Response Rate and Prognostic Impact of Salvage Chemotherapy after Nivolumab in Patients with Advanced Gastric Cancer.

OBJECTIVE: Nivolumab is recommended as a third-line treatment in patients with unresectable advanced or recurrent gastric cancer. Although recent studies have demonstrated the prognostic impact of salvage chemotherapy after immune checkpoint inhibitors in several malignancies, its clinical significance remains unclear in patients with gastric cancer. This study aimed to investigate tumor response to subsequent chemotherapy after nivolumab in patients with advanced gastric cancer and assess the prognostic effect of salvage chemotherapy. METHODS: We retrospectively enrolled 31 patients with unresectable advanced or recurrent gastric cancer receiving nivolumab. RESULTS: Twenty-two and nine patients received nivolumab as third-line and fourth- to sixth-line treatments, respectively. The objective response rate (ORR) and disease control rate (DCR) to nivolumab were 20.0% (4/20) and 55.0% (11/20), respectively. Eleven patients received salvage chemotherapy after nivolumab. The ORR and DCR to salvage chemotherapy were 37.5% (3/8) and 75.0% (6/8), respectively. The median progression-free survival and overall survival following salvage chemotherapy were 285 and 360 days, respectively. CONCLUSION: Our preliminary study indicates that nivolumab exposure may enhance subsequent chemosensitivity in patients with advanced gastric cancer.

Assessment of sentinel node concept in esophageal cancer based on lymph node micrometastasis.

PURPOSE: The clinical significance of lymph node micrometastasis remains unclear in patients with esophageal cancer. Therefore, accurate assessment of lymph node status including micrometastasis is important when performing sentinel node (SN) navigation surgery. The purpose of the present study was to investigate the adequacy of SN concept based on lymph node micrometastasis determined by immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR) in patients with esophageal cancer. METHODS: A total of 57 patients with esophageal cancer who were preoperatively diagnosed as having T1-T2 (cT1-T2) and N0 (cN0) were enrolled. They underwent standard esophagectomy with lymph node dissection. One day before surgery, a total of 3 mCi of 99mTechnetium-tin colloid was endoscopically injected into the submucosa around the tumor. During the operation, radioisotope uptake in the lymph nodes was measured using Navigator GPS. All dissected lymph nodes were investigated by RT-PCR using the double marker of CEA and SCC, hematoxylin-eosin (HE) staining, and IHC. RESULTS: Node-positive incidence identified by HE and IHC was 12.3% (7/57) and 19.3% (11/57), respectively. RT-PCR demonstrated micrometastasis in four of 46 patients without nodal metastasis determined by HE staining and IHC. No non-SN metastases were found in 42 patients without micrometastasis identified by IHC and RT-PCR of SN. Accuracy and false negative rates were 100% (57/57) and 0% (0/42), respectively. CONCLUSIONS: SN concept might be acceptable in patients with cT1-T2 and cN0 esophageal cancer, even in the presence of micrometastasis identified by IHC and RT-PCR.

The utility of rapid diagnosis of lymph node metastasis in gastric cancer using a multiplex real-time reverse transcription polymerase chain reaction assay.

BACKGROUND: Lymph node metastasis is the most important prognostic factor in gastric cancer. However, diagnosis by hematoxylin and eosin staining or immunohistochemistry is not always sufficient for the detection of cancer cells because only representative number of slices are examined. Cancer cells may, therefore, be missed by traditional histological methods. Recently, reverse transcription polymerase chain reaction (RT-PCR) methods have been introduced for improved detection of cancer cells. The purpose of this study was to evaluate the utility of a prototype RT-PCR assay run on the Cepheid SmartCycler system compared to conventional RT-PCR using the LightCycler system. PATIENTS AND METHODS: Forty-seven overt metastatic lymph nodes from 8 patients with advanced gastric cancer and 22 benign lymph nodes from patients without malignant tumor who received surgery were obtained with informed consent. We examined the lymph nodes by RT-PCR, using markers for CEA and CK19 and the LightCycler and SmartCycler systems. RESULTS: In the singlex assay, the sensitivity of CEA and CK19 was 91.5 and 70.2% in the LightCycler system, and 97.9 and 95.7% in the SmartCycler system, respectively. In the multiplex assay, the sensitivity was 91.5% in the LightCycler system and 100% in the SmartCycler system, respectively. CONCLUSION: In this study, rapid diagnosis using RT-PCR by the SmartCycler system had higher accuracy for detecting lymph node metastasis than the conventional LightCycler system. The SmartCycler system is more effective for the diagnosis of lymph node metastasis in gastric cancer when run with the prototype assay.

Vascular endothelial growth factor-C and -D expression correlates with lymph node micrometastasis in pN0 early gastric cancer.

BACKGROUND AND OBJECTIVES: Vascular endothelial growth factors (VEGF)-C and -D play an important role in lymphangiogenesis, and the expressions of these factors are related to lymphatic invasion and lymph node metastasis in various malignant neoplasms. The present study investigates the expression of VEGF-C and -D in early gastric cancer and analyzes its relationship to lymph node micrometastasis determined by reverse transcription-polymerase chain reaction (RT-PCR). METHODS: We examined 1,828 lymph nodes obtained from 80 patients with node-negative early gastric cancer. All dissected lymph nodes were examined by RT-PCR for CEA mRNA in addition to hematoxylin-eosin staining. The resected primary specimens were immunostained using anti-VEGF-C and -D polyclonal antibodies. RESULTS: The incidence of lymph node micrometastasis determined by RT-PCR was 23.8% (19/80). The high expression of VEGF-C and -D was found in 27.5% (22/80) and in 21.3% (17/80), respectively. The expression of VEGF-C and -D was closely related to lymph node micrometastasis (P = 0.0390 and 0.0213, respectively). CONCLUSIONS: We demonstrated a close relationship between micrometastasis and VEGF-C and -D expression of the primary tumor. Thus, levels of VEGF-C and -D expression might be useful for predicting micrometastasis in patients with early gastric cancer.

Morphological distribution of metastatic foci in sentinel lymph nodes with gastric cancer.

BACKGROUND: The TNM classification defines micrometastasis (MM) and isolated tumor cells (ITC) in lymph nodes (LN). Sentinel node (SN) navigation surgery has been introduced in gastrointestinal cancer. Few reports have examined the morphological distribution of MM and ITC of SN in gastric cancer. The purpose of this study was to clarify the clinical significance of the morphological distribution of cancer cells in SNs according to metastasis (MA), MM, and ITC. METHODS: All dissected LNs obtained from 160 consecutive patients with mapped SNs arising from cT1-2 N0 tumors were examined. Metastasis in these LNs was examined by histology and cytokeratin staining. The distribution of MA, MM, and ITC was classified as marginal sinus (MS), intermediate sinus (IS), parenchymal (PA), and diffuse types (DF). RESULTS: Nodal metastases were detected in 65 SNs from 30 patients and MA, MM, and ITC accounted for 53.9%, 21.5%, and 24.6%, respectively. MS, IS, PA, and DF accounted for 57%, 6%, 17%, and 20.0%, respectively. Patients with metastasis of non-MS had more nodal metastasis in non-SNs (P = .025) and had nodal metastasis in second tier (P = .009), compared with the patients with metastasis of MS. The incidence of metastasis in non-MS was higher in tumors larger than 40 mm than those smaller than 40 mm (P = .011). CONCLUSION: When performing SN navigation surgery in gastric cancer, we should keep in mind that the patients with tumor larger than 40 mm in size and nodal metastasis of non-MS may have non-SN metastasis and nodal metastasis in second tier.

Detection of micrometastases in sentinel node navigation surgery for gastric cancer.

Although lymph node metastasis is one of the important prognostic factors for patients with gastric cancer, the clinical significance of micrometastasis remains controversial. In the 6th edition of the TMN classification, micrometastases were classified as micrometastasis (MM) and isolated tumor cells (ITC) according to its greatest dimension. The accurate diagnosis of micrometastases is required when considering less invasive surgery, especially in early stage of gastric cancer. Since generating useful information about micrometastases by conventional RT-PCR is time-consuming, this procedure is not useful for rapid diagnosis during surgery. Recently some new methods of genetic diagnosis have reduced the amount of time required to obtain information about micrometastases in lymph nodes to 30-40 min. Such methodology can be clinically applied during less invasive surgery. The sentinel node (SN) concept has recently been applied to gastric cancer and SN navigation surgery (SNNS) is ideal for reduction of lymphadenectomy in patients with early gastric cancer. However, we should think about some conditions to establish SN concept for gastric cancer: the particle size of radioisotope, relationship between metastatic area and RI uptake, and the diagnosis of micrometastases by various method such as histological examination, immunostaining and RT-PCR. Here, we described the current status of MM and ITC in the lymph nodes and the SN concept in gastric cancer.

Analysis of T-helper type 1 and 2 cells and T-cytotoxic type 1 and 2 cells of sentinel lymph nodes in breast cancer.

The immune suppression of sentinel lymph node (SN) is directly influenced by primary tumors. It has been reported that the T-helper type 1 (Th1) to T-helper type 2 (Th2) ratio or T-cytotoxic type 1 (Tc1) to T-cytotoxic type 2 (Tc2) ratio of lymph node lymphocytes could be used to evaluate direct immunological circumstances. We attempted to evaluate the Th1 to Th2 cell and Tc1 to Tc2 cell balance in SN and non-SN and to clarify the immunological status of sentinel nodes in breast cancer. To evaluate this balance, SN and non-SN were identified by radioguided methods and lymph node lymphocytes were collected, and prepared for flow cytometry. The Th1 to Th2 and Tc1 to Tc2 ratio were calculated by 3-color flow cytometry. The ratio of SN and non-SN was compared. The results demonstrated that SN was detected in 24 out of 24 patients (100%). As regards the correlation between SN and non-SN in the same patients, the Th1 to Th2 ratio in SN was significantly lower than that in non-SN for all patients (p<0.05). Among clinicopathological factors, a larger tumor diameter, histology and nodal involvement affected the decreased Th1 to Th2 ratio in SN significantly (p<0.05). We reached the conclusion that the increasing immunosuppressive conditions derived from the tumor may deteriorate the Th1 to Th2 ratio of SN in an earlier stage as compared with non-SN. According to the tumor extension and nodal involvement, the Th1 to Th2 ratio in SN was significantly suppressed. The current result supports that mainly helper T-cell paralysis occurred first in SN and this seems to be a favorable condition in forming lymph node metastases in SN. Moreover, the immunologic interaction between the primary site and regional lymph nodes may serve as useful criteria for identifying sentinel nodes.

Clinical application and outcomes of sentinel node navigation surgery in patients with early gastric cancer.

Sentinel node navigation surgery (SNNS) has been recognized as a minimally invasive tool for individualized lymphadenectomy in patients with early gastric cancer (EGC). The aim of this study was to compare clinicopathological factors, adverse events, and clinical outcomes between sentinel node mapping (SNM) and SN dissection (SND) groups and assess the clinical utility of SNNS in patients with EGC. The clinical data of 157 patients with EGC, diagnosed as clinical T1N0M0 with tumors ≤ 40 mm, undergoing SNNS between March 2004 and April 2016 were retrospectively reviewed. Twenty-seven patients were excluded from the analysis. In the remaining 130 patients, 59 and 71 patients underwent standard lymphadenectomy for SNM and SND, respectively. The sentinel node detection rate in the SNM and SND groups was 98.3% (58/59) and 100% (71/71), respectively. Two (3.5%), 15 (25.9%), and 41 (70.7%) patients having sentinel nodes underwent total gastrectomy, proximal gastrectomy (PG), and distal gastrectomy (DG), respectively, in the SNM group. One (1.4%), 5 (7.0%), 10 (14.1%), 39 (54.9%), and 16 (22.5%) patients underwent PG, DG, segmental gastrectomy, local resection, and endoscopic submucosal dissection, respectively, in the SND group. There was no significant difference in postoperative complications between the SNM and SND groups (P = 0.781). Survival did not differ between the both groups (P = 0.856). The present results suggest that personalized surgery with SND provides technical safety and curability related with a favorable survival outcome in patients with EGC.

Sudden hemorrhage without skin invasion in a patient with breast cancer: a case report and literature review.

We report a rare case of sudden hemorrhage caused by breast cancer. A 70-year-old Japanese woman noted fresh bleeding from her left breast. On physical examination, continuous hemorrhage accompanied by an open cavity was observed in the left breast. Mammography and ultrasonography revealed a well-circumscribed mass, with solid and cystic components, that was highly suggestive of intracystic breast carcinoma with direct skin invasion. Computed tomography and bone scintigraphy showed no distant metastasis. Aspiration biopsy of the lesion showed several clusters of adenocarcinoma cells. Modified radical mastectomy was performed with a presumptive diagnosis of stage III B left breast cancer. Invasive ductal carcinoma without skin invasion was diagnosed histologically. To the best of our knowledge, only 6 other cases of sudden hemorrhage caused by breast cancer without skin invasion have been reported in Japan. We review the literature and discuss the clinical characteristics of this unusual phenomenon.

Sentinel node navigation surgery for gastroduodenal neuroendocrine tumors: Two case reports.

The percentage of gastroduodenal neuroendocrine tumors (NETs) among all gastroenteropancreatic (GEP) NETs has gradually increased worldwide. Sentinel node navigation surgery (SNNS) has been developed as a personalized approach in the surgical strategy for early gastrointestinal tract cancers. We herein report 2 cases of gastroduodenal NETs treated with SNNS. Technetium-tin colloid including indocyanine green was endoscopically injected into the submucosa around a tumor the day before surgery. Basin dissection including the sentinel nodes (SNs), which were identified by Navigator GPS and near-infrared fluorescence imaging, was performed during laparoscopic surgery. SNs were intraoperatively examined using hematoxylin-eosin (HE) staining.SNs were detected in 2 patients. Lymph node metastasis was intraoperatively identified in 1 of the 2 patients. Consequently, 1 patient with metastatic SNs underwent laparoscopic gastrectomy with lymphadenectomy. Pathological findings identified submucosal NET measuring 6.0 mm × 5.0 mm.Our results suggest that SNNS is a promising surgical tool for detecting subclinical lymph node metastasis in patients with gastroduodenal NETs.

Evaluation of colloid size for sentinel nodes detection using radioisotope in early gastric cancer.

The purpose of this study was to investigate the relationship between colloid size and the detection of sentinel nodes (SN) in early gastric cancer. Three size of 99mTechnetium-tin colloids (500, 100 and 50 nm) were preoperatively injected into the submucosa under endoscopic control. Lymph node metastasis and micrometastasis was examined. RI-uptake in the hottest nodes and the total RI-uptake in the hot nodes were highest in the size of 100 nm. At least one lymph node metastasis, including micrometastasis, was included in the hot nodes. RI-labeled colloid size was one of the important factors to detect SN in early gastric cancer.

[Lymph nodes mapping for detection of sentinel nodes in patients with papillary thyroid cancer].

We examined the feasibility of sentinel lymph node biopsy for papillary thyroid cancer. In the dye injection method, 1% of isosulfan blue dye was injected around the tumor of 32 patients intra-operatively, and in the radioisotope (RI) colloid injection method, 99mTc-tin colloid was injected in 23 patients 1 day preoperatively. Lymph node mapping for detection of sentinel nodes was performed after thyroidectomy and central and modified lateral neck lymph node dissections. All dissected nodes were examined postoperatively by hematoxylineosin staining to determine whether or not metastasis was present. In the dye injection method, sentinel lymph nodes were identified in 30 (94%) of the 32 patients. Lymph node metastases were found in 14 patients, and some sentinel lymph nodes had papillary cancer metastasis in 13 patients. There was only 1 false-negative case. Sensitivity and accuracy of sentinel lymph node biopsy was 93% (13/14) and 97% (29/30). With the RI method, detection rate, sensitivity and accuracy of sentinel lymph node biopsy was 96% (22/23), 90% (9/10) and 95% (21/22), respectively. Our preliminary study indicated that sentinel lymph node biopsy was feasible in patients with thyroid cancer. It may be helpful in avoiding unnecessary lymph node dissection and improving quality of life in patients with thyroid cancer.

Utility of the GeneSearch breast lymph node assay for the rapid evaluation of sentinel lymph nodes in breast cancer.

BACKGROUND: The potential for reducing the need for second surgery for axillary lymph node dissection (ALND) has made the intraoperative evaluation of sentinel lymph nodes (SLNs) attractive. The goal of the current study was to evaluate the clinical application of the breast lymph node (BLN) assay, a real-time reverse transcriptase-polymerase chain reaction assay for SLN metastases, by comparing this test with routine pathologic examination. METHODS: A total of 117 patients with breast cancer underwent breast surgery with SLN biopsy. Each SLN was cut in half along the plane of the longest dimension. Half of each lymph node was examined by the 2 markers of the BLN assay, mammaglobin and cytokeratin 19, and the other half was examined by hematoxylin and eosin staining (H&E) and immunohistochemical staining (IHC) for pancytokeratins. RESULTS: A total of 204 SLNs were obtained from 117 patients. H&E staining identified metastases in 31 SLNs (15.2%), and IHC staining detected metastases in 6 SLNs; 40 SLNs from 32 patients were found to be positive for metastasis using the BLN assay. The assay results were correlated with the pathologic diagnoses by H&E and IHC staining (P<.001). The sensitivity of the BLN assay compared with pathologic findings classified according to the TNM classification was 95.7% for macrometastases, 60.0% for micrometastases, and 55.6% for isolated tumor cells. CONCLUSIONS: The 2-marker BLN assay performs in a manner that is comparable to, and analyzes more tissue than, routine pathologic examination. Therefore, clinical intraoperative use of the BLN assay for SLNs may result in a reduction in the need for second surgery for ALND.

Sentinel node micrometastases have high proliferative potential in gastric cancer.

BACKGROUND: The 6th edition of the TNM classification has recently defined "sentinel nodes (SN)," "micrometastasis," and "isolated tumor cells (ITC)." The present study examines the frequency and proliferative activity of such metastases with focus on the SNs of gastric cancer. METHODS: We enrolled 133 patients with cT1-2 tumors (cT1: 104, cT2: 29) and mapped SNs. Lymph node metastases were examined by routine histology and by immunohistochemistry with anti-cytokeratin. We used the Ki-67 antibody to detect the primary tumor and lymph node metastases to evaluate proliferative activity. RESULTS: The number of patients with SNs metastases and metastatic SNs was 19 and 52, respectively. The frequencies of macrometastasis, micrometastasis, and ITC were 48%, 25%, and 27%, respectively. Ki-67 expression in the tumor closely correlated with lymphatic invasion (P = 0.0001), venous invasion (P < 0.0001), and lymph node metastasis (P < 0.0001). Cells in 96% of macrometastases, 92% of micrometastases, and 29% of ITCs were Ki-67 positive. CONCLUSIONS: We showed that micrometastasis and some ITCs in SNs had proliferative activity. We suggest that micrometastasis and ITCs should be removed, especially during SN navigation surgery, until their clinical significance is clarified.

Intramammary sentinel lymph node in patients with breast cancer: report of four cases.

To analyze breast cancer patients with intramammary sentinel lymph node, we reviewed T1-T2N0 breast cancer patients who underwent sentinel lymph node mapping using radioisotope methods. Intramammary sentinel lymph (ISN) nodes were detected in 4 of 166 patients. Three of four ISNs were present in completely different quadrants of the breast from those of primary lesions. Although two patients had no involved nodes, including ISNs, the remaining two with T2 tumor had metastasis of ISNs alone with resulting upstaging. We should keep in mind the presence of intramammary SN in regions apart from the primary tumor, particularly when performing breast conservative surgery.

Area of nodal metastasis and radioisotope uptake in sentinel nodes of upper gastrointestinal cancer.

BACKGROUND: Sentinel node navigation surgery has been introduced for the treatment of gastrointestinal tumor. As few studies have examined relationships between metastatic area and radioisotope uptake in sentinel nodes, the present study examined this relationship for gastric and esophageal cancers. METHODS: Subjects comprised 43 patients (esophageal cancer, n = 19; gastric cancer, n = 24) with < or =3 lymph node metastases in whom sentinel node mapping with radio-guided methods was performed. Radioisotope uptake was measured after surgery for all dissected lymph nodes. Metastatic area was calculated using the following formula: metastatic area (%) = (area of metastasis/total area of lymph node) x 100. Based on radioisotope uptake, lymph nodes were divided into RI(-) and RI(+) groups. RESULTS: In 35 patients, > or =1 metastatic node was present among the sentinel nodes. In 1 patient, no sentinel nodes were detected. No lymph node metastasis was found in sentinel nodes in the remaining seven patients. Lymph nodes were diagnosed as metastatic using preoperative imaging. Mean (+/-SD) metastatic area was significantly higher for RI(-) (68.3 +/- 20.5%) than for RI(+) (15.1 +/- 20.8%; P < 0.0001). Radioisotope uptake was decreased in lymph nodes with >60% metastatic area. CONCLUSIONS: The fact that radioisotope uptake is not detectable in some lymph nodes with >60% metastatic area must be considered when planning sentinel node navigation surgery.

Evaluation of sentinel node concept in gastric cancer based on lymph node micrometastasis determined by reverse transcription-polymerase chain reaction.

OBJECTIVE: To determine the adequacy of sentinel node (SN) concept based on micrometastasis using immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR) in gastric cancer. SUMMARY BACKGROUND DATA: The SN concept has recently been introduced in gastrointestinal tract cancers. The precise detection of lymph node metastasis including micrometastasis is important for SN navigation surgery. METHODS: Sixty-one patients with gastric cancer who were preoperatively diagnosed with T1-T2 (cT1-T2) and N0 (cN0) were enrolled. They underwent standard radical gastrectomy with lymph node dissection. One day before surgery, 4 mCi of (99m)Technetium-tin colloid was endoscopically injected into the submucosa around the tumor. During surgery, radioisotope uptake in the lymph node was measured using Navigator GPS. All dissected lymph nodes were examined by RT-PCR in addition to hematoxylin and eosin staining and IHC. RESULTS: Sentinel nodes were identified in all patients (100%). The incidences of metastasis determined by hematoxylin and eosin and IHC were 8.2% (5 of 61) and 13.1% (8 of 61), respectively. Micrometastases undetectable by IHC were identified in 14 patients (23.0%) by RT-PCR. Only 1 patient had micrometastasis detectable by RT-PCR in lymph nodes other than SN, but this patient had a cT2 tumor. In patients with cT1 and cN0 tumors, the false negative and accuracy rates were 0% and 100%, respectively. CONCLUSIONS: Although the incidence of micrometastasis detected by RT-PCR was quite high, SN navigation identified such metastasis in all patients except one. Thus, the SN concept was applicable to patients with cT1 and cN0 gastric cancer, even when micrometastasis was detectable by RT-PCR.

Initial metastatic, including micrometastatic, sites of lymph nodes in esophageal squamous cell carcinoma.

BACKGROUND AND OBJECTIVES: It is important to identify the initial lymph node metastasis when performing less invasive surgery. The purpose of the present study was to analyze locations of solitary lymph node metastasis and micrometastasis in esophageal carcinoma. METHODS: We retrospectively analyzed the initial sites of lymph node metastasis in esophageal cancer. Sixty-five consecutive patients with solitary lymph node metastasis, and 33 pN0 patients with only lymph node micrometastasis detected by immunohistochemistry, were classified according to tumor location and tumor depth. RESULTS: The location of lymph node metastasis in the 22 patients with superficial cancer was limited to recurrent nerve nodes (RN) in the upper thoracic esophagus; RN, paraesophageal nodes (PE), or perigastric nodes (PG) in the middle or lower thoracic esophagus. Thirty-six patients with advanced cancer had lymph node metastasis at RN, PE, or PG locations, while in the remaining seven, lymph node metastasis was found in areas far from the primary tumor. Regarding the 33 patients with lymph node micrometastasis, the locations of micrometastasis were similar to those of solitary metastasis. CONCLUSIONS: Although less invasive surgery, such as reduction of lymphadenectomy, may be suitable for superficial cancer, it should be performed with special care in advanced cancer.

Particle size of tin and phytate colloid in sentinel node identification.

BACKGROUND: Sentinel node navigation surgery (SNNS) has recently been introduced for various types of carcinoma. Numerous radioisotopes are used as tracers for SNNS. However, few reports have examined particle sizes of isotope colloids used in SNNS. MATERIALS AND METHODS: Tin and phytate colloids were used in the present study. Isotonic sodium chloride and tin solutions were mixed ratios of 1:4, 1:2, 1:1, 2:1, and 4:1. Calcium solution and Tc-phytate were mixed at ratios of 1:4, 1:2, 1:1, 2:1 and 4:1. Particle size was measured using a Coulter Model N4SD Sub-micron Particle Analyzer. RESULTS: When isotonic sodium chloride and tin solutions were mixed at ratios of 1:4, 1:2, 1:1, 2:1, and 4:1, particle size was 47 +/- 9, 96 +/- 10, 712 +/- 83, 925 +/- 66 and 1079 +/- 132 nm, respectively. As the ratio of tin solution decreased, colloid particle size increased. Particle size of phytate colloid varied from 174 +/- 39 nm to 1222 +/- 283 nm, according to calcium concentration. Phytate colloid particle size became larger as the ratio of phytate solution decreased. CONCLUSIONS: We ascertained that the particle size of tin and phytate colloids is controllable by manipulating the conditions under which the colloids form. These results will offer useful information when SNNS is performed.

Value of magnetic resonance cholangiopancreatography with secretin stimulation in the evaluation of pancreatic exocrine function after pancreaticogastrostomy.

BACKGROUND/PURPOSE: The aim of this study was to assess the value of magnetic resonance cholangiopancreatography with secretin stimulation (secretin-MRCP) in evaluating the remnant pancreatic exocrine reserve after pancreaticogastrostomy with pancreaticoduodenectomy. METHODS: Forty-three patients who had undergone pancreaticoduodenectomies and who were given pancreaticogastrostomies for reconstruction were studied. Dynamic MRCPs, using a half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence were obtained before and up to 10 min after secretin administration. The morphologic features and diameter of the main pancreatic duct were monitored and graded before and after secretin stimulation. The results were compared with those of endoscopic findings, secretin stimulation testing with a collection of pancreatic fluid, N-benzoyl- L-tyrosyl-p-aminobenzoic acid (BT-PABA) excretion testing, and fecal chymotrypsin concentration. RESULTS: The results of secretin-MRCP were classified into three distinct groups: a good-secretion group (group 1; n=22; 51%), a moderate-secretion group (group 2; n=10; 23%), and a poor-secretion group (group 3; n=11; 26%). This MRCP classification correlated significantly with the concentrations of the pancreatic enzymes p-type amylase, lipase, and trypsin in the gastric juice. The BT-PABA test value was 59.8% in group 1, 46.1% in group 2, and 46.5% in group 3, and was significantly higher in group 1 than in groups 2 or 3. The fecal chymotrypsin concentration was 20.5 U/g in group 1, 14.5 U/g in group 2, and 0.7 U/g in group 3, and there was a significant correlation between the MRCP classification and fecal chymotrypsin concentration. CONCLUSIONS: MRCP with secretin stimulation favorably reflected the presence of remnant pancreatic exocrine function. Therefore, secretin-MRCP is a feasible and effective follow-up examination method to evaluate remnant pancreatic exocrine function after pancreaticogastrostomy.