Lymph Node Molecular Analysis with OSNA Enables the Identification of pT1 CRC Patients at Risk of Recurrence: A Multicentre Study

Early-stage colorectal carcinoma (CRC)-pT1-is a therapeutic challenge and presents some histological features related to lymph node metastasis (LNM). A significant proportion of pT1 CRCs are treated surgically, resulting in a non-negligible surgical-associated mortality rate of 1.5-2%. Among these cases, approximately 6-16% exhibit LNM, but the impact on survival is unclear. Therefore, there is an unmet need to establish an objective and reliable lymph node (LN) staging method to optimise the therapeutic management of pT1 CRC patients and to avoid overtreating or undertreating them. In this multicentre study, 89 patients with pT1 CRC were included. All histological features associated with LNM were evaluated. LNs were assessed using two methods, One-Step Nucleic Acid Amplification (OSNA) and the conventional FFPE plus haematoxylin and eosin (H&E) staining. OSNA is an RT-PCR-based method for amplifying CK19 mRNA. Our aim was to assess the performance of OSNA and H&E in evaluating LNs to identify patients at risk of recurrence and to optimise their clinical management. We observed an 80.9% concordance in LN assessment using the two methods. In 9% of cases, LNs were found to be positive using H&E, and in 24.7% of cases, LNs were found to be positive using OSNA. The OSNA results are provided as the total tumour load (TTL), defined as the total tumour burden present in all the LNs of a surgical specimen. In CRC, a TTL ≥ 6000 CK19 m-RNA copies/µL is associated with poor prognosis. Three patients had TTL > 6000 copies/μL, which was associated with higher tumour budding. The discrepancies observed between the OSNA and H&E results were mostly attributed to tumour allocation bias. We concluded that LN assessment with OSNA enables the identification of pT1 CRC patients at some risk of recurrence and helps to optimise their clinical management.

Dilemmas in the Clinical Management of pT1 Colorectal Cancer

Implementation of population-based colorectal cancer screening programs has led to increases in the incidence of pT1 colorectal cancer. These incipient invasive cancers have a very good prognosis and can be treated locally, but more than half of these cases are treated with surgery due to the presence of histological high-risk criteria. These high-risk criteria are suboptimal, with no consensus among clinical guidelines, heterogeneity in definitions and assessment, and poor concordance in evaluation, and recent evidence suggests that some of these criteria considered high risk might not necessarily affect individual prognosis. Current criteria classify most patients as high risk with an indication for additional surgery, but only 2-10.5% have lymph node metastasis, and the residual tumor is present in less than 20%, leading to overtreatment. Patients with pT1 colorectal cancer have excellent disease-free survival, and recent evidence indicates that the type of treatment, whether endoscopic or surgical, does not significantly impact prognosis. As a result, the protective role of surgery is questionable. Moreover, surgery is a more aggressive treatment option, with the potential for higher morbidity and mortality rates. This article presents a comprehensive review of recent evidence on the clinical management of pT1 colorectal cancer. The review analyzes the limitations of histological evaluation, the prognostic implications of histological risk status and the treatment performed, the adverse effects associated with both endoscopic and surgical treatments, and new advances in endoscopic treatment.

Talar metastasis of mucinous lung adenocarcinoma with fluid-fluid levels: a rare presentation mimicking a benign tumor

The differential diagnosis of bone tumors in the talus is broad and includes both benign and malignant conditions. Metastases, although very rare, are one of these conditions. The typical nonspecific clinical and radiological presentations of metastases are a diagnostic challenge, and a high level of suspicion is needed in order to perform an adequate diagnostic approach. Moreover, they can present with features which have classically been associated with benign conditions such as fluid-fluid levels. We present a rare case of talar metastasis of a mucinous pulmonary adenocarcinoma that presented with fluid-fluid levels and was initially misdiagnosed as a giant-cell tumor with areas of secondary aneurysmal bone cyst transformation.

Tumour Cell Seeding to Lymph Nodes from In Situ Colorectal Cancer

Lymph node (LN) metastasis is an important prognostic factor in colorectal cancer (CRC). We aimed to demonstrate the presence of lymphatic vessels (LV) in the mucosa of in-situ (pTis) CRC, and of detectable tumour burden in regional LNs. This is an observational retrospective study of 39 surgically resected in situ CRCs. The number of LVs was evaluated in both pTis and normal mucosa using D2-40 immunostains. All LNs were assessed with both H&E and the One Step Nucleic Acid Amplification (OSNA) assay, and the results were correlated with clinicopathological features. D2-40 immunohistochemisty revealed LVs in the lamina propria of all pTis CRC (100%), being absent in normal mucosa. A median of 16 LNs were freshly dissected per patient, and all cases were pN0 with H&E. Molecular LN analysis with OSNA revealed the presence of low amounts of tumour burden in 11/39 (28%) cases (range 400 to 4270 CK19 mRNA copies/µL), which had no clinical consequences. This study demonstrates the presence of LVs in the lamina propria in 100% of pTis CRC, as well as the presence of low amounts of tumour burden in regional LNs, only detected by molecular methods. Given the prognostic value of LN tumour burden, its molecular quantification may help a patient's clinical management.

Minimally Invasive Tissue Sampling Findings in 12 Patients With Coronavirus Disease 2019

BACKGROUND

Minimally invasive tissue sampling (MITS), a postmortem procedure that uses core needle biopsy samples and does not require opening the body, may be a valid alternative to complete autopsy (CA) in highly infectious diseases such as coronavirus disease-19 (COVID-19). This study aimed to (1) compare the performance of MITS and CA in a series of COVID-19 deaths and (2) evaluate the safety of the procedure.

METHODS

From October 2020 to February 2021, MITS was conducted in 12 adults who tested positive before death for COVID-19, in a standard, well-ventilated autopsy room, where personnel used reinforced personal protective equipment. In 9 cases, a CA was performed after MITS. A thorough histological evaluation was conducted, and the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was evaluated by real-time reverse-transcription polymerase chain reaction (RT-PCR) and immunohistochemistry.

RESULTS

The diagnoses provided by MITS and CA matched almost perfectly. In 9 patients, COVID-19 was in the chain of events leading to death, being responsible for diffuse alveolar damage and mononuclear T-cell inflammatory response in the lungs. No specific COVID-19 features were identified. Three deaths were not related to COVID-19. All personnel involved in MITS repeatedly tested negative for COVID-19. SARS-CoV-2 was identified by RT-PCR and immunohistochemistry in the MITS samples, particularly in the lungs.

CONCLUSIONS

MITS is useful for evaluating COVID-19-related deaths in settings where a CA is not feasible. The results of this simplified and safer technique are comparable to those of CA.

PD-L1 Expression in Non-Small Cell Lung Cancer: Data from a Referral Center in Spain

Anti-programmed cell death (PD1)/ligand-1 (PD-L1) checkpoint inhibitors have improved the survival of non-small cell lung cancer (NSCLC) patients. Additionally, PD-L1 has emerged as a predictive biomarker of response. Our goal was to examine the histological features of all PD-L1 cases of NSCLC analyzed in our center between 2017 and 2020, as well as to correlate the expression values of the same patient in different tested samples. PD-L1 immunohistochemistry (IHC) was carried out on 1279 external and internal samples: 482 negative (tumor proportion score, TPS < 1%; 37.7%), 444 low-expression (TPS 1–49%; 34.7%) and 353 high-expression (TPS ≥ 50%; 27.6%). Similar results were observed with samples from our institution (N = 816). Significant differences were observed with respect to tumor histological type (p = 0.004); squamous carcinoma was positive in a higher proportion of cases than other histological types. There were also differences between PD-L1 expression and the type of sample analyzed (surgical, biopsy, cytology; p < 0.001), with a higher frequency of negative cytology. In addition, there were cases with more than one PD-L1 determination, showing heterogeneity. Our results show strong correlation with the literature data and reveal heterogeneity between tumors and samples from the same patient, which could affect eligibility for treatment with immunotherapy.

Prospective Evaluation of Single Nucleotide Variants by Two Different Technologies in Paraffin Samples of Advanced Non-Small Cell Lung Cancer Patients

Targeted therapies are a new paradigm in lung cancer management. Next-generation sequencing (NGS) techniques have allowed for simultaneous testing of several genes in a rapid and efficient manner; however, there are other molecular diagnostic tools such as the nCounter® Vantage 3D single nucleotide variants (SNVs) solid tumour panel which also offer important benefits regarding sample input and time-to-response, making them very attractive for daily clinical use. This study aimed to test the performance of the Vantage panel in the routine workup of advanced non-squamous non-small cell lung cancer (NSCLC) patients and to validate and compare its outputs with the Oncomine Solid Tumor (OST) panel DNA kit, the standard technique in our institution. Two parallel multiplexed approaches were performed based on DNA NGS and direct digital detection of DNA with nCounter® technology to evaluate SNVs. A total of 42 advanced non-squamous NSCLC patients were prospectively included in the study. Overall, 95% of samples were successfully characterized by both technologies. The Vantage panel accounted for a sensitivity of 95% and a specificity of 82%. In terms of predictive values, the probability of truly presenting the SNV variant when it is detected by the nCounter panel was 82%, whereas the probability of not presenting the SNV variant when it is not detected by the platform was 95%. Finally, Cohen's Kappa coefficient was 0.76, indicating a substantial correlation grade between OST and Vantage panels. Our results make nCounter an analytically sensitive, practical and cost-effective tool.