Summary of Consensus Session
The first presentation given by Dr. Sasano was “Pathological assessment of therapeutic effect in neoadjuvant chemotherapy in breast carcinoma patients.” First, he presented the criteria reported in the General rules for the clinical and pathological finding of breast cancer. Then, he stressed about the importance of appropriate processing of the specimens, such as fixation and sampling. He also mentioned that the same principles apply to the assessment of Ki-67. Standardizing the processing of the samples is far more important than setting the rule for assessment.
The second presentation by Dr Ohno was entitled “Treatment after systemic chemotherapy”. pCR in the breast and axillary lymph nodes predicts a favorable prognosis. Although non-pCR of either the breast or lymph nodes predicts poorer prognosis compared to pCR, a standard subsequent postoperative treatment has not been established.
After these presentations, Dr Bartlett and Dr. Kawabata joined the discussion. The first discussion was about response evaluation during preoperative chemotherapy not prior to surgery. Currently the role of response evaluation in this setting in daily practice is mostly to detect early signs of progression using mostly ultrasonography and physical examination. Since early response to preoperative chemotherapy reportedly predicts further response to preoperative chemotherapy, more research to strategically tailor subsequent chemotherapy seems important. Pathological assessment, such as core needle biopsy during preoperative chemotherapy, is still experimental and seems to require a strong rationale.
The second issue was local management of tumor and axilla after preoperative chemotherapy. There has been a lack of definition of positive margin, and margins were defined as positive when tumor cells were present at the surface (18%) or the tumor free distance to the surface was <2mm (50%) in questionnaires. Sixty eight percent of surgeons consider a free margin of < 5mm as negative, which is defined as positive by the Japanese Breast Cancer Society. Dr Bartlett informed us that the definition of a positive margin is also unclear in the UK. The degree of surgical clearance is a related issue to the definition of positive margin. Questionnaires show 10%, 43% and 47% of surgeons achieve a margin width of <5mm, 5-10mm, and 10-20mm, respectively. Irrespective of the definition of positive margin, negative margins obtained is the standard care of breast conserving surgery and re-excision is indicated to achieve surgical clearance. EIC is thought to contribute to compromised margins.
There are two types of tumor shrinkage (concentric and dendritic) on the effects of anticancer drugs. Most surgeons (22/28) removed tumor based on the new margin in the concentric shrinkage pattern whereas 71% of them excised tumor at the original extent at presentation in the dendritic pattern. The decision making of the excision area has not been affected after chemotherapy by tumor phenotype.
Axillary staging after chemotherapy is an acceptable approach in patients who presented without axillary involvement. Most surgeons think sentinel lymph node biopsy is not acceptable for patients with positive nodes proved by fine needle aspiration even if they experienced negative node after chemotherapy (negative conversion). Subsequent axillary lymph node dissection is a current standard care for patients with positive sentinel nodes. Innovate nomogram, however, may lead to spare completion of subsequent ALND for them. (Dr. Hiroshi Ishiguro and Dr. Tomoharu Sugie, KBCCC)