Understanding the problem of inadequately staging early ovarian cancer

Abstract 

Background

Early ovarian cancer patients are often incompletely staged during initial surgery. This omission can have serious adverse consequences for the prognosis of patients as the completeness of surgical staging has been identified as an independent prognostic parameter for survival. The reasons for the problem of inadequate staging of early ovarian cancer are largely unknown. We have analysed the data of a large randomised trial in early ovarian cancer in which detailed information of the surgical staging procedure was monitored.⁵

Methods

Data of the EORTC Adjuvant ChemoTherapy In Ovarian Neoplasm (ACTION) Trial were used in which 448 early ovarian cancer patients were randomised between postoperative chemotherapy in one arm and observation following surgery in the other. In this trial strict criteria for surgical staging were advised but optimal, complete staging was performed in only 1/3 of patients. Staging characteristics of the incompletely staged patients were analysed and factors that could explain the failure to perform a complete staging were studied.

Results

Sampling of para-aortic nodes was omitted in 78% of the incompletely staged patients, while 52% of these patients had no pelvic lymph node dissection. Taking blind biopsies from different peritoneal sites was not performed in more than 1/3 of the incompletely staged group. Omission of the staging steps ranged from 3% (infracolic omentectomy) to 55% (biopsy of the right hemi-diaphragm). A significant difference (p=0.04) between the fraction of completely staged patients was found when comparing institutes who entered less than 5 patients (21%) versus those who included more than 20 patients (37%) in the trial.

Conclusions

Even in a randomised trial in which comprehensive surgical staging was strongly advised in the study protocol the majority of patients (66%) were incompletely staged. Factors relating to a lack of surgical skills attributed most to the number of incompletely staged patients, but insufficient knowledge of the tumour behaviour and routes of spread of ovarian cancer also contributed substantially to this problem. Multicentre trials recruiting patients from many institutes with small volume contribution to the study, run the risk of inadequate adherence to the study protocol.

Keywords: Staging laparotomy, Early ovarian cancer, Surgical staging, Incomplete staging, Multicentre trials