Breast-Conserving Surgeries With and Without Cavity Shave Margins Have Different Re-excision Rates and Associated Overall Cost: Institutional and Patient-Driven Decisions for Its Utilization

Analysis of Specimen Mammography with Artificial Intelligence to Predict Margin Status

BACKGROUND

Intraoperative specimen mammography is a valuable tool in breast cancer surgery, providing immediate assessment of margins for a resected tumor. However, the accuracy of specimen mammography in detecting microscopic margin positivity is low. We sought to develop an artificial intelligence model to predict the pathologic margin status of resected breast tumors using specimen mammography.

METHODS

A dataset of specimen mammography images matched with pathologic margin status was collected from our institution from 2017 to 2020. The dataset was randomly split into training, validation, and test sets. Specimen mammography models pretrained on radiologic images were developed and compared with models pretrained on nonmedical images. Model performance was assessed using sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC).

RESULTS

The dataset included 821 images, and 53% had positive margins. For three out of four model architectures tested, models pretrained on radiologic images outperformed nonmedical models. The highest performing model, InceptionV3, showed sensitivity of 84%, specificity of 42%, and AUROC of 0.71. Model performance was better among patients with invasive cancers, less dense breasts, and non-white race.

CONCLUSIONS

This study developed and internally validated artificial intelligence models that predict pathologic margins status for partial mastectomy from specimen mammograms. The models' accuracy compares favorably with published literature on surgeon and radiologist interpretation of specimen mammography. With further development, these models could more precisely guide the extent of resection, potentially improving cosmesis and reducing reoperations.

Cost-Efficacy Analysis of Use of Frozen Section Histology for Margin Assessment During Breast Conservation Surgery in Breast Cancer Patients

BACKGROUND

Margin assessment is an essential component of breast conservation surgery (BCS). Re-excision of infiltrated margin(s) detected on paraffin section histology (PSH) needs reoperation, adding time, inconvenience and cost. Intra-operative assessment of margins using frozen section histology (IFSH) can potentially obviate need for re-operation, thus facilitating one-step oncologically complete BCS.

METHODS

IFSH and PSH reports of consecutive patients undergoing BCS (2010-2020) were reviewed. Accuracy and cost-efficacy of IFSH were assessed, considering PSH as gold standard. Cost of achieving oncologically complete BCS in whole cohort with IFSH (Scenario-A) was calculated and compared using appropriate statistical tests, with hospital costs for the cohort in a hypothetical Scenario-B, where IFSH was presumed not to have been used and all patients with infiltrated margin(s) on PSH would have been re-operated.

RESULTS

Of the 367 patients screened, 39 were excluded due to incomplete IFSH data. Of 328 patients analyzed, 59 (18%) had one or more margins were reported infiltrated on IFSH, managed by re-excision or mastectomy in the same sitting, thus avoiding a reoperation. Additional 8 (2.4%) had involved margins on PSH (False negative IFSH). Significantly higher number of reoperations (p < 0.001) would have been needed in scenario-B. Average cost of the first operation with use of IFSH was Indian Rupees (INR) 25791 which included INR660 as IFSH cost. The average cost of reoperation was INR23724 which could be avoided in 59 (18%) by use of IFSH. The average cost per patient to achieve oncologically complete surgery in scenario A utilizing IFSH was significantly lower (p = 0.001) by INR3101 (11.7%), c.w. that in scenario B. Significant cost-saving with IFSH was maintained in cost-efficacy analysis undertaken with various higher and lower costs assumptions.

CONCLUSIONS

Use of IFSH facilitates one-step oncologically complete BCS in majority of patients and results in considerable cost saving, resulting in avoidance of reoperations, besides preventing patient anxiety and delay in adjuvant treatment.

TRIAL REGISTRATION

Clinical Trials Registry-India (CTRI/2021/08/035896).

Cost minimization in breast conserving surgery: a comparative study of radiofrequency spectroscopy and full cavity shave margins

BACKGROUND

In an effort to minimize positive margins and subsequent re-excision after breast conserving surgery (BCS), many providers and facilities have implemented either a Full Cavity Shave (FCS) approach or adding the MarginProbe Radiofrequency Spectroscopy System.

OBJECTIVE

We sought to create a functioning Pro-Forma for use by facilities and payers to evaluate and compare the cost savings of implementing FCS or MarginProbe based on personalized variable inputs.

METHODS

A decision tree demonstrating three possible surgical pathways, BCS, BCS + FCS, and BCS + MarginProbe was developed with clinical inputs for re-excision rate, mastectomy as 2nd surgery, rate of reconstruction, and rate of 3rd surgery derived by a literature review. A surgical pathway cost formula was created using the decision tree and financial inputs derived by utilizing the nation's largest database of privately billed health insurance claims and Medicare claims data (fairhealth.org). Using the surgical pathway formula and financial inputs, a customizable Pro-Forma was created for immediate cost savings analysis of BCS + FCS and BCS + Marginprobe using variable inputs. Costs are from the perspective of third-party payers.

RESULTS

Utilizing MarginProbe to reduce re-excisions for positive margins can be associated with better cost-savings than FCS due to the increased pathology processing costs by using an FCS approach. The reduction in re-excision provided by both FCS and MarginProbe offset their increased expense to various degrees with cost savings of each method improving as baseline re-excisions rates increase, until ultimately each may become cost-neutral or cost-prohibitive when compared to BCS alone. Our data suggest that in the privately insured population, MarginProbe provides a cost-savings over BCS alone when baseline re-excision rates are over 20% and that FCS becomes cost-saving when baseline re-excision rates are over 29%. For Medicare patients, MarginProbe provides a cost-savings when baseline re-excision rates exceed 34%, and FCS becomes cost-saving for re-excision rates over 52%. Our Pro-Forma allows an individual provider or institution to evaluate the cost savings of the FCS approach and/or utilization of the MarginProbe device such that the additional cost or cost-savings of utilizing one or both of these methods can be quickly calculated based on their facility's volume and baseline re-excision rate.

CONCLUSIONS

Our data suggest that utilizing either an FCS approach or the MarginProbe radiofrequency spectroscopy system may be a cost-saving solution to reducing the rate of re-excisions depending on a facility or practice's surgical volume and baseline re-excision rate. The degree to which each of these interventions provides an added cost or cost-savings to healthcare payers can be evaluated by utilizing the Pro-Forma outlined herein with customizable variable inputs.

Breast-Conserving Surgery Margin Guidance Using Micro-Computed Tomography: Challenges When Imaging Radiodense Resection Specimens

BACKGROUND

Breast-conserving surgery (BCS) is an integral component of early-stage breast cancer treatment, but costly reexcision procedures are common due to the high prevalence of cancer-positive margins on primary resections. A need exists to develop and evaluate improved methods of margin assessment to detect positive margins intraoperatively.

METHODS

A prospective trial was conducted through which micro-computed tomography (micro-CT) with radiological interpretation by three independent readers was evaluated for BCS margin assessment. Results were compared to standard-of-care intraoperative margin assessment (i.e., specimen palpation and radiography [abbreviated SIA]) for detecting cancer-positive margins.

RESULTS

Six hundred margins from 100 patients were analyzed. Twenty-one margins in 14 patients were pathologically positive. On analysis at the specimen-level, SIA yielded a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 42.9%, 76.7%, 23.1%, and 89.2%, respectively. SIA correctly identified six of 14 margin-positive cases with a 23.5% false positive rate (FPR). Micro-CT readers achieved sensitivity, specificity, PPV, and NPV ranges of 35.7-50.0%, 55.8-68.6%, 15.6-15.8%, and 86.8-87.3%, respectively. Micro-CT readers correctly identified five to seven of 14 margin-positive cases with an FPR range of 31.4-44.2%. If micro-CT scanning had been combined with SIA, up to three additional margin-positive specimens would have been identified.

DISCUSSION

Micro-CT identified a similar proportion of margin-positive cases as standard specimen palpation and radiography, but due to difficulty distinguishing between radiodense fibroglandular tissue and cancer, resulted in a higher proportion of false positive margin assessments.