Redefining Perineural Invasion in Head and Neck Cutaneous Squamous Cell Carcinoma

Perineural Invasion in Head and Neck Cutaneous Squamous Cell Carcinoma

Background/Objectives: Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer, with a lifetime risk of 14-20% that is rising every year. Although prognosis for cSCC is generally good, certain high-risk features of cSCC portend increased rates of nodal and distant metastasis, recurrence, and disease-specific mortality. One such high-risk factor is perineural invasion (PNI), which is broadly defined as the invasion of cancer into and around nerves. Compared to other high-risk factors, PNI presence is associated with the highest risk for locoregional and distant metastasis. Still, the mechanisms underlying the pathogenesis of PNI remain poorly understood. Recent studies suggest the migration and invasion of tumors into nerves is a result of complex molecular crosstalk within the tumor-nerve microenvironment, wherein the milieu of signaling molecules simultaneously promote neuronal growth and tumor cell invasion. Methods: Understanding the molecular and cellular mechanisms that promote PNI will lead to future developments of targeted therapies that may improve locoregional control and survival. Results/Conclusions: In our article, we aim to provide a comprehensive review of recent findings about the pathogenesis of PNI, clinical implications of PNI-positive disease in cSCC, available treatment modalities, and potential future therapeutic targets.

A radiomics model for predicting perineural invasion in stage II-III colon cancer based on computer tomography

BACKGROUND

Colon cancer, a frequently encountered malignancy, exhibits a comparatively poor survival prognosis. Perineural invasion (PNI), highly correlated with tumor progression and metastasis, is a substantial effective predictor of stage II-III colon cancer. Nonetheless, the lack of effective and facile predictive methodologies for detecting PNI prior operation in colon cancer remains a persistent challenge.

METHOD

Pre-operative computer tomography (CT) images and clinical data of patients diagnosed with stage II-III colon cancer between January 2015 and December 2023 were obtained from two sub-districts of Sun Yat-sen Memorial Hospital (SYSUMH). The LASSO/RF/PCA filters were used to screen radiomics features and LR/SVM models were utilized to construct radiomics model. A comprehensive model, shown as nomogram finally, combining with radiomics score and significant clinical features were developed and validated by area under the curve (AUC) and decision curve analysis (DCA).

RESULT

The total cohort, comprising 426 individuals, was randomly divided into a development cohort and a validation cohort as a 7:3 ratio. Radiomics scores were extracted from LASSO-SVM models with AUC of 0.898/0.726 in the development and validation cohorts, respectively. Significant clinical features (CA199, CA125, T-stage, and N-stage) were used to establish combining model with radiomics scores. The combined model exhibited superior reliability compared to single radiomics model in AUC value (0.792 vs. 0.726, p = 0.003) in validation cohorts. The radiomics-clinical model demonstrated an AUC of 0.918/0.792, a sensitivity of 0.907/0.813 and a specificity of 0.804/0.716 in the development and validation cohorts, respectively.

CONCLUSION

The study developed and validated a predictive nomogram model combining radiomics scores and clinical features, and showed good performance in predicting PNI pre-operation in stage II-III colon cancer patients.

Management Approaches for High-Risk Cutaneous Squamous Cell Carcinoma with Perineural Invasion: An Updated Review

OPINION STATEMENT

Cutaneous squamous cell carcinoma (cSCC) stands as the second most prevalent non-melanoma skin cancer worldwide, comprising approximately 20% of all cutaneous malignancies. Determining its precise incidence poses challenges; however, reports indicate a global increase in its prevalence. At the time of diagnosis, the majority of cSCCs are localized, resulting in favorable 5-year cure rates surpassing 90%. Nevertheless, a subset of patients (3-7%) encounters locally advanced or metastatic cSCC, leading to substantial morbidity and mortality. The risk of metastasis ranges from 0.1% to 9.9%, carrying an associated mortality risk of 2.8%. Factors influencing recurrence, metastasis, and disease-specific mortality underscore the significance of perineural invasion (PNI) as a key indicator. Patients with PNI may manifest clinical symptoms and/or radiologic signs of PNI, while the majority remain asymptomatic, and PNI is frequently identified upon histologic examination. Despite its lower frequency compared to other cancer types, PNI serves as a recognized adverse prognostic factor for cSCC. Surgery is the elective treatment for these patients, while the role of adjuvant radiotherapy (ART) is yet contentious and have not been conclusively assessed, particularly in clear surgical margin. Prospective comparative studies are required to comprehensively evaluate the benefit and the risks of ART for cSCC and PNI patients.

Reconceiving Perineural Invasion in Cutaneous Squamous Cell Carcinoma: From Biological to Histopathological Assessment

BACKGROUND

Perineural invasion (PNI) is a complex molecular process histologically represented by the presence of tumor cells within the peripheral nerve sheath and defined when infiltration into the 3 nerve sheath layers can be clearly identified. Several molecular pathways have been implicated in cSCC. PNI is a well-recognized risk factor in cutaneous squamous cell carcinoma (cSCC) and its accurate assessment represents a challenging field in pathology daily practice.

SUMMARY

As a highly intricate and dynamic process, PNI involves a contingent on bidirectional signaling interactions between the tumor and various nerve components, such as Schwann cells and neurons. The current staging systems recommend the identification of PNI as a dichotomous variable (presence vs. absence) to identify a subgroup of high-risk patients. However, recent further insights revealed that the evaluation of morphological PNI-related features in cSCC may enhance the prognostic stratification of patients and may optimize the current staging guidelines for recurrence risk assessment and improvement of patient selection for postoperative adjuvant treatments. Furthermore, recent emerging biomarkers could redefine early PNI detection.

KEY MESSAGES

This review provides updated insights into cSCC with PNI, focusing on molecular and cellular pathogenic processes, and aims to increase knowledge on prognostic relevant PNI-related histological features.

Dickkopf-1 drives perineural invasion via PI3K-AKT signaling pathway in head and neck squamous cancer

Perineural invasion (PNI) leads to the poor prognosis of head and neck squamous cancer (HNSCC) patients, but the mechanism of PNI remains unclear. Dickkopf-1 (DKK1), a secretory protein in the Wnt signaling pathway, was found indeed upregulated in HNSCC cells and tissues. Higher expression of DKK1 was statistically relevant to T stage, N stage, PNI, and poor prognosis of HNSCC. DKK1 overexpression enhanced the migration abilities of cancer cells. Moreover, DKK1-overexpressing cancer cells promoted cancer cells invasion of peripheral nerves in vitro and in vivo. Mechanistically, DKK1 could promote the PI3K-AKT signaling pathway. The migration abilities of neuroblastoma cells, which were enhanced by DKK1-overexpressing HNSCC cell lines, could be reversed by an inhibitor of Akt (MK2206). The association of DKK1 with PNI was also confirmed in HNSCC samples. Variables, including T stage, N stage, DKK1 expression, and PNI, were used to establish a nomogram to predict the survival probability and disease-free probability at 3 and 5 years. In summary, DKK1 can promote the PI3K-AKT signaling pathway in tumor cells and then could induce neuritogenesis and facilitate PNI. MK2206 may be a potential therapeutic target drug for HNSCC patients with PNI.

Prognostic and predictive biomarkers in head and neck cancer: something old, something new, something borrowed, something blue and a sixpence in your shoe

A biomarker is a measurable indicator of biological or pathological processes or the response to an exposure or intervention and is used to guide management decisions. In head and neck pathology, biomarkers are assessed by histological criteria and immunohistochemical and molecular studies. Surgical resection remains the mainstay of management of many head and neck malignancies. Adjuvant radiotherapy and/or systemic therapy may be administered depending on the presence of adverse prognostic factors identified on histopathological or immunohistochemical examination. In this review, we outline the clinically relevant prognostic and predictive factors in head and neck malignancies including conventionally recognised factors such as tumour size, depth of invasion, lymphovascular and perineural invasion and margin status as well as novel evolving factors such as recurrent genetic rearrangements and assessment of immune checkpoints. Practical issues are discussed to assist with recognising and reporting of these factors. A summary of useful tools such as structured pathology report formats is also included to assist with comprehensive reporting of all clinically relevant parameters, minimise risk and improve workflow efficiencies.

Extensive Perineural Invasion vs Nerve Caliber to Assess Cutaneous Squamous Cell Carcinoma Prognosis

Importance

Perineural invasion (PNI) is an adverse risk feature in cutaneous squamous cell carcinoma (CSCC) that affects patient prognosis and disease management. However, research comparing different PNI patterns on patient outcomes is limited.

Objective

To compare 4 assessments of PNI in CSCC, their associations with poor outcomes, and implications for their inclusion in the Brigham and Women's Hospital (BWH) staging system.

Design, Setting, and Participants

This retrospective cohort study was performed at a single tertiary care institution and compared 4 PNI assessments: nerve caliber, number of involved nerves per section, PNI maximal depth, and PNI location with respect to tumor. Patients with primary, localized, invasive CSCC with PNI diagnosed between January 1, 2000, and December 31, 2017, were identified via an electronic in-house database. Available pathology slides were secondarily reviewed by study authors. Relevant patient and tumor characteristics and outcomes were abstracted from the medical record. Data analysis was performed between September 6 and October 20, 2022.

Main Outcomes and Measures

Risks of recurrence, disease-specific death, and a composite end point (any poor outcome) were calculated via multivariable stepwise Fine and Gray competing-risks regression. Considered revisions to the BWH staging system were assessed via receiver operating characteristic curves and test characteristics.

Results

This study included 140 patients with CSCC, with a mean (SD) age of 75.1 (11.2) years. More than half of the patients were men (93 [66.4%]), and most identified as White (132 [94.3%]). Of the 4 PNI assessments studied, only involvement of multiple nerves was associated with poor outcomes. Perineural invasion of 5 or more distinct nerves (extensive PNI [ePNI]) was independently associated with local recurrence (subhazard ratio [SHR], 13.83 [95% CI, 3.50-54.62]; P < .001), disease-specific death (SHR, 6.20 [95% CI, 1.59-24.21]; P = .009), and any poor outcome (SHR, 10.21 [95% CI, 2.88-36.15]; P < .001). A revised BWH staging system with substitution of ePNI for large-caliber PNI resulted in improved area under the curve and test characteristics compared with current BWH staging criteria that use nerve caliber as the measure of PNI.

Conclusions and Relevance

The findings of this cohort study suggest that ePNI is the best prognostic measure of PNI. Because ePNI obviated the need for a micrometer and had superior prognostic capacity to nerve caliber in this cohort, ePNI should be considered for inclusion in CSCC tumor staging. Inclusion of ePNI as a high-risk factor in CSCC staging systems may optimize patient selection for primary treatment and adjuvant interventions.