Purpose

Basal cell carcinoma (BCC) is the most commonly diagnosed skin cancer and is treated by surgical resection. Incomplete tumor removal requires surgical revision, leading to significant healthcare costs and impaired cosmesis. We investigated the clinical feasibility of a surgical navigation system for BCC surgery, based on molecular tissue characterization using rapid evaporative ionization mass spectrometry (REIMS).

Methods

REIMS enables direct tissue characterization by analysis of cell-specific molecules present within surgical smoke, produced during electrocautery tissue resection. A tissue characterization model was built by acquiring REIMS spectra of BCC, healthy skin and fat from ex vivo skin cancer specimens. This model was used for tissue characterization during navigated skin cancer surgery. Navigation was enabled by optical tracking and real-time visualization of the cautery relative to a contoured resection volume. The surgical smoke was aspirated into a mass spectrometer and directly analyzed with REIMS. Classified BCC was annotated at the real-time position of the cautery. Feasibility of the navigation system, and tissue classification accuracy for ex vivo and intraoperative surgery were evaluated.

Results

Fifty-four fresh excision specimens were used to build the ex vivo model of BCC, normal skin and fat, with 92% accuracy. While 3 surgeries were successfully navigated without breach of sterility, the intraoperative performance of the ex vivo model was low (< 50%). Hypotheses are: (1) the model was trained on heterogeneous mass spectra that did not originate from a single tissue type, (2) during surgery mixed tissue types were resected and thus presented to the model, and (3) the mass spectra were not validated by pathology.

Conclusion

REIMS-navigated skin cancer surgery has the potential to detect and localize remaining tumor intraoperatively. Future work will be focused on improving our model by using a precise pencil cautery tip for burning localized tissue types, and having pathology-validated mass spectra.

中文翻译：

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皮肤癌手术中的导航组织表征。

目的

基底细胞癌（BCC）是最常诊断的皮肤癌，可通过手术切除进行治疗。肿瘤切除不彻底需要手术矫正，从而导致可观的医疗费用和美容功能受损。我们基于使用快速蒸发电离质谱（REIMS）进行的分子组织表征，研究了BCC外科手术导航系统的临床可行性。

方法

REIMS通过分析电灼组织切除过程中产生的外科手术烟雾中存在的细胞特异性分子，实现直接组织表征。通过从离体皮肤癌样本中获取BCC，健康皮肤和脂肪的REIMS光谱，建立了组织表征模型。该模型用于导航性皮肤癌手术期间的组织表征。相对于轮廓切除的体积，可通过光学跟踪和实时显示烧灼来进行导航。将手术烟雾吸入质谱仪中，并用REIMS直接分析。在电烙术的实时位置标注了分类BCC。评估了导航系统的可行性以及离体和术中手术的组织分类准确性。

结果

54个新鲜切除标本用于建立BCC，正常皮肤和脂肪的离体模型，准确度达92％。尽管成功进行了3项手术而不破坏无菌性，但离体模型的术中表现却很低（<50％）。假设是：（1）在不是源自单一组织类型的异质质谱上训练模型；（2）在手术期间切除混合组织类型并呈现给模型；（3）质谱图不正确经病理证实。

结论

REIMS导航的皮肤癌手术具有在手术中检测和定位剩余肿瘤的潜力。未来的工作将集中在通过使用精确的铅笔烧灼尖端来燃烧局部组织类型并具有经过病理验证的质谱图来改进我们的模型。