The sentinel node in breast cancer: acceptable false-negative rate

Prospective evaluation of factors influencing success rates of sentinel node biopsy in 814 breast cancer patients

OBJECTIVE

This prospective multicenter study was performed to assess the reliability of sentinel lymph node (SLN) biopsy in breast cancer and to analyze factors potentially influencing success rates.

METHODS

In 21 departments, SLN biopsy and consecutive axillary lymph node dissection were performed in 814 breast cancer patients. The 80 surgeons involved were free in the choice of lymphography technique. The detection rate and the sensitivity, as well as the impact of lymphography technique, patient selection, technical procedure and learning curves, were evaluated.

RESULTS

The blue dye technique was used in 137 patients, radiocolloid in 169 patients, and combined blue dye/radiocolloid in 508 patients. The identification rate for the sentinel node was 83.9% for the entire group and showed a significant dependence on the lymphography technique (blue dye, 71.6%; radiocolloid, 78.8%; combined blue dye and radiocolloid, 89.6%). The overall sensitivity in detecting lymph node metastases was 91.3%. Immunostaining for cytoceratine revealed micrometastases in 19 (5.1%) of 374 patients in whom H/E staining was negative. The combined subdermal/peritumoral injection of the colloid showed a significantly higher identification rate than subdermal or peritumoral injection alone (96.8%, 84.6%, 78.6%; p < 0.001). There was also a significant higher detection rate in cases of SLN biopsy performed prior to lumpectomy, compared to SLN biopsy following lumpectomy (94.7% versus 82.8%; p < 0.001). Furthermore, there was a close correlation between the number of performed examinations and the detection rate.

CONCLUSION

SLN mapping predicts the axillary lymph node status accurately. Learning curves and several technical features influence the detection rate significantly. However, the false negative rate was independent of experience and injection technique.

How many cases are enough for accreditation in sentinel lymph node biopsy in breast cancer?

BACKGROUND

There is considerable argument concerning the number of sentinel node biopsy cases with axillary dissection that surgeons should perform before they are eligible on abandoning axillary dissection in negative sentinel node patients.

DATA SOURCES

Papers that (1) address directly or indirectly the subject of credentialing or of learning curve, (2) report on a surgeon's performance, (3) are reported as feasibility or learning curve studies, or both, (4) discuss the learning curve issue, and (5) express an expert's opinion on the learning curve.

CONCLUSIONS

The number of procedures of the learning curve can not be fixed for all surgeons. Only surgeons in specialized breast cancer centers can succeed in meeting current recommendations with 20 to 30 cases. Surgeons from affiliated community hospitals will need more than 30 cases, whereas broad-based surgeons might need as many as 60 cases with their current caseload. Not all surgeons will be able to offer the procedure to their patients by the current recommendations.

Women's choice between sentinel lymph node biopsy and axillary clearance

PURPOSE

To determine whether women would choose sentinel lymph node biopsy (SLNB) or axillary clearance (AC) for breast cancer treatment when they are given a single choice based on clear information about morbidity and mortality.

METHODS

The expected 5-year survival rate of women with breast cancer after either SLNB or AC was calculated using a utility analysis of established literature. The difference in survival was one in 1000. This and other detailed information on SLNB and AC was presented in a questionnaire, which provided subjects with a scenario and a choice between SLNB and AC. After a pilot study of 40 subjects, the questionnaire was mailed to 400 women (who had no mammographic abnormality) attending Breast Screen and handed to 100 women (who were over 40 years of age and had breast symptoms but not cancer) attending the rooms of two surgical specialists.

RESULTS

One hundred and twenty one of the 243 respondents to the mailed questionnaires (49.8%) chose SLNB and 35% of the 100 consulting room subjects chose SLNB rather than AC.

CONCLUSIONS

Women faced with the possibility of having breast cancer seem to be very conservative in their choice of treatment, many choosing the increased morbidity of AC rather than the very small (one in 1000) increased risk of death at 5 years from SLNB. This raises questions about proposals to offer SLNB as standard treatment and demands that women are fully informed about any increased risk of death when making their choice between SLNB and AC.

What doctors and patients think about false-negative sentinel lymph nodes in vulvar cancer

The sentinel lymph node procedure is a relatively new, minimally-invasive method for the assessment of nodal status in malignancies such as breast cancer, cutaneous melanoma and vulvar cancer. Although highly accurate, this new method is inevitably associated with a certain false-negative rate, possibly leading to worse survival in a small subset of patients. The clinical implementation of the sentinel lymph node procedure is therefore a matter of ongoing debate, especially among doctors. The aim of this study was to assess opinions on the acceptable false-negative rate of the sentinel lymph node procedure in patients with vulvar cancer, who in the past had undergone standard routine radical vulvectomy and complete inguinofemoral lymphadenectomy (and frequently experienced complications), and in gynecologists treating patients with vulvar cancer. Structured questionnaires were sent to both patients and gynecologists. The patients had been treated for vulvar cancer between 1985 and 1993, and were all in complete remission with a median follow-up of 118 months (range: 76-185). Questions to the patients dealt with experienced side-effects of the standard treatment and opinion on the acceptable false-negative rate of the sentinel lymph node procedure. The response rate among patients was 91% (106/117). Forty per cent of the patients experienced one or more infections in the legs (cellulitis) and 49% of the patients still experience either severe pain and/or severe lymphedema in the legs. Sixty-six per cent of the patients preferred complete inguinofemoral lymphadenectomy in preference to a 5% false-negative rate of the sentinel lymph node procedure of 5%. Their preference was not related to age or the side-effects they had experienced. The response rate among gynecologists was 80% (80/100), of whom 60% were willing to accept a 5-20% false-negative rate of the sentinel lymph node procedure. While gynecologists may consider the sentinel lymph node procedure to be a promising diagnostic tool, the majority of vulvar cancer patients, who have undergone complete inguinofemoral lymphadenectomy in the past and have frequently experienced complications, would not advise introduction of this technique because they do not want to take any risk of missing a lymph node metastasis.

Impact of the axillary nodal status on sentinel node mapping in breast cancer and its relevance for technical proceeding

OBJECTIVE

The aim of this study is to analyze whether the axillary status influences the lymphatic mapping procedure in malignant breast disease and whether clinically relevant consequences for the technique of Sentinel Node (SN) biopsy may be drawn from this information.

MATERIALS AND METHODS

SN biopsy was performed in 150 consecutive patients using a combination of the radioguided and the blue-dye technique. Axillary status was compared with the number of detected nodes. In cases of numerous nodes with tracer uptake, the radioactivity of each radiolabeled node was measured separately in a dose calibrator. We analyzed whether an increased tracer uptake could possibly indicate a 'true' or 'dominant' SN. Blue dye uptake was registered and compared with radioactivity. The findings were related to the histologic results.

RESULTS

In patients with a positive axillary status, significantly more radiolabeled nodes were detected than in node negative patients (median 3 vs. 2; p < 0.001). In 54/86 patients with numerous SNs a 'dominant' node with at least twice the radioactivity than other marked nodes could be identified (62.8%). From 26 cases with axillary involvement, 20 patients (76.9%) were identified by the 'dominant' and the remaining six women (23.1%) by others than the seemingly leading SN.

CONCLUSION

Axillary lymph node involvement influences the drainage pattern in breast cancer. Patients with numerous SNs have an increased risk of axillary involvement. A high tracer uptake does not permit the identification of a 'true' SN. A lack of surgical accuracy may lead to pitfalls if the axilla is not screened carefully for all radioactive nodes.

The modified tangential irradiation technique for breast cancer: how to cover the entire axillary region

PURPOSE

The two-portal tangential irradiation technique has usually been applied to breast cancer patients after breast-conserving surgery (1, 2) and is expected to irradiate the axillary lymph node region to some extent (3). We investigated the range of the axillary region covered by this technique and tried to devise an optimal irradiation technique (modified tangential irradiation) that would cover the axillary lymph node region properly.

METHODS AND MATERIALS

We checked the status of the surgical clips left at axillary lymph node sites by reviewing the simulator films and planning CT scans of 63 patients who underwent axillary dissection of level I, I-II, or I-III lymph nodes. Then we created the modified tangential irradiation technique and applied this technique to 16 patients and checked the irradiation volume by CT scans.

RESULTS

We found that all of the surgical clips on lateral-view simulator films were on the ventral side of the dorsal edge line of the humeral head. All but one clip were on the caudal side of the caudal edge line of the humeral head. Accordingly, it is possible to irradiate almost all axillary lymph node regions by setting the dorsal edge of the irradiation field on lateral-view simulator films at the dorsal edge of the humeral head and the cranial edge at the caudal edge of the humeral head.

CONCLUSIONS

All breast tissue and the entire axillary lymph node region can be covered by the modified tangential irradiation technique without increasing the lung volume irradiated.