Improved diagnosis, therapy and outcomes for patients with CUP

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.

Cancers of Unknown Primary: A Descriptive Study in the U.S. Military Health System

INTRODUCTION

Cancers of unknown primary (CUP) are defined as histologically confirmed metastatic cancers that do not have an identified primary site of origin despite an appropriate diagnostic workup. Although accessibility to and quality of medical care influence diagnosis of cancer including CUP, previous studies describing CUP have generally been conducted in patients with various accessibilities to care. This study aimed to describe the demographic, histologic, and temporal trend characteristics of CUP patients in the DoD Cancer Registry of the Military Health System (MHS), which provides universal health care access, reducing the potential effects of accessibility to care on research results.

MATERIALS AND METHODS

The data were obtained from the DoD's Automated Central Tumor Registry (ACTUR), which collects cancer data from beneficiaries who were diagnosed or received treatment in the MHS. We described the demographic and histologic distributions in CUP patients aged 18 years or older diagnosed from 1987 to 2013. We calculated the proportion of CUP patients among all metastatic cancers and the most common histologic categories of those tumors. We then evaluated whether the proportion of histologic types changed over time.

RESULTS

CUP comprised 13.3% of all metastatic cancers in ACTUR during the study period. The majority of CUP within ACTUR was moderately and well-differentiated adenocarcinoma (51.3%) and poorly differentiated carcinomas (23.2%) followed by squamous cell carcinomas (12.5%). The percentages of CUP among metastasized cancers of the same histologic category ranged 12%-15% for moderately and well-differentiated adenocarcinomas, squamous cell, and poorly differentiated carcinomas, and 41%-46% for malignant neuroendocrine carcinomas and undifferentiated neoplasms. However, the percentages varied by sex, race, and age for certain pathologies. The proportion of CUP patients among all metastatic cancer patients has steadily declined from 22.4% to 8.3% from 1987 to 2013.

CONCLUSION

The proportion and trends of CUP in the ACTUR were generally consistent with other descriptive CUP studies. This study provides a description of CUP in a health care system with universal access in the USA and provides a foundation for future studies on CUP.

Cancers of unknown primary: Survival by histologic type, demographic features, and treatment in the U.S. Military Health System

BACKGROUND

Cancers of unknown primary (CUP), a group of heterogenous metastatic cancers lacking a known primary site, have poor prognosis. This study compared survival of CUP by histologic type, patient characteristics, and treatment in the U.S. Military Health System (MHS), which provides universal care to its members.

METHODS

Patients histologically diagnosed with CUP were identified from the U.S. Department of Defense (DoD)'s Automated Central Tumor Registry. Median survival with 95 % confidence intervals was calculated for demographic and treatment variables by histologic type. A multivariable accelerated failure time model estimated time ratios and 95 % confidence intervals.

RESULTS

The study included 3358 CUP patients. The most prevalent CUP in this study was well- and moderately-differentiated adenocarcinomas. Median survival varied by histologic type with squamous cell carcinoma having the longest at 25.1 months and poorly-differentiated carcinomas having the shortest at 3.0 months. For each histologic type, survival was generally similar by sex and active-duty status although women with well- and moderately-differentiated adenocarcinoma had longer survival than their male counterparts. Younger patients tended to have longer survival than those aged 65 years or older. Generally, there were no racial differences in survival except poorer survival for Black patients than White patients in the group of other histologic types. Patients with chemotherapy and radiation treatment generally had improved survival whereas patients with squamous cell carcinoma who received chemotherapy had shorter survival than those without.

CONCLUSION

Survival generally did not differ between racial groups, which may be related to equal healthcare access despite racial background. Further studies are warranted to better understand how survival in the MHS compares with that in the general U.S.

POPULATION

Prognostic factors among patients with brain metastases from cancer of unknown primary site

PURPOSE

Cancers of an unknown primary site (CUPs) have a dismal prognosis, and the situation is even worse for CUPs patients with brain metastases (BM-CUPs). This study aims to give better insight into the occurrence and survival of BM-CUPs patients.

METHODS

Cases were selected from the Netherlands Cancer Registry (1,430 BM-CUPs/17,140 CUPs). Baseline characteristics between CUPs patients with and without BM were tested using chi-square tests and Mann-Whitney U tests. Patients' overall survival (OS) times were estimated by the Kaplan-Meier method and prognostic factors on OS was assessed using Cox proportional hazards regression analyses.

RESULTS

The proportion of BM-CUPs patients among CUPs increased from 8% in 2009-2010 to 10% in 2017-2018 (p < 0.001). Most patients presented with multiple brain lesions (53%). Survival of BM-CUPs improved over time: one-year OS increased from 10% for patients diagnosed in 2009-2010 to 17% (2017- 2018) (p < 0.01), and median survival times increased from 1.8 months to 2.2 months. Independent predictors of poor survival were multiple (HR 1.25; p < 0.01) or unknown (HR 1.48; p < 0.01) locations of BM, unknown/poorly/undifferentiated carcinoma histology (HR 1.53; p < 0.01), or clinical symptoms of BM (HR 1.74; p < 0.01), accompanying liver metastasis (HR 1.43; p < 0.01) and more than one metastatic site outside the brain compared to none (HR 1.52; p < 0.01).

CONCLUSION

The incidence of patients with BM-CUPs is steadily increasing over time and overall prognosis remains dismal. Our results, however, show distinct patient subgroups that exhibit comparatively better outcomes, and more predictors may likely still be identified.

Carcinoma of Unknown Primary Site (CUP) With Metastatic Renal-Cell Carcinoma (mRCC) Histologic and Immunohistochemical Characteristics (CUP-mRCC): Results From Consecutive Patients Treated With Targeted Therapy and Review of Literature

BACKGROUND

Carcinoma of unknown primary site (CUP) is a heterogenous group of metastatic cancer with no detectable primary tumor site. Diagnostic assessment occasionally presents CUP with metastatic renal-cell carcinoma (mRCC) histologic and immunohistochemical characteristics (CUP-mRCC). Efficacy and toxicity data for vascular endothelial growth factor inhibitor therapies in CUP-mRCC patients are few.

PATIENTS AND METHODS

We retrospectively reviewed consecutive patients with CUP-mRCC at a single institution between 2007 and 2018. Treatment outcomes were assessed from initiation of renal-cell carcinoma-specific therapy, including response rate, progression-free survival, and overall survival.

RESULTS

Ten patients with CUP-mRCC were identified. Median age was 64 years. Histologies were clear-cell (30%), papillary type II (20%), and unclassified renal-cell (50%) carcinoma. International Metastatic Renal Cell Carcinoma Database Consortium risk group were favorable, intermediate, and poor in 0, 40%, and 60%, respectively. One patient received empiric first-line chemotherapy. Targeted treatments were pazopanib (n = 7), sunitinib (n = 2), and sorafenib (n = 1). Objective response rate was 40%, progression-free survival was 2.5 months (95% confidence interval, 1.2-3.8), and overall survival was 5.7 months (95% confidence interval, 0-24.0). Stratified for International Metastatic Renal Cell Carcinoma Database Consortium risk, overall survival in intermediate versus poor risk group were 18.6 months and 2.3 months, respectively. Second-line therapy did not result in disease control. No new or unexpected toxicities were observed.

CONCLUSION

CUP-mRCC treated with vascular endothelial growth factor-targeted therapy is valid, feasible, and safe even though these patients had several negative prognostic factors. CUP-mRCC patients should be identified among CUP patients for specific renal-cell carcinoma therapy.

Immunohistochemistry for Diagnosis of Metastatic Carcinomas of Unknown Primary Site

Immunohistochemistry has become an essential ancillary examination for the identification and classification of carcinomas of unknown primary site (CUPs). Over the last decade, the diagnostic accuracy of organ- or tumour-specific immunomarkers and the clinical validation of effective immunohistochemical panels has improved significantly. When dealing with small sample sizes, diagnostic accuracy is crucial, particularly in the current era of targeted molecular and immune-based therapies. Effective systematic use of appropriate immunohistochemical panels enables accurate classification of most of the undifferentiated carcinomas as well as careful preservation of tissues for potential molecular or other ancillary tests. This review discusses the algorithmic approach to the diagnosis of CUPs using CK7 and CK20 staining patterns. It outlines the most frequently used tissue-specific antibodies, provides some pitfalls essential in avoiding potential diagnostic errors and discusses the complementary tools, such as molecular tumour profiling and mutation-specific antibodies, for the improvement of diagnosis and prediction of the treatment response.

Predictors of care for patients with cancer of unknown primary site in three Australian hospitals

AIM

Cancer of unknown primary site (CUP) is a medically challenging malignancy with a poor prognosis. We describe an incident tertiary CUP patient cohort and identify factors predictive of specific types of health care.

METHODS

We reviewed the medical records of 217 patients diagnosed with CUP (2006-2011) in three public hospitals in New South Wales, Australia. We systematically abstracted data and performed multivariable logistic regression to identify factors predictive of tumor biopsy, surgery, chemotherapy, radiotherapy and palliative care.

RESULTS

The median age at CUP diagnosis was 75 years (range 23-98) and 52% were male. The most common mode of presentation was emergency department admission (57%). Serum tumor markers were performed in 42%, fine needle aspiration alone in 15% and core biopsy in 52%. Younger age, health service referral, oncologist review and a family history of cancer predicted receipt of a biopsy (77%). Cancer-related surgery (17%) was more likely in younger patients, those presenting with pain, and those with single lymph node metastases. Younger age and good performance score predicted receipt of chemotherapy (22%). The location of metastases predicted receipt of radiotherapy (28%). Older age, emergency presentation, poor performance score and no oncology review predicted receipt of palliative care only (52%); 77% were referred for palliative care during hospitalization.

CONCLUSION

The determinants of care were generally consistent with international CUP clinical guidelines. Areas of future research include potential underinvestigation and undertreatment of older patients, overuse of certain low-value diagnostic tests, suboptimal use of immunohistochemistry and mammography and underreferral to palliative care.

Precision medicine based on epigenomics: the paradigm of carcinoma of unknown primary

Epigenetic alterations are a common hallmark of human cancer. Single epigenetic markers are starting to be incorporated into clinical practice; however, the translational use of these biomarkers has not been validated at the 'omics' level. The identification of the tissue of origin in patients with cancer of unknown primary (CUP) is an example of how epigenomics can be incorporated in clinical settings, addressing an unmet need in the diagnostic and clinical management of these patients. Despite the great diagnostic advances made in the past decade, the use of traditional diagnostic procedures only enables the tissue of origin to be determined in ∼30% of patients with CUP. Thus, development of molecularly guided diagnostic strategies has emerged to complement traditional procedures, thereby improving the clinical management of patients with CUP. In this Review, we present the latest data on strategies using epigenetics and other molecular biomarkers to guide therapeutic decisions involving patients with CUP, and we highlight areas warranting further research to engage the medical community in this unmet need.