|Year : 2017 | Volume
| Issue : 3 | Page : 539-542
Interneural tissue clearance in axillary dissection for breast cancer: What is the importance?
Parth Kanaiyalal Patel, Ashok Kumar Sinha, Shashikant Saini
Bhagwan Mahaveer Cancer Hospital and Research Centre, Jaipur, Rajasthan, India
|Date of Web Publication||24-May-2018|
Dr. Parth Kanaiyalal Patel
Bhagwan Mahaveer Cancer Hospital and Research Centre, Jaipur, Rajasthan
Source of Support: None, Conflict of Interest: None
BACKGROUND: Breast cancer is the most common cancer in women and second most common type of cancer overall. The prime objectives of axillary surgery in the management of breast cancer are 1) accurate staging, 2) treatment to cure and 3) quantitative information of metastatic lymph nodes for prognostic purposes and allocation to adjuvant protocols. During axillary dissection, all 3 level lymphnodes are removed, while the important axillary structures (axillary vein, long thoracic and thoracodorsal nerves) are preserved. The latter two structures are particularly vulnerable to injury when dissecting the tissue between them (the interneural tissue). METHODS: This prospective non-randomized study, conducted on 125 female patients, who underwent axillary lymphadenectomy for breast cancer has evaluated the importance of dissection of the Interneural tissue during axillary dissection in breast cancer surgery by reviewing the lymph node yield and metastasis rate. The interneural tissue was excised separately after a routine axillary dissection. RESULTS: Lymph nodes were found in the interneural tissue of 70 out of 125 patients (56%). The average number of interneural lymph nodes recovered per specimen was 1.3. The interneural tissue lymph nodes were positive for metastasis in 10 (8%) patients. There was no incidence of isolated metastasis in the internerve tissue nodes. CONCLUSIONS: There is a significant incidence of lymph nodes (56%) and axillary node metastases (8%) in the tissue lying between the long thoracic and thoracodorsal nerves. Therefore, meticulous dissection and excision of this interneural tissue is strongly recommended to optimize decision making regarding adjuvant treatment and outcome.
Keywords: Axillary lymph node dissection, breast cancer, complication, interneural tissue
|How to cite this article:|
Patel PK, Sinha AK, Saini S. Interneural tissue clearance in axillary dissection for breast cancer: What is the importance?. Indian J Cancer 2017;54:539-42
| » Introduction|| |
It is generally agreed that axillary node status in potentially curable breast cancer is considered the single best predictor of outcome and the main determinant of allocation to adjuvant therapy. The prime objectives of axillary surgery in the management of breast cancer are (1) accurate staging, (2) treatment to cure, and (3) quantitative information of metastatic lymph nodes for prognostic significance and allocation to adjuvant protocols. During the St. Gallen Conference in 1998, the International Consensus Panel advanced the statement that the most relevant factors for the estimation of risk in breast cancer management remain the nodal status and the number of nodes involved. Furthermore, the 1998 revision of the British Association of Surgical Oncology guidelines for surgeons in the management of symptomatic breast disease is that histological node status should be obtained in at least 90% of invasive breast cancers in women having a planned curative operation. Despite the intense arguments and fierce controversy over the years, axillary dissection has been performed for decades as a routine procedure in the management of potentially curable breast cancer. The method has been accepted among the most health providers within the profession as an integral part of the surgical treatment to stage the disease and treat accordingly. No physical examination, no imaging techniques, and no molecular markers can replace axillary surgery for staging purposes. The objectives of axillary surgery are best obtained by carrying out a complete axillary clearance. Nonetheless, less radical surgery is generally performed by carrying out a sampling procedure with a yield of about four nodes or a partial axillary dissection Level I–II with at least ten nodes recovered. Understaging, the axilla is detrimental to outcome, and furthermore, locoregional tumor control is important for survival.
Nevertheless, axillary dissection is associated with significant morbidity such as seroma, shoulder stiffness, upper limb numbness, lymphedema, and chances of nerve injury. This emphasizes the importance of determining and resecting the whole of the potentially involved groups of axillary lymph nodes (ALNs) to optimize the surgical procedure while minimizing its morbidity.
The aim of this study is to examine the lymph node yield and metastasis rate within the tissue between the long thoracic nerve and thoracodorsal nerve (the interneural tissue), and consequently, to determine the potential risk factors which are associated with the metastasis of these nodes and whether this tissue can be left in situ to minimize the risk of nerve injury without compromising the oncologic procedure.
| » Patients and Methods|| |
A retroprospective nonrandomized clinicopathological study was conducted on 125 female patients who underwent surgery for operable breast cancer at the Bhagwan Mahaveer Cancer Hospital and Research Centre, Jaipur, Rajasthan, India, between December 2008 and November 2016. After tissue diagnosis and metastatic workup, the tumor, node, and metastasis staging  was then assigned for every patient, and the patients with metastatic disease were excluded from the study.
Twenty-four (19%) underwent breast conserving surgery and one hundred and one patients (81%) underwent modified radical mastectomy (MRM). During surgery, while doing axillary clearance, interneural tissue was removed separately and sent for histopathological examination. Data of clinical stage, primary tumor histopathology report, i.e., histological type, grade, tumor size and their location, multicentricity, number of metastatic lymph nodes in the axilla level and interneural tissue, extracapsular spread, lymphovascular invasion (LVI), perineural invasion (PNI), and ER/PR/HER2 status were correlated with interneural tissue metastasis.
| » Results|| |
The average age of the patients was 48.7 years (range: 24–76 years). Thirty-six patients (29%) were premenopausal and 89 (71%) were postmenopausal. [Table 1]a shows the stage categories of the patients according to the American Joint Committee on Cancer staging system 7th edition. Fifty-nine patients (47%) were Stage II which was the most common. One hundred and one (81%) patients underwent MRM and 24 (19%) patients underwent breast-conserving surgery. The most common histological type was invasive duct carcinoma (111 patients, 89%) and mostly Grade I-60 (48%), followed by invasive lobular carcinoma in 7 (6%), mucinous carcinoma in 1 (1%), malignant phyllodes tumor in 1 (1%), and medullary carcinoma in 5 (4%).
The tumor was located in the upper outer quadrant in 53 patients (42.4%), in the lower outer quadrant in 21 patients (16.8%), in the upper inner quadrant in 31 (24.8%), and in the lower inner quadrant in 7 (5.6%). It was retroareolar in 13 patients (10.4%). The association between tumor site and interneural tissue node metastasis was statistically significant (P = 0.01) [Table 2]. The T-stage of the tumor was T1, T2, T3, and T4 in 34 (27%), 70 (56%), 11 (9%), and 8 (6%) patients, respectively. In one patient, the size of the breast lump was not known as the patient came with histopathology report after lumpectomy had been performed elsewhere [Table 3]. The total number of lymph nodes analyzed per patient ranged between 6 and 41 (average 16 lymph nodes). Among the 125 patients, 78 (62%) showed metastasis to ALNs and 47 patients (38%) had no lymph node metastasis.
|Table 2: Correlation between axillary nodal status and the presence of the interneural tissue nodes in 125 breast cancer patients|
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|Table 3: Correlation between positivity of interneural tissue nodes and the tumor site, T-stage and axillary nodal metastasis in 125 breast cancer patients|
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Lymph nodes were found in the interneural tissue of 70 out of 125 patients (56%). The average number of interneural lymph nodes recovered per specimen was 1.3 (range: 1–16) [Table 1]b. The interneural tissue lymph nodes represented about 8% of the total number of lymph nodes in these patients. Among the 77 patients with ALN metastasis, the interneural lymph nodes were recovered in 46 patients (60%), 10 (8%) of them had interneural node metastasis. In pathologically negative axilla (48 patients), the interneural tissue lymph nodes were recovered in 24 patients (50%) [Table 2]. Ten (8%) out of 125 patients were found to have metastatic disease in the interneural tissue lymph nodes. The percentage of the metastatic interneural tissue lymph nodes to the total number of the metastatic ALNs ranged from 4% to 54% [Table 1]c. In those 10 patients, metastatic disease was also found in other ALNs. The association between axillary lymph nodes metastasis and interneural tissue node metastasis was statistically significant (P = 0.02). There was no incidence of isolated metastasis in the interneural nodes in the absence of metastatic disease to other lymph nodes in the axilla. Out of 125 patients, only 16 patients had extranodal extension (ENE) positive, while 7/10 patients with positive interneural tissue lymph nodes had ENE positive. Here, ENE is proved to be a risk factor for interneural tissue node metastasis.
The 10 patients with interneural tissue node metastasis were not statistically distinguished by the tumor size (P = 0.2) [Table 3]. Relation of the other histological parameters such as LVI and PNI with interneural tissue metastasis was also not statistically significant (P = 0.9) [Table 4]. None of the 125 patients had injury of either of the two nerves, the long thoracic or the thoracodorsal nerves.
|Table 4: Correlation between positivity of interneural tissue nodes and the lymphovascular invasion, perivascular invasion, and extranodal spread metastasis in 125 breast cancer patients|
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| » Discussion|| |
Lymph node metastasis and tumor size are significantly associated with the survival of patients with breast cancer. However, the management of the axilla is currently far from being uniform and includes axillary node biopsy or sampling, sentinel lymph node biopsy (SLNB), partial or lower axillary clearance, complete axillary clearance, and radiotherapy to the regional lymph nodes alone or in combination with a surgical procedure. The extent to which the axilla should be addressed to provide accurate pathologic information remains unclear. Some authors believe in that a complete axillary clearance is necessary to provide accurate information for staging and prognostic purposes. Opponents, however, feel that a partial axillary dissection reliably assesses the axillary status and at the same time is associated with less morbidity., The clinically negative axilla is currently being assessed by the SLNB., However, in patients with clinically palpable ALNs and patients with clinically negative axilla with positive SLNB, the complete ALN dissection (ALND) still remains the only reliable method to determine the lymph node status.
Although long considered a safe surgical procedure, ALND is associated with the risk of complications, including nerve injury. Injury of either of the long thoracic or the thoracodorsal nerves, significantly increase the morbidity such as muscular weakness and atrophy with more or less deformity.
In 1983, Rosen et al. subdivided the ALNs into three levels according to their location in relation to the pectoralis minor muscle. It is widely held that the involvement of the lymph nodes occurs in a stepwise continuous fashion and that the level of involvement at diagnosis has an important bearing on prognosis and so it is recommended that ALND to be carried out from Level I to Level III in a stepwise manner. Accordingly, to ensure complete axillary dissection, the interneural tissue should be dissected adequately, being a part of level two groups against the chest wall between the long thoracic and the thoracodorsal nerves.
Although in routine practice ten ALNs are the minimum recommendation in ALND specimen for proper staging and further therapy planning,, a more recent study  recommended a minimum of 16 nodes as a target to ensure a high level of confidence that the axilla is free from metastasis. The interneural tissue lymph nodes represented about 8% of the total number of lymph nodes. The results of this study showed that the interneural tissue contains lymph nodes in the majority of cases (56%) and that the lymph nodes contain metastatic disease in 8% of cases. These results are in accordance with the previous studies which also reported the similar findings., In view of results of the our studies, clearance of the interneural tissue is strongly recommended to optimize the lymph node yield and decision-making regarding adjuvant treatment and prognosis in patients with operable breast cancer.
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Conflicts of interest
There are no conflicts of interest.
| » References|| |
Blichert-Toft M. Axillary surgery in breast cancer management – Background, incidence and extent of nodal spread, extent of surgery and accurate axillary staging, surgical procedures. Acta Oncol 2000;39:269-75.
Goldhirsch A, Ingle JN, Gelber RD, Coates AS, Thürlimann B, Senn HJ, et al.
Thresholds for therapies: Highlights of the st gallen international expert consensus on the primary therapy of early breast cancer 2009. Ann Oncol 2009;20:1319-29.
Blamey RW. The British association of surgical oncology guidelines for surgeons in the management of symptomatic breast disease in the UK (1998 revision). BASO breast specialty group. Eur J Surg Oncol 1998;24:464-76.
Roses DF, Brooks AD, Harris MN, Shapiro RL, Mitnick J. Complications of level I and II axillary dissection in the treatment of carcinoma of the breast. Ann Surg 1999;230:194-201.
Edge SB, Compton CC. The American Joint Committee on Cancer: The 7th
edition of the AJCC cancer staging manual and the future of TNM. Ann Surg Oncol 2010;17:1471-4.
Senofsky GM, Moffat FL Jr., Davis K, Masri MM, Clark KC, Robinson DS, et al.
Total axillary lymphadenectomy in the management of breast cancer. Arch Surg 1991;126:1336-41.
Rosen PP, Lesser ML, Kinne DW, Beattie EJ. Discontinuous or “skip” metastases in breast carcinoma. Analysis of 1228 axillary dissections. Ann Surg 1983;197:276-83.
Boova RS, Bonanni R, Rosato FE. Patterns of axillary nodal involvement in breast cancer. Predictability of level one dissection. Ann Surg 1982;196:642-4.
Veronesi U, Galimberti V, Zurrida S, Pigatto F, Veronesi P, Robertson C, et al.
Sentinel lymph node biopsy as an indicator for axillary dissection in early breast cancer. Eur J Cancer 2001;37:454-8.
Giuliano AE, Jones RC, Brennan M, Statman R. Sentinel lymphadenectomy in breast cancer. J Clin Oncol 1997;15:2345-50.
Schell SR. Patient outcomes after axillary lymph node dissection for breast cancer: Use of postoperative continuous local anesthesia infusion. J Surg Res 2006;134:124-32.
Carter CL, Allen C, Henson DE. Relation of tumor size, lymph node status, and survival in 24,740 breast cancer cases. Cancer 1989;63:181-7.
Fitzgibbons PL, Page DL, Weaver D, Thor AD, Allred DC, Clark GM, et al.
Prognostic factors in breast cancer. College of American Pathologists consensus statement 1999. Arch Pathol Lab Med 2000;124:966-78.
Somner JE, Dixon JM, Thomas JS. Node retrieval in axillary lymph node dissections: Recommendations for minimum numbers to be confident about node negative status. J Clin Pathol 2004;57:845-8.
Mostafa A, Mokbel K, Engledow A, Leris AC, Choy C, Wells C, et al.
Is dissection of the internerve tissue during axillary lymphadenectomy for breast cancer necessary? Eur J Surg Oncol 2000;26:153-4.
Rabie AS, Eldweny HI, Abdel Maksoud IG, Elbasmy AA. Value of internerve tissue dissection during axillary lymphadenectomy for early breast cancer. J Egypt Natl Canc Inst 2007;19:249-53.
[Table 1], [Table 2], [Table 3], [Table 4]