The aim of this study was to reproduce the ACOSOG Z0011 trial criteria in 384 women with early-stage T1 - T2 invasive breast cancer with clinically negative axilla, undergoing BCS and SLNB. Of the total number of women, 87(22.6%) underwent ALND and 297 (77.3%) were spared from further treatment. If we had applied the ACOSOG Z0011 trial criteria, 82/87 (94.3%) more women might have benefitted from the omission of ALND, corresponding to 379 women spared from axillary surgery, i.e., 98.7% of all women undergoing SLNB.
In 2016, Verheuvel et al. investigated 916 cases undergoing ALND for SLN involvement or positive axillary lymph node diagnosed by ultrasound-guided biopsy. Of the total number of patients, 558 (61%) could have benefitted from the omission of ALND. Those authors considered micrometastases and ITC as N0. In 2013, Delpech et al applied the same criteria to 125 SLN-positive patients undergoing ALND. Among those women, 87 (69.7%) were potentially eligible for omission of ALND(11). In our study, we found an even higher number of cases in which ALND could have been avoided.
The pre-established concept of ALND in all patients with SLN involvement has currently undergone modifications. When the SLN technique emerged in the late nineties, it was a major advance in women with negative axilla who would no longer require ALND. Nevertheless, SLN-positive patients still received axillary dissection. ALND may cause complications such as postoperative seroma, infection, sensory disturbances in the ispilateral arm in the medium and long-term, in addition to lymphedema in up to 40% of cases at the 10-year follow-up(12). Complications after ALND interfere negatively in the quality of life of these women, increasing treatment expenses(13).
In 2014, Sackey et al. compared a group of women undergoing SLNB alone to another group undergoing ALND due to positive SLN and found a significantly lower risk of lymphedema in women who had not received ALND. In 2013, in a long-term follow-up study, De Gournay et al. failed to find any case of lymphedema in the SLNB group, while lymphedema rates were 10.3% in the ALND group and 7% in the SLNB group followed by ALND(14, 15). It can be inferred that the omission of ALND in a public health care facility of a developing country such as ours, could reduce the cost of surgical treatment and management of potential sequelae related to ALND. Furthermore, it could promote a better quality of life in a large number of women by reducing the possibility of lymphedema.
Lymph node involvement in the remaining axilla ranges from 20% to 40% in SLN-positive patients(1, 2, 3). In the recent past, studies have attempted to correlate predictive factors for lymph node involvement in the remaining axilla. Memorial Sloan-Kettering Cancer Center – MSCC created a nomogram using factors correlated with the tumor: size, histologic type, nuclear grade, lymphovascular invasion, multifocality and estrogen receptor, thus screening a group of SLN-positive women who might benefit from the omission of ALND(3). A number of attempts have been made to reproduce and validate the MSCC nomogram, with conflicting results(16, 17).
Currently, both locoregional and distant disease control have improved by systemic therapy, allowing for less extensive axillary surgery. Studies have demonstrated that even with the potential persistence of disease in the remaining axilla, regional recurrence rates have not corresponded to these possibilities(10).
Radiation therapy after BCS using tangential fields to the axilla in the ACOSOG Z0011 trial probably covers the remaining positive axillary nodes(18). The AMAROS trial also showed that radiation therapy had promising results in local and systemic disease control, as well as in comorbidities, lymphedema in particular(9). Thus, regional axillary treatment with surgery or even radiation therapy omitted in some select cases, may confer benefits in quality of life and reduce treatment costs.
The novelty of the ACOSOG Z0011 trial lies in the demonstration of good outcomes without any further treatment of the remaining axilla in women with up to 2 involved SLN(18).
The current study has some limitations. This is a retrospective study and initially in our center it was routine practice to consider the presence of micrometastases and ITC as a positive axilla. Over time, there was a change in concept and this practice was abandoned. Therefore, a possible explanation for such a high number of ALND that could have been avoided is the number of patients with micrometastases and ITC. Currently considered N0, these patients were entered in the case study of N1, and underwent ALND at the time.
In addition to reproducing ACOSOG Z0011 trial criteria(19), this study showed a paradigm shift in axillary treatment over the years. It enabled us to make a critical evaluation of our routine practice, which is no different from other referral centers worldwide(11, 19). Self-criticism is fundamental for program implementation to provide patients with the best treatment, along with the least associated comorbidities and lowest cost possible, since this is a public health care facility in a developing country.