Surgical staging of para-aortic LN in patients with locally advanced cervix cancer and no evidence of metastases in preoperative PET/CT imaging.

Abstract

To the editor: We read with great interest the article entitled 'Cost-effectiveness of para-aortic lymphadenectomy before chemoradiotherapy in locally advanced cervical cancer' [1]. The authors used a modified Markov model which utilised estimates extrapolated from other published series and came to the conclusion that such staging would be cost effective in patients when positron emission tomography/computed tomography (PET/CT) imaging shows no evidence of para-aortic lymph node (PALN) metastasis. The incidence PALN metastasis varies from 5% in the International Federation of Gynecology and Obstetrics (FIGO) stage I cervix cancer patients to 38% in stage III in various surgically and PET staging studies [2]. Table 1 taken from a review article [2] shows the prevalence of para-aortic nodal metastases according to FIGO stage from published literature [3,4,5,6]. Table 1 Prevalence of para-aortic nodal metastasis in locally advanced cervical cancer according to the FIGO stage Even if the authors are right in their assumption that PALN surgical staging is 100% sensitive and specific in the cohort of patients who have <5 mm sized lymph node at the time of surgery, surely not all patients, regardless of their probability of harbouring microscopic PALN will benefit from surgical staging? In general, the different methods of staging, be it pretherapeutic surgical PALN staging (n=184) [4], pretherapeutic PET staging (n=206) [7], or post-chemo radiotherapy pelvic and PALN dissection (n=73) [8] result in similar survival. Here in Melbourne, Australia, we have extensively utilised both laparoscopic as well as PET staging in cervix cancer. Five hundred thirty-six locally advanced cervix cancer patients (squamous cell carcinoma or adenocarcinoma histology) were treated with curative intent using radiotherapy at Peter MacCallum Cancer Centre between 1996 and 2010. Based on initial assessment, 38 of these patients were planned for surgical evaluation of nodes followed by radical hysterectomy. Since positive nodes were found on frozen section, hysterectomy was abandoned and definitive radiotherapy was given. Seventeen out of these 38 patients (44%) have relapsed. On the other hand, 69 patients had both PET and laparoscopic staging, and of these 27 (39%) have failed. Three hundred twenty patients were staged with PET only, of these 36% have failed and 109 patients had neither PET nor laparoscopic staging, of these 34 (31%) have relapsed. Ninety-seven of the 536 patients (18%) had PALN metastasis detected by either PET alone (n=67; of these 38 [56%] have relapsed), surgical staging alone (n=9; of these seven patients [77%] have relapsed) or both PET & laparoscopic staging (n=21; and of these 14 [66%] have relapsed). We would like to highlight that in the group that had a PET followed by laparoscopic staging, only three out of 21patients had a false negative PET where laparoscopic surgery recovered metastatic node(s) in the para-aortic region. Of these three patients, one has relapsed. As this study has shown that it is difficult to identify a suitable patient group who would benefit from surgical staging in addition to a PET/PET-CT staging, we have since abandoned the routine practice of pretherapeutic laparoscopic staging. It would indeed be useful if authors of this paper could describe precisely how would they select patients for PALN staging from a cohort of locally advanced cervix cancer patients, where PET/CT have not shown any metastatic node in para-aortic region.