Pathological margins and advanced cutaneous squamous cell carcinoma of the head and neck

Surgical Approaches to Pre-Auricular Cutaneous Squamous Cell Carcinomas Extending to the Temporal Bone

BACKGROUND

Standardized surgical approaches to advanced pre-auricular cutaneous squamous cell carcinomas (cSCC) are lacking.

METHODS

Fifty-four patients who underwent lateral temporal bone resection (LTBR) for pre-auricular cSCC were grouped into "Levels" of increasing disease spread. Surgical approaches to achieve negative-margin resection were designed for each Level and replicated on cadaveric specimens.

RESULTS

Level 1 extended to the external auditory canal, requiring LTBR ± superficial parotidectomy. Level 2 involved the retromandibular space ± temporomandibular joint, necessitating partial mandibulectomy, in addition to the above. Level 3 and 4 involved the deep parotid, being situated either away from (> 5 mm) or close (≤ 5 mm) to the anterior carotid sheath (ACS), respectively. These tumors require radical parotidectomy, with incorporation of the ACS for Level 4. Level 5 involved the ACS at the skull base and should be treated non-surgically.

CONCLUSION

This Level-based system will hopefully lead to further prospective studies and improvements in outcomes for advanced pre-auricular cSCC.

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.

The hidden Australian skin cancer epidemic, high-risk cutaneous squamous cell carcinoma: a narrative review

Deaths from non-melanoma skin cancers (NMSCs) have almost doubled in Australia in recent years. Cutaneous squamous cell carcinoma (cSCC) constitutes approximately 20% of NMSCs, but is responsible for most of the deaths. Most skin cancers are easy to diagnose and treat and therefore cSCC are often trivialised; however, there is a high-risk subgroup of cSCC (HRcSCC) that is associated with a high risk of metastasis and death. The definition of early HRcSCC and our ability to identify them is evolving. Many significant prognostic factors have been identified, but a universally accepted prognostic index does not exist. Guidelines for workup, treatment, and follow-up leave many important decisions open to broad interpretation by the treating physician or multidisciplinary team. Some of the treatments used for metastatic cSCC are not supported by robust evidence and the prognosis of metastatic cSCC is guarded. In this review, we highlight the rapid rise in NMSC deaths and discuss some of the deficiencies in our knowledge of how to define, diagnose, stage, and manage HRcSCC.

Prognostic Outcomes of Cutaneous Squamous Cell Carcinoma in Solid Organ Transplant Recipients: A Retrospective Comparative Cohort Study

INTRODUCTION

Cutaneous squamous cell carcinoma (cSCC) is the second most common cutaneous neoplasm, and its incidence is on the rise. While most cSCCs have an excellent prognosis, certain risk factors, especially immunosuppression, have been associated with higher rates of local recurrence (LR), metastasis, and poor prognosis. This study aims to assess the risk factors for LR and metastasis development in cSCC among solid organ transplant recipients (SOTRs) and compare these rates with those in immunocompetent patients.

MATERIALS AND METHODS

A retrospective observational study included cSCC cases from the University Hospital Reina Sofía in Córdoba, Spain, between 2002 and 2019. Demographic, clinical, and histopathological data were collected. Local recurrence and metastasis rates were analyzed, along with progression-free survival. Univariate analyses were performed to identify prognostic factors in SOTRs.

RESULTS

Among 849 cSCC cases, we found higher rates of local recurrence and metastasis in tumors developed by SOTRs compared to those in immunocompetent individuals. However, no significant differences in local recurrence, metastasis, or progression-free survival were observed between the two groups. Risk factors for adverse outcomes in SOTRs included tumor size > 2 cm, depth > 4 mm, and a higher Clark level. A total of 34.4% of SOTRs developed a second primary cSCC during the follow-up.

CONCLUSIONS

In our study, cSCCs in SOTRs did not exhibit statistically significant differences in the rates of adverse outcomes compared to immunocompetent patients. The prognosis of cSCCs in SOTRs may be more related to other tumor-dependent risk factors than to the immunosuppression status itself. Future studies are needed to refine risk stratification and follow-up protocols to ensure the optimal management of high-risk cSCC cases, particularly among immunosuppressed patients.

The prognostic significance of lymphovascular invasion in cutaneous squamous cell carcinoma

BACKGROUND

The majority of cutaneous squamous cell carcinomas (cSCC) have a favourable prognosis. However, a subset of cases follow an aggressive disease course with progression to metastasis and death. Several histopathological parameters are associated with poor outcomes, but lymphovascular invasion (LVI) has not been well studied.

OBJECTIVE

To assess the prognostic significance of LVI in cSCC and determine associations between LVI and cSCC.

METHODS

A retrospective review of 486 consecutive cases of cSCC over a 5-year period from a single centre was stratified by the presence or absence of LVI. Logistic regression and multivariate survival analysis were used to determine associations of LVI and prognostic significance of LVI, respectively.

FINDINGS

LVI was present in 41 cases (9.2%). LVI was significantly associated with increasing depth of invasion, microanatomical tumour location (subcutis vs. dermis), and tumour dimensions (P < 0.05). Univariate survival analysis revealed significantly lower 2-year overall survival rates for patients with LVI (37.1%) compared with those without (66.6%) (95% CI = 60.6-73.3, P < 0.001). LVI was also found to be an independent marker of poor disease-specific survival (HR = 0.232 (95% CI = 0.090-0.600), P = 0.003), poor overall survival (HR 0.338 (95% CI = 0.184-0.623), P < 0.001) and poor disease-free survival (HR 0.461 (95% CI = 0.230-0.923), P = 0.029) through multivariate analysis.

CONCLUSIONS

This study confirms that LVI is an independent poor prognosticator in cSCC, with significantly worse survival indices at 2 years. Future systems of risk stratification for cSCC should incorporate LVI.

Mohs micrographic surgery for keratinocyte carcinomas: clinicopathological predictors of the number of stages

Background

The number of Mohs stages needed to remove a keratinocyte carcinoma affects resource use, expenses, and repair complexity. This study aimed to identify clinicopathological predictors associated with increased or decreased stages and areas for further research.

Methods

A retrospective review was conducted from a single private practice with two Mohs surgeons of 2788 consecutive Mohs cases between January 2017 and December 2021, analyzing the average number of stages taken versus national norms (P = 0.21) and subgroups using unpaired t tests (*<0.05).

Results

Several tumor features were significantly associated with fewer stages: squamous cell carcinomas, Mohs appropriate use criteria score of 7 or 8, preoperative size <0.25 cm2, tumors on the lips and extremities (including hands/fingers), and smoking. Clinicopathological features significantly associated with more stages included Mohs appropriate use criteria score of 9, recurrent skin cancers, basal cell carcinomas, tumor size of 2.25-3.99 cm2, cancers on ears, solid organ transplant patients, treatment delays >180 days, and patients ≥90 years old.

Conclusions

Significant predictors exist for both increased and decreased numbers of Mohs micrographic surgery stages required to eradicate a tumor, which may help Mohs surgeons facilitate, plan, and allocate resources more effectively. Areas for further research in Mohs micrographic surgery are identified.

Management of Cutaneous Head and Neck Squamous and Basal Cell Carcinomas for Immunocompromised Patients

The incidence of non-melanoma skin cancer (NMSC) continues to rise, and more than one million cases are diagnosed in the United States each year. The increase in prevalence has been attributed to increased lifespan and improvements in survival for conditions that increase the risk of these malignancies. Patients who are immunocompromised have a higher risk of developing NMSC compared to the general population. In immunosuppressed patients, a combination of prevention, frequent surveillance, and early intervention are necessary to reduce morbidity and mortality. In this review, we collate and summarize current knowledge regarding pathogenesis of head and neck cutaneous SCC and BCC within immunocompromised patients, examine the potential role of the immune response in disease progression, and detail the role of novel immunotherapies in this subset of patients.

Impact of AJCC 8 pT staging in cutaneous head and neck squamous cell carcinoma in a nonselected real-world patient sample

OBJECTIVE

Our aim was to evaluate characteristics associated with worse survival and the effectiveness of AJCC 8 in a real-world cohort of HNCSCC from South Brazil.

METHODS

A 10-year retrospective cohort study (2011-2020) at a tertiary care center comprising 647 HNCSCC excised from 435 patients.

RESULTS

At multivariable analysis, ear/nose/zygomatic or periorbital site, compromised or exiguous margins, and advanced pT stage were independent factors associated to DFS, while age, pN, and loco-regional recurrence were independent factors associated to DSS. Cox-regression multivariable models showed that the pT stage was statistically significant for the DFS, but not DSS. A significant distinction was only observed between T1 and T2.

CONCLUSION

It was only in the lower categories of AJCC 8 (T1 and T2) that we were able to demonstrate the ability to stratify tumors with a significant risk of poor disease-related outcomes.

The efficacy of dermoscopy in defining the surgical margins of cutaneous squamous cell carcinoma: a retrospective study

Objective

To investigate the diagnostic value of dermoscopy in defining the tumor margin of cutaneous squamous cell carcinoma (cSCC) for the appropriate surgical margin.

Methods

A total of 90 cSCC patients were enrolled in the study. All patients were recruited into two groups: those who preserved intact macroscopic features of neoplasms without or after incisional biopsy and those with uncertain residual tumors after excisional biopsy. A dermoscopy-defined surgical margin of 8mm outward was used according to the tumor boundaries observed with the naked eye and dermoscopy. All excised tumor specimens were divided into serial sections according to the four "3, 6, 9, 12" directions at every 4-mm interval from the dermoscopy-detected tumor margin. Pathological examination was performed at 0 mm, 4 mm, and 8 mm margins to confirm tumor remnants.

Results

Retrospective analysis of dermatoscopic results showed inconsistent clinical and dermatoscopic borders in 43 of 90 cases (47.8%). The ability of dermoscopy to detect tumor borders showed no statistical difference between the two groups (p > 0.05). In the unbiopsy or incisional biopsy group, 66.6% of the tumors were resected with a 4-mm margin and 98.3% with an 8-mm margin, with significant differences (p = 0.047). For patients with inconspicuous clinical evidence of residual tumor after excisional biopsy, the tumor clearance rate was 53.3% at 0 mm, 93.3% at 4 mm, and 100.0% at 8 mm. Statistically significant differences were noted between 0 mm and 4 mm (p = 0.017), as well as between 0 mm and 8 mm (p = 0.043) but did not differ between 4 mm and 8 mm (p > 0.05).

Conclusions

Dermoscopy defined the tumor margin of cSCC better than visual inspection alone. Direct dermoscopic-guided surgery with at least 8-mm expansion was recommended for high-risk cSCC. Dermoscopy also assisted in identifying surgical margins at the healing biopsy site, making 8 mm still the recommended expansion range.

Evidence from Clinical Studies Related to Dermatologic Surgeries for Skin Cancer

Simple Summary

Although significant progress in pharmacotherapy for skin cancer has been made in the past several years, surgical removal of primary skin cancer is still the first choice of treatment unless distant metastases are evident. In the surgical treatment of primary skin tumors, the surgical margin is critical not only for reducing the possibility of tumor recurrence but also for minimizing the cosmetic and functional complications associated with wide local excision. In contrast, dermatologic surgeries including lymph node dissection and skin graft can cause various complications, and these complications are frequently associated with significant morbidity and discomfort. In this review, we summarize the evidence from previous clinical studies regarding the optimal surgical margin for skin cancer and the methods for diminishing the complications associated with dermatologic surgery.

Abstract

Despite the significant progress made in the past several years in pharmacotherapies for skin cancer, such as BRAF/MEK inhibitors, immune checkpoint inhibitors, and Hedgehog pathway inhibitors, surgical removal of primary skin cancer is still the first choice of treatment unless distant metastases are evident. In cases of lymph node metastases with clinically palpable lymphadenopathy, lymph node dissection (LND) is typically performed for most skin cancers. In the surgical treatment of primary skin tumors, the surgical margin is critical not only for reducing the possibility of tumor recurrence but also for minimizing the cosmetic and functional complications associated with wide local excision. In contrast, dermatologic surgery can cause various complications. Although skin graft is frequently used for reconstruction of the surgical defect, extensive graft necrosis may develop if optimal stabilization of the graft is not obtained. LND also sometimes causes complications such as intraoperative or postoperative bleeding and postoperative lymphoceles. Moreover, as in other types of surgery, surgical site infection, intraoperative anxiety, and intraoperative and postoperative pain may also develop. These complications are frequently associated with significant morbidity and discomfort. In this review, we summarize the evidence from previous clinical studies regarding the optimal surgical margin for skin cancer and the methods for diminishing the complications associated with dermatologic surgery.

Narrower clinical margin in high or very high-risk squamous cell carcinoma: a retrospective, multicenter study of 1,000 patients

BACKGROUND AND OBJECTIVES

In cutaneous squamous cell carcinoma (cSCC), adherence to guideline-recommended fixed surgical margins is often difficult, and narrower margins are preferable. This study aimed to evaluate relapse and disease-specific death with narrower margins for high or very high-risk cSCC.

PATIENTS/METHODS

We retrospectively investigated high or very high-risk cSCC patients who underwent tumor excision. Patients were divided into guideline-recommended standard margin group (SMG) and narrower-margin group (NMG). Co-primary outcomes were local relapse, SCC relapse, and SCC death. Cumulative incidence function (CIF) was used to describe SCC death probability and competing risk mortality. Gray's test was used to compare differences in CIF between the groups.

RESULTS

In total, 1,000 patients with cSCC (high-risk, 570; very high-risk, 430) were included. In the high-risk cohort, there were no significant differences in incomplete excision rate (IER) between SMG and NMG (2.6 % vs. 3.0 %, P > 0.99). However, in the very high-risk cohort, IER in SMG was significantly lower than in NMG (8.9 % vs. 16.2 %, P = 0.03). No significant differences were observed between SMG and NMG for local relapse (high-risk, P = 0.56; very high-risk, P = 0.70), SCC relapse (high-risk, P = 0.30; very high-risk, P = 0.47), and SCC death (high-risk, P = 0.23; very high-risk, P = 0.83).

CONCLUSIONS

Surgical margin size has limited impact on margin control, relapse, and disease-specific death in high-risk cSCC.

Knapperer Resektionsrand bei Plattenepithelkarzinomen mit hohem oder sehr hohem Risiko: eine retrospektive multizentrische Studie mit 1000 Patienten

HINTERGRUND UND ZIELE

Bei kutanen Plattenepithelkarzinomen (PEK) ist die Einhaltung der in Leitlinien empfohlenen festen Resektionsränder oft schwierig und knappere Ränder sind wünschenswert. Ziel dieser Studie war die Bewertung des Auftretens von Rezidiven und krankheitsspezifischen Todesfällen bei knapperen Resektionsrändern für PEK mit hohem oder sehr hohem Risiko.

PATIENTEN/METHODEN

PEK-Patienten mit hohem oder sehr hohem Risiko, bei denen eine Tumorexzision durchgeführt wurde, wurden retrospektiv untersucht. Die Patienten wurden in eine Gruppe mit Standardrand gemäß Leitlinienempfehlung (standard margin group, SMG) und eine Gruppe mit knapperen Rändern (narrower-margin group, NMG) eingeteilt. Gemeinsame primäre Endpunkte waren lokales Rezidiv, PEK-Rezidiv und PEK-bedingter Tod. Die Wahrscheinlichkeit eines PEK-bedingten Tods und konkurrierender Mortalitätsrisiken wurde mittels kumulativer Inzidenzfunktion (CIF) beschrieben. Unterschiede bei der CIF zwischen den Gruppen wurden mit dem Test nach Gray verglichen.

ERGEBNISSE

Insgesamt wurden 1.000 Patienten mit PEK (hohes Risiko, 570; sehr hohes Risiko, 430) eingeschlossen. In der Kohorte mit hohem Risiko gab es keine signifikanten Unterschiede bei der unvollständigen Exzisionsrate (IER) zwischen SMG und NMG (2,6 % vs. 3,0 %, P > 0,99). In der Kohorte mit sehr hohem Risiko war die IER in der SMG jedoch signifikant geringer als in der NMG (8.9 % vs. 16.2 %, P = 0,03). Keine signifikanten Unterschiede zwischen SMG und NMG wurden für Lokalrezidiv (hohes Risiko, P = 0.56; sehr hohes Risiko, P = 0,70), PEK-Rezidiv (hohes Risiko, P = 0,30; sehr hohes Risiko, P = 0,47) und PEK-bedingtem Tod (hohes Risiko, P = 0,23; sehr hohes Risiko, P = 0,83) beobachtet.

SCHLUSSFOLGERUNGEN

Die Größe des Resektionsrands hat einen begrenzten Einfluss auf Randkontrolle, Rezidive und krankheitsspezifischen Tod bei PEK mit hohem Risiko.

Modern views on skin biopsy in the diagnostic algorithm of dermatooncological diseases

Background. Malignant neoplasms of the skin are fairly common tumors in the world population and among the population of Ukraine. The main method of diagnosing skintumors is a biopsy, which allows establishing a diagnosis at an early stage and ensures the cure of most patients. Purpose. To evaluate modern recommendations for skin biopsy in the diagnosis of dermato-onсological diseases. Materials and methods. The search for sources of information was conducted using the MEDLINE/PubMed, EMBASE/ExcerptaMedica, CochraneLibrary, PubMed та Google Scholar databases using the following keywords: skin biopsy, skin tumors, diagnosis, melanoma. Among the identified sources, works without statistical analysis, descriptions of individual cases, articles without conclusions, and sources with duplicate results were excluded. The search depth was 10 years. Results. As a result of the conducted search, 57 publications were found that corresponded to the declared purpose. The most common methods are: puncture, shaving, excisional and incisional biopsy. Most guidelines recommend full-thickness excisional biopsy as the preferred procedure for the diagnosis of suspected melanoma. It is indicated that a statistically significant mortality rate was found in the puncture biopsy group. Most observations showed no significant differences in melanoma recurrence between excisional biopsy and puncture groups. Given the clinical diversity of melanoma, there is no uniformity in the types of biopsies performed to diagnose melanoma. The most inaccurate method turned out to be the punch biopsy method, which is associated with an increased risk of underdiagnosis of melanoma. Conclusions. A skin biopsy is a mandatory first step to establish a definitive diagnosis of a skin tumor. Excisional complete biopsy is the most justified in most cases of diagnosis. Rational biopsy technique remains an issue that needs further study.

Local Tumor Infiltration and Locoregional Recurrence in Desmoplastic Cutaneous Squamous Cell Carcinoma

BACKGROUND

Perusal of the literature of cutaneous squamous cell carcinoma (SCC) reveals that the role of the desmoplastic subtype is indistinct. Data on local infiltration and recurrence are inconsistent dependent on surgical technique, histological method, and investigated collective.

OBJECTIVE

The aim of the study was to analyze local infiltration and locoregional recurrence of the desmoplastic subtype under a uniform procedure.

METHODS AND MATERIALS

Between 2005 and 2015, 320 SCCs were analyzed and histological sections of all tumors were examined. Data collection included locoregional recurrence, metastasis rate, and tumor-specific death. The median follow-up was 36.5 months.

RESULTS

The desmoplastic subtype required significant more re-excisions (70.0% vs 23.9%, p < .001), more interventions until tumor-free margins were achieved (maximal 6 vs 2; p < .001), showed more widespread tumor infiltration with larger excisional margins (median 9 mm, 2-51 mm vs median 4 mm, 1-10 mm; p < .001), and a 5-fold higher local recurrence rate (26.7% vs 5.0%, p < .001). The metastasis rate (16.6% vs 2.3%, p < .001) was increased.

CONCLUSION

The desmoplastic subtype is characterized by a widespread local infiltration associated with perineural infiltration. It seems to be a marker for decreased histological detectability with a high rate of locoregional recurrence and metastasis.

Adjuvant therapy for high-risk cutaneous squamous cell carcinoma: 10-year review

Standard of care for high-risk cutaneous squamous cell carcinoma (cSCC) is surgical excision of the primary lesion with clear margins when possible, and additional resection of positive margins when feasible. Even with negative margins, certain high-risk factors warrant consideration of adjuvant therapy. However, which patients might benefit from adjuvant therapy is unclear, and supporting evidence is conflicting and limited to mostly small retrospective cohorts. Here, we review literature from the last decade regarding adjuvant radiation therapy and systemic therapy in high-risk cSCC, including recent and current trials and the role of immune checkpoint inhibitors. We demonstrate evidence gaps in adjuvant therapy for high-risk cSCC and the need for prognostic tools, such as gene expression profiling, to guide patient selection. More large-cohort clinical studies are needed for collecting high-quality, evidence-based data for determining which patients with high-risk cSCC may benefit from adjuvant therapy and which therapy is most appropriate for patient management.

New Developments in the Management of Cutaneous Squamous Cell Carcinoma

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. List important prognostic features that affect cutaneous squamous cell carcinoma risk. 2. Summarize the changes to the AJCC Cancer Staging Manual, Eighth Edition, staging system for cutaneous squamous cell carcinoma. 3. Evaluate the draining nodal basin with appropriate imaging modalities. 4. Recommend adjuvant radiation therapy in the correct clinical setting for high-risk tumors. 5. Recognize the currently available treatments for advanced cutaneous squamous cell carcinoma.

SUMMARY

This continuing medical education article reviews the features, management, and prognosis of cutaneous squamous cell carcinoma with an emphasis on high-risk squamous cell carcinoma and data from the past 3 years. This review will discuss the primary tumor management, high-risk features of a squamous cell carcinoma, changes to the American Joint Committee on Cancer staging system, and the utility of sentinel lymph node biopsy, and critically review the evidence regarding adjuvant therapy.

Surgeons reaching satisfying outcomes without surgery: nasal dorsum skin cancer recurrence treated with electrochemotherapy

Cutaneous squamous cell carcinoma of the head and neck district are generally treated with surgery. Surgery is the standard treatment in early stages and local advanced tumors, followed by adjuvant therapy, radiation or concurrent chemoradiation therapy. Local recurrence treatment depends on previous therapies, though radical surgery is often the first choice at the expense of anatomy preservation. We present the case of a patient with cutaneous squamous cell carcinoma of the nasal dorsum which relapsed after surgery and radiation therapy. The patient refused radical surgery and electrochemotherapy under general anesthesia was administered. After 6 months from treatment, the patient showed a complete clinical response. Electrochemotherapy could be considered as an alternative to surgery in small lesion when other approaches are refused.

Therapeutic effects of ephrin B receptor 2 inhibitors screened by molecular docking on cutaneous squamous cell carcinoma

Background: Cutaneous squamous cell carcinoma (CSCC) is the most known form type of metastatic skin cancer. Activation of ephrin B receptor 2 (EphB2) signaling can promote the metastasis, invasion, and angiogenesis of CSCC cells. Therefore, EphB2 may act as a therapeutic target for CSCC. Here, we screened the inhibitors for EphB2 using molecular docking and then evaluated the effects of the identified inhibitors on cancer-related features of CSCC cells.Methods: The Schrodinger docking tool was used to predict the three-dimensional structure of EphB2 protein and its ligand binding sites, and EphB2 inhibitors were screened by high-throughput virtual screening combined with molecular docking. The effects of EphB2 inhibitors were analyzed for cell viability, proliferation, apoptosis, migration, invasion, and xenograft tumor growth.Results: In vitro experiments, the identified small-molecule inhibitors markedly inhibited the skin cancer cells proliferation, induced apoptosis, altered the cell cycle, and inhibited cell invasion and migration in our study. In a xenograft model, the identified small-molecule inhibitors induced changes in the epithelial mesenchymal transition, which affected the progression of CSCC.Conclusion: EphB2 small-molecule inhibitors had anti-CSCC effects, establishing a solid theoretical basis for clinical research.