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EDITORIALS |
From the Department of Surgical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas.
Correspondence: Address correspondence to: S. Eva Singletary, MD, FACS, Department of Surgical Oncology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Box 444, Houston, TX 77030-4095; Fax: 713-792-2225; E-mail: esinglet{at}mdanderson.org
In this issue of the Annals of Surgical Oncology, Balch and colleagues evaluate the accuracy of sentinel lymph node dissection (SLND) in 32 women with stage II or III breast cancer who received induction chemotherapy (IC) containing doxorubicin or paclitaxel and radiotherapy.1 They report that the accuracy of SLND in these women was similar to that found in patients with early stage breast cancer, with the implication that axillary lymph node dissection might be avoided for women in this patient group.
IC has become the standard of care for patients with locally advanced breast cancer (LABC) and, increasingly, for selected patients with smaller operable breast tumors. Numerous studies have shown that as many as 80% of patients with LABC achieve either a partial or complete response to IC, often becoming good candidates for breast-conservation therapy (BCT) (reviewed in reference 2). IC has also been shown to downstage axillary lymph nodes from positive to negative in 25%–44% of LABC patients.3–5 Response to IC is an important prognostic indicator of overall survival in patients with LABC and may be helpful in identifying patients who would be good candidates for investigational studies. Subsequent studies have demonstrated that IC is also useful for the treatment of patients with smaller tumors (stage IIA–IIIA), allowing the use of minimally invasive procedures for management of the primary tumor and the axilla.3,4
Initially, IC strategies used anthracycline-containing drug regimens, with taxane drugs (paclitaxel, docetaxel) reserved for cross-over treatment in nonresponding patients. More recently, taxanes have been used in combination with anthracyclines, resulting in improved outcomes compared with anthracycline regimens alone. The current trend is toward the sequential use of a taxane drug and an anthracycline combination, with local therapy at the end. Using the drugs in sequence is associated with fewer complications, while maintaining similar, if not better, antitumor activity.5
The increasing use of IC in a wide spectrum of patients is occurring simultaneously with the growing acceptance of SLND as a substitute for axillary lymphadenectomy (ALND). Clinicians have thus become concerned that IC might interfere with the structure or function of the lymphatic system, making SLND more difficult. Two particular areas of concern are: (1) whether the sentinel node can be found; and (2) whether the false-negative rate is prohibitively high, meaning that a significant number of patients could be undertreated. The results published here by Balch and colleagues are consistent with those found in the majority of published studies, indicating that SLND can be performed with acceptable accuracy in this patient group. As shown in Table 1, the median value for percent of cases in which the sentinel node could be identified was similar in the patient series who received IC compared with those who did not (88% vs. 93%, respectively). Likewise, the median false-negative rates (11% vs. 6%, respectively) were not radically different between the two groups of studies.6
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There are three likely outcomes with regard to nodal status that might occur as a result of IC: nodes that were initially positive can remain positive, nodes that were initially negative can remain negative, and nodes that were initially positive can be downstaged to negative. What is the current best treatment strategy based on these three outcomes?
For patients whose nodal status does not change with IC, the treatment options are relatively straightforward. For those who are node positive after the completion of IC, SLND should be bypassed, and the surgeon should proceed with a standard ALND. For patients who are initially node negative and who remain node negative after IC, the current policy at our institution and others is to offer SLND and no further treatment of the axillary nodes if the SLND is negative.
The controversy arises in considering the patient who is initially node positive and who becomes node negative after IC. This is an increasingly common occurrence; from 25% to 44% of LABC patients receiving IC are downstaged from node positive to node negative. Should these patients still receive ALND? Although we still perform a SLND with an ALND on such patients at M.D. Anderson to accrue more detailed information about treatment effectiveness, axillary irradiation has been shown to be as effective as surgery for clinically negative axilla.10 If these patients are receiving BCT or postmastectomy irradiation, it may be appropriate to treat the axilla with radiotherapy if the SLND is negative.
The study by Balch and coworkers represents another piece of evidence that broadens our definition of the patient who is an appropriate candidate for noninvasive approaches in the management of breast cancer. Although BCT and SLND were originally restricted to patients with very early stage breast cancer, the use of IC has allowed patients with more advanced disease to have access to these effective treatment options that can offer a better quality of life to the cancer survivor.
Received for publication May 12, 2003. Accepted for publication May 20, 2003.
REFERENCES
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