Perineural spread in head and neck skin cancer

Adjuvant therapy for intermediate risk factors in oral cancer: Can we reach a consensus?

Oral carcinoma is a common disease that poses challenges in treatment management, especially for advanced cases. Adjuvant therapies, such as radiation and chemoradiation therapy, are typically used for advanced oral cancer patients. However, there is uncertainty regarding the use of adjuvant therapy for early-stage patients with certain soft histological parameters. The UICC manual of clinical oncology suggests that adjuvant therapy for such parameters is desirable but not essential. These parameters include perineural invasion, lymphovascular invasion, single nodal positivity, and patterns of invasion, which complicate the decision-making process for including adjuvant therapy. This review aims to provide evidence-based literature for effectively managing this patient group and developing treatment protocols based on current evidence.

Unraveling the Mysteries of Perineural Invasion in Benign and Malignant Conditions

Perineural invasion (PNI) is defined as the dissemination of neoplastic cells within the perineural space. PNI can be a strong indicator of malignancy and is linked to poor prognosis and adverse outcomes in various malignant neoplasms; nevertheless, it can also be seen in benign pathologic conditions. In this review article, we discuss various signaling pathways and neurotrophic factors implicated in the development and progression of PNI. We also describe the methodology, benefits, and limitations of different in vitro, ex vivo, and in vivo models of PNI. The spectrum of presentation for PNI can range from diffuse spread within large nerves ("named" nerves) all the way through localized spread into unnamed microscopic nerves. Therefore, the clinical significance of PNI is related to its extent rather than its mere presence or absence. In this article, we discuss the guidelines for the identification and quantification of PNI in different malignant neoplasms based on the College of American Pathologists (CAP) and World Health Organization (WHO) recommendations. We also describe benign pathologic conditions and neoplasms demonstrating PNI and potential mimics of PNI. Finally, we explore avenues for the future development of targeted therapy options via modulation of signaling pathways involved in PNI.

Nerves in gastrointestinal cancer: from mechanism to modulations

Maintenance of gastrointestinal health is challenging as it requires balancing multifaceted processes within the highly complex and dynamic ecosystem of the gastrointestinal tract. Disturbances within this vibrant environment can have detrimental consequences, including the onset of gastrointestinal cancers. Globally, gastrointestinal cancers account for ~19% of all cancer cases and ~22.5% of all cancer-related deaths. Developing new ways to more readily detect and more efficiently target these malignancies are urgently needed. Whereas members of the tumour microenvironment, such as immune cells and fibroblasts, have already been in the spotlight as key players of cancer initiation and progression, the importance of the nervous system in gastrointestinal cancers has only been highlighted in the past few years. Although extrinsic innervations modulate gastrointestinal cancers, cells and signals from the gut's intrinsic innervation also have the ability to do so. Here, we shed light on this thriving field and discuss neural influences during gastrointestinal carcinogenesis. We focus on the interactions between neurons and components of the gastrointestinal tract and tumour microenvironment, on the neural signalling pathways involved, and how these factors affect the cancer hallmarks, and discuss the neural signatures in gastrointestinal cancers. Finally, we highlight neural-related therapies that have potential for the management of gastrointestinal cancers.

Management of periocular cutaneous squamous cell carcinoma with perineural invasion: a case series and literature review

Purpose: To review and elucidate the complex, multimodal management of periocular cutaneous squamous cell carcinoma (SCC) with perineural invasion (PNI), and offer practical, evidence-based patient care recommendations.Methods: Three exemplary cases of high-risk periocular cutaneous SCC with PNI were selected from a single surgeon's experience. The clinical courses, management, and clinical outcomes, with follow-up intervals of 19, 19, and 24 months after presentation, were reviewed. The English-language literature on PNI, with attention to the management of cutaneous SCC of the head and neck (SCCHN), was reviewed.Results: PNI of cutaneous SCCHN portends aggressive tumor behavior and a worsened prognosis. Treatment is multimodal, with varied combinations of surgical excision, radiotherapy (RT), and systemic chemotherapy. Retrospective reports from multiple institutions involve heterogenous patient populations, treatment strategies, and confounding variables that preclude formulation of a standardized treatment paradigm. Newer, comparative studies of advanced RT techniques (e.g., hyper-fractionation), novel systemic chemotherapeutic agents (e.g., cetuximab, cemiplimab), and varied integrative regimens are providing additional insights. Prompt initiation of adjuvant therapies (within 6-8 weeks of surgery), and careful evaluation of lymphatic basins can increase oncologic control. Utilizing deep-tissue fixation of advancement flaps and eyelid stabilization can enhance functional and aesthetic results.Conclusion: Management of cutaneous SCC with PNI remains complex and in most cases requires combined-modality therapy directed by a multidisciplinary tumor board. With novel therapies and new treatment patterns, optimal combinations and intensities of individual modalities require further elucidation. The oculofacial plastic surgeon plays a pivotal role - in diagnosis, coordination of interdisciplinary management, thoughtful surgical reconstruction, and postoperative surveillance.

Perineural invasion as a prognostic factor for intrahepatic cholangiocarcinoma after curative resection and a potential indication for postoperative chemotherapy: a retrospective cohort study

Background

In the past four decades, the incidence of cholangiocarcinoma, especially intrahepatic cholangiocarcinoma (ICC), has raised rapidly worldwide. Completeness of resection, max size of tumor and etc. are widely recognized as prognostic factors. However, the prognosis significance of perineural invasion (PNI) on recurrence-free survival (RFS) and overall survival (OS) in ICC patients is controversial.

Methods

ICC patients who underwent curative hepatectomy and diagnosed pathologically were retrospectively analyzed. Patients were grouped by existence of PNI and outcomes were compared between groups. The potential relationship between PNI and postoperative chemotherapy was also investigated.

Results

There was no significant difference in demographic, clinical staging or tumor index between two groups, except positive hepatitis B surface antigen and CA19–9. PNI negative group showed a better prognosis in RFS (P < 0.0001) and OS (P < 0.0001). COX regression analyses showed PNI as an independent risk factor in RFS and OS. ICC with postoperative chemotherapy showed better effects in the whole cohort on both RFS (P = 0.0023) and OS (P = 0.0011). In PNI negative group, postoperative chemotherapy also showed significant benefits on RFS and OS, however not in PNI positive group (P = 0.4920 in RFS and P = 0.8004 in OS).

Conclusion

PNI was an independent risk factor in R0-resected ICC, presenting worse recurrence and survival outcomes. Meanwhile, negative PNI may act as an indication of postoperative chemotherapy.

Clinical and Incidental Perineural Invasion of Cutaneous Squamous Cell Carcinoma: A Systematic Review and Pooled Analysis of Outcomes Data

Importance

Perineural invasion (PNI) in cutaneous squamous cell carcinoma (CSCC) has been associated with an increased risk of poor outcomes. Patients with PNI may present with clinical symptoms and/or radiologic evidence of PNI (clinical PNI [CPNI]), yet most patients are asymptomatic and PNI is often found on histologic examination (incidental PNI [IPNI]). Evidence-based estimates of the risks of disease-related outcomes comparing IPNI and CPNI are limited in the dermatology literature.

Objectives

To review and synthesize outcomes data for patients with CSCC and CPNI or IPNI.

Data Sources

A systematic review was conducted in MEDLINE and EMBASE for English-language articles published since inception to November 11, 2016.

Study Selection

All studies that reported a disease-related outcome (local recurrence, nodal metastasis, distant metastasis, or disease-specific death) of CSCCs with CPNI and IPNI were included.

Data Extraction and Synthesis

Articles were screened for eligibility, and any possible discrepancies in this screening were resolved. Data extracted included study characteristics, tumor characteristics, treatments performed, and disease-related outcomes. Overall risks of disease-related outcomes were generated by pooling patients from eligible studies. χ2 Statistics and Fisher exact tests were used to evaluate differences in disease-related outcomes.

Main Outcomes and Measures

Risks of disease-related outcomes and 5-year recurrence-free, disease-specific, and overall survival.

Results

A total of 12 studies containing 241 patients with CPNI and 381 patients with IPNI were included in the systematic review and analysis. The overall risks of local recurrence and disease-specific death were significantly higher in patients with CSCC and CPNI compared with those with CSCC and IPNI (local recurrence, 37% vs 17%; P < .001; disease-specific death, 27% vs 6%; P < .001). The risks of nodal metastasis and distant metastasis did not differ significantly by PNI classification. Patients with CSCC and CPNI had poorer mean 5-year recurrence-free survival and disease-specific survival compared with patients with IPNI (recurrence-free survival, 61% vs 76%; P = .009; disease-specific survival, 70% vs 88%; P = .002).

Conclusions and Relevance

Patients with CSCC and CPNI are at an increased risk of local recurrence and disease-specific death compared with patients with CSCC and IPNI and have a 30% risk of death. Patients with PNI may benefit from increased long-term surveillance. Further studies are needed to establish standardized guidelines on follow-up and dermatologic surveillance in this high-risk patient population.

Recurrent Squamous Cell Carcinoma of the Eyelid Presenting as Trigeminal Neuralgia

This paper describes two patients with squamous cell carcinoma (SCC) of the periocular and periorbital skin who presented with trigeminal neuralgia. Both patients had previous cutaneous SCC of the scalp treated successfully with surgical resection but later presented with neuro-ophthalmic findings suggesting perineural invasion (PNI) of SCC. PNI of SCC in the periocular skin or orbit can lead to devastating effects if malignant cells seed into the orbit and adjacent cranial nerves as our two patients developed an orbital apex syndrome. Patients with a history of SCC of the scalp and forehead who later develop neuro-ophthalmological deficits or patients with persistent ocular symptoms should, in particular, be followed with a low threshold for cutaneous SCC or PNI of recurrent disease. SCC metastasizing into the periocular tissues and orbit by neural invasion is rare and carries a poor prognosis. The urgency for a prompt diagnosis and evaluation by a multidisciplinary team is warranted to prevent untoward outcomes of this skin cancer. 

The Role of Postoperative Radiotherapy for Large Nerve Perineural Spread of Cancer of the Head and Neck

Large nerve perineural spread (LNPNS) is an uncommon but serious sequelae of cutaneous and salivary gland malignancies arising in the head and neck. This distinct clinical entity is caused by malignant cell spread along the course of larger (named) cranial nerves in a bidirectional pattern of spread toward the origins of the nerve in the brainstem and/or its most distal branches residing in the dermis. Untreated, LNPNS causes multiple cranial neuropathies that significantly impact on quality of life and ultimately is fatal. Curative treatment involves en bloc surgical resection of all known involved sites of gross disease followed by risk-adapted postoperative radiotherapy (PORT) to improve local control. We review the evidence for contemporary practice and outline the processes involved in the delivery of PORT using the zonal anatomical classification.

Perineural Spread of Cutaneous Squamous Cell Carcinoma Manifesting as Ophthalmoplegia

An 89-year-old female presented with horizontal diplopia and was diagnosed with VI nerve palsy attributed to a microvascular event. She subsequently progressed to develop an orbital apex syndrome, with neuroimaging demonstrating tumour invasion. Eighteen months earlier, she had squamous cell carcinoma of the forehead excised with clear margins. Intraneural and perineural spread of squamous carcinoma from the face to the cranial cavity is an important cause of delayed cranial nerve palsies after local excision of the skin tumour.

Management of squamous cell and basal cell carcinomas of the head and neck with perineural invasion

Perineural invasion (PNI) occurring in non-melanoma skin cancers (NMSC) is associated with an increased risk of locoregional recurrence and reduced disease-free survival. This necessitates early and accurate diagnosis, appropriate risk-stratification and a clear management strategy. The diagnosis of PNI is based on careful clinical assessment, imaging and histopathology. Surgery, preferably with margin control, and definitive or adjuvant radiotherapy (ART) are established treatment strategies for PNI. Clinical uncertainty remains over the role of ART in incidental PNI. This review synthesises current literature to ascertain which clinicopathological features impart a higher risk to individuals with PNI in NMSC, in order to provide treatment algorithms, including the identification of patient subsets that are most likely to benefit from ART. This includes those with extratumoural PNI, involvement of larger-calibre nerves, tumour invasion beyond dermis, recurrent tumour or diffuse intratumoural spread. Patients with clinical PNI may be optimally managed by a multidisciplinary head and neck cancer service that is best placed to offer skull base surgery and intensity-modulated radiation therapy (IMRT). The management options presented are stratified by histological subtype and a new classification of PNI into low-risk, medium-risk and high-risk groups.

The prognostic effect of perineural invasion in esophageal squamous cell carcinoma

Background

Perineural invasion (PNI) is correlated with adverse survival in several malignancies, but its significance in esophageal squamous cell carcinoma (ESCC) remains to be clearly defined. The objective of this study was to determine the association between PNI status and clinical outcomes.

Methods

We retrospectively evaluated the PNI of 433 patients with ESCC treated with surgery between 2000 and 2007 at a single academic center. The resulting data were analyzed using Spearman’s rank correlation, the Kaplan-Meier method, Cox proportional hazards regression modeling and Harrell’s concordance index (C-index).

Results

PNI was identified in 209 of the 433 (47.7%) cases of ESCC. The correlation analysis demonstrated that PNI in ESCC was significantly correlated with tumor differentiation, infiltration depth, pN classification and stage (P < 0.05). The five-year overall survival rate was 0.570 for PNI-negative tumors versus 0.326 for PNI-positive tumors. Patients with PNI-negative tumors exhibited a 1.7-fold increase in five-year recurrence-free survival compared with patients with PNI-positive tumors (0.531 v 0.305, respectively; P < 0.0001). In the subset of patients with node-negative disease, PNI was evaluated as a prognostic predictor as well (P < 0.05). In the multivariate analysis, PNI was an independent prognostic factor for overall survival (P = 0.027). The C-index estimate for the combined model (PNI, gender and pN status) was a significant improvement on the C-index estimate of the clinicopathologic model alone (0.739 v 0.706, respectively).

Conclusions

PNI can function as an independent prognostic factor of outcomes in ESCC patients, and the PNI status in primary ESCC specimens should be considered for therapy stratification.

Perineural invasion in pT3N0 rectal cancer: the incidence and its prognostic effect

BACKGROUND

The authors' purpose was to explore the incidence and prognostic significance of perineural invasion (PNI) in pT3N0 rectal cancer.

METHODS

Pathologic materials from resected specimens of 173 patients with pT3N0 rectal cancer were retrospectively collected. PNI-positivity was categorized into 2 groups: surrounding the nerve sheath (SS-PNI) and invading through the nerve sheath (TS-PNI). The rate of PNI-positivity was compared with PNI as initially recorded in the original reports. Patients' outcome was studied in groups with different PNI status, and multivariate analysis was performed to determine its prognostic value.

RESULTS

In this retrospective analysis, PNI-positivity was found in 24.3% of all cases, in which SS-PNI and TS-PNI were 11% and 13.3%, respectively, and was related to lymphovascular invasion. Only 7.5% of patients' specimens were reported as PNI-positive in the original reports. Detection of SS-PNI was likelier to be missed than TS-PNI. The rates of local recurrence, disease-free survival, and overall survival at 5 years were similar between the groups of SS-PNI and TS-PNI. The 5-year local recurrence rate was more than 2.5-fold higher in the PNI-positive group compared with the PNI-negative group (22.7% vs 7.9%, respectively; P = .017). Multivariate analysis proved that PNI-positivity was the only independent risk factor for predicting 5-year local recurrence rate, whereas only sampled lymph nodes was related to 5-year disease-free survival and overall survival.

CONCLUSIONS

PNI is a common pathologic feature in rectal cancer. The definition of PNI should include SS-PNI and TS-PNI. Rectal cancer patients who are PNI-positive are at higher risk of local recurrence and should be considered for more intensive treatment.

Contralateral cranial polyneuropathy due to perineural invasion by a cutaneous squamous cell carcinoma

Cutaneous malignancies may spread to underlying nerves, a process known as perineural invasion (PNI). We report a patient who was found to have PNI presenting as a cranial polyneuropathy on the contralateral side of the face many years after the resection of a squamous cell carcinoma. All diagnostic testing was unrevealing until nerve biopsy was performed. This emphasizes the long asymptomatic period between treatment of a cutaneous malignancy and detection of PNI, and the development of PNI at a site distant from the original malignancy. Biopsy of a clinically involved nerve may permit diagnosis of PNI when other studies are normal.

Perineural invasion in cancer: a review of the literature

Perineural invasion (PNI) is the process of neoplastic invasion of nerves and is an under-recognized route of metastatic spread. It is emerging as an important pathologic feature of many malignancies, including those of the pancreas, colon and rectum, prostate, head and neck, biliary tract, and stomach. For many of these malignancies, PNI is a marker of poor outcome and a harbinger of decreased survival. PNI is a distinct pathologic entity that can be observed in the absence of lymphatic or vascular invasion. It can be a source of distant tumor spread well beyond the extent of any local invasion; and, for some tumors, PNI may be the sole route of metastatic spread. Despite increasing recognition of this metastatic process, there has been little progress in the understanding of molecular mechanisms behind PNI and, to date, no targeted treatment modalities aimed at this pathologic entity. The objectives of this review were to lay out a clear definition of PNI to highlight its significance in those malignancies in which it has been studied best. The authors also summarized current theories on the molecular mediators and pathogenesis of PNI and introduced current research models that are leading to advancements in the understanding of this metastatic process.

Skin cancer of the head and neck with perineural invasion: defining the clinical target volumes based on the pattern of failure

PURPOSE

To analyze patterns of failure in patients with head-and-neck cutaneous squamous cell carcinoma (HNCSCC) and clinical/radiologic evidence of perineural invasion (CPNI), in order to define neural clinical target volume (CTV) for treatment planning.

METHODS AND MATERIALS

Patients treated with three-dimensional (3D) conformal or intensity-modulated radiotherapy (IMRT) for HNCSCC with CPNI were included in the study. A retrospective review of the clinical charts, radiotherapy (RT) plans and radiologic studies has been conducted.

RESULTS

Eleven consecutive patients with HNCSCCs with CPNI were treated from 2000 through 2007. Most patients underwent multiple surgical procedures and RT courses. The most prevalent failure pattern was along cranial nerves (CNs), and multiple CNs were ultimately involved in the majority of cases. In all cases the involved CNs at recurrence were the main nerves innervating the primary tumor sites, as well as their major communicating nerves. We have found several distinct patterns of disease spread along specific CNs depending on the skin regions harboring the primary tumors, including multiple branches of CN V and VII. These patterns and the pertinent anatomy are detailed in the this article.

CONCLUSIONS

Predictable disease spread patterns along cranial nerves supplying the primary tumor sites were found in this study. Awareness of these patterns, as well as knowledge of the relevant cranial nerve anatomy, should be the basis for CTV definition and delineation for RT treatment planning.

What is the role of adjuvant radiotherapy in the treatment of cutaneous squamous cell carcinoma with perineural invasion?

BACKGROUND

Perineural invasion (PNI) in cutaneous squamous cell carcinoma (SCC) is infrequent, occurring in 2.5% to 14% of patients, but it is important prognostically, because it carries an increased risk of recurrence and metastasis. Although both excision and Mohs micrographic surgery (MMS) are used to treat SCC with PNI, postoperative radiation therapy (XRT) often is recommended to minimize the risk of recurrence. To date, the effectiveness of adjuvant XRT in this setting has not been determined definitively.

METHODS

The authors evaluated the effectiveness of adjuvant XRT in treating SCC with PNI by performing a thorough literature review.

RESULTS

For SCC with PNI, the local control rate after MMS with or without XRT was from 92% to 100% compared with a control rate from 38% to 100% after standard excision with or without XRT. A better prognosis was associated with negative pretreatment magnetic resonance imaging or computed tomography findings than with positive radiographic evidence of PNI. Primary SCC with PNI was associated with better local control than recurrent SCC with PNI. When treatment outcomes were stratified by PNI type, SCC with microscopic PNI and SCC with extensive PNI had local control rates from 78% to 87% and from 50% to 55%, respectively. Adjuvant XRT was associated in selected patients with 100% local control.

CONCLUSIONS

Few studies addressed the effectiveness of adjuvant XRT in patients who have SCC with PNI. Although XRT has been established as an adjuvant treatment for selected patients, the extent of nerve involvement by tumor, particularly in the setting of other high-risk features, may be helpful in defining its role. In the future, a multicentered, prospective, randomized clinical trial will be needed to assess the true efficacy of adjuvant XRT in the treatment of patients with SCC and PNI.

Perineural spread of facial squamous cell carcinoma

A 64 year old man presented with progressive impairment of right sided cranial nerves. Chronic immunosuppression for renal transplantation had resulted in multiple squamous cell carcinomata of the head and neck. Magnetic resonance imaging and subsequent right facial nerve biopsy confirmed perineural spread of a squamous cell carcinoma as the cause of the multiple cranial neuropathies.

Cutaneous Carcinoma with Mixed Histology: A Potential Etiology for Skin Cancer Recurrence and an Indication for Mohs Microscopically Controlled Surgical Excision

Cutaneous carcinomas with mixed histology describe nonmelanoma skin cancers which have more than one histologic subtype. These include basal cell carcinomas with concurrent aggressive growth patterns (such as sclerosing, infiltrating, micronodular, keratinizing, and tumors with perineural involvement) and nonaggressive growth patterns (such as superficial, nodular, and follicular) and squamous cell carcinomas with concurrent poorly differentiated and well-differentiated components. One mechanism of recurrence of nonmelanoma skin cancer may very well result from the inadequate initial treatment of cutaneous tumors with mixed histology. If the aggressive histologic subtype of the original tumor is initially not suspected based upon the pathology observed from a superficial biopsy specimen, the clinician may initiate therapy that would be appropriate for the less aggressive variant that was diagnosed. Subsequently, the more aggressive tumor may persist and eventually manifest as a clinical recurrence of the cancer. This is particularly important when there is perineural tumor involvement. We describe two patients whose skin cancers had more than one histologic subtype to demonstrate the histologic features of cutaneous malignancies with more than one pathologic pattern and to emphasize how inaccurate a single diagnostic biopsy can be. We also suggest that clinicians consider Mohs surgical excision of nonmelanoma skin cancers since this technique incorporates microscopically controlled removal of the tumor with complete pathologic evaluation of all surgical margins for any residual cancer.

Perineural spread of cutaneous malignancy to the brain

BACKGROUND

The retrospective analysis was performed to investigate the role of stereotactic radiotherapy (SRT) techniques for patients with intracranial perineural spread (PNS) of a primary cutaneous malignancy.

METHODS

Five patients were identified who received SRT from 1993 to 2003 for cutaneous malignancies with intracranial PNS to the cavernous sinus (n = 3) or Meckel's cave (n = 2). Patients were treated with GammaKnife stereotactic radiosurgery (n = 2), linear accelerator (linac)-based fractionated SRT (n = 2), or linac-based stereotactic radiosurgery (n = 1).

RESULTS

The median overall survival (OS) periods from diagnoses of cutaneous malignancy and intracranial PNS were 63.0 months (range, 22.0-102.2 months) and 25.5 months (range, 22.0-55.2 months), respectively. The median OS from SRT was 24.2 months (range, 19.5-53.2 months). One patient was alive and without evidence of disease at 53 months of follow-up. The median durations of local and regional control from SRT were 19.5 months (range, 1.5-53.2 months) and 7.0 months (range, 1.5-53.2 months), respectively.

CONCLUSIONS

Previous reports generally have recommended that patients with intracranial PNS receive palliative external-beam radiotherapy. Results from the current study suggest that some of these patients may have prolonged survival, or even may be cured. Judicious use of SRT should be considered in their management.

Alopecia neoplastica caused by desmoplastic melanoma

A 50-year-old man presented with a 6-month history of localized alopecia on the left frontal area of the scalp. Biopsy revealed desmoplastic melanoma with associated neurotropism. Wide excision was performed and showed desmoplastic melanoma extending to excision margins. Hair follicles were focally reduced in number and were infiltrated by melanoma cells. He has subsequently required multiple wide excisions, exenteration of the left eye and radiotherapy. He has had multiple recurrences and has developed involvement of the first division of the trigeminal nerve intracranially. To the authors' knowledge, this is the first reported case of desmoplastic melanoma presenting as alopecia.