Application of the sentinel node concept in breast cancer surgery

Abstract

This thesis consisted a series of sentinel node biopsy (SNB) studies in Chinese

patients to evaluate its impact on the management of breast cancer.

Pilot studies

The first SNB pilot study was performed in 30 patients using the blue dye

technique. Accuracy was verified by axillary lymph node dissection (ALND). The

success rate was 83% and the false-negative rate was 25%. The second pilot study

was performed in 50 patients using combined mapping with isotope and dye. The

success rate was 94% with no false-negative. SNB is shown to be feasible and

accurate in Chinese.

The optimal mapping method

Combined mapping was superior to the blue dye technique. This could be due to

the mapping technique or improved experience. One hundred and twenty-three

women were randomly assigned to either the blue dye or combined mapping.

Combined mapping had a higher success rate than the blue dye technique (100%

versus 86%). False-negative rates were similar (0% versus 4.5%). Combined

mapping is the preferred method.

Accuracy of frozen section (FS)

FS was used intra-operatively to guide the need of ALND. In 260 SNB, FS was

compared to serial section and immuno-histochemical staining. FS detected 53 of

86 patients with SN metastases with a false-negative rate of 38.4%. The

false-negative rates for macro-, micro-metastases and isolated tumour cells (ITC)

were 2.4%, 57.7% and 94.4%. FS was accurate to diagnose macro-metastases but

not micro-metastases and ITC.

Can we skip ALND in SN metastases?

139 patients with SNB and ALND were studied to identify predictive factors for

non-SN metastases. 55 had metastatic SN but 38 (69%) had no residual

metastases in non-SN. Tumours <3 cm, a single metastatic SN, micro-metastases

and absence of extra-capsular spread were significant factors to predict no

residual nodal disease. Non-SN metastases were found in 42%, 19% and 0% when

SN contained macro-, micro-metastases and ITC. Based on risk of non-SN

involvement, ALND is indicated for macro- and micro-metastases but not for

ITC.

Extended indication for ductal carcinoma in situ (DCIS)

SNB may be useful for staging of patients with a pre-operative diagnosis of DCIS

because invasive cancer is not infrequently found on pathological examination of

resected specimens after surgical excision. One hundred and seven patients with

DCIS on core biopsy underwent SNB. Thirty-two patients (29.9%) were upstaged

to invasive cancer and 9 (28.1%) had SN metastases. Performing SNB reduced the

re-operation rate from 29.9% to 1.9%. Palpable mass and radiological mass lesion

were associated with upstage.

Extended indication: Sentinel Node Occult Lesion Localisation (SNOLL)

Radioisotope is used to localise non-palpable breast cancer and SN. Seventy-four

patients with non-palpable breast cancers underwent SNOLL. Radioisotope was

injected into cancer and gamma probe guided breast cancer and SN resection.

Primary cancer was removed in 73 patients (99%) after the first-round excision

and 82% had complete excision. Gamma probe identified SN in 82% and

supplementary blue dye increased SN detection to 97%.

SNB modified the practice of breast cancer surgery. It has a major impact on the

diagnosis, staging and treatment of breast cancer.