In gynecologic oncology, laparoscopic surgery is considered capable of potentially providing a sufficient degree of visualization, via optical magnification, for allowing for optimal performance and accurate verification of resection, while simultaneously allowing for preservation of vital structures, such as small vessels, that may be barely visible to the naked eye [
18,
19]. This study aimed to explore the effectiveness of laparoscopy versus laparotomy for the treatment of apparent early-stage ovarian tumors. The results confirmed the favorable prognostic outcomes of laparoscopy for reducing the lengths of hospital stays and the rates of postoperative complications in patients with apparent early-stage ovarian tumors. Specifically, the aggregated effect size revealed that laparoscopic surgery was significantly associated with fewer complications (OR = 0.433, 95 % CI: 0.215 to 0.869, Z = −2.353,
P = 0.019) and shorter postoperative hospital stays (WMD = −0.974, SE = 0.220, Z = −4.420,
P < 0.001). These findings are consistent with those from studies reporting the advantages of laparoscopy in treating ovarian tumors [
7,
12,
20]. Lee [
12] reported that complete surgical staging via laparoscopy (
n = 26) resulted in reduced blood loss, earlier diet resumption, lower postoperative pain scores, and shorter hospital stays compared with staging via laparotomy (
n = 113) in patients with apparent early-stage ovarian cancer. Laparoscopic surgery has been associated with less intraoperative blood loss and shorter postoperative hospital stays compared with laparotomy [
17,
21]. A major concern regarding laparoscopic surgery is the risk of port-site metastasis, which has incidence rates of 1 %–16 % [
13]. However, in a number of studies on apparent early-stage ovarian cancer, no cases of port-site metastasis or recurrence were reported in patients who had undergone laparoscopy [
14,
22]. Additionally, the inability to utilize fine tactile assessment during laparoscopic surgery to assess the extent of disease may result in the non-recognition of occult metastatic deposits of disease that may be situated within difficult to visualize areas within the abdomen and pelvis. To compensate for this deficiency in the use of laparoscopic surgery for staging, we suggest that preoperative examinations, such as PET-CTs, be used to detect early metastases so that they can be resected in a timely manner. Notably, it is impossible to summarize the hospital stay outcomes in this meta-analysis because of the studies’ considerable heterogeneity, which could have resulted from specific differences in the patients’ conditions and the study designs [
20,
23,
24].
In this meta-analysis, no significant difference was detected in the recurrence rates (OR = 0.707, 95 % CI: 0.245 to 2.037, Z = −0.642,
P = 0.521) of patients with apparent early-stage ovarian tumors who were treated laparoscopically and those who underwent laparotomy. Koo [
13] conducted a prospective study with a mean follow-up period of 31 months and found that tumor recurrence occurred in 2 (8.3 %) patients in the laparoscopy group and 2 (3.8 %) in the laparotomy group (
P = 0.585). There was no significant difference in the mean disease-free survival time, which was excellent in both groups (59 months after laparoscopy versus 66 months after laparotomy,
P = 0.367). Studies have reported that laparoscopy decreases surgical morbidity and improves cancer-related survival times by preserving patients’ cellular immunity [
25‐
27]. In this study, the pooled disease-free survival time was not computed because the related data were only available in two of the included studies (Koo 2013 & Lee 2011). Koo (2013) reported that laparoscopy and laparotomy were associated with disease-free survival times of 59.3 ± 3.78 months and 66.3 ± 1.92 months, respectively. In contrast, Lee (2011) found that patients with apparent early-stage ovarian tumors who received laparoscopy or laparotomy had disease-free survival times of 13.3 ± 10.2 months and 25.7 ± 15.0 months, respectively. However, in a large series that included the laparoscopic staging of 300 patients with apparent early-stage ovarian cancers, laparoscopic surgical management exhibited excellent safety in terms of recurrence and death from disease; 25 patients (8.3 %) underwent immediate laparoscopic staging and 10 (3.3 %) underwent delayed laparoscopic staging, and the 3-year disease free survival and overall survival rates were 85.1 % and 93.6 %, respectively, for all patients [
28]. Future research should include more studies with relatively longer follow-ups to investigate recurrence rates and survival outcomes.
The current review retrieved clinical studies published through May 2014 that estimated the prognostic outcomes of laparoscopic treatment for apparent early-stage ovarian tumors. The findings of our review and meta-analysis are therefore valuable for physicians and policy makers, given the benefits of laparoscopic treatment in terms of reducing hospital stays and complication rates for patients with early-stage ovarian tumors. We employed random-effects models based on the heterogeneity of the true effects distribution, which avoided the bias of overstating the precision of findings in fixed-effects models. A limitation of the current study is the small number of studies and the limited numbers of participants involved. This reflects the paucity of high-quality clinical trials that address the efficacy of laparoscopic surgery for treating ovarian tumors. Generalizations of this study’s conclusions to all patients with early-stage ovarian tumors should be considered with caution, and there is still considerable need for higher quality studies with relatively larger sample sizes to address this topic.