Predictive factors for positive surgical margins in the treatment of breast ductal carcinoma in situ

Tissue-probe contact assessment during robotic surgery using single-fiber reflectance spectroscopy

The introduction of robotic surgery has improved minimally invasive surgery, and now robotic surgery is used in several areas of surgical oncology. Several optical techniques can be used to discriminate cancer from healthy tissue based on their optical properties. These technologies can also be employed with a small fiber-optic probe during minimally invasive surgery; however, for acquiring reliable measurements, some optical techniques require the fiber-optic probe to be in direct contact with the tissue. The lack of tactile feedback in robotic surgery makes assessing tissue-probe contact suitable for optical contact measurements challenging for the surgeon. In this study, we investigated the use of single fiber reflectance (SFR) to determine tissue-probe contact adequately. A machine learning-based algorithm was developed to classify if direct tissue-probe contact was present during the measurement in an ex-vivo tissue setup. Using this classification algorithm, an average accuracy of 93.9% was achieved for assessing probe-tissue contact, suggesting that this technique can be utilized to assess tissue-probe contact in an in vivo clinical setting.

Is the Number or Proximity of Margins Less than 2 mm Associated with an Increased Mastectomy Rate in Patients Attempting Breast Conservation Therapy for Ductal Carcinoma In Situ?

BACKGROUND

Consensus guidelines recommend ≥ 2 mm margins in patients undergoing partial mastectomy (PM) for ductal carcinoma in situ (DCIS). It is unknown whether the number or proximity of margins less than 2 mm is associated with an increased mastectomy rate in patients attempting breast conservation therapy (BCT) for DCIS. The aim of this study is to examine this relationship.

PATIENTS AND METHODS

An institutional database review identified 208 patients with DCIS who underwent PM at a tertiary referral center and community hospitals from July 2020 to June 2023. Patients with a history of breast cancer, previous surgery for breast cancer, ipsilateral invasive carcinoma, papillary carcinoma, Paget's disease, more lobular carcinoma in situ (LCIS) than DCIS present, initial mastectomy, no DCIS present, routine shave margins (of all vectors), and ≥ 2 mm margins of all six vectors were excluded. Selective intraoperative margin re-excisions were included.

RESULTS

A total of 208 patients who met inclusion criteria were retrospectively reviewed. 122 (25%) had one close/positive (< 2 mm) margin and 86 (18%) had two or more close/positive margins. Of the patients with one close/positive margin, 7% (9/122) eventually underwent mastectomy. Of the patients with two or more close/positive margins, 20% (17/86) eventually underwent mastectomy. Overall, no patients with opposing margins underwent mastectomy.

CONCLUSIONS

Patients undergoing PM for DCIS have a mastectomy rate that is increased threefold, with two or more close/positive margins at initial PM, when compared with those with only one close/positive margin. The presence of opposing close/positive margins at initial PM did not increase the mastectomy rate and most were cleared with re-excision.

Positive surgical margins after breast-conserving surgery for ductal carcinoma in-situ: does histologic grade or estrogen receptor status matter?

PURPOSE

DCIS has been shown to have a higher rate of positive margins following breast-conserving surgery (BCS) than invasive breast cancer. We aim to analyze certain factors of DCIS, specifically histologic grade and estrogen receptor (ER) status, in patients with positive surgical margins following BCS to determine if there is an association.

METHODS

A retrospective review of our institutional patient registry was performed to identify women with DCIS and microinvasive DCIS who underwent BCS by a single surgeon from 1999 to 2021. Demographics and clinicopathologic characteristics between patients with and without positive surgical margins were compared using chi-square or Student's t-test. We assessed factors associated with positive margins using univariate and multivariable logistic regression.

RESULTS

Of the 615 patients evaluated, there was no significant difference in demographics between the patients with and without positive surgical margins. Increasing tumor size was an independent risk factor for margin positivity (P =  < 0.001). On univariate analysis both high histologic grade (P = 0.009) and negative ER status (P =  < 0.001) were significantly associated with positive surgical margins. However, when adjusted in multivariable analysis, only negative ER status remained significantly associated with margin positivity (OR = 0.39 [95% CI 0.20-0.77]; P = 0.006).

CONCLUSION

The study confirms increased tumor size as a risk factor for positive surgical margins. We also demonstrated that ER negative DCIS was independently associated with a higher rate of positive margins after BCS. Given this information, we can modify our surgical approach to reduce rate of positive margins in patients with large-sized ER negative DCIS.

Reoperation rate of ductal carcinoma in situ: impact of tomosynthesis (3D) and spot magnification

BACKGROUND

Surgical planning depends on precise preoperative assessment of the radiological extent of ductal carcinoma in situ (DCIS). Despite different modalities used, reoperation rates for DCIS due to involved margins are high.

PURPOSE

To evaluate the impact of additional imaging views (spot magnification, tomosynthesis) on surgical reoperation rate of DCIS.

MATERIAL AND METHODS

The retrospective single institute study includes 157 patients with biopsy-proven pure DCIS seen on mammogram as microcalcifications and treated with breast-conserving surgery. Patients have been divided into three groups according to additional imaging performed: spot magnification, tomosynthesis, and none. All breast images (mammograms, spot magnification, tomosynthesis) were reviewed and the maximum extent of pathological microcalcifications was recorded. Radiological size was compared to final histopathological size. Reoperation rate due to inadequate margins was recorded.

RESULTS

Reoperation rates (25%) due to inadequate margins were as follows: spot (18%), tomosynthesis (27%), none (31%); P = 0.488. Spot magnification, tomosynthesis, and digital zoom of full-field digital mammography predicted similarly the final histopathological size. Reoperation group had a significantly greater preoperative radiological median size (26 mm vs. 20 mm; P = 0.014) as well as median size of disease on final histopathological report (29 mm vs. 14 mm; P < 0.001). Discrepancy between radiological and final histopathological size became greater with increasing DCIS extent.

CONCLUSION

The main factors for reoperations are DCIS size and discordance between radiological and histopathological sizes. The use of additional imaging views (spot magnification, tomosynthesis) did not reduce reoperation rate.

The effect of the tumor-to-skin distance on axillary lymph node metastasis in breast cancer

OBJECTIVE

Tumor-to-skin distance is known to have an effect on axillary lymph node metastasis but has no clinical use with nomograms. This study aimed to investigate the effect of tumor-to-skin distance on axillary lymph node metastasis alone and in combination with nomogram for clinical use.

METHODS

A total of 145 patients who underwent surgery for breast cancer (T1-T2 stage) and whose axillary lymph nodes were evaluated (axillary dissection or sentinel lymph node biopsy) between January 2010 and December 2020 were included in the study. Tumor-to-skin distance and other pathological data of the patients were evaluated.

RESULTS

Of the 145 patients, 83 (57.2%) had metastatic lymph nodes in the axilla. Tumor-to-skin distance was different in terms of lymph node metastasis (p=0.045). In the receiver operating characteristic curve for tumor-to-skin distance, area under curve was 0.597 (95%CI 0.513-0.678, p=0.046), area under curve of the nomogram was 0.740 (95%CI 0.660-0.809), p<0.001) and nomogram+tumor-to-skin distance was 0.753 (95%CI 0.674-0.820), p<0.001). No statistical difference was found for axillary lymph node metastasis between the nomogram+tumor-to-skin distance and the nomogram alone (p=0.433).

CONCLUSION

Although tumor-to-skin distance demonstrated a significant difference in axillary lymph node metastasis, it had a poor association with an area under curve value of 0.597 and did not produce a significant improvement in predicting lymph node metastasis when combined with the nomogram. The tumor-to-skin distance may be unlikely to enter clinical practice.

MRI predictors of tumor-positive margins after breast-conserving surgery

PURPOSE

The purpose of this study is to identify predictors of tumor-positive surgical margins after breast-conserving surgery on dynamic contrast-enhanced (DCE) MRI.

MATERIALS AND METHODS

We conducted a retrospective study of consecutive women who underwent DCE MRI before breast-conserving surgery from 2005 to 2014. Patient demographics, indication for surgery, MRI findings, biopsy pathology results, and surgical outcomes were reviewed. The unpaired t-test and chi-square test were used to compare the positive and negative margins groups.

RESULTS

554 women (mean age, 56; range, 26-90) underwent DCE MRI before 575 breast-conserving surgeries for invasive carcinoma (n = 473) or ductal carcinoma in situ (DCIS) (n = 102). Positive margins requiring re-excision occurred in 19.7% (93/473) of surgeries for invasive carcinoma and 31.4% (32/102) of surgeries for DCIS. For invasive carcinoma surgeries, positive margins were more common when MRI demonstrated the finding of non-mass enhancement (NME) rather than the finding of enhancing mass (33.8% [22/65] versus 16.9% [61/360], p < 0.01). Tumor size on MRI was significantly larger in the positive margins group (2.5 cm versus 1.9 cm, p < 0.001). Positive margins were more common with invasive lobular rather than invasive ductal histology at core biopsy (38.3% [18/47] versus 16.0% [56/350], p < 0.001). For DCIS surgeries, there were no significant differences in positive margin rates related to MRI features.

CONCLUSION

For invasive carcinoma surgeries, positive margins are associated with NME on MRI, larger tumor size on MRI, and lobular histology at core biopsy. These findings may be used to predict which patients are at risk for positive margins after breast-conserving surgery.