BCC-One-Stop-Study

Multicentre, Interventional Prospective Study to Evaluate the Efficiency of Pre- and Postoperative Margin Determination of Basal Cell Carcinomas Using Optical Coherence Tomography and Line-field Confocal Optical Coherence Tomography During Micrographically Controlled Surgery

Basal cell carcinoma (BCC) is the most common malignant skin tumour. The standard treatment is micrographically controlled surgery (MMS), which achieves high cure rates but requires considerable time and personnel. A key problem is the inadequate preoperative determination of tumour margins, which often leads to multiple cycles of excision.

The aim of this multicentre, prospective, randomised controlled intervention study is to evaluate line-field confocal optical coherence tomography (LC-OCT) for preoperative margin determination in BCC within the framework of MMS.

Research question:

Can preoperative LC-OCT-assisted margin marking increase the efficiency of MMS by reducing the number of excision cycles required without compromising oncological safety?

Methodology:

Approximately 290 patients with histologically confirmed BCC will be enrolled at five German centres and randomly assigned to either standard MMS or MMS with upstream LC-OCT margin determination. In the intervention group, the excision margin will be specifically extended if a tumour is detected in the LC-OCT.

Primary endpoint:

Number of MMS cycles required to achieve R0 resection.

Secondary endpoints:

Total duration of surgery, size of surgical defect, cosmetic outcome (POSAS), patient satisfaction and stress, sensitivity and specificity of LC-OCT compared to histopathology.

Significance:

The study addresses the clinical conflict of objectives between complete tumour removal and maximum tissue preservation. Successful implementation could optimise MMS through modern imaging, conserve surgical resources and improve patient care in the long term.

Study Overview

• Status: Not yet recruiting
• Conditions: Basal Cell Carcinoma
• Intervention / Treatment: Diagnostic test: Margin Mapping with Line-field confocal optical coherence tomography

Detailed Description

Basal cell carcinoma (BCC) is the most common type of skin cancer worldwide and occurs predominantly in fair-skinned populations. In Germany, approximately one in three individuals will develop BCC during their lifetime. Although BCC rarely metastasizes, it shows locally destructive growth with irregular, finger-like extensions into surrounding tissue, which can make complete surgical removal challenging. The majority of tumors arise in the sun-exposed head and neck region.

Micrographic surgery (Mohs micrographic surgery, MMS) represents the gold standard treatment for high-risk BCC, as it allows complete margin control and offers the highest cure rates. However, MMS is often time-consuming and resource-intensive because multiple sequential excision stages may be required until histopathology confirms complete tumor removal (R0 resection). Preoperative estimation of tumor margins is usually based on clinical examination and dermoscopy with a standard safety margin of 2-3 mm. This approach may be inaccurate, particularly in tumors with subclinical extension, which can lead either to unnecessarily large excisions or to residual tumor tissue requiring additional surgical stages.

Non-invasive imaging techniques have increasingly been investigated to improve the preoperative assessment of BCC margins. Optical coherence tomography (OCT) and the more recently developed line-field confocal optical coherence tomography (LC-OCT) allow high-resolution, real-time imaging of the skin. These technologies enable visualization of skin structures with near-histological resolution and can detect characteristic morphological features of BCC in vivo. Previous studies have demonstrated good diagnostic accuracy of OCT and LC-OCT for the detection and subtyping of BCC and suggest that these methods may also be useful for defining tumor margins before surgery.

In particular, LC-OCT combines the advantages of conventional OCT with the cellular resolution of confocal microscopy, allowing both vertical and horizontal imaging of the skin at high resolution. This enables detailed visualization of tumor architecture and potentially facilitates the detection of subclinical tumor extensions beyond the clinically visible borders.

The present multicenter randomized controlled study aims to evaluate whether LC-OCT-guided preoperative margin assessment can improve the efficiency of MMS. In the intervention group, the lateral tumor margins are examined preoperatively using LC-OCT. If tumor structures are detected at the planned resection margin, the surgical margin is extended accordingly before the first excision step. MMS is then performed according to the standard surgical protocol with histopathological examination of the margins. In centers where available, excised tissue may additionally be examined postoperatively using ex vivo LC-OCT or confocal microscopy to correlate imaging findings with histopathology.

The study investigates whether this image-guided approach can reduce the number of surgical stages required to achieve complete tumor removal, while maintaining oncological safety. By enabling more accurate preoperative mapping of tumor margins, LC-OCT-guided surgery may improve surgical planning and increase the likelihood of complete excision in the first stage of MMS. In addition, improved margin delineation could allow more tissue-sparing surgery, potentially leading to smaller surgical defects and better cosmetic outcomes.

Overall, this study evaluates the clinical utility of integrating LC-OCT into the surgical workflow of MMS. The results may provide evidence for a more efficient and resource-conserving surgical strategy in the treatment of basal cell carcinoma while maintaining the high oncological safety standards of micrographic surgery.

• Study Type: Interventional
• Enrollment (Estimated): 290
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Julia Welzel, MD; Phone Number: 00498214007401; Email: julia.welzel@uk-augsburg.de
• Study Contact Backup: Name: Sandra Schuh, MD, M.Sc.; Phone Number: 0049821400167508; Email: sandra.schuh@uk-augsburg.de

Study Locations

• Germany
  • Augsburg, Germany
    • University Hospital Augsburg
    • Contact: Julia Welzel, MD; Email: julia.welzel@uk-augsburg.de
    • Principal Investigator: Julia Welzel, MD
    • Contact: Sandra Schuh, MD, M.Sc.; Email: sandra.schuh@uk-augsburg.de
    • Sub-Investigator: Sandra Schuh, MD, M.Sc.
    • Sub-Investigator: Deborah Winkler, MD
    • Sub-Investigator: Janis Thamm, MD
    • Sub-Investigator: Hanna Wirsching, MD
    • Sub-Investigator: Pelinsu Yilmaz, MD
    • Sub-Investigator: Franziska Reisch, MD
    • Sub-Investigator: Sophia Schlingmann, MD
    • Sub-Investigator: Oliver Mayer, MD
  • Dresden, Germany
    • University Hospital Dresden
    • Contact: Sarah Hobelsberger, MD; Email: sarah.hobelsberger@ukdd.de
    • Contact: Frank F Gellrich, MD; Email: FrankFriedrich.Gellrich@ukdd.de
    • Principal Investigator: Sarah Hobelsberger, MD
    • Sub-Investigator: Frank F Gellrich, MD
  • Erlangen, Germany
    • University Hospital Erlangen
    • Contact: Carola Berking, MD; Email: carola.berking@uk-erlangen.de
    • Principal Investigator: Carola Berking, MD
    • Contact: Moritz Ronicke, MD; Email: moritz.ronicke@uk-erlangen.de
    • Sub-Investigator: Moritz Ronicke, MD
    • Sub-Investigator: Leonie Staats, MD
    • Sub-Investigator: Michael Höner, MD
  • Munich, Germany
    • Ludwig Maximilian University Hospital
    • Contact: Elke C Sattler, MD; Email: elke.sattler@med.uni-muenchen.de
    • Contact: Charlotte Gust, MD; Email: charlotte.gust@med.uni-muenchen.de
    • Principal Investigator: Elke Sattler, MD
    • Sub-Investigator: Charlotte Gust, MD
    • Sub-Investigator: Quirine Eijkenboom, MD
    • Sub-Investigator: Benedikt Reiner, MD
    • Sub-Investigator: Surina Frey, MD
    • Sub-Investigator: Nina Janjic, MD
    • Sub-Investigator: Martin Flatz, MD
    • Sub-Investigator: Lea Jakob, MD
    • Sub-Investigator: Stephanie Steckmeier, MD
  • Munich, Germany
    • München Klinik
    • Contact: Daniela Hartmann, MD, PhD; Email: daniela.hartmann@muenchen-klinik.de
    • Contact: Maximilian Deußing, MD; Email: maximilian.deussing@muenchen-klinik.de
    • Principal Investigator: Daniela Hartmann, MD
    • Sub-Investigator: Maximilian Deußing, MD
    • Sub-Investigator: Fabia Daxenberger, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults (≥18 years) with basal cell carcinoma (BCC) scheduled for Mohs micrographic surgery (MMS),
• Diagnosis confirmed by dermoscopy and histopathology or optical coherence tomography (OCT),
• No limitation regarding tumor size or BCC subgroups.

Exclusion Criteria:

• Poor LC-OCT image quality,
• Incomplete adherence to the study protocol,
• Previous treatment of the BCC,
• Anatomical sites that are difficult to access with LC-OCT (e.g., inner ear, medial canthus of the eye).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention group (LC-OCT); Preoperative tumour margin assessment using LC-OCT with targeted extension of resection margins in cases where imaging reveals tumour evidence.	Diagnostic test: Margin Mapping with Line-field confocal optical coherence tomography; Both groups undergo micrographically controlled excision (Mohs surgery) in accordance with standard procedure. Surgical margins are examined histopathologically as usual (e.g. Tübingen cake, Munich method). If tumour remnants are detected, re-excision (MMS cycle) is performed until the tumour is completely removed (R0). The difference in the intervention group is that they will receive preoperative (and if available) postoperative margin mapping of the BCC before surgery.
No Intervention: Control group (standard MMS); Conventional clinical/dermatoscopic margin determination, as is customary in everyday clinical practice.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of surgical excision cycles (MMS cycles) required until complete tumour removal	Primary endpoints: Number of surgical excision cycles (MMS cycles) required until complete tumour removal (R0 status). This target parameter is directly related to the main question of whether preoperative margin assessment using LC-OCT increases the efficiency of MMS. A significant difference (e.g. fewer MMS cycles in the intervention group) would prove that the image-guided procedure is more effective.	On the day of surgery (Day 0), after the first histopathological margin assessment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total duration of the surgical procedure	Total duration of the surgical procedure (in minutes) → Recorded from the incision to the end of the operation.	intraoperatively, on the day of surgery (Day 0)
Area of the surgical defect after complete tumour removal	Area of the surgical defect after complete tumour removal (in cm²) → Documented for the purpose of assessing tissue preservation.	after the last excision, before wound closure
Cosmetic outcome of the scar	Cosmetic outcome of the scar (e.g. using Patient and Observer Scar Assessment Scale (POSAS)). The observer scale of the POSAS consists of six items (vascularity, pigmentation, thickness, relief, pliability and surface area). All items are scored on a scale ranging from 1 ('like normal skin') to 10 ('worst scar imaginable'). The sum of the six items results in a total score of the POSAS observer scale. Categories boxes are added for each item. Furthermore, an overall opinion is scored on a scale ranging from 1 to 10. All parameters should preferably be compared to normal skin on a comparable anatomic location. → Assessment after a defined post-operative period.	at follow-up 2, approx. week 6-12
Patient satisfaction	Patient satisfaction → Determined by validated questionnaire (e.g. Likert scale for subjective evaluation of the process and result). A 5-point Likert scale is a popular rating scale for surveys that uses five options to measure opinions, attitudes, or perceptions, typically ranging from "Strongly Disagree" to "Strongly Agree," with a neutral option in the middle.	week 6-12
Correlation between LC-OCT findings and histopathological margin status	Correlation between LC-OCT findings and histopathological margin status → Specification of sensitivity, specificity, positive and negative predictive value of LC-OCT.	within 7 days after surgery
Number of unexpected tumour detections in peripheral areas originally assessed as tumour-free	Number of unexpected tumour detections in peripheral areas originally assessed as tumour-free → Evaluation of the diagnostic reliability of LC-OCT.	within 7 days after surgery
Occurrence of complications or adverse events	Occurrence of complications or adverse events (e.g. delayed wound healing, infection) → To assess the safety of the procedure.	until completion of the second follow-up (i.e., by week 6-12)

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
The proportion of each BCC subtype (nodular, superficial, or infiltrative BCC) if BCC was not excised in a one-step operation.	For lesions in which (LC)-OCT margin assessment did not result in a one-step operation, the proportion of each BCC subtype (nodular, superficial, or infiltrative BCC) should be determined.	within 7 days after surgery
the proportion of BCCs whose margins in the first surgical step were not tumor-free (i) laterally and (ii) in depth if BCC was not excised in a one-step operation.	For lesions in which (LC)-OCT margin assessment did not result in a one-step operation, the proportion of BCCs whose margins in the first surgical step were not tumor-free (i) laterally and (ii) in depth should be determined.	within 7 days after surgery
Anatomical Location of Skin Lesions Assessed by LC-OCT Imaging	For lesions in which (LC)-OCT margin assessment did not result in a one-step operation, it should be assessed, whether the anatomical location had an influence. The anatomical location of each included skin lesion will be documented using standardized dermatological body site mapping (International Classification of Anatomical Sites for Dermatology). Assessment will be performed by line-field confocal optical coherence tomography (LC-OCT), which provides high-resolution vertical and horizontal images of epidermal and dermal structures. For each lesion, the exact body site (e.g., face - nasal sidewall; trunk - upper back; extremities - dorsal forearm) will be recorded according to the predefined anatomical site categories.	Baseline (Day 0)

Collaborators and Investigators

• Sponsor: University Hospital Augsburg
• Investigators: Principal Investigator: Julia Welzel, MD, University Hospital Augsburg

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): August 31, 2026
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: November 21, 2025
• First Submitted That Met QC Criteria: March 16, 2026
• First Posted (Actual): March 19, 2026

Study Record Updates

• Last Update Posted (Actual): March 19, 2026
• Last Update Submitted That Met QC Criteria: March 16, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: skin cancer; BCC; basal cell carcinoma; margin assessment; Mohs micrographic surgery; MMS; LC-OCT; line-field confocal optical coherence tomography; margin mapping; one stop shop
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Neoplasms by Histologic Type; Neoplasms, Glandular and Epithelial; Skin Diseases; Carcinoma; Neoplasms, Basal Cell; Skin and Connective Tissue Diseases; Skin Neoplasms; Carcinoma, Basal Cell
• Other Study ID Numbers: BCC-One-Stop-Study

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No