Diagnostic accuracy of laparoscopy following computed tomography (CT) scanning for assessing the resectability with curative intent in pancreatic and periampullary cancer

Background
Surgical resection is the only potentially curative treatment for pancreatic and periampullary cancer. A considerable proportion of
patients undergo unnecessary laparotomy because of underestimation of the extent of the cancer on computed tomography (CT)
scanning. Laparoscopy can detect metastases not visualised on CT scanning, enabling better assessment of the spread of cancer (staging
of cancer). This is an update to a previous Cochrane Review published in 2013 evaluating the role of diagnostic laparoscopy in assessing
the resectability with curative intent in people with pancreatic and periampullary cancer.
Objectives
To determine the diagnostic accuracy of diagnostic laparoscopy performed as an add-on test to CT scanning in the assessment of
curative resectability in pancreatic and periampullary cancer.
Search methods
We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE via PubMed, EMBASE via OvidSP (from
inception to 15 May 2016), and Science Citation Index Expanded (from 1980 to 15 May 2016).
Selection criteria
We included diagnostic accuracy studies of diagnostic laparoscopy in people with potentially resectable pancreatic and periampullary
cancer on CT scan, where confirmation of liver or peritoneal involvement was by histopathological examination of suspicious (liver or
peritoneal) lesions obtained at diagnostic laparoscopy or laparotomy. We accepted any criteria of resectability used in the studies. We
included studies irrespective of language, publication status, or study design (prospective or retrospective). We excluded case-control
studies.
Data collection and analysis
Two review authors independently performed data extraction and quality assessment using the QUADAS-2 tool. The specificity of
diagnostic laparoscopy in all studies was 1 because there were no false positives since laparoscopy and the reference standard are one
and the same if histological examination after diagnostic laparoscopy is positive. The sensitivities were therefore meta-analysed using a
univariate random-effects logistic regression model. The probability of unresectability in people who had a negative laparoscopy (posttest
probability for people with a negative test result) was calculated using themedian probability of unresectability (pre-test probability)
from the included studies, and the negative likelihood ratio derived from the model (specificity of 1 assumed). The difference between
the pre-test and post-test probabilities gave the overall added value of diagnostic laparoscopy compared to the standard practice of CT
scan staging alone.
Main results
We included 16 studies with a total of 1146 participants in the meta-analysis. Only one study including 52 participants had a low risk
of bias and low applicability concern in the patient selection domain. The median pre-test probability of unresectable disease after CT
scanning across studies was 41.4% (that is 41 out of 100 participants who had resectable cancer after CT scan were found to have
unresectable disease on laparotomy). The summary sensitivity of diagnostic laparoscopy was 64.4% (95% confidence interval (CI)
50.1% to 76.6%). Assuming a pre-test probability of 41.4%, the post-test probability of unresectable disease for participants with a
negative test result was 0.20 (95% CI 0.15 to 0.27). This indicates that if a person is said to have resectable disease after diagnostic
laparoscopy and CT scan, there is a 20% probability that their cancer will be unresectable compared to a 41% probability for those
receiving CT alone.
A subgroup analysis of people with pancreatic cancer gave a summary sensitivity of 67.9% (95% CI 41.1% to 86.5%). The post-test
probability of unresectable disease after being considered resectable on both CT and diagnostic laparoscopy was 18% compared to
40.0% for those receiving CT alone.
Authors’ conclusions
Diagnostic laparoscopy may decrease the rate of unnecessary laparotomy in people with pancreatic and periampullary cancer found
to have resectable disease on CT scan. On average, using diagnostic laparoscopy with biopsy and histopathological confirmation of
suspicious lesions prior to laparotomy would avoid 21 unnecessary laparotomies in 100 people in whom resection of cancer with
curative intent is planned.