Unknown primary adenocarcinomas: a single-center experience

New Genetic Technologies in Diagnosis and Treatment of Cancer of Unknown Primary

Simple Summary

The NGS and other molecular techniques creates huge hopes for effective CUP patients treatment and to select them for molecularly targeted therapies (agnostic therapies) and immunotherapy. Development of diagnostic technologies and biologically targeted therapies could make CUP’ patients access to modern therapies and change their outcome.

Abstract

Cancer of unknown primary (CUP) represents a rare oncological and heterogeneous disease in which one or more metastases are present, but the location of the primary site is unknown. Pathological diagnosis, using immunohistochemistry, of such metastatic materials is challenging and frequently does not allow for determining the tissue of origin (ToO). The selection of systemic therapy in patients with CUP is usually based on empiric grounds, and the prognosis is generally unfavourable. New molecular techniques could identify the tissue of origin and be used to select systemic agnostic therapies in various malignancies with specific molecular abnormalities. Targetable driver mutations or gene rearrangements in cancer cells may be identified using various molecular assays, of which particularly valuable are next-generation sequencing techniques. These assays may identify tumour sources and allow personalized treatments. However, current guidelines for CUP management do not recommend routine testing of gene expression and epigenetic factors. This is mainly due to the insufficient evidence supporting the improvement of CUP’s prognosis by virtue of this approach. This review summarizes the advantages and disadvantages of new genetic techniques in CUP diagnostics and proposes updating the recommendations for CUP management.

Successful treatment using immunotherapy in combination with chemotherapy for metastatic squamous cell carcinoma of unknown primary origin with bulky abdominal mass: A case report

RATIONALE

Cancer of unknown primary (CUP) means that the primary focus cannot be found after preliminary clinical evaluation. It accounts for 2.3% to 5% of newly diagnosed cancer cases. Due to the lack of standard treatment, CUP is usually associated with poor prognosis and is the third to fourth most common cause of cancer-related deaths.

PATIENT CONCERNS

We report the case of a 42-year-old female patient who was admitted to the hospital for intermittent right abdominal pain and abdominal distension. Abdominal computed tomography (CT) showed a large abdominal mass of unknown origin, which was difficult to resect due to its close relationship with surrounding tissues. Twenty days later, the patient had enlarged left supraclavicular lymph nodes, and percutaneous biopsy revealed squamous cell carcinoma. In addition, next-generation sequencing (NGS) of tissue and blood samples showed immune-related mutations and PD-L1 expression.

DIAGNOSES

The patient was diagnosed with metastatic squamous cell carcinoma of unknown primary origin, with a bulky abdominal mass.

INTERVENTIONS

The patient was treated with carboplatin, albumin-binding paclitaxel, and immune checkpoint inhibitor (carilizumab). After 6 cycles, the patient was switched to maintenance treatment with carilizumab.

OUTCOMES

The general condition of the patient improved, and the lesion was significantly reduced. The treatment efficacy was assessed as partial remission according to Response Evaluation Criteria in Solid Tumors. The patient benefited from immunotherapy combined with chemotherapy.

LESSONS

There is no recommended standard treatment for most CUPs, which leads to their poor prognoses. By performing NGS for patients and targeting immune-related positive predictors, immunotherapy combined with chemotherapy may prolong the overall survival of patients. This case report suggests that immunotherapy combined with chemotherapy is feasible and effective in patients with CUP.

The Diminishing Importance of Primary Site Identification in Cancer of Unknown Primary: A Canadian Single-Center Experience

BACKGROUND

Cancer of unknown primary (CUP) describes patients with metastatic disease without an identified primary tumor site. Successful diagnosis and treatment of these patients remains difficult. Published guidelines on CUP have highlighted "favorable" subtype groups. We investigated a series of CUP patients to review adherence to guidelines, and identification of primary cancers or "favorable" subtypes.

METHODS

Patients with histologically confirmed CUP at an academic institution from 2012 to 2018 were identified. Patient demographics, tumor presentation, diagnostic work-up and treatment information were retrospectively collected from electronic data records for descriptive analysis and compared to published clinical guidelines. The primary endpoint was the proportion of patients where the primary site was identified. Multivariable logistic regression models were used to identify factors associated with primary site identification. Kaplan-Meier survival curves were used to determine factors associated with poorer OS.

RESULTS

Three hundred and five patients were included with a median follow-up time of 4.3 months. Primary tumor sites were identified in 109 patients (37.5%), which was most commonly lung cancer (33%). Statistical analyses did not identify any demographic or initial presentation factors associated with identifying the primary or not. More diagnostic tests did not increase the likelihood of primary site identification (P=0.44). Patients with an identified primary did not have longer OS than other patients (median 5.2 months vs. 4.7 months, P=0.47). 57 patients (18.7%) who had a defined "favorable" subtype experienced superior OS (36.6 months vs. 3.8 months; P<0.0001). Further, patients with good prognostic status who followed published treatment guidelines had longer OS (17.6 months vs. 13.2 months; P=0.04).

CONCLUSIONS

CUP remains a difficult cancer to diagnose and treat. These results suggest identifying the primary has less impact than anticipated, but particular efforts to identify patients with "favorable" subtypes of CUP is important prognostically.

Cancer of Unknown Primary: A Review on Clinical Guidelines in the Development and Targeted Management of Patients with the Unknown Primary Site

Cancer of unknown primary (CUP) is a malignant widespread metastatic disease without an identifiable primary site after extensive clinical investigation. Recently, a decline is observed in the diagnosis of CUP, mainly due to improvement in detection of the primary tumors, thus decreasing the unknown primaries. Worldwide, CUP is the sixth to eighth most common malignancy, accounting for 2.3% to 5% of a new cancer diagnosis. CUP is third to fourth most common cause of death due to cancer-related mortality. The prognosis of CUP is depressing with the median survival of three to six months in the previous studies, but according to recent studies, median survival is less than one year. High risk for developing CUP is seen in heavy smokers (26 or more cigarettes/day) and individuals with the lowest quartiles of waist circumference. A weak association is observed with the use of alcohol consumption and low level of education. Human papillomavirus DNA plays a role in those with squamous cell carcinoma of unknown primaries in head and neck regions. In the diagnosis of CUP, comprehensive medical history, complete physical examination (including genitourinary, rectal exam, and breast examination in women) and necessary laboratory tests are crucial.

Whole-body positron emission tomography-computed tomography (PET/CT) is the investigation of choice to assess the entire body for CUP. Multiparametric 3T-MRI (MP-MRI) is used to examine the local soft tissue status, helps in the staging of the tumor, and to determine the extent of involvement of tissue for medical as well as prognostic purposes. Immunohistochemistry outlines the specific markers, including caudal-related homeobox protein (CDX2), homeobox protein Nkx-3.1 (NKX3-1), paired box gene 8 (PAX8), special AT-rich sequence-binding protein 2 (SATB2), thyroid transcription factor 1 (TTF-1), and splicing factor 1 (SF1) with the focus on the effectiveness of lineage-restricted transcription factors. Patients response to treatment can be evaluated by the gene expression profiling (GEP) test that also predicts tissue of origin (TOO). Tumor identified through gene profiling is sensitive to platinum/taxane therapy, others that are not TOO tumors are resistant to platinum/taxane. The new therapeutic method based on molecular profiling is associated with higher treatment response. In comprehensive genomic profiling, it is observed that there is at least one clinically appropriate genomic alteration in CUP that can influence the targeted therapy. The targeted therapeutic approach will not only improve the disease outcome but will also be cost-effective and save time from finding the primary site.

Identification of a metastatic lung adenocarcinoma of the palate mucosa through genetic and histopathological analysis: a rare case report and literature review

Background

Cancers of unknown primary origin (CUPs) are reported to be the 3-4th most common causes of cancer death. Recent years have seen advances in mutational analysis and genomics profiling. These advances could improve accuracy of diagnosis of CUPs and might improve the prognosis of patients with CUPs.

Case presentation

A 76-year old male with an adenocarcinoma of unknown primary origin in the lung presented with another tumor of the palate mucosa. The tumor cells in the pleural effusion were all negative for immunohistochemical markers (TTF-1 and Napsin A) and lung-specific oncogenic driver alterations (EGFR mutation and ALK translocation). The tumor of the palate mucosa was likewise identified as an adenocarcinoma, and the cells showed cytological similarities with the tumor cells in the pleural effusion; TTF-1, Napsin A, EGFR mutation and ALK translocation were all negative. This result suggested that origins of the tumors of the palate mucosa and in the lung were the same, even though the origin had not yet been determined. Next, we addressed whether the tumor of the palate mucosa was a primary tumor or not. Secretory carcinoma (SC), which is a common type of minor salivary gland tumor (MSGT), was suspected; however, mammaglobin was negative and ETV6-NTRK3 (EN) fusion was not observed. Other MSGTs were excluded based on histological and immunohistochemical findings. Furthermore, an additional examination demonstrated an oncogenic KRAS mutation at codon 12 (p.G12D) in both palate tumor and in pleural effusion. KRAS mutation is known to exist in one-third of lung adenocarcinomas (LUADs), but quite rare in MSGTs. The possibility of metastasis from other organs was considered unlikely from the results of endoscopic and imaging studies. This result indicated that the primary site of the CUP was indeed the lung, and that the tumor of the palate mucosa was a metastasis of the LUAD.

Conclusions

A tumor of the palate mucosa that showed diagnostic difficulties was determined to be a metastatic LUAD by genomic alterations and histopathological findings.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5277-1) contains supplementary material, which is available to authorized users.

Implementation of a metastatic malignancy of unknown primary origin service led by a palliative physician

BACKGROUND

Cancer of unknown primary is the fourth most common cause of cancer death in the United Kingdom. National guidance in 2010 recommended the establishment of a dedicated unknown primary team to facilitate targeted investigation and symptom control. A service development project was undertaken to identify those affected by malignancy of unknown origin and institute a pathway for coordinating their care led by a palliative physician.

METHOD

In order to describe the patient population and illness trajectory and to assess the effect of the new pathway on the clinical outcomes we used a retrospective and prospective comparative case notes survey to identify the pre- and post-pathway population. This took place in secondary care. Inclusion criteria were patients with metastatic disease with no known primary; exclusion criteria were where the site of metastasis was so suggestive of a primary that it would be managed as per that disease process. 88 patients were included.

RESULTS

Mean age was 72.5 years. The mean survival time from presentation was 81.8 days. There was no difference pre or during pathway implementation in age, performance status or survival time. There was no reduction in the numbers referred for tumour directed therapy. There was a non-statistically significant reduction in the number who died in hospital during the pathway implementation.

CONCLUSIONS

This study suggests having a metastatic malignancy of unknown primary origin service led by a palliative physician does not reduce the number referred for tumour directed therapy. It also adds evidence of the poor prognosis and thus the need for early palliative care input.