Controversies in surgery in ovarian cancer — what is its real role?

Laparoscopy for diagnosing resectability of disease in women with advanced ovarian cancer

BACKGROUND

This is an update of a Cochrane Review that was originally published in 2014, Issue 2.The presence of residual disease after primary debulking surgery is a highly significant prognostic factor in women with advanced ovarian cancer. In up to 60% of women, residual tumour of > 1 cm is left behind after primary debulking surgery (defined as suboptimal debulking). These women might have benefited from neoadjuvant chemotherapy (NACT) prior to interval debulking surgery instead of primary debulking surgery followed by chemotherapy. It is therefore important to select accurately those women who would best be treated with primary debulking surgery followed by chemotherapy from those who would benefit from NACT prior to surgery.

OBJECTIVES

To determine if performing a laparoscopy, in addition to conventional diagnostic work-up, in women suspected of advanced ovarian cancer is accurate in predicting the resectability of disease.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 6) in the Cochrane Library; MEDLINE via Ovid, Embase via Ovid, MEDION and Science Citation Index and Conference Proceedings Citation Index (ISI Web of Science) to July 2018. We also checked references of identified primary studies and review articles.

SELECTION CRITERIA

We included studies that evaluated the diagnostic accuracy of laparoscopy to determine the resectability of disease in women who are suspected of advanced ovarian cancer and planned to receive primary debulking surgery.

DATA COLLECTION AND ANALYSIS

Pairs of review authors independently assessed the quality of included studies using QUADAS-2 and extracted data on study and participant characteristics, index test, target condition and reference standard. We extracted data for two-by-two tables and summarised these graphically. We calculated sensitivity and specificity and negative predictive values.

MAIN RESULTS

We included 18 studies, reporting on 14 cohorts of women (including 1563 participants), of which one was a randomised controlled trial (RCT). Laparoscopic assessment suggested that disease was suitable for optimal debulking surgery (no macroscopic residual disease or residual disease < 1 cm (negative predictive values)) in 54% to 96% of women who had macroscopic complete debulking surgery (no visible disease at end of laparotomy) and in 69% to 100% of women who had optimal debulking surgery (residual tumour < 1 cm at end of laparotomy).Only two studies avoided partial verification bias by operating on all women independent of laparoscopic findings, and provided data to calculate sensitivity and specificity. These two studies had no false positive laparoscopies (i.e. no women had a laparoscopy indicating unresectable disease and then went on to have optimal debulking surgery (no disease > 1 cm remaining)).Due to the large heterogeneity pooling of the data was not possible for meta-analysis.

AUTHORS' CONCLUSIONS

Laparoscopy may be a useful tool to identify those women who have unresectable disease, as no women were inappropriately unexplored. However, some women had suboptimal primary debulking surgery, despite laparoscopy predicting optimal debulking and data are at high risk of verification bias as only two studies performed the reference standard (debulking laparotomy) in test (laparoscopy)-positive women. Using a prediction model does not increase the sensitivity and will result in more unnecessarily explored women, due to a lower specificity.

Laparoscopy for diagnosing resectability of disease in patients with advanced ovarian cancer

BACKGROUND

The presence of residual tumour after primary debulking surgery is the most important prognostic factor in patients with advanced ovarian cancer. In up to 60% of cases, residual tumour of more than 1 cm is left behind, stressing the necessity of accurately selecting those patients who should be treated with primary debulking surgery and those who should receive neoadjuvant chemotherapy instead.

OBJECTIVES

To determine if performing an open laparoscopy after the diagnostic work-up of patients suspected of advanced ovarian cancer is accurate in predicting the resectability of disease.

SEARCH METHODS

We searched MEDLINE, EMBASE, The Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Register of Diagnostic Test Accuracy Studies, MEDION and ISI Web of Science to February 2013. Furthermore, we checked references of identified primary studies and review articles.

SELECTION CRITERIA

We included studies that evaluated the diagnostic accuracy of laparoscopy to determine the resectability of disease in patients who are suspected of advanced ovarian cancer and planned to receive primary debulking surgery.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the quality of included studies using QUADAS-2 and extracted data on study and patients' characteristics, index test, target condition and reference standard. Data for two-by-two tables were extracted and summarised graphically. Sensitivity and specificity and negative predictive values were calculated.

MAIN RESULTS

We included seven studies reporting on six cohorts. Between 27% to 64% of included patients per study were positive on laparoscopy (too extensive disease to warrant laparotomy) and between 36% to 73% were negative (disease suitable for debulking laparotomy). Only two studies avoided partial verification bias and provided data to calculate sensitivity and specificity, which did not justify meta-analysis. These two studies had a sensitivity of 0.70 (95% confidence interval (CI) 0.57 to 0.82) and 0.71 (95% CI 0.44 to 0.90); however, the specificity of both studies was 1.00 (95% CI 0.90 to 1.00). In these two studies there were no false positives, i.e. no patients for whom laparoscopy indicated that major surgery would not be successful and should be avoided, whereas, in reality the patient could be successfully operated upon. Negative predictive values (NPV), for those patients who were diagnosed with having not too extensive disease correctly identified were 0.75 (95% CI 0.55 to 0.86) and 0.96 (95% CI 0.56 to 0.99) due to a different prevalence. Although the studies did report sufficient data to calculate NPVs, we judged these estimates too heterogeneous to meta-analyse.Three studies described the development or validation of a prediction model with a clear cut-off for test positivity. Sensitivity and specificity of these prediction models were 0.30 to 0.70 and 0.89 to 1.00, respectively. However, one of these studies suffered from partial verification bias.

AUTHORS' CONCLUSIONS

Laparoscopy is a promising test, but the low number of studies and the differences between the included studies do not allow firm conclusions to be drawn from these data. Due to a difference in prevalence, there is a wide range in negative predictive values between studies. Two studies verified all patients. These imply a high specificity of laparoscopy in diagnosing resectability and have a good sensitivity. Both studies show that the use of criteria for unresectable disease will result in no patients inappropriately unexplored. However, there will still be patients undergoing unsuccessful primary laparotomy. Using a prediction model does not increase the sensitivity and will result in more unnecessarily explored patients, due to a lower specificity.