Sentinel Node Mapping in British Columbia: An example of the importance of surgical oncology outcomes research NL Davis MD FRCSC Head of Surgical Oncology
BC Surgical Oncology Network Vision Equitable, accessible and integrated cancer surgery for British Columbians.
Challenges Equitable: Equal availability of the highest quality cancer surgery anywhere in BC How do we measure quality? How do we feed this information back to physicians? Accessible: Easily accessed services without waits How do we ensure care for patients in remote or small communities? Integrated: Into the formal cancer system How do we ensure multidisciplinary care and when is it mandatory?
Sentinel Node Mapping: An example of overcoming challenges through outcomes research New procedure that takes technologic advances and combines with a new surgical procedure that ultimately results in enhanced staging and management of the axilla in patients with breast cancer
The Importance of Nodal Staging in Breast Cancer • The status of lymph nodes in virtually all solid tumours is the most powerful predictor of survival and recurrence. • Treatment plans including addition of radiation to the axilla as well as chemotherapy are therefore based on node involvement.
Sentinel Node Mapping • A surgical technique that involves identification and removal of a dominant node in a lymph drainage basin. • Dye is injected around the cancer, and travels through the lymphatic system where it is filtered by the sentinel node. • The sentinel node is identified either visually or with a gamma probe that emits an auditory signal. • The node is removed and sent for enhanced pathologic review.
Advantages of Sentinel Node Dissection • Reduced morbidity • Enhanced detection of positive nodes. • As a result of the intensified pathology review, it has been suggested that identification of micrometastasis is enhanced . • This is not a therapeutic procedure
Can the Sentinel Node be reliably detected and removed? • In most cases the sentinel node can be identified. • However, identification of the node by individual surgeons varied significantly. Most series report between 5% - 25% inability to detect sentinel nodes. • It is estimated that surgeons should perform at least 20 procedures to gain experience with the technique. Krag et al NEJM 1998
False Negative Sentinel Node Biopsy • This refers to the number of women who have positive axillary lymph nodes on final pathology but the sentinel node biopsy was reported as negative. • This appears to be both surgeon and institution related and varies in the literature between 5–13%. • A false negative rate of 10% is estimated to have about a negative impact on survival from breast cancer, perhaps in the range of 5%.
Recognizing that there is a surgical learning curve and both institutional and surgical variation, the literature suggests the following standards should be in place in centers offering SLNM
Guidelines for Sentinel Node Dissection • Institutional review board panels • Radiation safety • Training/Validation studies • Data Collection • Hospital/Surgeon Credentialing • Outcomes measurements : False negative rates • Follow-up/ quality assurance programs
SENTINEL NODE BIOPSY FOR BREAST CANCER IN B C: 1996-2001 Ivo A. Olivotto MD, FRCPC Clinical Professor, Radiation Oncology Vancouver Island Cancer Centre, Victoria, BC for B Chua, J Donald, A Hayashi, C Rusnak, N Davis BC Cancer Agency
OBJECTIVES • To describe the current practice of sentinel node biopsy (SNB) for breast cancer in BC. • To describe outcomes of SNB in BC, 19962001. • To make recommendations for practice for surgeons considering adopting SNB. BC Cancer Agency
Methods Surveys of • 28 SNB practising surgeons identified from BCCA database (Feb 2001) • nuclear medicine physicians from five departments • pathologists from seven departments • 50 surgeons who performed breast cancer surgery but not SNB Patient Outcomes • 547 SNBs by 28 surgeons in 12 hospitals BC Cancer Agency
Methods Outcomes of SNB • Identification rate = No. cases 1 SN identified No. cases performed • Accuracy = No. true positive + true negative SNB No. cases 1 SN identified • False-neg rate = No. cases w neg SN and pos NSN No. cases 1 SN were identified and axillary metastases present BC Cancer Agency
Surgeon Training and Implementation(Survey: 25 surgeons; 89% response) • Training: • Formal training course = 5 (20%) • Intraoperative mentoring alone = 12 (48%) • Both = 6 (24%) • Self-teaching = 2 (8%) • Evaluation support: • SNB as part of a validation study = 12 (48%) • No data management support = 10 (40%) • No participation in randomized trials BC Cancer Agency
Survey of 25 SNB practising surgeons • Factors considered indications for SNB • T1, T2 invasive tumor = 24 (96%) • Clinically negative axilla = 24 (96%) • DCIS = 8 (32%) • T3 invasive tumor = 15 (60%) • T4 invasive tumor = 3 (12%) • Multifocal invasive tumor = 6 (24%) • Clinically positive axilla = 4 (16%) BC Cancer Agency
No. SNB performed by 25 surgeons, (1996 until Feb 2001) Mean = 19; Range = 1-80 per surgeons BC Cancer Agency
Patient Outcomes of SNB 1996–2001 • Overall identification rate = 88% (95% CI, 85%–91%) • Median no. SN biopsied = 2 (range, 1–16) • Completion axillary dissection in 509 cases (93%) • Blue dye alone would have mapped 70% of SNs • Radio-colloid alone would have mapped 93% of SNs BC Cancer Agency
Variation of ID rate with surgeon experience P=0.26 BC Cancer Agency
False Negative Rates • Overall false-negative rate = 22% (95% CI, 16%–29%) • Overall accuracy = 92% (95% CI, 90%–95%) BC Cancer Agency
SummaryOutcomes of SNB 1996–2001 BC Cancer Agency
Conclusions • In the absence of a planned process, considerable variation has evolved in the practice of SNB in BC. • Data collection was retrospective. Outcomes may have been different if surgeons were participating in prospective evaluation. • However, BC Identification and Accuracy rates are low and False Negative rates are high compared to the published literature.
Feed back to surgeons • Any surgeon who requested it received their own false negative rate therefore this study acted as a quality assurance program for practicing surgeons
Next Steps • A Surgical Breast Tumour Group has been formed, lead by Dr. A. Hayashi in Victoria,BC • A guideline has been written and endorsed by the Breast Tumour group that encompasses the best practice for undertaking Sentinel node mapping • This practice guideline will be communicated via the Surgical Oncology program communications group
Next Steps • A data entry form has been developed for surgeons to collect their outcomes for SLNM • Surgeons will be encouraged to participate in prospective data collection regarding SLNM • To facilitate this, we need web based reporting of outcomes • Synoptic reports
Surgical Outcomes are important • There is a need in the Province for an approach to educate surgeons and to provide feed back to surgeons about our outcomes. • This study has resulted in a strategy to enhance sentinel node mapping outcomes in the province • This study highlights the need to reduce surgical variation. • It highlights the need to define appropriate surgical outcomes for all tumour sites • The need to communicate results to our colleagues