Journal of Surgical Oncology 2001;77:73

LETTER TO THE EDITOR

Reply to Drs. JastrzeÎbski and Kopacz

Dear Sir,We appreciate the letter by Drs. JastrzeÎbski and

Kopacz regarding our article [1]. Their observations areimportant. I would like to address these in the order inwhich they are raised.

At present, internal mammary sentinel lymph node(SLN) biopsy is not performed at most institutions sinceinternal mammary dissection has been largely aban-doned. However, internal mammary SLNs are clinicallyrelevant, because they have the same prognostic sig-ni®cance as axillary nodal metastases. Currently, SLNbiopsy has been investigated in the internal mammarylymph node chains. In our previous study [1], blue dyedid not allow visualization of internal mammary SLNs inmost patients. The blue dye travels rapidly throughthe lymphatic vessels, and may not remain in the inter-nal mammary lymph nodes long enough for surgicalidenti®cation and excision. On the other hand, internalmammary SLNs could be identi®ed by lymphoscintigra-phy and gamma-probe guided method. As pointed out byDrs. JastrzeÎbski and Kopacz, however, these nodes arenot always visible due to shine-through from radio-activity at the primary injection site which, in cases ofinner quadrant lesions, is close to the internal mammarychain.

It has been hypothesized that a subareolar injectionof material would drain to the same lymph node as aperitumoral injection, regardless of the location of thetumor [2]. If this theory is correct, subareolar injectionavoids the overlap of the diffusion zone in medial lesionswith the internal mammary lymph nodes. However, thereremains a question as to whether subareolar and peri-tumoral injections may always drain to the same SLN.Internal mammary SLN biopsy is feasible, but furtherstudy is required to assess the role of SLN biopsy of theinternal mammary nodes. We recommend that surgeonslearning internal mammary SLN biopsy should perform a

back-up internal mammary lymph node biopsy during thelearning period.

In our previous study [1], 99 m technetium (Tc)-labeled human serum albumin (HSA) (particle size: 2±3 nm) was injected two hours before surgery. The SLNscould not be visualized the day after injection because99 m-Tc HSA is too small and migrates so rapidly andextensively. However, the use of large rather than smalldiameter radioisotope is preferred because large diametertracers identify only one or two SLNs even the day afterinjection [3]. A 24-hour delay allows a marked decreasein radiation exposure of the surgeon and hospital staff dueto the passage of four half-lives of the radioisotope. Moreimportantly, it makes it possible to perform the SLNbiopsy at anytime the next day after the injection ofradioisotope. This is convenient for surgeons in a tightoperating room schedule. Recently, therefore, we haveused 99 m-Tc stannous phytate (particle size: 200±1000 nm) [3], which is available in Japan.

I appreciate Drs. JastrzeÎbski's and Kopacz's commentsand their insightful observations.

Masakuni Noguchi, MD

Kanazawa University Hospital13-1, Takara-machiKanazawa, Japan

REFERENCES

1. Noguchi M, Tsugawa K, Miwa K: Internal mammary chain senti-nel lymph node identi®cation in breast cancer. J Surg Oncol2000;73:75±80.

2. Klimberg VS, Rubio IT, Henry R, et al.: Subareolar versusperitumoral injection for location of the sentinel lymph node. AnnSurg 1999;6:860±865.

3. Noguchi M: Review article. Sentinel lymph node biopsy as analternative to routine axillary lymph node dissection in breastcancer patients. J Surg Oncol 2001;76:144±156.

ß 2001 Wiley-Liss, Inc.