Optimal therapeutic management of patients with distinct clinicopathological cancer of unknown primary subsets

A comparison of DNA sequencing and gene expression profiling to assist tissue of origin diagnosis in cancer of unknown primary

Cancer of unknown primary (CUP) is a syndrome defined by clinical absence of a primary cancer after standardised investigations. Gene expression profiling (GEP) and DNA sequencing have been used to predict primary tissue of origin (TOO) in CUP and find molecularly guided treatments; however, a detailed comparison of the diagnostic yield from these two tests has not been described. Here, we compared the diagnostic utility of RNA and DNA tests in 215 CUP patients (82% received both tests) in a prospective Australian study. Based on retrospective assessment of clinicopathological data, 77% (166/215) of CUPs had insufficient evidence to support TOO diagnosis (clinicopathology unresolved). The remainder had either a latent primary diagnosis (10%) or clinicopathological evidence to support a likely TOO diagnosis (13%) (clinicopathology resolved). We applied a microarray (CUPGuide) or custom NanoString 18-class GEP test to 191 CUPs with an accuracy of 91.5% in known metastatic cancers for high-medium confidence predictions. Classification performance was similar in clinicopathology-resolved CUPs - 80% had high-medium predictions and 94% were concordant with pathology. Notably, only 56% of the clinicopathology-unresolved CUPs had high-medium confidence GEP predictions. Diagnostic DNA features were interrogated in 201 CUP tumours guided by the cancer type specificity of mutations observed across 22 cancer types from the AACR Project GENIE database (77,058 tumours) as well as mutational signatures (e.g. smoking). Among the clinicopathology-unresolved CUPs, mutations and mutational signatures provided additional diagnostic evidence in 31% of cases. GEP classification was useful in only 13% of cases and oncoviral detection in 4%. Among CUPs where genomics informed TOO, lung and biliary cancers were the most frequently identified types, while kidney tumours were another identifiable subset. In conclusion, DNA and RNA profiling supported an unconfirmed TOO diagnosis in one-third of CUPs otherwise unresolved by clinicopathology assessment alone. DNA mutation profiling was the more diagnostically informative assay. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Laparoscopic Surgery for a Patient With Multiple Liver Metastases of Unknown Origin Concomitant With Gallbladder Tumor

BACKGROUND

The liver is the digestive organ where metastatic adenocarcinoma of unknown primary site is most often observed.

CASE REPORT

A 74-year-old man was diagnosed with a growing gallbladder tumor and multiple liver tumors limited to the left lateral sector. Liver tumors were suggested to be primary or secondary adenocarcinoma with no relation to the gallbladder tumor. Also for diagnostic purposes, laparoscopic full-thickness resection of the gallbladder, laparoscopic lateral sectionectomy and lymph node sampling were performed. The final histopathological diagnosis was hyperplastic polyp of the gallbladder and metastatic poorly differentiated adenocarcinoma of the liver. Liver tumors were suspected to originate from the stomach, duodenum, or small intestine; however, the primary sites could not be identified. The patient has been closely followed up without any chemotherapy 3 months after surgery.

CONCLUSION

Laparoscopic surgery can be strongly recommended for patients with multiple liver tumors of unknown origin concomitant with a gallbladder tumor.

Descriptive epidemiology of cancer of unknown primary in South Korea, 1999-2017

BACKGROUND

Cancers of unknown primary (CUPs) are tumors found after metastasizing from unidentified primary sites; these tumors generally have unknown treatment strategies, expected treatment results, and prognosis. We assessed the epidemiological characteristics of CUPs in Korea.

METHODS

We extracted records for 1999 through 2017 from the Korea Central Cancer Registry using the International Statistical Classification of Diseases and Related Health Problems (10th revision) codes for CUP as defined by the International Agency for Research on Cancer. Age-standardized rates and relative survival rates were calculated.

RESULTS

The CUPs constituted 2.1 % of the total number of cancer registrations in 1999, declining to 0.7 % in 2017. The incidence rate decreased for both sexes (5.35 to 2.20 for men, 3.15 to 1.77 for women). Patients aged 80 years and older had the highest incidence rate at 40.2, and 86.3 % of CUPs occurred in those 50 years of age or older. The cases of retroperitoneum and peritoneum sites increased over time. Cases diagnosed by microscopic methods and death certification only were 62.3 % and 7.9 %, respectively. The malignant neoplasm of the retroperitoneum and peritoneum and unknown primary site had the highest and lowest survival rates, respectively. The 5-year relative survival rate increased over time from 14.2 % (1999-2002) to 27.3 % (2013-2017).

CONCLUSIONS

Our analysis of data from the Korea Central Cancer Registry found decreasing rates of CUP, although with consistent disparities by patient age and sex. Advancements in diagnostic technology may be decreasing the number of CUP diagnoses. Expanding the amount of information recorded in the registry may further improve diagnostic accuracy.

[2018 Consensus statement by the Spanish Society of Pathology and the Spanish Society of Medical Oncology on the diagnosis and treatment of cancer of unknown primary]

Cancer of unknown primary is defined as a heterogeneous group of tumours that present with metastasis, and in which attempts to identify the original site have failed. They differ from other primary tumours in their biological features and how they spread, which means they can be considered a separate entity. There are several hypotheses regarding their origin, but the most plausible explanation for their aggressiveness and chemoresistance seems to involve chromosomal instability. Depending on the type of study done, cancer of unknown primary can account for 2-9% of all cancer patients, mostly 60-75 years old. This article reviews the main clinical, pathological and molecular studies conducted to analyse and determine the origin of cancer of unknown primary. The main strategies for patient management and treatment, by both clinicians and pathologists, are also addressed.

2018 consensus statement by the Spanish Society of Pathology and the Spanish Society of Medical Oncology on the diagnosis and treatment of cancer of unknown primary

Cancer of unknown primary (CUP) is defined as a heterogeneous group of tumours that present with metastasis, and in which attempts to identify the original site have failed. They differ from other primary tumours in their biological features and how they spread, which means that they can be considered a separate entity. There are several hypotheses regarding their origin, but the most plausible explanation for their aggressiveness and chemoresistance seems to involve chromosomal instability. Depending on the type of study done, CUP can account for 2–9% of all cancer patients, mostly 60–75 years old. This article reviews the main clinical, pathological, and molecular studies conducted to analyse and determine the origin of CUP. The main strategies for patient management and treatment, by both clinicians and pathologists, are also addressed.

Unknown primary adenocarcinomas: a single-center experience

This study aimed to elucidate the clinical and prognostic characteristics of a homogeneous group of patients with cancer of unknown primary (CUP). Between 1999 and 2014, CUP was diagnosed in 159 (1.3%) of 11,742 cancer patients at Trakya University Hospital (Edirne, Turkey). Ninety-seven (61%) of the 159 patients were retrospectively reviewed. Among these, 61 (62.8%) patients with adenocarcinoma were included in this study. The most frequently predicted primary tumor site was the lung (37.7%), and 59% of the patients were smokers. There was a significant relationship between smoking and the lung as a potential primary cancer site (p = 0.042). The most frequent site of metastasis was the liver (60.7%). The median number of metastases per patient was two, but patients with liver metastases had a median of five metastases. The overall median survival time was 7 months. Median survival was significantly longer in patients with a predicted primary site than in patients without the predicted site (7 vs. 6 months, respectively; p = 0.038). When the patients with predicted ovarian and peritoneal tumors were excluded from the comparison, the statistical p value was still close to significant (p = 0.07). Multivariate analysis revealed that smoking, liver metastasis, serum alkaline phosphatase ≥92 U/L, and progression in response to chemotherapy were independent predictors of a poor prognosis. The present study identified several independent prognostic factors in patients with unknown primary adenocarcinomas who received chemotherapy. Smoking, the presence of liver metastasis, and response to chemotherapy were independent risk factors for both progression-free and overall survival.

A Simple Risk Model to Predict Survival in Patients With Carcinoma of Unknown Primary Origin

Carcinoma of unknown primary origin (CUP) is characterized by diverse histological subtypes and clinical presentations, ranging from clinically indolent to frankly aggressive behaviors. This study aimed to identify prognostic factors of CUP and to develop a simple risk model to predict survival in a cohort of Asian patients.We retrospectively reviewed 190 patients diagnosed with CUP between 2007 and 2012 at a single medical center in Taiwan. The clinicopathological parameters and outcomes of our cohort were analyzed. A risk model was developed using multivariate logistic regression and a prognostic score was generated.The prognostic score was calculated based on 3 independent prognostic variables: the Eastern Cooperative Oncology Group (ECOG) scale (0 points if the score was 1, 2 points if it was 2-4), visceral organ involvement (0 points if no involvement, 1 point if involved), and the neutrophil-to-lymphocyte ratio (0 points if ≤3, 1 point if >3). Patients were stratified into good (score 0), intermediate (score 1-2), and poor (score 3-4) prognostic groups based on the risk model. The median survival (95% confidence interval) was 1086 days (500-1617, n = 42), 305 days (237-372, n = 75), and 64 days (44-84, n = 73) for the good, intermediate, and poor prognostic groups, respectively. The c-statistics using the risk model and ECOG scale for the outcome of 1-year mortality were 0.80 and 0.70 (P = 0.038), respectively.In this study, we developed a simple risk model that accurately predicted survival in patients with CUP. This scoring system may be used to help patients and clinicians determine appropriate treatments.

Neuroendocrine cell carcinoma of unknown primary arising in long standing history of multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease that targets myelinated axons in the central nervous system (CNS). Cancer of unknown primary site (CUP) is a well-recognised clinical disorder, accounting for 3–5% of all malignant epithelial tumors. CUP is clinically characterised as an aggressive disease with early dissemination. Studies of cancer risk in MS patients have shown inconsistent findings. An increased risk of malignancy in patients with MS has been suggested, but recently serious questions have been raised regarding this association. Use of disease-modifying therapies might contribute to an increased cancer risk in selected MS patients. The concurrence of MS and CUP is exceptionally rare. Here we describe the case of a neuroendocrine carcinoma of unknown primary diagnosed in a male patient with a nine-year history of MS. The discussion includes data from all available population-based register studies with estimates of certain malignancies in patients with MS.

Rapid reduction in the incidence of cancer of unknown primary. A population-based study

BACKGROUND

Cancer of unknown primary (CUP) carries a dismal prognosis due to the two hallmarks of 1) being metastatic with 2) no known specific treatment. An organ-labeled diagnosis of cancer should therefore be sought. In this study, we have analyzed population-based incidence and survival data of CUP over the latest 40 years.

MATERIAL AND METHODS

Complete national data on 23 004 CUP-patients from the Cancer Registry of Norway sampled from 1971 to 2010 are presented, with absolute and age-adjusted incidence rates correlated to the total cancer incidence. One-year relative survival rates were calculated.

RESULTS

The incidence of CUP increased both in absolute numbers and as a fraction of total cancer incidence during the first half of the period. There has been a substantial decrease in incidence over the latest 20 years, now being responsible of only 1.7% and 1.2% of the total cancer incidence in females and males, respectively, with an age-adjusted incidence rate of 3.5 and 3.8, respectively. The one-year relative survival rate has increased and was slightly below 20% for both sexes in 2010.

CONCLUSION

Better diagnostics, both radiological and pathological, is probably responsible for a substantially lower incidence. Improved treatment for cancers in general also benefits the CUP-group.

Inflammation as a validated prognostic determinant in carcinoma of unknown primary site

Background:

Carcinoma of unknown primary (CUP) is a clinical presentation with a poor prognosis. Inflammation-based prognostic systems are stage-independent prognostic predictors in various malignancies. We aimed to assess the accuracy of the modified Glasgow Prognostic Score (mGPS), neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR) as objective prognostic models in CUP.

Methods:

We derived inflammatory scores in 60 consecutive CUP referrals to the Imperial College oncology unit between 1996 and 2011. Patient demographics, treatment and staging data and full blood profiles were collected. An independent cohort of 179 patients presenting to the Taipei Veterens Hospital between 2000 and 2009 were used as a ‘validation' data set. Uni- and multivariate survival analysis was used to predict the overall survival (OS).

Results:

Sixty patients were included: median age 61 (range: 33–86); 51% men; median OS 5.9 months (0.7–42.9); 88% with distant metastases. On univariate analysis NLR >5 (P=0.04) and mGPS (score 1–2) (P=0.03) correlated with OS. Multivariate analysis demonstrated significant hazard ratios for NLR; 2.02 (CI 1.0–4.1) (P=0.04) and mGPS; 1.52 (CI 1.0–2.3) (P=0.03). These findings were reinforced by analysis of the validation data.

Conclusion:

NLR and mGPS are independent, externally validated prognostic markers in CUP, with superior objectivity compared with performance status.