor marker levels (CA19-9, DUPAN-2, and Span-1) temporarily decreased, disease control deteriorated, and the patient died 12 months after the initial diagnosis.

Durvalumab and tremelimumab in patients with advanced rare cancer: a multi-centre, non-blinded, open-label phase II basket trial

Background

Dual inhibition of cytotoxic T-lymphocyte associated protein 4 (CTLA-4) and programmed death ligand 1 (PD-L1) has been shown to be an effective treatment strategy in many cancers. We sought to determine the objective response rate of combination durvalumab (D) plus tremelimumab (TM) in parallel cohorts of patients with carefully selected rare cancer types in which these agents had not previously been evaluated in phase II trials and for which there was clinical or biological rationale for dual immune checkpoint inhibitor therapy to be active.

Methods

We designed a multi-centre, non-blinded, open-label phase II basket trial with each of the following 8 rare cancers considered a separate phase II trial: salivary carcinoma, carcinoma of unknown primary (CUP) with tumour infiltrating lymphocytes and/or expressing PD-L1, mucosal melanoma, acral melanoma, osteosarcoma, undifferentiated pleomorphic sarcoma, clear cell carcinoma of the ovary (CCCO) or squamous cell carcinoma of the anal canal (SCCA). The primary objective was to evaluate the response rate of the combination of D and TM, and the secondary objectives were to evaluate the tolerability and safety of D and TM combination. Eligible patients had advanced, metastatic or recurrent, or unresectable cancer with no known life-prolonging treatment option, age ≥16 years, ECOG performance status 0 or 1. Patients received D (1500 mg IV) + TM (75 mg IV) on Day 1 q4 weeks for 4 cycles followed by D q4 weeks until disease progression. This trial is registered with ClinicalTrials.gov, NCT02879162.

Findings

From December 14th, 2016, to August 14, 2019, 140 patients enrolled into seven cohorts. The rare melanoma cohorts were closed due to lack of accrual. Of the 140 patients enrolled, 138 were eligible, 138 were evaluable for toxicity and 128 (91%) were evaluable for response. Durable responses were noted in all cohorts except for osteosarcoma. The overall response rate for eligible patients was 16% (95% CI: 10-23%). The response rates in each cancer cohort were undifferentiated pleomorphic sarcoma 15% (n = 3/20; 95% CI 3-38%), salivary carcinoma 20% (n = 4/20; 95% CI: 6-44%), CUP 17% (n = 3/18; 95% CI 4-41%), SCCA 10% (n = 2/20; 95% CI 12-32%) and CCCO 21% (n = 8/39; 95% CI 9-37%). Grade 3/4 adverse events were rare, where 4 patients experienced grade 4 related events and39 patients experienced grade 3 events.

Interpretation

Durvalumab + tremelimumab treatment resulted in meaningful responses in salivary carcinoma and CCCO and deserves further exploration in front-line studies.

Funding

AstraZeneca and Canadian Cancer Society.

SMARCA4-deficient epithelioid sarcoma revealed by comprehensive genomic profiling, leading to a notable response by nivolumab treatment

A 50-year-old man presented with a bulky mass in the left thigh and was referred to our department. He showed an impaired Eastern Cooperative Oncology Group performance status of 3 due to swelling of the left thigh and pain. Imaging analysis revealed a large mass measuring 16 cm in the left thigh and right forearm, along with the bilateral adrenal gland, right lung, right axillary lymph nodes, liver, and left femur. Despite additional tests, including pathological examination, the primary origin of the tumors could not be identified. Because of the rapid tumor progression, he was placed on nivolumab (NIVO; 240 mg/body, every 2 weeks) monotherapy based on the diagnosis of cancer of unknown primary, unfavorable type. Simultaneous comprehensive genomic profiling (CGP) test revealed a high tumor mutation burden (15.69 Muts/Mb) and a truncating mutation of SMARCA4, along with loss of BRG1 expression detected by additional immunohistochemical (IHC) analysis. Based on the predominance of soft tissue in the lesion, histological and IHC findings, and genomic phenotype, the patient was finally re-diagnosed with SMARCA4-deficient, SMARCB1/INI-1-preserved epithelioid sarcoma (ES). He showed a dramatic improvement in physical and laboratory findings at 5 weeks after the initial NIVO dose. Although he experienced immune-related adverse events, such as liver dysfunction, colitis and relative adrenal failure, and severe sepsis due to pulmonary cyst infection, he was able to overcome these complications. By the 12th dose of NIVO (13 months after the initial treatment), he has exhibited a positive response to NIVO without any additional complications. Among SMARCA4-deficient tumors, there have been multiple reports on the sensitivity of SMARCA4-deficient thoracic tumors to immune checkpoint inhibitors (ICIs), including PD-1 blockade agents. This case indicates that SMARCA4-deficient SMARCB1/INI-1-preserved ES may share molecular pathological characteristics with SMARCA4-deficient thoracic tumors, given their similar sensitivity to ICIs. In addition, CGP may play an important role in hypothesizing the primary site of tumors and guiding treatment selection for rare cancers, as in the present case, which lacks established treatment options. Further data accumulation is essential to validate this approach.

Outcomes and molecular profiles in sarcomatoid carcinoma of unknown primary: the Mayo Clinic experience

BACKGROUND

Sarcomatoid carcinomas (SC) are rare tumors with both epithelial and mesenchymal characteristics, linked to aggressive behavior and poor prognosis. Sarcomatoid carcinoma of unknown primary (SCUP) is an exceedingly rare subset with limited literature and no standardized management guidelines. This study aims to characterize the clinical presentations, treatment patterns, and genomic landscape of SCUP.

PATIENTS AND METHODS

Data were retrospectively collected from the Mayo Clinic Rochester Cancer of Unknown Primary Registry. Patients included had biopsy-proven SC with no identifiable primary tumor despite comprehensive diagnostic evaluations. Baseline characteristics, immunohistochemistry (IHC) results, next-generation sequencing (NGS) data, and treatment outcomes were analyzed. Statistical analyses included descriptive statistics, Kaplan-Meier survival estimates, and Cox proportional hazards regression.

RESULTS

Fifty-two SCUP patients were identified, with a median age of 60 years. Most patients presented with widely metastatic disease, particularly lytic bone lesions. Elevated alkaline phosphatase (ALP) was noted in nearly half of the patients. IHC showed high positivity for AE1/AE3 and OSCAR antibodies. Tumor NGS revealed 247 alterations, with TP53 being the most common mutation. Patients receiving definitive therapy had a median overall survival (OS) of 72 months, significantly longer than those receiving systemic therapy (14 months). Immunotherapy was a significant prognostic factor, reducing the risk of death by 90%.

CONCLUSIONS

This study provides essential insights into the clinical and genomic characteristics of SCUP, advocating for the integration of definitive therapy and immunotherapy in treatment protocols. Further prospective studies are needed to validate these findings and improve patient outcomes.

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.

Exploring the molecular landscape of cancer of unknown primary: A comparative analysis with other metastatic cancers

Cancer of unknown primary (CUP) tumors are biologically very heterogeneous, which complicates stratification of patients for treatment. Consequently, these patients face limited treatment options and a poor prognosis. With this study, we aim to expand on the current knowledge of CUP biology by analyzing two cohorts: a well-characterized cohort of 44 CUP patients, and 213 metastatic patients with known primary. These cohorts were treated at the same institution and characterized by identical molecular assessments. Through comparative analysis of genomic and transcriptomic data, we found that CUP tumors were characterized by high expression of immune-related genes and pathways compared to other metastatic tumors. Moreover, CUP tumors uniformly demonstrated high levels of tumor-infiltrating leukocytes and circulating T cells, indicating a strong immune response. Finally, the genetic landscape of CUP tumors resembled that of other metastatic cancers and demonstrated mutations in established cancer genes. In conclusion, CUP tumors possess a distinct immunophenotype that distinguishes them from other metastatic cancers. These results may suggest an immune response in CUP that facilitates metastatic tumor growth while limiting growth of the primary tumor.

The evolution of molecular management of carcinoma of unknown primary

PURPOSE OF REVIEW

There is significant need to improve diagnostic and therapeutic options for patients with cancer of unknown primary (CUP). In this review, we discuss the evolving landscape of molecular profiling in CUP.

RECENT FINDINGS

Molecular profiling is becoming accepted into the diagnostic work-up of CUP patients with tumour mutation profiling now described in international CUP guidelines. Although tissue-of-origin (ToO) molecular tests utilising gene-expression and DNA methylation have existed some time, their clinical benefit remains unclear. Novel technologies utilising whole genome sequencing and machine learning algorithms are showing promise in determining ToO, however further research is required prior to clinical application. A recent international clinical trial found patients treated with molecularly-guided therapy based on comprehensive-panel DNA sequencing had improved progression-free survival compared to chemotherapy alone, confirming utility of performing genomic profiling early in the patient journey. Small phase 2 trials have demonstrated that some CUP patients are responsive to immunotherapy, but the best way to select patients for treatment is not clear.

SUMMARY

Management of CUP requires a multifaceted approach incorporating clinical, histopathological, radiological and molecular sequencing results to assist with identifying the likely ToO and clinically actionable genomic alternations. Rapidly identifying a subset of CUP patients who are likely to benefit from site specific therapy, targeted therapy and/or immunotherapy will improve patient outcomes.

Site-specific therapy guided by a 90-gene expression assay versus empirical chemotherapy in patients with cancer of unknown primary (Fudan CUP-001): a randomised controlled trial

BACKGROUND

Empirical chemotherapy remains the standard of care in patients with unfavourable cancer of unknown primary (CUP). Gene-expression profiling assays have been developed to identify the tissue of origin in patients with CUP; however, their clinical benefit has not yet been demonstrated. We aimed to evaluate the efficacy and safety of site-specific therapy directed by a 90-gene expression assay compared with empirical chemotherapy in patients with CUP.

METHODS

This randomised controlled trial was conducted at Fudan University Shanghai Cancer Center (Shanghai, China). We enrolled patients aged 18-75 years, with previously untreated CUP (histologically confirmed metastatic adenocarcinoma, squamous cell carcinoma, poorly differentiated carcinoma, or poorly differentiated neoplasms) and an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, who were not amenable to local radical treatment. Patients were randomly assigned (1:1) by the Pocock and Simon minimisation method to receive either site-specific therapy or empirical chemotherapy (taxane [175 mg/m2 by intravenous infusion on day 1] plus platinum [cisplatin 75 mg/m2 or carboplatin area under the curve 5 by intravenous infusion on day 1], or gemcitabine [1000 mg/m2 by intravenous infusion on days 1 and 8] plus platinum [same as above]). The minimisation factors were ECOG performance status and the extent of the disease. Clinicians and patients were not masked to interventions. The tumour origin in the site-specific therapy group was predicted by the 90-gene expression assay and treatments were administered accordingly. The primary endpoint was progression-free survival in the intention-to-treat population. The trial has been completed and the analysis is final. This study is registered with ClinicalTrials.gov (NCT03278600).

FINDINGS

Between Sept 18, 2017, and March 18, 2021, 182 patients (105 [58%] male, 77 [42%] female) were randomly assigned to receive site-specific therapy (n=91) or empirical chemotherapy (n=91). The five most commonly predicted tissues of origin in the site-specific therapy group were gastro-oesophagus (14 [15%]), lung (12 [13%]), ovary (11 [12%]), cervix (11 [12%]), and breast (nine [10%]). At the data cutoff date (April 30, 2023), median follow-up was 33·3 months (IQR 30·4-51·0) for the site-specific therapy group and 30·9 months (27·6-35·5) for the empirical chemotherapy group. Median progression-free survival was significantly longer with site-specific therapy than with empirical chemotherapy (9·6 months [95% CI 8·4-11·9] vs 6·6 months [5·5-7·9]; unadjusted hazard ratio 0·68 [95% CI 0·49-0·93]; p=0·017). Among the 167 patients who started planned treatment, 46 (56%) of 82 patients in the site-specific therapy group and 52 (61%) of 85 patients in the empirical chemotherapy group had grade 3 or worse treatment-related adverse events; the most frequent of these in the site-specific therapy and empirical chemotherapy groups were decreased neutrophil count (36 [44%] vs 42 [49%]), decreased white blood cell count (17 [21%] vs 26 [31%]), and anaemia (ten [12%] vs nine [11%]). Treatment-related serious adverse events were reported in five (6%) patients in the site-specific therapy group and two (2%) in the empirical chemotherapy group. No treatment-related deaths were observed.

INTERPRETATION

This single-centre randomised trial showed that site-specific therapy guided by the 90-gene expression assay could improve progression-free survival compared with empirical chemotherapy among patients with previously untreated CUP. Site-specific prediction by the 90-gene expression assay might provide more disease information and expand the therapeutic armamentarium in these patients.

FUNDING

Clinical Research Plan of Shanghai Hospital Development Center, Program for Shanghai Outstanding Academic Leader, and Shanghai Anticancer Association SOAR PROJECT.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Real-world data on efficacy/safety and economic impact of nivolumab administered every 2 and 4 weeks among Japanese patients

AIM

A new treatment interval for nivolumab administration at 480 mg every 4 weeks, in addition to 240 mg every 2 weeks, was approved in Japan in 2020. Using model-based evaluation, it was speculated that the effects or safety of nivolumab do not differ between the two treatment intervals; however, real-world data on nivolumab efficacy, safety, and economic impact are lacking. Accordingly, we aimed to examine the effects of nivolumab treatment intervals (2 weeks vs. 4 weeks) in terms of efficacy, safety, and economic impact in Japanese patients with cancer.

METHODS

We retrospectively analyzed 126 patients treated with nivolumab. The patients were divided into two groups depending on whether they received nivolumab at 240 mg every 2 weeks (2-week group) or 480 mg every 4 weeks (4-week group).

RESULTS

Efficacy results found no significant difference between the 4- and 2-week groups considering median overall survival (p = 0.70) and median progression-free survival (p = 0.57). The incidence of any grade and ≥  grade 3 immune-related adverse events did not differ between the 4-week and 2-week groups (any grade, p = 0.13; ≥  grade 3, p = 0.36). Excluding drug costs, the 4-week group had significantly lower medical costs than the 2-week group (2-week vs. 4-week: mean, 94,659 JPY [679.0 USD] vs. 58,737 JPY [421.3 USD]; p < 0.05).

CONCLUSION

Collectively, our findings suggest that nivolumab 480 mg every 4 weeks may be more effective than nivolumab 240 mg every 2 weeks in terms of economic impact.

Recommendations for the use of next-generation sequencing (NGS) for patients with advanced cancer in 2024: a report from the ESMO Precision Medicine Working Group

BACKGROUND

Advancements in the field of precision medicine have prompted the European Society for Medical Oncology (ESMO) Precision Medicine Working Group to update the recommendations for the use of tumour next-generation sequencing (NGS) for patients with advanced cancers in routine practice.

METHODS

The group discussed the clinical impact of tumour NGS in guiding treatment decision using the ESMO Scale for Clinical Actionability of molecular Targets (ESCAT) considering cost-effectiveness and accessibility.

RESULTS

As for 2020 recommendations, ESMO recommends running tumour NGS in advanced non-squamous non-small-cell lung cancer, prostate cancer, colorectal cancer, cholangiocarcinoma, and ovarian cancer. Moreover, it is recommended to carry out tumour NGS in clinical research centres and under specific circumstances discussed with patients. In this updated report, the consensus within the group has led to an expansion of the recommendations to encompass patients with advanced breast cancer and rare tumours such as gastrointestinal stromal tumours, sarcoma, thyroid cancer, and cancer of unknown primary. Finally, ESMO recommends carrying out tumour NGS to detect tumour-agnostic alterations in patients with metastatic cancers where access to matched therapies is available.

CONCLUSION

Tumour NGS is increasingly expanding its scope and application within oncology with the aim of enhancing the efficacy of precision medicine for patients with cancer.

Marked Response to Nivolumab by a Patient With SMARCA4-Deficient Undifferentiated Urothelial Carcinoma Showing High PD-L1 Expression: A Case Report

BACKGROUND

SMARCA4 is a component gene of the SWI/SNF (SWItch/Sucrose NonFermentable) chromatin remodeling complex; undifferentiated tumors associated with its functional deletion have been described in several organs. However, no established treatment for these tumors currently exists.

CASE

In this study, we report a case of a SMARCA4-deficient undifferentiated urothelial carcinoma with high PD-L1 expression that was effectively treated with nivolumab after early relapse following treatment for non-invasive bladder cancer. The histological morphology of the rhabdoid-like undifferentiated tumor of unknown primary led us to suspect a SWI/SNF-deficient tumor, and subsequent immunostaining led to the diagnosis of a SMARCA4-deficient undifferentiated tumor. This effort also led to the identification of the developmental origin of this SMARCA4-deficient undifferentiated tumor as a non-invasive bladder cancer. We also carried out a detailed immune phenotypic assay on peripheral T cells. In brief, a phenotypic change of CD8+T cells from naive to terminally differentiated effector memory cells was observed.

CONCLUSION

Regardless of the organ of cancer origin or cancer type, SWI/SNF-deficient tumors should be suspected in undifferentiated and dedifferentiated tumors, and immune checkpoint inhibitors may be considered as a promising treatment option for this type of tumor. The pathogenesis of SMARCA4-deficient anaplastic tumors awaits further elucidation for therapeutic development.

A case of pelvic squamous cell carcinoma of unknown primary origin that responded well to radiotherapy and nivolumab

Squamous cell carcinoma of unknown primary origin in the pelvis is rare. We report a case of a 64-year-old woman with a large osteolytic squamous cell carcinoma of unknown primary origin in the pelvis that presented with p16 expression. The patient presented with leg pain and swelling and was admitted to our hospital. Computed tomography scans of the pelvis revealed a large osteolytic tumor. A computed tomography-guided needle biopsy was performed, and pathological examination revealed neoplastic cells with metastatic squamous cell carcinoma presenting with p16 expression. Despite a whole-body examination, tumor origin remained undetected. The patient was treated for this metastatic squamous cell carcinoma of unknown primary using palliative radiotherapy for hip pain and nivolumab. Remarkable reduction in the tumor marker levels and tumor size were obtained after therapy. Finally, partial remission and progression-free survival for more than 7 months were achieved. In conclusion, we experienced a rare case with a large p16-positive squamous cell carcinoma of unknown primary in pelvis, which responded well to radiotherapy and nivolumab.

The intricate dance of tumor evolution: Exploring immune escape, tumor migration, drug resistance, and treatment strategies

Recent research has unveiled fascinating insights into the intricate mechanisms governing tumor evolution. These studies have illuminated how tumors adapt and proliferate by exploiting various factors, including immune evasion, resistance to therapeutic drugs, genetic mutations, and their ability to adapt to different environments. Furthermore, investigations into tumor heterogeneity and chromosomal aberrations have revealed the profound complexity that underlies the evolution of cancer. Emerging findings have also underscored the role of viral influences in the development and progression of cancer, introducing an additional layer of complexity to the field of oncology. Tumor evolution is a dynamic and complex process influenced by various factors, including immune evasion, drug resistance, tumor heterogeneity, and viral influences. Understanding these elements is indispensable for developing more effective treatments and advancing cancer therapies. A holistic approach to studying and addressing tumor evolution is crucial in the ongoing battle against cancer. The main goal of this comprehensive review is to explore the intricate relationship between tumor evolution and critical aspects of cancer biology. By delving into this complex interplay, we aim to provide a profound understanding of how tumors evolve, adapt, and respond to treatment strategies. This review underscores the pivotal importance of comprehending tumor evolution in shaping effective approaches to cancer treatment.

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.

Advances in Cancer Research: Current and Future Diagnostic and Therapeutic Strategies

Cancers of unknown primary (CUP) exhibit significant cellular heterogeneity and malignancy, which poses significant challenges for diagnosis and treatment. Recent years have seen deeper insights into the imaging, pathology, and genetic characteristics of CUP, driven by interdisciplinary collaboration and the evolution of diagnostic and therapeutic strategies. However, due to their insidious onset, lack of evidence-based medicine, and limited clinical understanding, diagnosing and treating CUP remain a significant challenge. To inspire more creative and fantastic research, herein, we report and highlight recent advances in the diagnosis and therapeutic strategies of CUP. Specifically, we discuss advanced diagnostic technologies, including 12-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography (18F-FDG PET/CT) or 68Ga-FAPI (fibroblast activation protein inhibitor) PET/CT, liquid biopsy, molecular diagnostics, self-assembling nanotechnology, and artificial intelligence (AI). In particular, the discussion will extend to the effective treatment techniques currently available, such as targeted therapies, immunotherapies, and bio-nanotechnology-based therapeutics. Finally, a novel perspective on the challenges and directions for future CUP diagnostic and therapeutic strategies is discussed.

All-cause and immune checkpoint inhibitor-associated acute kidney injury in immune checkpoint inhibitor users: a meta-analysis of occurrence rate, risk factors and mortality

Background

Immune checkpoint inhibitors (ICIs) have been associated with acute kidney injury (AKI). However, the occurrence rate of ICI-related AKI has not been systematically examined. Additionally, exposure to proton pump inhibitors (PPIs) and non-steroidal anti-inflammatory drugs (NSAIDs) were considered as risk factors for AKI, but with inconclusive results in ICI-related AKI. Our aim was to analyse the occurrence rate of all-cause AKI and ICI-related AKI and the occurrence rates of severe AKI and dialysis-requiring AKI, and to determine whether exposure to PPIs and NSAIDs poses a risk for all-cause and ICI-related AKI.

Methods

This study population was adult ICI recipients. A systematic review was conducted by searching MEDLINE, Embase and PubMed through October 2023. We included prospective trials and observational studies that reported any of the following outcomes: the occurrence rate of all-cause or ICI-related AKI, the relationship between PPI or NSAID exposure and AKI development or the mortality rate in the AKI or non-AKI group. Proportional meta-analysis and pairwise meta-analysis were performed. The evidence certainty was assessed using the Grading of Recommendations Assessment, Development and Evaluation framework.

Results

A total of 120 studies comprising 46 417 patients were included. The occurrence rates of all-cause AKI were 7.4% (14.6% from retrospective studies and 1.2% from prospective clinical trials). The occurrence rate of ICI-related AKI was 3.2%. The use of PPIs was associated with an odds ratio (OR) of 1.77 [95% confidence interval (CI) 1.43-2.18] for all-cause AKI and an OR of 2.42 (95% CI 1.96-2.97) for ICI-related AKI. The use of NSAIDs was associated with an OR of 1.77 (95% CI 1.10-2.83) for all-cause AKI and an OR of 2.57 (95% CI 1.68-3.93) for ICI-related AKI.

Conclusions

Our analysis revealed that approximately 1 in 13 adult ICI recipients may experience all-cause AKI, while 1 in 33 adult ICI recipients may experience ICI-related AKI. Exposure to PPIs and NSAIDs was associated with an increased OR risk for AKI in the current meta-analysis.

Phase II Trial of Nivolumab in Metastatic Rare Cancer with dMMR or MSI-H and Relation with Immune Phenotypic Analysis (the ROCK Trial)

PURPOSE

Mismatch repair deficiency (dMMR)/microsatellite instability-high (MSI-H) are positive predictive markers for immune checkpoint inhibitors. However, data on the activity of nivolumab in advanced dMMR/MSI-H rare cancers and more accurate biomarkers are worth exploring.

PATIENTS AND METHODS

We conducted a multicenter phase II, open-label, single-arm clinical trial to explore the effectiveness and safety of nivolumab monotherapy in patients with advanced rare cancers with dMMR/MSI-H, in parallel with immune phenotype analysis, to explore new biomarkers. A Bayesian adaptive design was applied. Characterization of peripheral blood mononuclear cells (PBMC) was characterized by multicolor flow cytometric analysis and CyTOF using samples collected before and after the intervention. The dMMR was identified by the complete loss of MLH1/MSH2/MSH6/PMS2.

RESULTS

From May 2018 to March 2021, 242 patients were screened, and 11 patients were enrolled, of whom 10 were included in the full analysis. Median follow-up was 24.7 months (interquartile range, 12.4-31.5). Objective response rate was 60% [95% confidence interval (CI), 26.2-87.8] by central assessment and 70% (95% CI, 34.8-93.3) by local investigators. Median progression-free survival was 10.1 months (95% CI, 0.9-11.1). No treatment-related adverse events of grade 3 or higher were observed. Patients with a tumor mutation burden of ≥10/Mb showed a 100% response rate (95% CI, 47.8-100). Responders had increased T-bet+ PD-1+ CD4+ T cells in PBMC compared with nonresponders (P < 0.05).

CONCLUSIONS

The trial met its primary endpoint with nivolumab, demonstrating clinical benefit in advanced dMMR/MSI-H rare solid cancers. Besides, the proportion of T-bet+ PD-1+ CD4+ T-cells may serve as a novel predictive biomarker.

Autopsy-Confirmed Undifferentiated Carcinoma of the Liver With Rapid Bone Metastasis

A male in his late 70s, with progressive hip pain, was diagnosed with a metastatic iliac bone tumor, initially misinterpreted as septic arthritis. Despite extensive imaging, the primary tumor site was undetected until autopsy, which confirmed undifferentiated carcinoma of the liver with secondary lung involvement. The patient's poor performance status and rapid health decline precluded aggressive treatment, leading to his demise. This case underscores the difficulties in diagnosing such carcinomas and suggests that early identification and innovative therapies like nivolumab could potentially extend life in similar cases.

Cancer of unknown primary histologically, genetically and spatially diagnosed as left ovary‑derived cancer: A case report

Cancer of unknown primary (CUP) is a heterogeneous syndrome of metastatic cancer in which the primary site cannot be determined even after a standard and comprehensive search. The present report describes a case in which the spatial distribution of the lymph node metastases contributed to the identification of the primary site. While the standard workup did not identify the primary tumor, genomic profiling analysis was useful in therapeutic management. A 68-year-old woman presented with a cancerous pleural effusion (adenocarcinoma). The primary site could not be identified, and the pleural effusion resolved spontaneously. After 11 months, the patient had elevated Krebs von den Lungen-6 and cancer antigen 125 levels, and multiple enlarged lymph nodes. Pathological diagnosis based on a biopsy sample of the para-aortic lymph nodes indicated that the tumor was a high-grade serous carcinoma of possible gynecological organ origin. The patient underwent surgery, including hysterectomy, bisalpingo-oophorectomy and lymph node dissection. Although there were no primary sites in the gynecological organs, marked lymphovascular invasion was found around the left ovary, suggesting a left ovary-derived tumor. Genetic testing revealed a high loss of heterozygosity score and high tumor mutational burden (TMB). The patient received paclitaxel and carboplatin therapy followed by a poly ADP-ribose polymerase inhibitor as regimens for ovarian cancer and achieved complete remission. The unique course of the disappearance of the effusion and the absence of tumor in the adnexa might be associated with the high immunogenicity of the tumor characterized by the high TMB. This case may provide insights into the pathogenesis of CUP.

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.

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.

Comparison of different predictive biomarker testing assays for PD-1/PD-L1 checkpoint inhibitors response: a systematic review and network meta-analysis

Background

Accurate prediction of efficacy of programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) checkpoint inhibitors is of critical importance. To address this issue, a network meta-analysis (NMA) comparing existing common measurements for curative effect of PD-1/PD-L1 monotherapy was conducted.

Methods

We searched PubMed, Embase, the Cochrane Library database, and relevant clinical trials to find out studies published before Feb 22, 2023 that use PD-L1 immunohistochemistry (IHC), tumor mutational burden (TMB), gene expression profiling (GEP), microsatellite instability (MSI), multiplex IHC/immunofluorescence (mIHC/IF), other immunohistochemistry and hematoxylin-eosin staining (other IHC&HE) and combined assays to determine objective response rates to anti-PD-1/PD-L1 monotherapy. Study-level data were extracted from the published studies. The primary goal of this study was to evaluate the predictive efficacy and rank these assays mainly by NMA, and the second objective was to compare them in subgroup analyses. Heterogeneity, quality assessment, and result validation were also conducted by meta-analysis.

Findings

144 diagnostic index tests in 49 studies covering 5322 patients were eligible for inclusion. mIHC/IF exhibited highest sensitivity (0.76, 95% CI: 0.57-0.89), the second diagnostic odds ratio (DOR) (5.09, 95% CI: 1.35-13.90), and the second superiority index (2.86). MSI had highest specificity (0.90, 95% CI: 0.85-0.94), and DOR (6.79, 95% CI: 3.48-11.91), especially in gastrointestinal tumors. Subgroup analyses by tumor types found that mIHC/IF, and other IHC&HE demonstrated high predictive efficacy for non-small cell lung cancer (NSCLC), while PD-L1 IHC and MSI were highly efficacious in predicting the effectiveness in gastrointestinal tumors. When PD-L1 IHC was combined with TMB, the sensitivity (0.89, 95% CI: 0.82-0.94) was noticeably improved revealed by meta-analysis in all studies.

Interpretation

Considering statistical results of NMA and clinical applicability, mIHC/IF appeared to have superior performance in predicting response to anti PD-1/PD-L1 therapy. Combined assays could further improve the predictive efficacy. Prospective clinical trials involving a wider range of tumor types are needed to establish a definitive gold standard in future.

Diagnosis of a SMARCA4-deficient undifferentiated tumor using multigene panel testing: A case report

Key Clinical Message

SMARCA4-deficient thoracic carcinoma is a malignant tumor that may present as cancer of unknown primary. This tumor is refractory and requires a novel approach. In addition to identifying therapeutic targets, multigene panel testing can reveal novel genetic mutations, leading to more pathologically relevant diagnoses and appropriate tumor care.

Abstract

SMARCA4-deficient undifferentiated tumors are characterized by SMARCA4 inactivation. We present a case of a 74-year-old man with an undifferentiated tumor and a novel SMARCA4 mutation detected using multigene panel testing. The tumor was multiagent and refractory to three chemotherapy lines. The test results helped guide appropriate medical management.

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.

[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.

From Biology to Diagnosis and Treatment: The Ariadne’s Thread in Cancer of Unknown Primary

Cancer of unknown primary (CUP) encloses a group of heterogeneous tumours, the primary sites for which cannot be identified at the time of diagnosis, despite extensive investigations. CUP has always posed major challenges both in its diagnosis and management, leading to the hypothesis that it is rather a distinct entity with specific genetic and phenotypic aberrations, considering the regression or dormancy of the primary tumour; the development of early, uncommon systemic metastases; and the resistance to therapy. Patients with CUP account for 1–3% of all human malignancies and can be categorised into two prognostic subsets according to their clinicopathologic characteristics at presentation. The diagnosis of CUP mainly depends on the standard evaluation comprising a thorough medical history; complete physical examination; histopathologic morphology and algorithmic immunohistochemistry assessment; and CT scan of the chest, abdomen, and pelvis. However, physicians and patients do not fare well with these criteria and often perform additional time-consuming evaluations to identify the primary tumour site to guide treatment decisions. The development of molecularly guided diagnostic strategies has emerged to complement traditional procedures but has been disappointing thus far. In this review, we present the latest data on CUP regarding the biology, molecular profiling, classification, diagnostic workup, and treatment.

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.

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.

Microsatellite Instability-high-positive Cancer of Unknown Primary Origin with a Long-term Survival after Surgery Alone

An 80-year-old woman was referred to our hospital for a thorough examination of enlarged lymph nodes on the lesser curvature of the stomach. Upon suspicion of malignant lymphoma, the patient underwent open lymphadenectomy and was diagnosed with lymph node metastasis of poorly differentiated adenocarcinoma. The patient was subsequently diagnosed with microsatellite instability-high cancer of unknown primary origin. Surgical removal of the affected lymph nodes achieved full remission. Chemotherapy was considered in case of recurrence or identification of the primary site. Recurrence has not occurred in three years since the surgery. However, a long-term survival without chemotherapy is rare.

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.

Case Report: Successful Immunotherapy Improved the Prognosis of the Unfavorable Subset of Cancer of Unknown Primary

Background

Cancer of unknown primary (CUP) is heterogeneous and has a wide variety of clinical presentations and a poor prognosis in most patients, with a median overall survival of only 6 months. The development of molecular profiling contributes to precision therapy, and targeted drugs and immune checkpoint inhibitors (ICIs) greatly promote individualized treatment.

Case presentation

Here, we reported a case of an unfavorable subset of CUP who had a long time of survival after the immunotherapy-prominent comprehensive treatment. A 48-year-old man presented with back pain and a cough. A diagnostic work-up showed bone marrow, multiple bones, and lymph node metastasis. Lymph node pathology implies metastatic poorly differentiated cancer. Next-generation sequencing (NGS) showed no special targets, but the tumor proportion score (TPS) of programmed death-ligand 1 (PD-L1) was 80% and the tumor mutation burden (TMB) was 16.7 per million bases. After two cycles of pembrolizumab 200 mg D1 plus nanoparticle albumin-bound (nab)-paclitaxel 200 mg D1&8 (q3w), PET-CT and bone marrow aspiration cytology showed a complete response (CR). Subsequently, pembrolizumab alone was used for three months. The left inguinal lymph nodes showed new metastasis. After two cycles of the combination treatment of pembrolizumab and (nab)-paclitaxel, a partial response (PR) was achieved. After seven months, retroperitoneal lymph nodes showed new metastasis, and the sequential treatment with radiotherapy and pembrolizumab exhibited encouraging efficacy. To date, the patient has survived nearly 40 months with the combination therapy.

Conclusions

The ICI-prominent comprehensive treatment provided clinical benefit for the reported case of CUP. Thus, CUP patients with markers of benefiting from immunotherapy should be actively treated with immunotherapy to improve their prognosis.

Systematic review of the CUP trials characteristics and perspectives for next-generation studies

BACKGROUND

Research on therapeutic strategies for patients with unknown primary cancer (CUP) has been underwhelming. This paper summarized and evaluated the CUP therapeutic research over the previous five years. Based on this evaluation, recommendations for clinical trial designs are made to improve the impact of CUP research on patients.

METHODS

Published and ongoing research were evaluated. PubMed was searched from January 1, 2015, to November 1, 2021. The start date of 2015 was chosen to identify research published after ESMO issued new diagnostic and therapeutic guidelines. The US National Library of Medicine indexed ongoing clinical trials.

FINDINGS

Of the 244 CUP studies indexed in PubMed, 11.9% were prospective studies, and 4.9% were clinical trials. The review protocol deemed 65 publications eligible for full-text review. Eleven studies evaluating therapeutic regimens were retained. The two prospective studies and non-randomized trials showed promising outcomes for site-specific treatments. Randomized clinical trials were less promising; however, the trials had recruitment challenges resulting in biased accrual and the inability to keep pace with advancing diagnostics and therapeutics. Most of the 35 ongoing studies were phase II single-arm trials assessing immune checkpoint inhibitors (ICI) or site-specific therapies among CUP patients with suspected favorable prognoses.

CONCLUSION

Our evaluation suggests two prospective clinical trial designs that addressed recent study design and recruitment challenges. A visionary approach uses a multi-arm, multistage randomized trial to address rapid advancements in diagnosis and therapy. A pragmatic approach utilizes a single-arm trial with historical controls to overcome comparison group and recruitment challenges.