Abstract
BACKGROUND:
Ovarian cancer is the sixth most common
cancer
among women. In addition to diagnosis and staging, primary surgery is
performed to achieve optimal cytoreduction (surgical efforts aimed at
removing the bulk of the tumour) as the amount of residual tumour is one
of the most important prognostic factors for survival of women with
epithelial
ovarian cancer. An optimal outcome of cytoreductive
surgery remains a subject of controversy to many practising
gynae-oncologists. The Gynaecologic Oncology group (GOG) currently
defines 'optimal' as having residual tumour nodules each measuring 1 cm
or less in maximum diameter, with complete cytoreduction (microscopic
disease) being the ideal surgical outcome. Although the size of residual
tumour masses after surgery has been shown to be an important
prognostic factor for advanced
ovarian cancer, it is unclear
whether it is the surgical procedure that is directly responsible for
the superior outcome that is associated with less residual disease.
OBJECTIVES:
To
evaluate the effectiveness and safety of optimal primary cytoreductive
surgery for women with surgically staged advanced epithelial
ovarian cancer
(stages III and IV).To assess the impact of various residual tumour
sizes, over a range between zero and 2 cm, on overall survival.
MAIN RESULTS:
There
were no RCTs or prospective non-RCTs identified that were designed to
evaluate the effectiveness of surgery when performed as a primary
procedure in advanced stage
ovarian cancer.We found 11
retrospective studies that included a multivariate analysis that met our
inclusion criteria. Analyses showed the prognostic importance of
complete cytoreduction, where the residual disease was microscopic that
is no visible disease, as overall (OS) and progression-free survival
(PFS) were significantly prolonged in these groups of women.
PFS was not
reported in all of the studies but was sufficiently documented to allow
firm conclusions to be drawn.When we compared suboptimal (> 1 cm)
versus optimal (< 1 cm) cytoreduction the survival estimates were
attenuated but remained statistically significant in favour of the lower
volume disease group There was no significant difference in OS and only
a borderline difference in PFS when residual disease of > 2 cm and
< 2 cm were compared (hazard ratio (HR) 1.65, 95% CI 0.82 to 3.31;
and HR 1.27, 95% CI 1.00 to 1.61, P = 0.05 for OS and PFS
respectively).
There was a high risk of bias due to the retrospective
nature of these studies where, despite statistical adjustment for
important prognostic factors, selection bias was still likely to be of
particular concern.
Adverse events, quality of life (QoL) and
cost-effectiveness were not reported by treatment arm or to a
satisfactory level in any of the studies.
AUTHORS' CONCLUSIONS:
During primary surgery for advanced stage epithelial
ovarian cancer
all attempts should be made to achieve complete cytoreduction. When
this is not achievable, the surgical goal should be optimal (< 1 cm)
residual disease. Due to the high risk of bias in the current evidence,
randomised controlled trials should be performed to determine whether it
is the surgical intervention or patient-related and disease-related
factors that are associated with the improved survival in these groups
of women. The findings of this review that women with residual disease
< 1 cm still do better than women with residual disease > 1 cm
should prompt the surgical community to retain this category and
consider re-defining it as 'near optimal' cytoreduction, reserving the
term 'suboptimal' cytoreduction to cases where the residual disease is
> 1 cm (optimal/near optimal/suboptimal instead of
complete/optimal/suboptima
