Abstract P2-01-22: The long term outcomes of Metasin RTqPCR intra-operative sentinel node analysis in early breast cancer

Background:

Axillary lymph node involvement is a prognostic factor in breast cancer and it is used to guide adjuvant therapy. Axillary clearance remains the standard of care in lymph node positive disease in most parts of the world. Usually this is performed as second procedure but immediate intra-operative node analysis allows clearance to be performed as part of the initial procedure where necessary.

The Metasin assay targets the breast epithelial cell markers CK19 and mammaglobin mRNA and detects the presence of breast tissue (metastatic disease) in the sentinel nodes. Evidence shows the Metasin assay to be fast (average assay time 41.2min) and accurate with a discordance rate below 4% compared with histology. The cost effectiveness of the assay has been reported in our previous studies.

Aim:

The aim of this study is to assess the risk of axillary recurrence following the use of the Metasin assay to guide axillary management.

Method:

This is a single centre retrospective study which included all patients presenting to a district general hospital with early clinically node negative breast cancer undergoing sentinel node biopsy between Oct 2011 and Dec 2014.

Alternate 2 mm slices of the node were examined intraoperatively using the Metasin assay and the remainder sent for histological examination. The results of the Metasin assay and histology were compared. The risk of axillary recurrence using the Metasin test to select patients for immediate axillary clearance was assessed.

Results:

1073 sentinel nodes from 545 patients were analysed during this three-year period. 2 patients were lost to follow up. 94 patients were node positive and underwent axillary clearance as part of their primary surgery. 449 patients had sentinel node biopsy with no further axillary procedure. There were 36 nodes (3.34%) with discordant results. Median follow up was 32 months (range 18 to 55 months).

Fourteen patients presented with recurrences (2.56%). The mean event free interval was 15 months. Of the 14 patients, 5 patients tested with Metasin had macrometastases and underwent immediate axillary clearance during the primary surgery. 7 patients were node negative and 2 patients were shown to have micrometastases. 11 patients recurred with distant metastases, 3 patients with local recurrence and 2 patients (0.36%) with axillary recurrences.

The two axillary recurrences occurred at 3 and 5 months after primary surgery. Both patients underwent Metasin intraoperative analyses of sentinel nodes which were negative. Subsequent histological examination confirmed no metastatic node involvement in one patient but micro-metastases in the other. Both of these patients had aggressive disease with local, axillary and distant metastasis and subsequently died of their disease.

Conclusions:

The Metasin assay is a reliable intraoperative test for sentinel node involvement and when used to guide surgical axillary management is associated with very low axillary recurrences (0.36% with a median follow up of 32 months).

Citation Format: Udayasankar S, Ashley E, Jenkins KS, Huws A, Sharaiha Y, Sai-Giridhar P, Thomas D, Munir A, Holt S, Khawaja S. The long term outcomes of Metasin RTqPCR intra-operative sentinel node analysis in early breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-01-22.

Abstract P1-05-21: A comparison of oncotype DX recurrence scores in a screen detected vs a symptomatic cohort of patients with breast cancer: A UK experience

Background:

In the Western World, it has been stated that breast cancers detected on a screening program are indolent. There have been many recent publications stating that breast screening is overdiagnosing and therefore overtreating patients with breast cancer. With the advent of genomic testing, it can now be determined which patients have an aggressive tumor requiring systemic chemotherapy. We therefore conducted a retrospective study in the UK on patients having oncotype DX testing in both screen detected and symptomatic cancers.

Materials and Methods:

Patients in our institution undergoing oncotype DX testing for invasive breast cancer which was ER positive and node negative were part of this study. The detection of the breast cancer was documented as either a screening case or a symptomatic one. The recurrence scores of the oncotype DX testing was then compared in the screening versus the symptomatic cohort.

Results:

155 patients were included in this study. They underwent Oncotype DX testing between 2008 to 2016. The age of the patients ranged from between 31 years to 78 years. Eighty-nine patients were reported to have a low recurrence score; 45 had an intermediate score; and 21 had a high result. Fifty eight patients were screen detected, while 97 patients were symptomatic presentations. In the screening population, 32 patients had a low recurrence score; 22 had an intermediate result and 4 had a high recurrence score resulting in the latter groups being considered for chemotherapy. In the symptomatic cohort, 57 had a low recurrence score; 23 had an intermediate result; and 17 had a high score.

Conclusion:

The results of our study depict that even patients in a screeining cohort will have a high number of intermediate recurrence scores and some with a high recurrence score. This shows that the hypothesis that screening detects a majority of breast cancers which are indolent not requiring further systemic treatment should be looked at again in light of our results with genomic testing.

Citation Format: Khawaja S, Parab A, Thomas D, Huws A, Munir A, Udayasankar S, Sharaiha Y, Holt S. A comparison of oncotype DX recurrence scores in a screen detected vs a symptomatic cohort of patients with breast cancer: A UK experience [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-05-21.

Abstract P1-03-12: A simulation study depicting the inconsistency of adjuvant online compared to genomic testing when determining the benefit of chemotherapy

Background: Prognostic factors have been used for years to determine the benefit of adjuvant chemotherapy in breast cancer. However, reporting of the size and grade of the tumor are affected by interobserver variability in reporting. This can result in a change in the results of adjuvant online and an impact on decision making of chemotherapy. On the contrary, genomic testing such as oncotype Dx is reproducible. The purpose of our study was to assess the effect of pathological discordance on the adjuvant online results on a cohort of patients who also underwent oncotype Dx testing.

Materials and Methods: A total of 143 patients' histologies were included in this study. The results of the Phase III WSG-Plan B trial concerning central vs. local grade discrepancy rates were utilized to randomly change the grade of the tumors. 61 percent of grade 1 cancers were upgraded to grade 2 and 2% upgraded to grade 3. 4 percent of grade 2 cancers were downgraded to grade 1 and 26% were upgraded to grade 3. 1 percent of grade 3 cancers were downgraded to grade 1 and 25% were downgraded to grade 2. Likewise, change was made in the size of the tumor in 20 percent of patients. 8 to 10mm, 18-20, 28-30, and 48-50mm changed to 11, 21, 31 and 51mm respectively. 11-13mm, 21-23, 31-33, and 51-53mm was changed to 10, 20, 30, and 50mm. Ten percent of patients had the ER and Her 2 status changed.

Results: The simulation results showed that when the grade was only altered, the spearman correlation of the predicted 10 year mortality on adjuvant online with the original data was significantly changed from 1 to a result of 0.788. When the changed size was additionally added, the coefficient was 0.836. With the altered ER status, the result was 0.749 and with the Her 2 change, the spearman correlation was minimally changed to 0.742. The scattergrams showed a large number of outliers when the alteration in size was added to the altered grade.

Conclusion: Our simulation study confirms that with minimal changes in the clinical parameters because of the lack of perfect correlation between pathologist's results, there is a significant difference in the 10 year predicted mortality on adjuvant online. This is one step further in understanding the lack of correlation between adjuvant online and oncotype Dx, and the inconsistency of chemotherapy decision making with the sole use of adjuvant online.

Citation Format: Khawaja S, Thomas D, Udayasankar S, Munir A, Huws A, Sharaiha Y, Holt S. A simulation study depicting the inconsistency of adjuvant online compared to genomic testing when determining the benefit of chemotherapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-03-12.