- classification of gastric cancer location for function preserving gastrectomy based on physiological lymphatic flow. - Background: The correlation between tumor location and lymphatic flow distribution in gastric cancer has been previously reported, and PTD (Proximal – Transitional – Distal) classification was proposed. - In this study, the distribution of dyed lymphatic flow was evaluated for each occupied area of the tumor.. - The tumors located in the watershed of the right and left gastroepiploic arteries near greater curvature had extensive lymphatic flow. - therefore, a newly circular region with a diameter of 5 cm is set on the watershed of the greater curvature between P and T zone as the ‘ n ’ zone. - In addition, for cancers located in the lesser P curvature, lymphatic flow to the greater curvature was not observed. - Conclusions: The advantage of the nPTD classification is that it provides not only proper nodal dissection but also adequate function-preserving gastrectomy. - In contrast, for cancers located in the ‘ n ’ zone, near-total gastrectomy is required because of the extensive lymphatic flow.. - Gastric cancer location is generally described based on the Japanese classification of gastric carcinoma [1, 2].. - into three equal parts: the lesser curvature and greater curvature of the stomach. - However, the most important aspect of gastric cancer curative surgery is the lymph node dissection [3, 4], and for surgical treatment, classi- fying tumor location using lymphatic flow is useful.. - Previously, our group found a correlation between gas- tric cancer tumor location and lymphatic flow distribu- tion and proposed the Proximal – Transitional – Distal (PTD) classification based on gastric cancer location and. - 1 Department of Surgical Oncology, Kanazawa Medical University, 1-1 Daigaku, Uchinada-machi, Kahoku-gun, Ishikawa 920-0293, Japan Full list of author information is available at the end of the article. - lymphatic flow (Fig. - The PTD classification is de- rived from gastric cancer-specific lymphatic flow obser- vation using the dye method of sentinel node biopsy.. - Subsequently, sentinel node biopsy is continued, and further lymphatic flow regularity is confirmed in early gastric cancer. - The sentinel lymph node biopsy indication for gastric cancer is the presence of a type 0 single lesion gastric cancer ≤5 cm in the long axis, which is clinically node-negative (cN0), as diagnosed by preoperative computed tomography [5, 8, 9].. - In this study, patients included were those with an observ- able lymphatic flow during sentinel node mapping, using the dye method, while patients with >. - 5 cm in the long axis or a pathologically invaded layer deeper than the sub- serosal layer, and those whose accurate lymphatic flow was not observed were excluded.. - 1 The PTD classification and the lymphatic compartment for gastric cancer. - b The gastric lymphatic compartments of the stomach. - The lymphatic flow was observed after 15 min, and the lymphatic basin and sen- tinel nodes were detected and recorded. - In the ICG fluorescence method, ICG diluted to 50 μg/. - 0.5 mL of the tracer was injected endoscopically into the submucosal layer’s four points around the tumor for mapping the day before surgery. - 1b, except for the lymphatic flow to the left paracardial lymph node (No. - Classifying the lymphatic flow to #2 is challenging be- cause of the multidirectional flow to l-GA and No. - 19 lymph node ahead and the lymphatic flow to p-GA nearby. - The lymphatic basin distribution was tabulated for each gastric cancer location, and gastric lymphatic flow regularity was examined. - the watershed between the left and right gastroepiploic arteries and the inflow point of the first descending branch of the left gastric artery. - Furthermore, we attempted to improve the PTD classification based on the distribu- tion of lymphatic flow. - Regarding data used for lymph node mapping, patients were allowed to opt out of the study at any time.. - However, no difference was observed in the other parameters. - Of the 36 metastasis-positive patients, 20 (56%) had only sentinel node metastasis. - Regarding survival prognosis, there was no gastric cancer recurrence in the 374 metastasis- negative cases. - One of the false-negative cases of rapid intraoperative diagnosis died of pancreatic cancer, but two were alive without recurrence. - The distribution pattern of the lymphatic basins. - Table 2 shows the number and distribution of the ob- served lymphatic compartments by the UML classifica- tion. - No lymphatic flow to r-GA and r-GEA was found in cancers confined to the U-region. - In addition, lymphatic flow to p-GA and # 2 was observed in U cancers only.. - Lymphatic flow to l-GEA was not observed in L cancers, whereas it was observed in 4.2% of M cancers and 46.2%. - Using the PTD classification for the distribution of lymphatic compartments (Table 2), the lymphatic flow to r-GA was not observed in P or T cancers, while lymphatic flow to p-GA or # 2 was not observed in T or D cancers. - In P cancers, the lymphatic flow was 26, 10, Table 1 Patients ’ characteristics. - Both cases were cancers on the greater curvature of the UM·MU region.. - In addition, lymphatic flow to l-GEA was observed in eight patients (4.5%) with T cancers. - most had an extensive lymphatic flow to l-GA, l- GEA, r-GEA, and were close to the right and left gastro- epiploic arteries watershed.. - Lymphatic flow to the contralateral side. - Cancers in the lesser curvature or greater curvature were extracted and are summarized in Table 5. - Lymphatic flow to the lesser curvature was observed at a high rate in the greater curvature, regardless of the occupying lon- gitudinal region. - Conversely, among cancers with the lesser curvature, 27% of T cancers and 59% of D cancers were lymphatic flow at the greater curvature, while P cancers did not.. - Even if the number of cases increased, there were no cases in which lymphatic flow to r-GA was observed in T cancer, and the boundary between T and D did not need to be changed. - On the other hand, there were P cancer patients with the lymphatic flow to r- GEA and T cancer to l-GEA. - These cancers were lo- cated in the greater curvature near the watershed of. - the right and left gastroepiploic arteries and had an extensive lymphatic flow to l-GA, l-GEA, and r-GEA.. - In addition, lymphatic flow to the contralateral side was observed mostly in T and D cancers. - however, lymphatic flow to the greater curvature was not ob- served in cancers in the lesser P curvature.. - The boundary line changed because of chal- lenging preoperative diagnosis of the boundary be- tween the P and T zones. - The point of greater curvature is the same as the watershed of the left and right gastroepiploic artery in the greater curvature. - In contrast, to facilitate site determination preoperatively, the boundary point of the lesser curvature between U and M was changed to the upper one-third point be- cause it is challenging to set the boundary of the old P and T zones preoperatively. - In the PL zone, not only r-GA and r-GEA but also lymphatic flow to l-GEA was not observed. - Moreover, there were no cases of lymph- atic flow to the l-GEA in the new T-zone. - Since the PL zone is set, there was no disadvantage to the patients in changing the boundary line of the lesser curvature of P and T zones. - In contrast, cancer in the ‘n’ zone had extensive lymphatic flow into the three basins of l-GA, l-GEA, and r-GEA.. - All percentage numbers represent the percentage of confirmed lymphatic flow per tumor location. - Table 4 An overview of the eight patients located in the T zone who had a lymphatic flow to l -GEA. - circumferential location of the tumor, Depth depth of invasion, ICG ICG fluorescence method, Patho pathological type due to Japanese Classification of Gastric cancer, Size the size of the long axis of the tumor. - however, lymphatic flow was not em- phasized in the current Japanese guideline.. - Lymph node dissection must be based on lymphatic flow. - In the present study, the size of the lesions was limited to ≤5 cm on the long axis. - It was difficult to omit dissection due to the widespread lymphatic flow in gastric cancer >. - 5 cm, and there was a concern that the dye method could not ac- curately cover the lymphatic flow in large lesions.. - The limitation of the old PTD classification is its diffi- culty in identifying the P and T boundary preoperatively.. - however, it is chal- lenging to determine the location of the tumor since the tumor is inside the stomach.. - We observed that tumors located in watersheds of the greater curvature have extensive lymphatic flow into the three basins of l -GA, l -GEA, and r -GEA, and limited surgery should be cautiously performed on them. - The center of the ‘n zone ’ is the watershed of the left and right gastroepiploic arteries in the greater curvature. - This watershed corre- sponds to the constriction of the greater curvature of Table 5 Lymphatic flow to the contralateral side distribution of. - observed lymphatic compartments in the lesser or greater curvature. - The boundary between the P and T zones is changed to the line that links the watershed point between the left and right gastroepiploic arteries to the upper one- third point of the lesser curvature. - In addition, the boundary point in the lesser curvature was changed to the upper one- third point following the settings of the U and M bound- ary. - If the tumor is localized to the PL, lymph node dissec- tion of the l-GEA may be omitted. - It is unclear why PL does not show lymphatic flow to the greater curvature, unlike T or D, but this is probably because the fornix has a large volume for receptive relaxation and the stomach wall is thin, resulting in less lymphatic conflu- ence than that of the body or antrum.. - Although sentinel node biopsy is required to diagnose node-negative cases since metastasis rarely spreads out of the basin in cT1N0 patients, the extent of nodal dissection can be limited to the lymphatic basins and dissection out of the basin is omitted without compromising cure [5–9]. - If the tumor is located in the PG, a proximal gastrectomy would be considered appropriate [17]. - Indeed, for gastric cancer deeper than. - a Tumor in the PL zone. - b Tumor in the PG zone. - c Tumor in the ‘ n ’ zone. - d Tumor in the T zone. - e Tumor in the D zone. - The handling of the No. - SK was responsible for the scientific conception of the study and the writing of the manuscript. - All authors (SK, NN, TM, HK, SF, TF, TI and HT) contributed to the literature review, data analysis, drafting, editing, critical revision of the manuscript, and approval of the final version of the manuscript.. - Japanese Gastric Cancer Association. - Gastric Cancer. - Surgical treatment of gastric cancer: 15-year follow-up results of the randomised nationwide Dutch D1D2 trial. - Robotic gastrectomy for gastric cancer. - PTD classification: proposal for a new classification of gastric cancer location based on physiological lymphatic flow. - Applicability of the proposed Japanese model for the classification of gastric cancer location: the “ PROTRADIST ” retrospective study. - Investigation of the freely available easy-to-use software ‘ EZR ’ for medical statistics. - Segmental gastrectomy for early cancer in the mid-stomach.. - Precision surgical approach with lymph-node dissection in early gastric cancer
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