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Original article
Sentinel lymph nodes with isolated tumour cells and micrometastases in breast cancer: clinical relevance and prognostic significance Syed Salahuddin Ahmed,1 Aye Aye Thike,1 Jabed Iqbal,1 Wei Sean Yong,2 Benita Tan,3 Preetha Madhukumar,2 Kong Wee Ong,2 Gay Hui Ho,2 Chow Yin Wong,3 Puay Hoon Tan1 1
Department of Pathology, Singapore General Hospital, Singapore 2 Department of Surgical Oncology, National Cancer Centre Singapore, Singapore 3 Department of General Surgery, Singapore General Hospital, Singapore Correspondence to Dr Syed Salahuddin Ahmed, Pathology Department, Histopathology, Singapore General Hospital, 20 College Road, Academia, Level 10, Diagnostics Tower, 169856, Singapore; syed.salahuddin. [email protected] Received 2 June 2013 Revised 14 August 2013 Accepted 3 September 2013 Published Online First 11 November 2013
ABSTRACT Aim We performed a retrospective review to determine the prognostic significance of isolated tumour cells (ITCs) and micrometastases to the sentinel lymph nodes of patients with breast cancer. Methods A total of 1044 patients with a diagnosis of invasive carcinoma of the breast who underwent surgical treatment including the sentinel lymph node biopsy procedure from July 2004 to October 2009 were included in the study. Results In 710 (68%) patients, no metastasis was seen to the sentinel lymph nodes. ITCs were detected in 22 (2.1%) patients, micrometastasis in 52 (5.0%) and macrometastases in 260 (24.9%). With a median followup of 28.8 months, disease recurrence was seen in 38 (3.6%) patients and 15 (1.5%) patients died of disease. No disease recurrence or deaths were recorded in women with ITCs in sentinel lymph nodes. In the micrometastasis group, 2 patients suffered disease recurrence and both died of disease. Conclusions We conclude that ITCs in the sentinel lymph nodes did not adversely impact disease free and overall survivals. Although only 2 recurrences with subsequent death occurred in the micrometastasis group, it may suggest a propensity for presence of micrometastases to augur a worse outcome, and justifies continued segregation of ITCs from micrometastasis.
INTRODUCTION
To cite: Ahmed SS, Thike AA, Iqbal J, et al. J Clin Pathol 2014;67: 243–250.
In patients with breast cancer (BC), the presence or absence of axillary lymph node (ALN) metastases is the single most important prognostic factor and predictor of eventual systemic disease.1 Due to its considered therapeutic effect, axillary lymph node dissection (ALND) seems justifiable despite the risk of morbidity associated with the procedure.2 3 However, additional metastasis is not identified in approximately 50–65% of patients with BC with disease in the sentinel lymph nodes (SLNs)2 4 and ALND in these cases offers no therapeutic benefits. ALND increases cost of care2 5 and morbidity. Acute complications such as arm swelling, numbness, infection, seroma formation, impaired shoulder mobility are seen in 20–30% patients.6 7 Approximately threefold increased risk of locoregional sensory loss and/or lymphoedema is seen in 39% of the patients.6 7 Over the last few decades, ALND has changed from therapeutic clearance of the ALN to selective sentinel lymph node dissection (SLND). SLND
Ahmed SS, et al. J Clin Pathol 2014;67:243–250. doi:10.1136/jclinpath-2013-201771
alone has shown excellent locoregional control of disease in patients with BC.6 8 The results of one randomised prospective study showed no statistically significant difference in disease free survival (DFS) and overall survival (OS) in early stage BC treated with SLND alone and those who also received ALND. DFS and OS in patients who received SLND alone was 82.3% and 91.8% compared with 83.9% and 92.5%, respectively in those who also received ALND.9 The use of SLND allows patients with BC with negative SLN to be spared of almost 60–70% of ALND and their associated morbidity. The SLNs era in BC started and gained popularity after a pilot study of SLND in BC was performed and published in 1993.10 In that study, the authors were able to identify the SLNs in patients with BC prior to surgery by a handheld Gamma probe after injecting a radioisotope tracer around the BC.10 11 All tumour deposits of 2 mm or less in the ALN were classified as lymph node positive micrometastasis in the pre-SLN era. The distinction between isolated tumour cells (ITCs) and micrometastasis was first introduced in 2002 in the sixth edition of the Cancer Staging Handbook of the American Joint Committee on Cancer (AJCC).12 13 The 7th edition of the Cancer Staging Handbook from the AJCC, published in 2010, defines ITCs in the SLN in BC patients as metastatic deposit of ≤0.2 mm, or confluent or non-confluent clusters of tumour cells not exceeding 200 tumour cells on a single histologic lymph node cross section, deposits of >0.2 to ≤2.0 mm as micrometastases and deposits >2 mm as macrometastases. In the AJCC Cancer Staging Handbook, these categories are staged as pN0 [i+], pN1(mi) and pN1.12 14 In the 2002 edition, pN0(i+) staging was assigned to cases where ITCs were detected by immunohistochemistry (IHC) and not by the routine H&E staining method. Later in the revised edition published in 2003 pN0(i+) was defined as presence of ITCs regardless of whether they were detected by routine H&E staining or by IHC. With the increasing use of SLND, the identification of ITCs and micrometastases is becoming a therapeutic dilemma. Some older studies with retrospective analysis have shown a relatively worse prognosis in patients with micrometastases,15 16 but these patients did not receive the current standard adjuvant chemotherapy. Similarly a prospective study involving 790 patients with early BC6 and 243
Downloaded from http://jcp.bmj.com/ on June 23, 2015 - Published by group.bmj.com
Original article some other studies have found no association between micrometastatic nodal disease and overall prognosis.17–19 Decreased 5 year survival was noted in a small but statistically significant 1–2% of patients with BC with ITCs and micrometastasis in the National Surgical Adjuvant Breast and Bowel Project B-32 study with an enrolment of 3884 patients.20 Similarly some other studies with long follow-up of 10–15 years have shown a relatively worse prognosis with micrometastases.21 22 ITCs, which are single cells or small clusters of cells ≤0.2 mm, typically do not show evidence of metastatic activity or penetration of vascular or lymphatic sinus walls. The possible impact of ITCs on the therapeutic strategy and the need for systemic adjuvant treatment remains undefined. With the debate now shifting to whether ALND is needed in patients with ITCs and micrometastases, we performed a retrospective review evaluating various clinicopathological parameters to determine prognostic significance of ITCs and micrometastases. We also aimed to establish if the characteristics of the tumour deposits in SLN may help in predicting further metastasis to non-SLN.
the size of the largest tumour deposit was used for classification. The SLNs were also evaluated for multifocality of tumour deposits (figure 3), location of metastatic deposit (subcapsular vs parenchymal), presence of tumour cells in capsular lymphatics (figure 4), subcapsular sinuses, intraparenchymal sinuses and the perinodal lymphatic channels. For confirmation of suspicious ITCs, IHC using antibodies CAM5.2 or AE1/AE3 was performed on paraffin sections.
Statistical analysis Data were analysed using the Statistical Package for Social Sciences (SPSS) for Windows, V.18. The relationship between clinicopathological parameters and SLN status was tested using the χ2 and Fisher’s exact tests. Survival outcomes were estimated with the Kaplan-Meier method and compared between the four categories of SLNs status: negative node, ITCs, micrometastases and macrometastases using the logrank statistics. A p value of less than 0.05 was considered to indicate statistical significance.
RESULTS
For SLNs submitted for intraoperative frozen section consultation, three histological levels macroscopically sliced at 2 mm intervals are evaluated to detect metastasis. After frozen section, the residual SLN are fixed in formalin, embedded in paraffin and three serial sections with H&E staining are examined. SLN metastases are classified according to the AJCC Cancer Staging Manual as ITCs (figure 1), micrometastasis (figure 2) and macrometastasis. When more than one tumour deposit was present in a single SLN or more than one SLN was involved,
One thousand four hundred and ten patients with BC were identified in our database. Three hundred and sixty-six patients with in situ carcinoma were excluded from the study. The SLN status and patient characteristics are shown in tables 1 and 2. The mean and median of SLNs examined were 2.6 and 2, respectively and the range was 1–7. The mean and median ages of the subjects were 53 years and 54 years and ranged from 23 years to 84 years. Ethnically, 881 (84.4%) were of Chinese origin, 46 (4.4%) Malay, 43 (4.1%) Indians and 74 (7.1%) others. Of the 1044 patients, 710 (68%) had SLN negative disease, 22 (2.1%) had ITCs, 52 (5.0%) micrometastases and 260 (24.9%) macrometastases to the SLNs (table 1). In ITCs and micrometastases, 66 (89.1%) patients had invasive ductal carcinoma (IDC) and 6 (10.9%) had invasive lobular carcinoma. Tumour factors that were associated with increased incidence of SLN metastases (ITCs, micrometastases and macrometastases) were tumour size greater than 20 mm ( p
Original article
Sentinel lymph nodes with isolated tumour cells and micrometastases in breast cancer: clinical relevance and prognostic significance Syed Salahuddin Ahmed,1 Aye Aye Thike,1 Jabed Iqbal,1 Wei Sean Yong,2 Benita Tan,3 Preetha Madhukumar,2 Kong Wee Ong,2 Gay Hui Ho,2 Chow Yin Wong,3 Puay Hoon Tan1 1
Department of Pathology, Singapore General Hospital, Singapore 2 Department of Surgical Oncology, National Cancer Centre Singapore, Singapore 3 Department of General Surgery, Singapore General Hospital, Singapore Correspondence to Dr Syed Salahuddin Ahmed, Pathology Department, Histopathology, Singapore General Hospital, 20 College Road, Academia, Level 10, Diagnostics Tower, 169856, Singapore; syed.salahuddin. [email protected] Received 2 June 2013 Revised 14 August 2013 Accepted 3 September 2013 Published Online First 11 November 2013
ABSTRACT Aim We performed a retrospective review to determine the prognostic significance of isolated tumour cells (ITCs) and micrometastases to the sentinel lymph nodes of patients with breast cancer. Methods A total of 1044 patients with a diagnosis of invasive carcinoma of the breast who underwent surgical treatment including the sentinel lymph node biopsy procedure from July 2004 to October 2009 were included in the study. Results In 710 (68%) patients, no metastasis was seen to the sentinel lymph nodes. ITCs were detected in 22 (2.1%) patients, micrometastasis in 52 (5.0%) and macrometastases in 260 (24.9%). With a median followup of 28.8 months, disease recurrence was seen in 38 (3.6%) patients and 15 (1.5%) patients died of disease. No disease recurrence or deaths were recorded in women with ITCs in sentinel lymph nodes. In the micrometastasis group, 2 patients suffered disease recurrence and both died of disease. Conclusions We conclude that ITCs in the sentinel lymph nodes did not adversely impact disease free and overall survivals. Although only 2 recurrences with subsequent death occurred in the micrometastasis group, it may suggest a propensity for presence of micrometastases to augur a worse outcome, and justifies continued segregation of ITCs from micrometastasis.
INTRODUCTION
To cite: Ahmed SS, Thike AA, Iqbal J, et al. J Clin Pathol 2014;67: 243–250.
In patients with breast cancer (BC), the presence or absence of axillary lymph node (ALN) metastases is the single most important prognostic factor and predictor of eventual systemic disease.1 Due to its considered therapeutic effect, axillary lymph node dissection (ALND) seems justifiable despite the risk of morbidity associated with the procedure.2 3 However, additional metastasis is not identified in approximately 50–65% of patients with BC with disease in the sentinel lymph nodes (SLNs)2 4 and ALND in these cases offers no therapeutic benefits. ALND increases cost of care2 5 and morbidity. Acute complications such as arm swelling, numbness, infection, seroma formation, impaired shoulder mobility are seen in 20–30% patients.6 7 Approximately threefold increased risk of locoregional sensory loss and/or lymphoedema is seen in 39% of the patients.6 7 Over the last few decades, ALND has changed from therapeutic clearance of the ALN to selective sentinel lymph node dissection (SLND). SLND
Ahmed SS, et al. J Clin Pathol 2014;67:243–250. doi:10.1136/jclinpath-2013-201771
alone has shown excellent locoregional control of disease in patients with BC.6 8 The results of one randomised prospective study showed no statistically significant difference in disease free survival (DFS) and overall survival (OS) in early stage BC treated with SLND alone and those who also received ALND. DFS and OS in patients who received SLND alone was 82.3% and 91.8% compared with 83.9% and 92.5%, respectively in those who also received ALND.9 The use of SLND allows patients with BC with negative SLN to be spared of almost 60–70% of ALND and their associated morbidity. The SLNs era in BC started and gained popularity after a pilot study of SLND in BC was performed and published in 1993.10 In that study, the authors were able to identify the SLNs in patients with BC prior to surgery by a handheld Gamma probe after injecting a radioisotope tracer around the BC.10 11 All tumour deposits of 2 mm or less in the ALN were classified as lymph node positive micrometastasis in the pre-SLN era. The distinction between isolated tumour cells (ITCs) and micrometastasis was first introduced in 2002 in the sixth edition of the Cancer Staging Handbook of the American Joint Committee on Cancer (AJCC).12 13 The 7th edition of the Cancer Staging Handbook from the AJCC, published in 2010, defines ITCs in the SLN in BC patients as metastatic deposit of ≤0.2 mm, or confluent or non-confluent clusters of tumour cells not exceeding 200 tumour cells on a single histologic lymph node cross section, deposits of >0.2 to ≤2.0 mm as micrometastases and deposits >2 mm as macrometastases. In the AJCC Cancer Staging Handbook, these categories are staged as pN0 [i+], pN1(mi) and pN1.12 14 In the 2002 edition, pN0(i+) staging was assigned to cases where ITCs were detected by immunohistochemistry (IHC) and not by the routine H&E staining method. Later in the revised edition published in 2003 pN0(i+) was defined as presence of ITCs regardless of whether they were detected by routine H&E staining or by IHC. With the increasing use of SLND, the identification of ITCs and micrometastases is becoming a therapeutic dilemma. Some older studies with retrospective analysis have shown a relatively worse prognosis in patients with micrometastases,15 16 but these patients did not receive the current standard adjuvant chemotherapy. Similarly a prospective study involving 790 patients with early BC6 and 243
Downloaded from http://jcp.bmj.com/ on June 23, 2015 - Published by group.bmj.com
Original article some other studies have found no association between micrometastatic nodal disease and overall prognosis.17–19 Decreased 5 year survival was noted in a small but statistically significant 1–2% of patients with BC with ITCs and micrometastasis in the National Surgical Adjuvant Breast and Bowel Project B-32 study with an enrolment of 3884 patients.20 Similarly some other studies with long follow-up of 10–15 years have shown a relatively worse prognosis with micrometastases.21 22 ITCs, which are single cells or small clusters of cells ≤0.2 mm, typically do not show evidence of metastatic activity or penetration of vascular or lymphatic sinus walls. The possible impact of ITCs on the therapeutic strategy and the need for systemic adjuvant treatment remains undefined. With the debate now shifting to whether ALND is needed in patients with ITCs and micrometastases, we performed a retrospective review evaluating various clinicopathological parameters to determine prognostic significance of ITCs and micrometastases. We also aimed to establish if the characteristics of the tumour deposits in SLN may help in predicting further metastasis to non-SLN.
the size of the largest tumour deposit was used for classification. The SLNs were also evaluated for multifocality of tumour deposits (figure 3), location of metastatic deposit (subcapsular vs parenchymal), presence of tumour cells in capsular lymphatics (figure 4), subcapsular sinuses, intraparenchymal sinuses and the perinodal lymphatic channels. For confirmation of suspicious ITCs, IHC using antibodies CAM5.2 or AE1/AE3 was performed on paraffin sections.
Statistical analysis Data were analysed using the Statistical Package for Social Sciences (SPSS) for Windows, V.18. The relationship between clinicopathological parameters and SLN status was tested using the χ2 and Fisher’s exact tests. Survival outcomes were estimated with the Kaplan-Meier method and compared between the four categories of SLNs status: negative node, ITCs, micrometastases and macrometastases using the logrank statistics. A p value of less than 0.05 was considered to indicate statistical significance.
RESULTS
For SLNs submitted for intraoperative frozen section consultation, three histological levels macroscopically sliced at 2 mm intervals are evaluated to detect metastasis. After frozen section, the residual SLN are fixed in formalin, embedded in paraffin and three serial sections with H&E staining are examined. SLN metastases are classified according to the AJCC Cancer Staging Manual as ITCs (figure 1), micrometastasis (figure 2) and macrometastasis. When more than one tumour deposit was present in a single SLN or more than one SLN was involved,
One thousand four hundred and ten patients with BC were identified in our database. Three hundred and sixty-six patients with in situ carcinoma were excluded from the study. The SLN status and patient characteristics are shown in tables 1 and 2. The mean and median of SLNs examined were 2.6 and 2, respectively and the range was 1–7. The mean and median ages of the subjects were 53 years and 54 years and ranged from 23 years to 84 years. Ethnically, 881 (84.4%) were of Chinese origin, 46 (4.4%) Malay, 43 (4.1%) Indians and 74 (7.1%) others. Of the 1044 patients, 710 (68%) had SLN negative disease, 22 (2.1%) had ITCs, 52 (5.0%) micrometastases and 260 (24.9%) macrometastases to the SLNs (table 1). In ITCs and micrometastases, 66 (89.1%) patients had invasive ductal carcinoma (IDC) and 6 (10.9%) had invasive lobular carcinoma. Tumour factors that were associated with increased incidence of SLN metastases (ITCs, micrometastases and macrometastases) were tumour size greater than 20 mm ( p
