Breast carcinoma detection in ex vivo fresh human breast surgical specimens using a fast slide-free confocal microscopy scanner: HIBISCUSS project

Abstract

Background: New generation ultra-fast fluorescence confocal microscopy allows the ex vivo intraoperative analysis of fresh tissue. The High resolution Imaging for Breast carcInoma detection in ex vivo Specimens after breast Conserving sUrgery by hiStolog Scanner (HIBISCUSS) project aimed to develop an online learning program to recognize the main breast tissue features on ultra-fast fluorescence confocal microscopy images and to evaluate the performance of surgeons and pathologists in diagnosing cancerous and non-cancerous breast tissue in ultra-fast fluorescence confocal microscopy images.

Methods: Patients who underwent conservative surgery or mastectomy for breast carcinoma (invasive or in situ lesions) were included. The fresh specimens were stained with a fluorescent dye and imaged using a large field-of-view (20 cm2) ultra-fast fluorescence confocal microscope.

Results: One hundred and eighty-one patients were included. The images from 55 patients were annotated to generate learning sheets and images from 126 patients were blindly interpreted by seven surgeons and two pathologists. The time for tissue processing and ultra-fast fluorescence confocal microscopy imaging was between 8 and 10 min. The training program was composed of 110 images divided into nine learning sessions. The final database for blind performance assessment comprised 300 images. The mean duration for one training session and one performance round was 17 and 27 min respectively. The performance of pathologists was almost perfect with 99.6 per cent (standard deviation (s.d.) 5.4 per cent) accuracy. Surgeons' accuracy significantly increased (P = 0.001) from 83 per cent (s.d. 8.4 per cent) in round 1 to 98 per cent (s.d. 4.1 per cent) in round 7 as well as the sensitivity (P = 0.004). Specificity increased without significance from 84 per cent (s.d. 16.7 per cent) in round 1 to 87 per cent (s.d. 16.4 per cent) in round 7 (P = 0.060).

Conclusion: Pathologists and surgeons showed a short learning curve in differentiating breast cancer from non-cancerous tissue in ultra-fast fluorescence confocal microscopy images. Performance assessment for both specialties supports ultra-fast fluorescence confocal microscopy evaluation for intraoperative management.

Registration number: NCT04976556 (http://www.clinicaltrials.gov).

Fig. 1

Synopsis of the study: from breast specimen collection to ultra-fast confocal microscopy images performance assessment a A total of 181 patients were included in the HIBISCUSS project and the corresponding breast surgical specimens (lumpectomy or samples from mastectomy) were imaged by the ultra-fast confocal microscope (UFCM). Tissues were then processed for further conventional histology (haematoxylin, eosin and saffron (HES) sections) and final diagnosis was collected. b In total, 110 UFCM images from 55 patients were used to develop a training material presented to seven surgeons and two pathologists. c Finally, 300 UFCM images from 126 patients were interpreted by the nine physicians in a blind performance assessment study. HIBISCUSS, High resolution Imaging for Breast carcInoma detection in ex vivo Specimens after breast Conserving sUrgery by hiStolog Scanner.

Fig. 2

Typical non-cancerous ultra-fast confocal microscopy images correctly identified by all seven surgeons and two pathologists at low magnification (lumpectomy section) and high magnification with corresponding haematoxylin, eosin and saffron sections (a, b, d, e, g, h UFCM images; c, f, i HES slides) (a–c) Lobules (in the inset). (d–f) Fibrosis (in the inset). (g–i) Fatty tissue and inflammatory cells (in the inset). UFCM, ultra-fast confocal microscope; HES, haematoxylin, eosin and saffron.

Fig. 3

Typical cancerous ultra-fast confocal microscopy images correctly identified by all the surgeons and pathologists at low magnification (lumpectomy section) and high magnification with corresponding haematoxylin, eosin and saffron sections (a, b, d, e, g, h UFCM images; c, f, i HES slides) (a–c) Invasive carcinoma of no special type. (d–f) Invasive lobular carcinoma. (g–i) Ductal carcinoma in situ. UFCM, ultra-fast confocal microscope; HES, haematoxylin, eosin and saffron.

Fig. 4

Performance of physicians for breast cancer detection in ultra-fast confocal microscopy images (a) Surgeons' and (b) pathologists' performance by round.

Fig. 5

Examples of ultra-fast confocal microscopy images not correctly classified by more than four surgeons at low magnification (lumpectomy section) and high magnification with corresponding haematoxylin, eosin and saffron section (a–c) Non-tumoural tissue incorrectly classified as tumoural tissue by five surgeons and one pathologist. (d–f) Non-tumoural tissue incorrectly classified as tumoural tissue by six surgeons. (g–i) Invasive carcinoma and ductal carcinoma in situ incorrectly classified as non-tumoural tissue by four surgeons. (j–l) Non-tumoural tissue incorrectly classified as tumoural tissue by six surgeons.