***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The recent publication of the results of the American College of Surgeons Oncology Group trial Z0011 has generated substantial interest in the medical community and public press . This trial demonstrated equivalent survival in patients with breast cancer and one to two positive sentinel lymph nodes ( SLNs ) who were r and omly assigned to SLN biopsy ( SLNB ) alone or SLNB followed by axillary lymph node dissection ( ALND ) .  Equally important , regional recurrence with SLNB alone was less than 1 % , despite the fact that an estimated 27 % of patients had additional metastases in the undissected axillary nodes . All patients underwent breast-conserving surgery ( BCS ) , systemic therapy as appropriate , and whole-breast irradiation ( WBRT ) with tangential fields ( TFs ) . Regional nodal irradiation ( RNI ) was not allowed in Z0011 . The st and ard of care for patients with positive SLNs has traditionally been a completion ALND . This results in excellent regional control and provides information that can guide treatment decisions for the radiation and medical oncologists . Because systemic therapy decisions increasingly rely on tumor size , grade , receptor status , and a variety of molecular profiles , there has been less dependence on the number of positive nodes for systemic therapy decision making . The radiation oncologist , however , has historically relied on ALND findings in the design of the radiation treatment fields ; the number of positive nodes provides information concerning the risk of involvement of the level III/supraclavicular ( SCV ) nodes . When this risk is clinical ly relevant , radiation oncologists commonly treat the level III/SCV region with an SCV field . Typically this is used for patients with four or more positive nodes and selected patients with one to three positive nodes . With computed tomography – based planning , this involves contouring level I through III nodes , which ensures adequate radiation to the target nodes that are at risk . Although the combination of ALND and axillary radiation increases the risk of lymphedema , minimal morbidity is associated with radiation to the undissected level III/SCV region or to the undissected axilla . With the recent publication of Z0011 , the optimal design of radiation fields for patients with positive SLNs who do not undergo ALND is uncertain . This will be increasingly important given that many patients with positive SLNs will forego ALND . In weighing whether such patients should receive RNI , it is important to consider the reason for the less than 1 % regional recurrence rate in Z0011 , despite the fact that an estimated 27 % of patients had additional undissected positive nodes . Systemic therapy , which the majority of patients in Z0011 received , may have played a significant role . Studies of patients with positive nodes have demonstrated that approximately 25 % of patients who are treated with chemotherapy have complete eradication of nodal disease . The long-term use of hormonal therapy may also contribute . It is also possible that the low regional recurrence rate is a reflection of the extensive processing of SLNs and subsequent detection of a burden of disease so low that it is held in check by the host immune system , analogous to patients with bone marrow micrometastases who never develop clinical ly evident metastases . A final possibility , and one that we believe is highly relevant , is that TF radiation that was used to treat the breast coincidently delivered radiation treatment to the lower axilla and eradicated the disease . If a large component of the axilla were in the TF region , this is likely to have contributed significantly . We believe that this observation is important and consequently that the results of Z0011 should not be extrapolated to patients who are treated with mastectomy without radiation , partial breast irradiation , irradiation of the breast in the prone position , intraoperative irradiation , or other techniques in which the axilla may not be included in the radiation fields . It is estimated that , using st and ard TFs , more than 50 % of level I and 20 % to 30 % of level II nodes receive 95 % of the prescribed radiation dose ; this is dependent on patient anatomy and where the radiation oncologist sets the upper TF border . Although the Z0011 protocol did not allow RNI , the degree to which the TFs covered level I and II nodes , and whether the radiation oncologist placed the superior border of the TFs to treat more of the level I and II nodes ( high tangents ) , was not documented in the trial . ( Currently the American College of Surgeons Oncology Group is working to extract this data . ) Although the contribution of high TFs to regional control in Z0011 remains uncertain , and the data that support the use of high TFs are based primarily on retrospective dosimetric studies , the use of high TFs has been shown in several studies to include the majority of level I and II nodes . There are several important points to make regarding Z0011 when considering the risk of additional positive nodes . First , patients who participated in this trial had favorable disease characteristics : the median age was 55 years , 70 % had T1 tumors , 82 % had estrogen receptor – positive disease , 71 % had only one positive SLN , and 44 % JOURNAL OF CLINICAL ONCOLOGY COMMENTS AND CONTROVERSIES VOLUME 29 NUMBER 34 DECEMBER 1 BACKGROUND If treatment of the axilla is indicated in patients with breast cancer who have a positive sentinel node , axillary lymph node dissection is the present st and ard . Although axillary lymph node dissection provides excellent regional control , it is associated with harmful side-effects . We aim ed to assess whether axillary radiotherapy provides comparable regional control with fewer side-effects . METHODS Patients with T1 - 2 primary breast cancer and no palpable lymphadenopathy were enrolled in the r and omised , multicentre , open-label , phase 3 non-inferiority EORTC 10981 - 22023 AMAROS trial . Patients were r and omly assigned ( 1:1 ) by a computer-generated allocation schedule to receive either axillary lymph node dissection or axillary radiotherapy in case of a positive sentinel node , stratified by institution . The primary endpoint was non-inferiority of 5-year axillary recurrence , considered to be not more than 4 % for the axillary radiotherapy group compared with an expected 2 % in the axillary lymph node dissection group . Analyses were by intention to treat and per protocol . The AMAROS trial is registered with Clinical Trials.gov , number NCT00014612 . FINDINGS Between Feb 19 , 2001 , and April 29 , 2010 , 4823 patients were enrolled at 34 centres from nine European countries , of whom 4806 were eligible for r and omisation . 2402 patients were r and omly assigned to receive  axillary lymph node dissection and 2404 to receive axillary radiotherapy . Of the 1425 patients with a positive sentinel node , 744 had been r and omly assigned to axillary lymph node dissection and 681 to axillary radiotherapy ; these patients constituted the intention-to-treat population . Median follow-up was 6·1 years ( IQR 4·1 - 8·0 ) for the patients with positive sentinel lymph nodes . In the axillary lymph node dissection group , 220 ( 33 % ) of 672 patients who underwent axillary lymph node dissection had additional positive nodes . Axillary recurrence occurred in four of 744 patients in the axillary lymph node dissection group and seven of 681 in the axillary radiotherapy group . 5-year axillary recurrence was 0·43 % ( 95 % CI 0·00 - 0·92 ) after axillary lymph node dissection versus 1·19 % ( 0·31 - 2·08 ) after axillary radiotherapy . The planned non-inferiority test was underpowered because of the low number of events . The one-sided 95 % CI for the underpowered non-inferiority test on the hazard ratio was 0·00 - 5·27 , with a non-inferiority margin of 2 . Lymphoedema in the ipsilateral arm was noted significantly more often after axillary lymph node dissection than after axillary radiotherapy at 1 year , 3 years , and 5 years . INTERPRETATION Axillary lymph node dissection and axillary radiotherapy after a positive sentinel node provide excellent and comparable axillary control for patients with T1 - 2 primary breast cancer and no palpable lymphadenopathy . Axillary radiotherapy results in significantly less morbidity . FUNDING EORTC Charitable Trust Background The r and omized EORTC 10981 - 22023 AMAROS trial investigates whether breast cancer patients with a tumor-positive sentinel node biopsy ( SNB ) are best treated with an axillary lymph node dissection ( ALND ) or axillary radiotherapy ( ART ) . The aim of the current sub study was to evaluate the identification rate and the nodal involvement . Methods The first 2,000 patients participating in the AMAROS trial were evaluated . Associations between the identification rate and technical , patient- , and tumor-related factors were evaluated . The outcome of the SNB procedure and potential further nodal involvement was assessed . Results In 65 patients , the sentinel node could not be identified . As a result , the sentinel node identification rate was 97 % ( 1,888 of 1,953 ) . Variables affecting the success rate were age , pathological tumor size , histology , year of accrual , and method of detection . The SNB results of 65 % of the patients ( n = 1,220 ) were negative and the patients underwent no further axillary treatment . The SNB results were positive in 34 % of the patients ( n = 647 ) , including macrometastases ( n = 409 , 63 % ) , micrometastases ( n = 161 , 25 % ) , and isolated tumor cells ( n = 77 , 12 % ) . Further nodal involvement in patients with macrometastases , micrometastases , and isolated tumor cells undergoing an ALND was 41 , 18 , and 18 % , respectively . Conclusions With a 97 % detection rate in this prospect i ve international multicenter study , the SNB procedure is highly effective , especially when the combined method is used . Further nodal involvement in patients with micrometastases and isolated tumor cells in the sentinel node was similar — both were 18 % Background The st and ard treatment of the axilla in breast cancer used to be an axillary lymph node dissection . An axillary lymph node dissection is known to give substantial risks of morbidity . In recent years the sentinel node biopsy has become common practice . Future r and omized study results will determine whether the expected decrease in morbidity can be proven . Methods Before the introduction of the sentinel node biopsy , we conducted a study in which 180 women of 50 years and older with T1/T2 cN0 breast cancer were treated with breast conserving therapy .  Instead of an axillary lymph node dissection regional radiotherapy was given in combination with tamoxifen ( RT-group ) . The study group was compared with 341 patients , with the same patient and tumour characteristics , treated with an axillary lymph node dissection ( S-group ) . Results The treatment groups were comparable , except for age . The RT-group was significantly older than the S-group . The median follow up was 7.2 years . The regional relapse rates were low and equal in both treatment groups , 1.1 % in RT-group versus 1.5 % in S-group at 5 years . The overall survival was similar ; the disease free survival was significant better in the RT-group . Conclusion Regional recurrence rates after regional radiotherapy are very low and equal to an axillary lymphnode dissection PURPOSE To develop a guideline for the use of sentinel node biopsy ( SNB ) in early stage breast cancer . METHODS An American Society of Clinical Oncology ( ASCO ) Expert Panel conducted a systematic review of the literature available through February 2004 on the use of SNB in early-stage breast cancer . The panel developed a guideline for clinicians and patients regarding the appropriate use of a sentinel lymph node identification and sampling procedure from hereon referred to as SNB . The guideline was review ed by selected experts in the field and the ASCO Health Services Committee and was approved by the ASCO Board of Directors . RESULTS The literature review identified one published prospect i ve r and omized controlled trial in which SNB was compared with axillary lymph node dissection ( ALND ) , four limited meta-analyses , and 69 published single-institution and multicenter trials in which the test performance of SNB was evaluated with respect to the results of ALND ( completion axillary dissection ) . There are currently no data on the effect of SLN biopsy on long-term survival of patients with breast cancer . However , a review of the available evidence demonstrates that , when performed by experienced clinicians , SNB appears to be a safe and acceptably accurate method for identifying early-stage breast cancer without involvement of the axillary lymph nodes . CONCLUSION SNB is an appropriate initial alternative to routine staging ALND for patients with early-stage breast cancer with clinical ly negative axillary nodes . Completion ALND remains st and ard treatment for patients with axillary metastases identified on SNB . Appropriately identified patients with negative results of SNB , when done under the direction of an experienced surgeon , need not have completion ALND . Isolated cancer cells detected by pathologic examination of the SLN with use of specialized techniques are currently of unknown clinical significance . Although such specialized techniques are often used , they are not a required part of SLN evaluation for breast cancer at this time . Data suggest that SNB is associated with less morbidity than ALND , but the comparative effects of these two approaches on tumor recurrence or patient survival are unknown The CONSORT ( Consoli date d St and ards of Reporting Trials ) statement is used worldwide to improve 
    Output:
    
The absence of knowledge on the extent of nodal involvement in the ART group appeared to have no major impact on the administration of adjuvant systemic therapy .
CONCLUSIONS ART is not inferior to cALND in the patients with clinical ly node-negative breast cancer who had a positive sentinel lymph node .
Information obtained by using cALND after SLNB may have no major impact on the administration of adjuvant systemic therapy