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Sentinel-lymph-node mapping in endometrial cancer – Authors' reply
Correspondence
Sentinel-lymph-node mapping in endometrial cancer Authors’ reply
Giorgio Bogani and colleagues articulate the dilemma of para-aortic node dissection in endometrial cancer staging, which is heightened with the development of the sentinel-lymphnode concept. The correspondents express concern for missed isolated para-aortic nodal metastases with a sentinel lymph node-only approach. This concern was challenged in the FIRES study1 in which we assigned high numbers of patients (196 [58%] of 340 total patients and 74 [74%] of 100 high-grade cases) to para-aortic lymphadenectomy as part of the gold standard lymphadenectomy. In this FIRES cohort, the sentinel lymph node biopsy did, in fact, identify two of the three patients with isolated para-aortic node metastases. Sentinel lymph nodes were not mapped successfully in the third patient, and her para-aortic nodal metastases would have been presumably identified by following the National Comprehensive Cancer Network (NCCN) recommended algorithm to complete lymphadenectomy in such a patient.2 Conventional wisdom suggests that cervical injection is inferior to myometrial or endometrial tracer injection of tracer because it will not map to the para-aortic regions. Although rates of para-aortic sentinel lymph node mapping are impressive following myometrial or endometrial tracer injection, this is an irrelevant observation if they do not replicate true patterns of disease spread. Most patients with fundal endometrial tumours have either pelvic-only nodal disease or para-aortic nodal disease coexisting with pelvic node metastases.3 The highest risk for isolated para-aortic node metastases occurs with deep myometrial invasion www.thelancet.com/oncology Vol 18 May 2017
of high grade tumours.4 Therefore, one can argue that tumours of the endometrium, and inner myometrium (fundal or otherwise) predominantly drain to the pelvic lymph nodes, and a cervical injection capitalises on this lymphatic pathway. Perhaps rather than focusing on the potential for the rare missed isolated para-aortic node occurrence, we should focus more on the benefits that sentinel lymph node biopsy has in identifying the more commonly occurring aberrant lymphatic path ways that had been historically overlooked (eg, presacral, internal iliac, or medial common iliac). These anatomical regions represented 20% of positive sentinel lymph node’s found in the FIRES population, and represent a larger proportion of patients than those with isolated para-aortic nodal metastases. Conven tional pelvic with para-aortic lymph adenectomy would have overlooked these metastases. This new staging technique creates a challenge for clinicians in prescribing adjuvant therapy, particularly radiotherapy, with partial information about the anatomic distribution and extent of nodal metastases. However, this is not unfamiliar territory. Currently not all patients with endometrial cancer receive comprehensive staging and therapeutic decisions are commonly made using incomplete data.5 As always, we will need to contemplate pre-operative or postoperative imaging to fill in the gaps of information. Ultimately, to determine whether the limitations of sentinel lymph node biopsy to characterise the extent of nodal metastases negatively affects outcomes for patients needs be determined in prospective studies: either a long term observational trial, or a trial in which women with high grade endometrial cancers are randomised to sentinel lymph node biopsy or lymphadenectomy.
I declare no competing interests.
Emma C Rossi [email protected] Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, NC 27514, USA 1
2
3
4
5
Rossi EC, Kowalski LD, Scalici J, et al. A comparison of sentinel lymph node biopsy to lymphadenectomy for endometrial cancer staging (FIRES trial): a multicentre, prospective, cohort study. Lancet Oncol 2017; 18: 384–92. Abu-Rustum NR. Sentinel lymph node mapping for endometrial cancer: a modern approach to surgical staging. J Natl Compr Canc Netw 2014; 12: 288–97. Creasman WT, Morrow CP, Bundy BN, Homesley HD, Graham JE, Heller PB. Surgical pathologic spread patterns of endometrial cancer. A Gynecologic Oncology Group Study. Cancer 1987; 60: 2035–41. Mariani A, Dowdy SC, Cliby WA, et al. Prospective assessment of lymphatic dissemination in endometrial cancer: a paradigm shift in surgical staging. Gynecol Oncol 2008; 109: 11–18. Foote JR, Gaillard S, Broadwater G, et al. Disparities in the surgical staging of high-grade endometrial cancer in the United States. Gynecol Oncol Res Pract 2017; 4: 1.
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Sentinel-lymph-node mapping in endometrial cancer Authors’ reply
Giorgio Bogani and colleagues articulate the dilemma of para-aortic node dissection in endometrial cancer staging, which is heightened with the development of the sentinel-lymphnode concept. The correspondents express concern for missed isolated para-aortic nodal metastases with a sentinel lymph node-only approach. This concern was challenged in the FIRES study1 in which we assigned high numbers of patients (196 [58%] of 340 total patients and 74 [74%] of 100 high-grade cases) to para-aortic lymphadenectomy as part of the gold standard lymphadenectomy. In this FIRES cohort, the sentinel lymph node biopsy did, in fact, identify two of the three patients with isolated para-aortic node metastases. Sentinel lymph nodes were not mapped successfully in the third patient, and her para-aortic nodal metastases would have been presumably identified by following the National Comprehensive Cancer Network (NCCN) recommended algorithm to complete lymphadenectomy in such a patient.2 Conventional wisdom suggests that cervical injection is inferior to myometrial or endometrial tracer injection of tracer because it will not map to the para-aortic regions. Although rates of para-aortic sentinel lymph node mapping are impressive following myometrial or endometrial tracer injection, this is an irrelevant observation if they do not replicate true patterns of disease spread. Most patients with fundal endometrial tumours have either pelvic-only nodal disease or para-aortic nodal disease coexisting with pelvic node metastases.3 The highest risk for isolated para-aortic node metastases occurs with deep myometrial invasion www.thelancet.com/oncology Vol 18 May 2017
of high grade tumours.4 Therefore, one can argue that tumours of the endometrium, and inner myometrium (fundal or otherwise) predominantly drain to the pelvic lymph nodes, and a cervical injection capitalises on this lymphatic pathway. Perhaps rather than focusing on the potential for the rare missed isolated para-aortic node occurrence, we should focus more on the benefits that sentinel lymph node biopsy has in identifying the more commonly occurring aberrant lymphatic path ways that had been historically overlooked (eg, presacral, internal iliac, or medial common iliac). These anatomical regions represented 20% of positive sentinel lymph node’s found in the FIRES population, and represent a larger proportion of patients than those with isolated para-aortic nodal metastases. Conven tional pelvic with para-aortic lymph adenectomy would have overlooked these metastases. This new staging technique creates a challenge for clinicians in prescribing adjuvant therapy, particularly radiotherapy, with partial information about the anatomic distribution and extent of nodal metastases. However, this is not unfamiliar territory. Currently not all patients with endometrial cancer receive comprehensive staging and therapeutic decisions are commonly made using incomplete data.5 As always, we will need to contemplate pre-operative or postoperative imaging to fill in the gaps of information. Ultimately, to determine whether the limitations of sentinel lymph node biopsy to characterise the extent of nodal metastases negatively affects outcomes for patients needs be determined in prospective studies: either a long term observational trial, or a trial in which women with high grade endometrial cancers are randomised to sentinel lymph node biopsy or lymphadenectomy.
I declare no competing interests.
Emma C Rossi [email protected] Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, NC 27514, USA 1
2
3
4
5
Rossi EC, Kowalski LD, Scalici J, et al. A comparison of sentinel lymph node biopsy to lymphadenectomy for endometrial cancer staging (FIRES trial): a multicentre, prospective, cohort study. Lancet Oncol 2017; 18: 384–92. Abu-Rustum NR. Sentinel lymph node mapping for endometrial cancer: a modern approach to surgical staging. J Natl Compr Canc Netw 2014; 12: 288–97. Creasman WT, Morrow CP, Bundy BN, Homesley HD, Graham JE, Heller PB. Surgical pathologic spread patterns of endometrial cancer. A Gynecologic Oncology Group Study. Cancer 1987; 60: 2035–41. Mariani A, Dowdy SC, Cliby WA, et al. Prospective assessment of lymphatic dissemination in endometrial cancer: a paradigm shift in surgical staging. Gynecol Oncol 2008; 109: 11–18. Foote JR, Gaillard S, Broadwater G, et al. Disparities in the surgical staging of high-grade endometrial cancer in the United States. Gynecol Oncol Res Pract 2017; 4: 1.
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