Staging Stomach Ca via Ultrasound Takes Hit

ATLANTA — Endoscopic ultrasound may not be as accurate a diagnostic tool for preoperative staging of gastric cancer as currently thought, a new study suggests.

Findings from preoperative endoscopic ultrasound (EUS) had a lower-than-expected concordance with those from postoperative pathologic assessment in a large series of patients undergoing a complete resection for gastric cancer, David J. Bentrem, M.D., reported at a symposium sponsored by the Society of Surgical Oncology.

For example, only 49% of patients with an EUS stage II lesion had a T2 lesion present on a traditional pathology report.

Overall accuracy was 57% for individual EUS T stage lesions and 50% for N stage lesions. The main reason for error was overstaging of the primary tumor, said Dr. Bentrem of Memorial Sloan-Kettering Cancer Center, New York.

The results are important because staging is used to define the eligibility of high-risk patients for neoadjuvant trials and is routinely used by clinicians to stratify risk and guide treatment planning, he said. Hence, physicians “need to know what they're getting with a test,” said Dr. Bentrem.

At present, EUS remains the best test for establishing the extent of locoregional disease, Dr. Bentrem said, adding that most patients with gastric cancer undergo EUS prior to enrollment in a neoadjuvant chemotherapy protocol at Memorial Sloan-Kettering.

The findings contradict an earlier study conducted at the same institution that found preoperative EUS T stage correlated with pathologic T stage in 89% of 43 patients with gastric carcinoma (J. Clin. Oncol. 1993;11:2380–5).

As for how the results could be so disparate—particularly with more than 10 years of additional experience using EUS—Dr. Bentrem told this newspaper that the earlier study included the institution's first 50 patients who underwent EUS followed by resection, and thus there was a “higher degree of scrutiny for these first patients.” The studies also had other methodologic differences.

The current study included 296 patients who underwent a preoperative clinical assessment of T and N stage with EUS and subsequent resection for gastric adenocarcinoma between 1993 and 2003. Patients who had received neoadjuvant therapy were excluded from analysis.

Of the 223 patients evaluated with EUS for T stage lesions, 127 patients (57%) were correctly staged, 25 (11%) were understaged, and 71 (32%) were overstaged.

Of the 218 patients evaluated with EUS for N stage lesions, 110 patients (50%) were correctly staged, 54 (25%) were understaged, and 54 (25%) were overstaged.

The overall accuracy of EUS for assessing the presence or absence of nodal disease was 71%.

The highest agreement between the two methods was in distinguishing high-risk patients from low-risk patients. Of the 150 patients deemed high risk or showing evidence of either serosal invasion or nodal disease on preoperative EUS, 76% were found to be high risk on traditional pathologic assessment.

EUS did not distinguish among individual T stages based on outcome, particularly between T2 and T3 lesions, Dr. Bentrem said. Many of the pathologic T2 lesions were overstaged and identified as T3 on EUS. Patients with EUS-identified T2 and T3 lesions had similar outcomes, with a median survival rate of about 36 months.

ATLANTA — Endoscopic ultrasound may not be as accurate a diagnostic tool for preoperative staging of gastric cancer as currently thought, a new study suggests.

Findings from preoperative endoscopic ultrasound (EUS) had a lower-than-expected concordance with those from postoperative pathologic assessment in a large series of patients undergoing a complete resection for gastric cancer, David J. Bentrem, M.D., reported at a symposium sponsored by the Society of Surgical Oncology.

For example, only 49% of patients with an EUS stage II lesion had a T2 lesion present on a traditional pathology report.

Overall accuracy was 57% for individual EUS T stage lesions and 50% for N stage lesions. The main reason for error was overstaging of the primary tumor, said Dr. Bentrem of Memorial Sloan-Kettering Cancer Center, New York.

The results are important because staging is used to define the eligibility of high-risk patients for neoadjuvant trials and is routinely used by clinicians to stratify risk and guide treatment planning, he said. Hence, physicians “need to know what they're getting with a test,” said Dr. Bentrem.

At present, EUS remains the best test for establishing the extent of locoregional disease, Dr. Bentrem said, adding that most patients with gastric cancer undergo EUS prior to enrollment in a neoadjuvant chemotherapy protocol at Memorial Sloan-Kettering.

The findings contradict an earlier study conducted at the same institution that found preoperative EUS T stage correlated with pathologic T stage in 89% of 43 patients with gastric carcinoma (J. Clin. Oncol. 1993;11:2380–5).

As for how the results could be so disparate—particularly with more than 10 years of additional experience using EUS—Dr. Bentrem told this newspaper that the earlier study included the institution's first 50 patients who underwent EUS followed by resection, and thus there was a “higher degree of scrutiny for these first patients.” The studies also had other methodologic differences.

The current study included 296 patients who underwent a preoperative clinical assessment of T and N stage with EUS and subsequent resection for gastric adenocarcinoma between 1993 and 2003. Patients who had received neoadjuvant therapy were excluded from analysis.

Of the 223 patients evaluated with EUS for T stage lesions, 127 patients (57%) were correctly staged, 25 (11%) were understaged, and 71 (32%) were overstaged.

Of the 218 patients evaluated with EUS for N stage lesions, 110 patients (50%) were correctly staged, 54 (25%) were understaged, and 54 (25%) were overstaged.

The overall accuracy of EUS for assessing the presence or absence of nodal disease was 71%.

The highest agreement between the two methods was in distinguishing high-risk patients from low-risk patients. Of the 150 patients deemed high risk or showing evidence of either serosal invasion or nodal disease on preoperative EUS, 76% were found to be high risk on traditional pathologic assessment.

EUS did not distinguish among individual T stages based on outcome, particularly between T2 and T3 lesions, Dr. Bentrem said. Many of the pathologic T2 lesions were overstaged and identified as T3 on EUS. Patients with EUS-identified T2 and T3 lesions had similar outcomes, with a median survival rate of about 36 months.

ATLANTA — Endoscopic ultrasound may not be as accurate a diagnostic tool for preoperative staging of gastric cancer as currently thought, a new study suggests.

Findings from preoperative endoscopic ultrasound (EUS) had a lower-than-expected concordance with those from postoperative pathologic assessment in a large series of patients undergoing a complete resection for gastric cancer, David J. Bentrem, M.D., reported at a symposium sponsored by the Society of Surgical Oncology.

For example, only 49% of patients with an EUS stage II lesion had a T2 lesion present on a traditional pathology report.

Overall accuracy was 57% for individual EUS T stage lesions and 50% for N stage lesions. The main reason for error was overstaging of the primary tumor, said Dr. Bentrem of Memorial Sloan-Kettering Cancer Center, New York.

The results are important because staging is used to define the eligibility of high-risk patients for neoadjuvant trials and is routinely used by clinicians to stratify risk and guide treatment planning, he said. Hence, physicians “need to know what they're getting with a test,” said Dr. Bentrem.

At present, EUS remains the best test for establishing the extent of locoregional disease, Dr. Bentrem said, adding that most patients with gastric cancer undergo EUS prior to enrollment in a neoadjuvant chemotherapy protocol at Memorial Sloan-Kettering.

The findings contradict an earlier study conducted at the same institution that found preoperative EUS T stage correlated with pathologic T stage in 89% of 43 patients with gastric carcinoma (J. Clin. Oncol. 1993;11:2380–5).

As for how the results could be so disparate—particularly with more than 10 years of additional experience using EUS—Dr. Bentrem told this newspaper that the earlier study included the institution's first 50 patients who underwent EUS followed by resection, and thus there was a “higher degree of scrutiny for these first patients.” The studies also had other methodologic differences.

The current study included 296 patients who underwent a preoperative clinical assessment of T and N stage with EUS and subsequent resection for gastric adenocarcinoma between 1993 and 2003. Patients who had received neoadjuvant therapy were excluded from analysis.

Of the 223 patients evaluated with EUS for T stage lesions, 127 patients (57%) were correctly staged, 25 (11%) were understaged, and 71 (32%) were overstaged.

Of the 218 patients evaluated with EUS for N stage lesions, 110 patients (50%) were correctly staged, 54 (25%) were understaged, and 54 (25%) were overstaged.

The overall accuracy of EUS for assessing the presence or absence of nodal disease was 71%.

The highest agreement between the two methods was in distinguishing high-risk patients from low-risk patients. Of the 150 patients deemed high risk or showing evidence of either serosal invasion or nodal disease on preoperative EUS, 76% were found to be high risk on traditional pathologic assessment.

EUS did not distinguish among individual T stages based on outcome, particularly between T2 and T3 lesions, Dr. Bentrem said. Many of the pathologic T2 lesions were overstaged and identified as T3 on EUS. Patients with EUS-identified T2 and T3 lesions had similar outcomes, with a median survival rate of about 36 months.