Preoperative and operative diagnosis of pancreatic cancer

Pancreatic Frozen Section Guides Operative Management With Few Deferrals and Errors

CONTEXT.—

Pancreatic adenocarcinoma is the third leading cause of cancer death in the United States. Surgery remains the mainstay of treatment, and frozen section analysis is used to confirm diagnosis and determine resectability and margin status.

OBJECTIVE.—

To evaluate use and accuracy of frozen section and how diagnosis impacts surgical procedure.

DESIGN.—

We reviewed patients with planned pancreatic resections between January 2014 and March 2019 with at least 1 frozen section. Pathology reports including frozen sections, preoperative cytology, and operative notes were reviewed. Frozen sections were categorized by margin, primary pancreatic diagnosis, metastasis, or vascular resectability. The deferral and error rates and surgeons' response were noted.

RESULTS.—

We identified 898 planned pancreatic resections and 221 frozen sections that were performed on 152 cases for 102 margins, 94 metastatic lesions, 20 primary diagnoses, and 5 to confirm vascular resectability. The diagnosis was deferred to permanent sections in 13 of 152 cases (8.6%) on 16 of 221 frozen sections (7.2%): 6 for metastasis, 8 for margins, and 2 for primary diagnosis. Discrepancies/errors were identified in 4 of 152 cases (2.6%) and 4 of 221 frozen sections (1.8%). Surgeon's response was different than expected in 8 of 221 frozen sections (3.6%), but their actions were explained by other intraoperative findings in 6 of 8.

CONCLUSIONS.—

Frozen section remains an important diagnostic tool used primarily for evaluation of margins and metastasis during pancreatectomy. In most cases, a definitive diagnosis is rendered, with occasional deferrals and few errors. Intraoperative findings explain most cases where surgeons act differently than expected based on frozen section diagnosis.

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 (post-test probability for people with a negative test result) was calculated using the median 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.

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). There has been no systematic review or meta-analysis assessing the role of diagnostic laparoscopy in assessing the resectability with curative intent in patients 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 Register of Diagnostic Test Accuracy Studies, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE via PubMed, EMBASE via OvidSP (from inception to 13 September 2012), and Science Citation Index Expanded (from 1980 to 13 September 2012).

SELECTION CRITERIA

We included diagnostic accuracy studies of diagnostic laparoscopy in patients 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 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. Therefore, the sensitivities were meta-analysed using a univariate random-effects logistic regression model. The probability of unresectability in patients who had a negative laparoscopy (post-test probability for patients with a negative test result) was calculated using the median 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

Fifteen studies with a total of 1015 patients were included in the meta-analysis. Only one study including 52 patients 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 40.3% (that is 40 out of 100 patients who had resectable cancer after CT scan were found to have unresectable disease on laparotomy). The summary sensitivity of diagnostic laparoscopy was 68.7% (95% CI 54.3% to 80.2%). Assuming a pre-test probability of 40.3%, the post-test probability of unresectable disease for patients with a negative test result was 0.17 (95% CI 0.12 to 0.24). This indicates that if a patient is said to have resectable disease after diagnostic laparoscopy and CT scan, there is a 17% probability that their cancer will be unresectable compared to a 40% probability for those receiving CT alone.A subgroup analysis of patients 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% for those receiving CT alone.

AUTHORS' CONCLUSIONS

Diagnostic laparoscopy may decrease the rate of unnecessary laparotomy in patients 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 23 unnecessary laparotomies in 100 patients in whom resection of cancer with curative intent is planned.

Frozen section diagnosis of pancreatic lesions

BACKGROUND

The clinical and radiologic diagnosis of pancreatic cancer and the safety of pancreatic resections have improved. These improvements, together with the indication for resection in some cases of complicated chronic pancreatitis, have reduced the necessity for confirmed preoperative tissue diagnosis. We investigated the clinical use and accuracy of frozen section diagnosis for pancreatic lesions.

DESIGN

We searched archival files for the years 1989-2000 for patients with pancreatic lesions who had received a diagnosis based on frozen section results. We compared the diagnosis of all frozen section slides with that of the permanent sections and reviewed the clinical follow-up notes. We evaluated histologic features useful in differentiating between malignant and benign pancreatic lesions.

RESULTS

A total of 538 patients underwent surgical biopsy and/or resection for suspected pancreatic lesions. Frozen section was requested in 131 cases (284 frozen sections). Ninety cases had frozen section of the pancreatic lesions, 70 cases had frozen section of metastatic sites, and 29 cases had frozen section of surgical margins. Of the 90 cases in which frozen section of the pancreatic lesions was requested, malignancy was diagnosed in 44, a benign lesion was diagnosed in 37, and the diagnosis was atypical and deferred in 9. In total, 3 false-negative frozen sections and 1 false-positive frozen section were identified for respective rates of 1.2% and 0.3%. In all cases in which the frozen section diagnosis was deferred or was inconsistent with the operative impression, and the surgeon acted on his/her impression, the operative diagnoses were subsequently confirmed by additional permanent sections and/or clinical follow-up. The most useful histologic features for the diagnosis of pancreatic adenocarcinoma in frozen sections were variation in nuclear size of at least 4:1, disorganized duct distribution, incomplete duct lumen, and infiltrating single cells.

CONCLUSIONS

Frozen sections are useful in conjunction with the impression at surgery for the management of patients with pancreatic lesions. Frozen sections of resection margins were 100% accurate; frozen sections of pancreatic lesions or metastatic sites were accurate in 98.3% of cases. We found an acceptable rate of deferred frozen section (6.6%). The experienced surgeon's impression of malignancy is reliable in cases in which frozen section is deferred or has negative findings.

Diagnosis and staging of pancreatic neoplasms

The relative value of current approaches to the diagnosis and staging of pancreatic cancer is discussed. A rational sequence of testing is recommended based on the clinical presentation of the patient and the local institutional expertise and facilities that are available.

Aspiration cytodiagnosis of pancreatic endocrine tumours

We have reviewed fine needle aspirates from 11 patients with pancreatic endocrine tumours and evaluated the diagnostic criteria as well as those proposed in the literature in an attempt to formulate reliable criteria for the cytological diagnosis of these tumours. As expected, no single criterion was reliable for diagnosis: however, cells with rounded or polygonal rather than a columnar shape, cytoplasmic granularity, and eccentricity of round or oval nuclei with a finely stippled, evenly distributed chromatin pattern were features which, taken together, usually enabled one to make a reliable diagnosis. A striking feature of the smears was the cellular monotony and absence of pleomorphism of the tumour cells. Immunocytochemistry and electron microscopy identified tumour products and confirmed the diagnosis.

Expert systems and the pancreatic cancer problem: decision support in the pre-operative diagnosis

In this paper, after reviewing the main issue in artificial intelligence, decision support systems, medical decision-making, expert systems and some of their applications in medicine, we focus on the diagnostic aspect of pancreatic cancer. We briefly examine the most significant applications both from the oncological and from the diagnostic point of view. We discuss the medical problems mentioning incidence and mortality, aetiological factors and diagnosis, considering the roles of surgery and adjuvant therapies. Finally we justify the decision to develop an expert system in such a medical domain and discuss the SPES (Surgical Pancreatic Expert System) project, its parts dealing with the different medical phases of pancreatic cancer diagnosis and therapy: pre-operative, intra-operative and adjuvant therapies. In particular we discuss diagnostic aspects of pancreatic cancer disease, pointing out the aims of the project, methodologies, tools used and future developments.

Pancreatic resection for pancreatic cancer

In the majority of patients, pancreatic resection is performed for a proved carcinoma or for a mass in the pancreas with clinical features of carcinoma. Preoperative preparation is similar to that for other cancer operations, and good nutritional status and normal clotting factors are important. In many patients with resectable lesions, preoperative histologic diagnosis is not possible.

Percutaneous fine needle aspiration cytology of the pancreas: advantages and pitfalls

Fine needle aspiration of the pancreas was performed in 62 patients with radiological suspicion of malignancy. All fine needle aspirates were taken under computed tomography or ultrasound guidance. Fine needle aspirates were positive in 31 of 41 patients with histologically or clinically confirmed pancreatic carcinoma. There were no false positive results. The sensitivity of this method for detecting malignant disease was 86%. Cytology was not able to provide conclusive results of benign conditions. Difficulties were encountered in diagnosing well differentiated carcinoma and neuroendocrine tumours and distinguishing them from reactive epithelium and islet cell hyperplasia, respectively. This resulted in a 12.1% false negative rate. There were no complications in our series. Percutaneous fine needle aspiration proved a reliable method of diagnosing pancreatic carcinoma.