| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
ORIGINAL ARTICLES |
From the Department of Surgery (GAP, HM), Dalhousie University, Halifax, Nova Scotia, Canada; and the Department of Surgery (PJL), McMaster University, Hamilton, Ontario, Canada.
Correspondence: Address correspondence and reprint requests to: Geoffrey A. Porter, MD, Department of Surgery, 7-007 Victoria Building, QEII Health Sciences Center, 1278 Tower Road, Halifax, Nova Scotia, B3H 2Y9, Canada; Fax: 902-473-6496; E-mail: geoff.porter{at}dal.ca
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
Methods: All active (n = 1172) general surgeons in Canada were sent a 31-item questionnaire.
Results: Of the 519 respondents who treated IBC, 138 (27%) performed SLNBx, whereas 378 (73%) did not. Surgeons who did not perform SLNBx most commonly cited a lack of adequate resources (64%). Of the 138 surgeons who performed SLNBx, 16% participated in one of the ongoing multicenter clinical trials. Of the 39 (28%) surgeons who abandoned routine concurrent axillary lymph node dissection, 20 (51%) performed <30 combined procedures before performing SLNBx alone. On multivariate analysis, surgical oncology training (P = .005), increasing proportion of practice devoted to breast disease (P < .001), and number of days per week in the operating room (P < .001) were associated with the use of SLNBx.
Conclusions: In contrast to the United States, SLNBx for IBC in Canada was not as common, and few surgeons participated in clinical trials. Fellowship-trained surgical oncologists and surgeons with a high exposure to breast disease seemed to be most involved in the development of SLNBx for IBC.
Key Words: Breast cancer • Sentinel node • Training • Survey
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
However, there is morbidity associated with ALND; it is predominately related to seroma formation, sensory changes, lymphedema, and chronic pain.2,3 Recently, sentinel lymph node biopsy (SLNBx) has emerged as a technique in which the first draining lymph node is identified by using a radioactive marker, blue dye, or both and excised.4,5 This has the potential to avoid full ALND and its attendant morbidity in many patients with invasive breast cancer.
SLNBx has been well established in malignant melanoma and is indeed the most important prognostic factor in patients with this disease.6,7 In breast cancer, it has been shown that SLNBx can accurately determine the status of the axillary lymph nodes—when the histopathologic examination of the sentinel lymph node is negative, the remaining nonsentinel lymph nodes within the axilla are unlikely to contain tumor cells. This has been reproduced in single and multi-institutional studies.8–13 Thus, if ALND has as its only goal to accurately stage a patient, it would seem that SLNBx would serve that purpose.
Unfortunately, there are three main potential problems. First, there is a learning curve associated with the technique. SLNBx in breast cancer requires a multidisciplinary involvement of nuclear medicine, surgery, and pathology. It has been well documented that the identification and accuracy rates of SLNBx improve with the number of procedures performed.10,13–15 Second, it is possible that ALND itself may be of therapeutic benefit. Although ALND has never been shown to offer a survival advantage in individual randomized clinical trials, most such trials have been underpowered to detect a clinically significant difference. A recent meta-analysis suggests the possibility of a modest survival improvement with ALND.16 Third, it is unclear whether patients with metastases found on SLNBx require completion ALND.
For these reasons and others, at present SLNBx is not the standard of care for patients with invasive breast cancer. Currently, two ongoing large North American randomized clinical trials investigating the use of SLNBx in breast cancer are actively accruing patients. The results of these trials should help further define the efficacy and role of SLNBx in breast cancer.
Although recent published clinical practice guidelines confirm ALND to be the standard of care in the surgical management of the axilla for patients with stage I and II invasive breast cancer,17,18 SLNBx is being performed commonly and has in fact supplanted ALND as the staging procedure of choice in the United States. The primary objective of this study is to describe the current use of SLNBx in breast cancer among Canadian surgeons. In addition, we sought to examine the techniques used for SLNBx, determine surgeon training in the procedure, and examine geographic- and surgical specialty–associated variations in the use of SLNBx.
|
METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
The survey was sent to all accredited general surgeons in Canada in July 2001. It was accompanied with a cover letter explaining the purpose of the study, and a self-addressed, stamped envelope was included to encourage return. The questionnaire was completed in an anonymous manner, and an embedded four-digit code within the survey allowed linkage for the investigators to establish response or nonresponse. A second mailing was sent to all surgeons who had not returned the questionnaire after 60 days.
Geographic boundaries were established a priori on the basis of population as follows: East (Newfoundland, Nova Scotia, New Brunswick, and Prince Edward Island), Central (Ontario and Quebec), and West (Manitoba, Saskatchewan, Alberta, British Columbia, and Territories). The presence and type of post–general surgery fellowship training were established as reported by the respondents, as was their practice setting (community, community with university affiliation, or academic) and volume of breast cancer surgery.
Univariate analyses included Student’s t-test to compare continuous variables and the 
2 test to compare categorical variables. Two-tailed tests were used whenever the data so allowed, and statistical significance was set a priori at P < .05. To control confounding, multivariate analysis was performed by using logistic regression to assess factors associated with surgeons who performed SLNBx for breast cancer. An independent data manager performed all data entry and data management. Statistical analysis was performed with SPSS software (SPSS Inc., Chicago, IL).
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
|
|
There were 138 (27%) surgeons who performed SLNBx in breast cancer: technical aspects are summarized in Table 3. Only 22 surgeons (16%) were participating in one of the multi-institutional randomized clinical trials; 9 (7%) of these surgeons never performed SLNBx outside the context of a clinical trial. Most surgeons (51%) who performed SLNBx in breast cancer learned the technique through a training course; however, 14% were self-taught, and 24% learned through observation of another surgeon. Only 12% of surgeons believed that a false-negative rate (number of patients with a negative SLNBx/number of patients with axillary node metastases) of >5% was acceptable (Table 4).
|
|
11 combined procedures, respectively. These 39 surgeons were significantly less likely to view ALND as the standard of care in the surgical management of invasive breast cancer compared with the 99 surgeons who routinely performed SLNBx and concurrent ALND (80% vs. 91%; P = .05). Characteristics of surgeons who did (n = 138) and did not (n = 381) perform SLNBx in breast cancer were compared (Table 4). Between the groups, no significant differences were identified in mean age or time from general surgery certification. On univariate analysis, female surgeon sex, academic practice setting, surgical oncology fellowship training, and a higher proportion of the surgeons’ practice dedicated to breast disease were associated with performing SLNBx in breast cancer (Table 4). An association was also identified between overall surgical volume (as measured by the number of days per week in the operating room) and performing SLNBx, although the highest rate of SLN biopsy was found in surgeons with "moderate" surgical volume (1.5–2.0 days per week in the operating room) (Table 4). On multivariate analysis, the following factors were found to be independently associated with the use of SLNBx: fellowship training in surgical oncology, number of days per week the surgeon was in the operating room, and percentage of the surgeons’ practice dedicated to breast disease (Table 4).
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
85% and an acceptable false-negative rate 5% should a selective use of SLNBx be proposed. However, these groups also recommend that the primary use of SLNBx in breast cancer at present should be in the context of one of the large randomized clinical trials and endorse ALND as the standard of care in the surgical staging of the axilla. The American College of Surgeons Oncology Group–sponsored randomized trial (Z0011) examining the use of SLNBx in breast cancer requires participating surgeons to have performed 20 combined SLNBx/ALND procedures.
As commonly occurs with new technology, SLNBx in breast cancer has entered mainstream clinical use before the completion of large clinical trials. The degree to which this occurs is likely dependent on multiple factors: the surgeon’s belief in adoption of the technique, patient demand, and results from nonrandomized clinical studies. A recent survey was performed of a random sample of Fellows of the American College of Surgeons in the United States.20 Of the 77% of all respondents who performed SLNBx for breast cancer, 55% did so as part of a clinical trial. Although the proportion of surgeons who had abandoned concurrent ALND was not reported, 28% of surgeons had abandoned ALND after performing 10 SLNBx with concurrent ALND. This study did not identify any differences in the use of SLNBx among academic and private-practice surgeons. It did seem from this study that most surgeons in the United States used a similar technique for SLNBx in breast cancer. The study was limited somewhat by its relatively low response rate of 41% (n = 410).
Canadian practice patterns in SLNBx for breast cancer are markedly different in several ways. Perhaps the greatest difference is the proportion of surgeons performing SLNBx. In this study, only 128 (20%) of the 640 completed questionnaires were returned by surgeons who had any experience in SLNBx for breast cancer, compared with 77% from the US survey.20 Clearly, neither study likely accurately reflects the proportion of surgeons performing SLNBx, because there is likely a large response bias associated with both surveys. However, because the methodology of the two studies was similar, there seems to be quite a disparity in the proportion of surgeons performing SLNBx.
At first glance, it would seem that Canadian surgeons have not embraced this technology in breast cancer, and certainly not to the same extent as their US counterparts, with only 27% of surgeons who treat breast cancer performing SLNBx. It could be interpreted from the results of this study that Canadian surgeons have adopted a more evidence-based approach to the adoption of this new technology and are awaiting the results of the critical randomized clinical trials. However, the paradoxical extremely low rate of participation in such trials by Canadian surgeons (4.2% compared with 55% among US surgeons20) would suggest another explanation. As opposed to a perceived lack of supporting evidence, the most commonly reported reason for not performing SLNBx in breast cancer was inadequate resources, specifically related to the capital equipment, nuclear medicine, and pathology backup required to perform this procedure. Both isosulfan blue (Lymphazurin; US Surgical Corp., Norwalk, CT) and appropriate radioisotopes are readily available in Canada. Within the Canadian health care system, the acquisition of new technology, such as the handheld gamma probe, would usually be sought from individual hospitals’ capital expenditure budgets. The ability to successfully obtain necessary funds commonly requires an individual motivated to "champion" the required equipment. In contrast to the United States, where the appropriate establishment of new technology may be financially beneficial to an institution, the opposite often occurs in the Canadian government-funded system. Hypothetically, if resources were made available to surgeons not presently performing SLNBx and the assumption were made that 50% of them thus adopted the technique, an approximate doubling of the number of surgeons performing SLNBx in Canada would occur.
This study describes the use of SLNBx in breast cancer at the present time. However, multiple questions remain, and in fact, more questions arise with these results. In the absence of phase III randomized clinical trials, it is difficult to determine how best to introduce new technologies, specifically new technologies with the potential to significantly reduce surgical morbidity. Of equal importance, it is also critical to ensure that such technology is being performed at acceptable quality standards. This study’s finding that 38% of the surgeons learned the SLNBx technique in a nonstructured fashion (self-taught or by observation of another surgeon) suggests that improvements are required in both the implementation and quality assurance of SLNBx in breast cancer.
This study identified three factors independently associated with surgeons who performed SLNBx in breast cancer: fellowship training in surgical oncology, increasing percentage of the surgeons’ practice dedicated to breast disease, and number of days per week the surgeon was in the operating room. The first two factors support the hypothesis that surgeons with more of an interest in breast cancer, either as self-reported or by fellowship training, seem to have explored the use of SLNBx earlier. The association of the number of days per week in the operating room and the use of SLNBx is interesting. This may represent a surrogate measure of resource availability. This is concordant with the identification of inadequate resources as the most common reason cited by surgeons for not performing SLNBx in breast cancer.
Response bias is a potential limitation of most surveys. The 59% response rate in this study approaches the conventional acceptable standard of 60%.21 Although we asked all surgeons to complete the questionnaire regardless of their involvement in breast cancer surgery, certain subspecialties seemed relatively underrepresented as respondents (critical care and transplantation); this suggests a nonresponse bias involving surgeons not performing breast cancer surgery. Otherwise stated, this study may not accurately quantify, and likely overestimates, the proportion of accredited Canadian general surgeons who perform breast cancer surgery. However, such a bias would not affect the findings among surgeons involved in the care of breast cancer patients. For logistical reasons, the questionnaire was administered only in English, likely explaining the relatively low response rate and consequent questionable generalizability of this study’s findings to Quebec surgeons. Finally, it has been suggested that in the United States, patient demand has played a large role in the rapid adoption of SLNBx in breast cancer.22 The role of patient demand was not examined in this study; this concept is very difficult to evaluate in the context of the government-funded Canadian health care system.
In summary, this study showed that the use of SLNBx in breast cancer in Canada is clearly still in evolution, with the minority of surgeons who treat breast cancer performing the procedure. Lack of institutional resources seemed to be a significant impediment to a more widespread experience. Although few Canadian surgeons rely entirely on SLNBx to stage the axilla after limited experience (<10 cases of SLNBx), few are participating in ongoing randomized trials. The results of such trials are critical to further define the role of SLNBx in the everyday surgical management of breast cancer. Surveys such as this are an important tool in determining resource requirements once the results of the ongoing clinical trials are known and disseminated.
|
Acknowledgments |
|---|
|
Footnotes |
|---|
This survey of Canadian surgeons found the use of sentinel lymph node biopsy in breast cancer to be less common than in the United States, and it is predominantly performed by surgical oncologists or surgeons who commonly treat breast cancer. Few surgeons are participating in ongoing clinical trials.
Received for publication June 4, 2002. Accepted for publication October 11, 2002.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
This article has been cited by other articles:
 |
|
 |
|
  S. Samphao, J. M. Eremin, M. El-Sheemy, and O. Eremin Management of the Axilla in Women With Breast Cancer: Current Clinical Practice and a New Selective Targeted Approach Ann. Surg. Oncol., May 1, 2008; 15(5): 1282 - 1296. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
