- Email: [email protected]
40. Surgical margin status after breast conserving surgery and presence of residual disease
ABSTRACTS
S81
Abstract 38 Table 1 All 57 (100)
Age, median (IQR), years Presentation Mass Skin Abnormality Histology Ductal Lobular Mixed Mammary cN+ pCR Breast pCR LN (of 52 cN+) LN+, median, IQR Total pCR (ypT0/is,ypN0)
Biologic Subtype N (%)
P Value
ER+/H2-17 (30)
H2+25 (44)
ER-/H2-15 (26)
55 (49e61)
55 (50e60)
53 (38e59)
60 (50e67)
15 (26) 41 (72)
3 (18) 13 (76)
6 (24) 19 (76)
9 (60) 6 (40)
49 (86) 4 (7) 4 (7) 52 (91) 22 (39) 21 (40) 8 (4e11) 20 (35)
14 (82) 2 (12) 1 (6) 16 (94) 1 (6) 1 (6) 8 (3e14) 0
24 (96) 0 1 (4) 23 (92) 15 (60) 15 (65) 0 (0e3) 14 (56)
11 (73) 2 (13) 2 (13) 13 (87) 6 (40) 5 (38) 5 (0e9) 6 (40)
0.11 0.36
0.18
Conflict of interest: No conflict of interest. http://dx.doi.org/10.1016/j.ejso.2016.06.044
39. Magnetic marker localization for non-palpable breast cancer: Initial experience B. Schermers1, J.A. Van der Hage1, F.H. Van Duijnhoven1, C.E. Loo2, H.A.O. Warnars2, B. Ten Haken3, T.J.M. Ruers1 1 The Netherlands Cancer Institute, Surgery, Amsterdam, Netherlands 2 The Netherlands Cancer Institute, Radiology, Amsterdam, Netherlands 3 University of Twente, Magnetic Detection, Enschede, Netherlands Introduction: Magnetic Marker Localization (MaMaLoc) was developed as a novel intra-operative localization technology for non-palpable breast cancer. It aims to replace other localization technologies. The MaMaLoc technology consists of a newly developed magnetic localization marker and a magnetic detector. We present the ex vivo and first in vivo experience with the technology. Material and methods: The magnetic marker was first implanted into a chicken breast. Imaging was obtained to assess the visibility of the marker on ultrasound (US), mammography, computed tomography (CT) and magnetic resonance imaging (MRI), which is essential for the intended image-guided placement of the marker. Next, the marker was implanted into two breast amputation specimens. Two surgeons were then tasked to perform breast conserving surgery (BCS) on a simulated lesion in the breast specimen using a magnetic detector. They scored the performance of the magnetic technology based upon their experience with other localization technologies. Next, an in vivo safety and feasibility study was designed. Fifteen patients with a unifocal lesion that were scheduled for primary BCS using a single iodine seed (Radioactive Seed Localisation, RSL) were included. Subjects received both the standard of care (RSL) and the experimental magnetic technology (MaMaLoc). Both iodine seed and magnetic marker were placed in a single session using US guidance. Up to 30 days after placement, BCS was performed. During surgery, the ability to transcutaneously detect the magnetic marker using the magnetic detector was recorded. Semi-objective data regarding the technology were obtained from radiologists and surgeons, utilizing a 5-points Likert scale ranging from ‘Strongly Disagree’ to ‘Strongly Agree’ and a set of statements regarding convenience, logistics, clinical applicability etcetera and tailored to specific radiology- or surgeryspecific characteristics. Results: Ex vivo data showed excellent visibility on US and mammography, by far the two most used imaging technologies for guided marker placement. On CT, visibility was slightly impaired due to a small artefact. On MRI, a susceptibility artefact obscured a large area of 7 cm diameter.
0.76 <0.001 <0.001 0.004 <0.001
Surgeons scored the technology better than wire-guided localization (WGL) and radioguided occult lesion localisation (ROLL), and at least comparable to RSL. The technology was therefore considered feasible. At the date of abstract submission, the in vivo study was still ongoing and results will be presented at the ESSO 2016 congress. Conclusions: Magnetic marker localization is a promising new technology to improve breast conserving surgery. It combines the benefits of RSL (planning flexibility, continuous re-assessment of surgical approach, accuracy, patient comfort) and of WGL: simplicity. Conflict of interest: No conflict of interest. http://dx.doi.org/10.1016/j.ejso.2016.06.045
40. Surgical margin status after breast conserving surgery and presence of residual disease E. Vos1, J. Gaal2, C. Verhoef1, C. Van Deurzen2, L. Koppert1 1 Erasmus MC Cancer Institute, Surgery, Rotterdam, Netherlands 2 Erasmus MC, Pathology, Rotterdam, Netherlands Background: The Dutch breast cancer guideline advises to accept focally positive margin after breast conserving surgery (BCS) for invasive breast cancer and not to perform re-excision which, in clinical practice, is the case in half of those patients. To shed a light on the safety of this advice we studied which clinicopathological characteristics are associated with a close, focally positive, and extensively positive margin and the presence and predictors of residual disease and local recurrence. Material and methods: All consecutively females undergoing BCS for primary DCIS or invasive (T1eT3) breast cancer between Jan 2005 and April 2014 at the Erasmus MC Cancer Institute were included. Definition of negative margin was tumor 2 mm width from inked margin, close was tumor <2 mm, focally positive was tumor reaching the inked margin over a length of 4 mm, and extensively positive was >4 mm. A subcohort was selected of all patients with re-excision except for those with a negative margin. Their excision specimens were revised by the pathologist. Follow-up information was collected until 1st July 2014. Results: In total, 499 patients were included and 178 (35.6%) had reexcision including 132 (74.2%) by mastectomy. From those 499 patients, 213 (42.7%) had negative margin of which 15.0% a re-excision, 161 (32.3%) had close margin of which 33.8% a re-excision, 59 (11.8%) had focally positive margin of which 66.2% a re-excision, and 67 (13.4%) had extensively positive margin of which 83.9% a re-excision. Higher differentiation grade, larger tumors, lobular type and tumor positive axillary lymph nodes were significantly associated with more involved tumor margins. Residual disease was present in 79 (54.1%) patients with re-excision and in 21 (34.5%) after close margin, 19 (48.7%) after focally positive margin, and in 38 (78.3%) after extensively positive margin. The presence of residual disease was statistically significantly associated with the length
S82 of tumor positive margin (HR 1.16 95% CI 1.02e1.31) and mitotic activity index (<10 vs 10) (HR 0.28 95% CI 0.09e0.84). Grow pattern (diffuse versus circumscript) was not associated with the presence of residual disease. Median time of follow-up was 52 months (interquartile range 24e79). The 5-year local recurrence rate after primary BCS only, re-excision with no residual disease and re-excision with residual disease present was 4.6%, 1.9%, 4.1% respectively. Conclusions: Focally positive margin after primary BCS is associated with higher likelihood of residual disease in the re-excision specimen in comparison to negative margin, but lower likelihood in comparison to extensively positive margin. The length of tumor reaching the inked margin is a predictor of the presence of residual disease and therefore can be used in clinical decision making whether to perform re-excision or not. Conflict of interest: No conflict of interest.
ABSTRACTS Results: Of the 58 patients who participated in this study, 55 completed the protocol. In 48 of the 55 (87%) treated patients, successful tumor ablation, as determined by negative findings on vacuum-assisted or core biopsies and imaging studies, was confirmed. The remaining 7 patients with biopsies positive for residual tumor underwent surgical resection. There were no local or distant recurrences in treated 55 patients with a median follow up of 47 (range 36e73) months. Conclusions: RFA can be safely used alone in patients with small breast tumors, provided that local tumor control must be regularly assessed by image-guided vacuum-assisted or core biopsies after ablation. RFA has several potential advantages over lumpectomy for the treatment of early stage breast cancer. Conflict of interest: No conflict of interest. http://dx.doi.org/10.1016/j.ejso.2016.06.047
http://dx.doi.org/10.1016/j.ejso.2016.06.046
41. A multi-center prospective study of radiofrequency ablation without surgical excision for small breast carcinomas T. Kinoshita1, H. Doihara2, N. Yamamoto3, T. Fujisawa4, M. Takahashi5, K. Aogi6, H. Tsuda7, M. Yoshida8, T. Hojo9, K. Jimbo1, S. Asaga1, S. Takayama1 1 National Cancer Center Hospital, Division of Breast Surgery, Tokyo, Japan 2 Okayama University Hospital, Department of Breast and Endocrine Surgery, Okayama, Japan 3 Chiba Cancer Center, Department of Breast Surgery, Chiba, Japan 4 Gunma Prefectural Cancer Center, Department of Breast Surgery, Ohta, Japan 5 Hokkaido Cancer Center, Department of Breast Surgery, Sapporo, Japan 6 Shikoku Cancer Center, Department of Breast Surgery, Matsuyama, Japan 7 National Defense Medical College Hospital, Department of Pathology, Tokorozawa, Japan 8 National Cancer Center Hospital, Department of Pathology, Tokyo, Japan 9 National Cancer Center Hospital East, Department of Breast Surgery, Kashiwa, Japan Background: As the management of breast carcinoma evolves toward less invasive treatments, the next step is the possibility of removing the primary tumor without surgery. The most promising noninvasive ablation technique is radiofrequency ablation (RFA), which can effectively kill tumor cells with a low complication rate. Our preliminary studies of RFA followed by standard surgical resection have indicated that this technique is effective for surgical ablation of small (2 cm) breast tumors without extensive intraductal components (EIC). Methods: To determine if RFA is oncologically and cosmetically appropriate for the local treatment of primary breast carcinoma, this multi-center prospective study used RFA as the sole local treatment of breast tumors 1.5 cm in size on ultrasound and MRI. Exclusion criteria include receiving of preoperative chemotherapy, or the presence of invasive lobular carcinoma or invasive ductal carcinoma with suspicious EIC. After confirmation that the standard baseline core biopsy for diagnosis and measurement of tumors markers (ER, PgR, HER-2/neu expression and the presence of the Ki-67 proliferative marker) have been obtained, consent will be obtained and the patient scheduled RFA. All patients received adjuvant radiation therapy. The use and choice of systemic therapy will be based on the information from the baseline core biopsy. The first primary endpoints of this study are successful tumor ablation, as evidenced by negative findings on vacuum-assisted or core biopsies and imaging studies after RFA. The second primary endpoints are the incidence of procedure related adverse events. Forty patients with small tumors that are clearly identifiable and measurable by ultrasound and MRI were enrolled. The response to ablation was evaluated with both vacuum-assisted or core biopsies and imaging studies every 3 months during the first year. The long-term outcomes were assessed using quality of life measurement scales and imaging studies every 6 months thereafter through year 5.
42. Towards the intraoperative use of diffuse reflectance spectroscopy during breast conserving surgery L.L. De Boer1, B.H.W. Hendriks2,3, T.M. Bydlon2, C.E. Loo4, F. Van Duijnhoven1, T.J.M. Ruers1,5 1 Netherlands Cancer Institute, Department of Surgery, Amsterdam, Netherlands 2 Philips Research, In-body Systems Group, Eindhoven, Netherlands 3 Delft University of Technology, Biomechanical Engineering, Delft, Netherlands 4 Netherlands Cancer Institute, Department of Radiology, Amsterdam, Netherlands 5 University Twente, MIRA Institute, Enschede, Netherlands Background: Tumor-free resection margins are indispensable for successful breast conserving surgery. This is a challenging requirement for surgeons since tumor tissue deposits can be difficult to recognize during surgery. Diffuse Reflectance Spectroscopy (DRS) is an optical technology that measures the spectral response of tissue after illumination with light. The measured DRS spectrum can be translated into optical parameters (i.e. blood, saturation, fat, water) providing an optical fingerprint of tissue which can be used for differentiating tissue types. In breast cancer, biological differences between normal tissue and tumor tissue, among other things, consist of changes in fat and water content. Here we investigate if real-time tissue characterization based on diffuse reflectance spectroscopy can be a feasible technology for the intra-operative detection of tumor deposits on a margin. Material and methods: To obtain a reliable correlation between the optical measurements and histology, our DRS technology was integrated into 16G biopsy needle which was used during routine US-guided biopsy (n ¼ 35) for breast cancer diagnosis. In each patient, optical measurements were obtained of normal tissue and tumor tissue. Furthermore, in five patients continuous measurements were obtained along the needle trajectory from normal tissue towards the tumor. At the final measurement location, a biopsy was taken to confirm histopathology. Results/Discussion: The optical parameters derived from the DRS measurements were used to discriminate normal tissue from tumor tissue. Saturation, fraction Mie scattering, collagen, amount of water and especially the fat content were significantly different between these tissue types. The mean fat content provided the best discrimination between normal and tumor tissue as it decreased from 74% to 26%. This decrease was observed in all patients, except one. DRS measurements showed an accuracy of 96% in predicting tissue diagnosis (tumor versus normal breast tissue). Additionally, the measurements obtained in the continuous mode proved that the fat content could display the transition from normal tissue to tumor tissue as these measurements followed the same trends as the initial point-measurements. Conclusions: DRS can real-time discriminate normal breast tissue from tumor tissue during breast biopsy procedures. Furthermore, the border of the tumor could be detected based on the optical parameters derived from the DRS measurements. Especially fat proved to be useful for detecting the tumor border. The next step towards implementation of
S81
Abstract 38 Table 1 All 57 (100)
Age, median (IQR), years Presentation Mass Skin Abnormality Histology Ductal Lobular Mixed Mammary cN+ pCR Breast pCR LN (of 52 cN+) LN+, median, IQR Total pCR (ypT0/is,ypN0)
Biologic Subtype N (%)
P Value
ER+/H2-17 (30)
H2+25 (44)
ER-/H2-15 (26)
55 (49e61)
55 (50e60)
53 (38e59)
60 (50e67)
15 (26) 41 (72)
3 (18) 13 (76)
6 (24) 19 (76)
9 (60) 6 (40)
49 (86) 4 (7) 4 (7) 52 (91) 22 (39) 21 (40) 8 (4e11) 20 (35)
14 (82) 2 (12) 1 (6) 16 (94) 1 (6) 1 (6) 8 (3e14) 0
24 (96) 0 1 (4) 23 (92) 15 (60) 15 (65) 0 (0e3) 14 (56)
11 (73) 2 (13) 2 (13) 13 (87) 6 (40) 5 (38) 5 (0e9) 6 (40)
0.11 0.36
0.18
Conflict of interest: No conflict of interest. http://dx.doi.org/10.1016/j.ejso.2016.06.044
39. Magnetic marker localization for non-palpable breast cancer: Initial experience B. Schermers1, J.A. Van der Hage1, F.H. Van Duijnhoven1, C.E. Loo2, H.A.O. Warnars2, B. Ten Haken3, T.J.M. Ruers1 1 The Netherlands Cancer Institute, Surgery, Amsterdam, Netherlands 2 The Netherlands Cancer Institute, Radiology, Amsterdam, Netherlands 3 University of Twente, Magnetic Detection, Enschede, Netherlands Introduction: Magnetic Marker Localization (MaMaLoc) was developed as a novel intra-operative localization technology for non-palpable breast cancer. It aims to replace other localization technologies. The MaMaLoc technology consists of a newly developed magnetic localization marker and a magnetic detector. We present the ex vivo and first in vivo experience with the technology. Material and methods: The magnetic marker was first implanted into a chicken breast. Imaging was obtained to assess the visibility of the marker on ultrasound (US), mammography, computed tomography (CT) and magnetic resonance imaging (MRI), which is essential for the intended image-guided placement of the marker. Next, the marker was implanted into two breast amputation specimens. Two surgeons were then tasked to perform breast conserving surgery (BCS) on a simulated lesion in the breast specimen using a magnetic detector. They scored the performance of the magnetic technology based upon their experience with other localization technologies. Next, an in vivo safety and feasibility study was designed. Fifteen patients with a unifocal lesion that were scheduled for primary BCS using a single iodine seed (Radioactive Seed Localisation, RSL) were included. Subjects received both the standard of care (RSL) and the experimental magnetic technology (MaMaLoc). Both iodine seed and magnetic marker were placed in a single session using US guidance. Up to 30 days after placement, BCS was performed. During surgery, the ability to transcutaneously detect the magnetic marker using the magnetic detector was recorded. Semi-objective data regarding the technology were obtained from radiologists and surgeons, utilizing a 5-points Likert scale ranging from ‘Strongly Disagree’ to ‘Strongly Agree’ and a set of statements regarding convenience, logistics, clinical applicability etcetera and tailored to specific radiology- or surgeryspecific characteristics. Results: Ex vivo data showed excellent visibility on US and mammography, by far the two most used imaging technologies for guided marker placement. On CT, visibility was slightly impaired due to a small artefact. On MRI, a susceptibility artefact obscured a large area of 7 cm diameter.
0.76 <0.001 <0.001 0.004 <0.001
Surgeons scored the technology better than wire-guided localization (WGL) and radioguided occult lesion localisation (ROLL), and at least comparable to RSL. The technology was therefore considered feasible. At the date of abstract submission, the in vivo study was still ongoing and results will be presented at the ESSO 2016 congress. Conclusions: Magnetic marker localization is a promising new technology to improve breast conserving surgery. It combines the benefits of RSL (planning flexibility, continuous re-assessment of surgical approach, accuracy, patient comfort) and of WGL: simplicity. Conflict of interest: No conflict of interest. http://dx.doi.org/10.1016/j.ejso.2016.06.045
40. Surgical margin status after breast conserving surgery and presence of residual disease E. Vos1, J. Gaal2, C. Verhoef1, C. Van Deurzen2, L. Koppert1 1 Erasmus MC Cancer Institute, Surgery, Rotterdam, Netherlands 2 Erasmus MC, Pathology, Rotterdam, Netherlands Background: The Dutch breast cancer guideline advises to accept focally positive margin after breast conserving surgery (BCS) for invasive breast cancer and not to perform re-excision which, in clinical practice, is the case in half of those patients. To shed a light on the safety of this advice we studied which clinicopathological characteristics are associated with a close, focally positive, and extensively positive margin and the presence and predictors of residual disease and local recurrence. Material and methods: All consecutively females undergoing BCS for primary DCIS or invasive (T1eT3) breast cancer between Jan 2005 and April 2014 at the Erasmus MC Cancer Institute were included. Definition of negative margin was tumor 2 mm width from inked margin, close was tumor <2 mm, focally positive was tumor reaching the inked margin over a length of 4 mm, and extensively positive was >4 mm. A subcohort was selected of all patients with re-excision except for those with a negative margin. Their excision specimens were revised by the pathologist. Follow-up information was collected until 1st July 2014. Results: In total, 499 patients were included and 178 (35.6%) had reexcision including 132 (74.2%) by mastectomy. From those 499 patients, 213 (42.7%) had negative margin of which 15.0% a re-excision, 161 (32.3%) had close margin of which 33.8% a re-excision, 59 (11.8%) had focally positive margin of which 66.2% a re-excision, and 67 (13.4%) had extensively positive margin of which 83.9% a re-excision. Higher differentiation grade, larger tumors, lobular type and tumor positive axillary lymph nodes were significantly associated with more involved tumor margins. Residual disease was present in 79 (54.1%) patients with re-excision and in 21 (34.5%) after close margin, 19 (48.7%) after focally positive margin, and in 38 (78.3%) after extensively positive margin. The presence of residual disease was statistically significantly associated with the length
S82 of tumor positive margin (HR 1.16 95% CI 1.02e1.31) and mitotic activity index (<10 vs 10) (HR 0.28 95% CI 0.09e0.84). Grow pattern (diffuse versus circumscript) was not associated with the presence of residual disease. Median time of follow-up was 52 months (interquartile range 24e79). The 5-year local recurrence rate after primary BCS only, re-excision with no residual disease and re-excision with residual disease present was 4.6%, 1.9%, 4.1% respectively. Conclusions: Focally positive margin after primary BCS is associated with higher likelihood of residual disease in the re-excision specimen in comparison to negative margin, but lower likelihood in comparison to extensively positive margin. The length of tumor reaching the inked margin is a predictor of the presence of residual disease and therefore can be used in clinical decision making whether to perform re-excision or not. Conflict of interest: No conflict of interest.
ABSTRACTS Results: Of the 58 patients who participated in this study, 55 completed the protocol. In 48 of the 55 (87%) treated patients, successful tumor ablation, as determined by negative findings on vacuum-assisted or core biopsies and imaging studies, was confirmed. The remaining 7 patients with biopsies positive for residual tumor underwent surgical resection. There were no local or distant recurrences in treated 55 patients with a median follow up of 47 (range 36e73) months. Conclusions: RFA can be safely used alone in patients with small breast tumors, provided that local tumor control must be regularly assessed by image-guided vacuum-assisted or core biopsies after ablation. RFA has several potential advantages over lumpectomy for the treatment of early stage breast cancer. Conflict of interest: No conflict of interest. http://dx.doi.org/10.1016/j.ejso.2016.06.047
http://dx.doi.org/10.1016/j.ejso.2016.06.046
41. A multi-center prospective study of radiofrequency ablation without surgical excision for small breast carcinomas T. Kinoshita1, H. Doihara2, N. Yamamoto3, T. Fujisawa4, M. Takahashi5, K. Aogi6, H. Tsuda7, M. Yoshida8, T. Hojo9, K. Jimbo1, S. Asaga1, S. Takayama1 1 National Cancer Center Hospital, Division of Breast Surgery, Tokyo, Japan 2 Okayama University Hospital, Department of Breast and Endocrine Surgery, Okayama, Japan 3 Chiba Cancer Center, Department of Breast Surgery, Chiba, Japan 4 Gunma Prefectural Cancer Center, Department of Breast Surgery, Ohta, Japan 5 Hokkaido Cancer Center, Department of Breast Surgery, Sapporo, Japan 6 Shikoku Cancer Center, Department of Breast Surgery, Matsuyama, Japan 7 National Defense Medical College Hospital, Department of Pathology, Tokorozawa, Japan 8 National Cancer Center Hospital, Department of Pathology, Tokyo, Japan 9 National Cancer Center Hospital East, Department of Breast Surgery, Kashiwa, Japan Background: As the management of breast carcinoma evolves toward less invasive treatments, the next step is the possibility of removing the primary tumor without surgery. The most promising noninvasive ablation technique is radiofrequency ablation (RFA), which can effectively kill tumor cells with a low complication rate. Our preliminary studies of RFA followed by standard surgical resection have indicated that this technique is effective for surgical ablation of small (2 cm) breast tumors without extensive intraductal components (EIC). Methods: To determine if RFA is oncologically and cosmetically appropriate for the local treatment of primary breast carcinoma, this multi-center prospective study used RFA as the sole local treatment of breast tumors 1.5 cm in size on ultrasound and MRI. Exclusion criteria include receiving of preoperative chemotherapy, or the presence of invasive lobular carcinoma or invasive ductal carcinoma with suspicious EIC. After confirmation that the standard baseline core biopsy for diagnosis and measurement of tumors markers (ER, PgR, HER-2/neu expression and the presence of the Ki-67 proliferative marker) have been obtained, consent will be obtained and the patient scheduled RFA. All patients received adjuvant radiation therapy. The use and choice of systemic therapy will be based on the information from the baseline core biopsy. The first primary endpoints of this study are successful tumor ablation, as evidenced by negative findings on vacuum-assisted or core biopsies and imaging studies after RFA. The second primary endpoints are the incidence of procedure related adverse events. Forty patients with small tumors that are clearly identifiable and measurable by ultrasound and MRI were enrolled. The response to ablation was evaluated with both vacuum-assisted or core biopsies and imaging studies every 3 months during the first year. The long-term outcomes were assessed using quality of life measurement scales and imaging studies every 6 months thereafter through year 5.
42. Towards the intraoperative use of diffuse reflectance spectroscopy during breast conserving surgery L.L. De Boer1, B.H.W. Hendriks2,3, T.M. Bydlon2, C.E. Loo4, F. Van Duijnhoven1, T.J.M. Ruers1,5 1 Netherlands Cancer Institute, Department of Surgery, Amsterdam, Netherlands 2 Philips Research, In-body Systems Group, Eindhoven, Netherlands 3 Delft University of Technology, Biomechanical Engineering, Delft, Netherlands 4 Netherlands Cancer Institute, Department of Radiology, Amsterdam, Netherlands 5 University Twente, MIRA Institute, Enschede, Netherlands Background: Tumor-free resection margins are indispensable for successful breast conserving surgery. This is a challenging requirement for surgeons since tumor tissue deposits can be difficult to recognize during surgery. Diffuse Reflectance Spectroscopy (DRS) is an optical technology that measures the spectral response of tissue after illumination with light. The measured DRS spectrum can be translated into optical parameters (i.e. blood, saturation, fat, water) providing an optical fingerprint of tissue which can be used for differentiating tissue types. In breast cancer, biological differences between normal tissue and tumor tissue, among other things, consist of changes in fat and water content. Here we investigate if real-time tissue characterization based on diffuse reflectance spectroscopy can be a feasible technology for the intra-operative detection of tumor deposits on a margin. Material and methods: To obtain a reliable correlation between the optical measurements and histology, our DRS technology was integrated into 16G biopsy needle which was used during routine US-guided biopsy (n ¼ 35) for breast cancer diagnosis. In each patient, optical measurements were obtained of normal tissue and tumor tissue. Furthermore, in five patients continuous measurements were obtained along the needle trajectory from normal tissue towards the tumor. At the final measurement location, a biopsy was taken to confirm histopathology. Results/Discussion: The optical parameters derived from the DRS measurements were used to discriminate normal tissue from tumor tissue. Saturation, fraction Mie scattering, collagen, amount of water and especially the fat content were significantly different between these tissue types. The mean fat content provided the best discrimination between normal and tumor tissue as it decreased from 74% to 26%. This decrease was observed in all patients, except one. DRS measurements showed an accuracy of 96% in predicting tissue diagnosis (tumor versus normal breast tissue). Additionally, the measurements obtained in the continuous mode proved that the fat content could display the transition from normal tissue to tumor tissue as these measurements followed the same trends as the initial point-measurements. Conclusions: DRS can real-time discriminate normal breast tissue from tumor tissue during breast biopsy procedures. Furthermore, the border of the tumor could be detected based on the optical parameters derived from the DRS measurements. Especially fat proved to be useful for detecting the tumor border. The next step towards implementation of