Frequency and characteristics of synchronous gastric cancers: Need for improved awareness and better detection

Abstract

The pathway of gastric cancer involves progression from atrophic gastritis to intestinal metaplasia to dysplasia and then cancer. The background mucosa in patients with gastric cancer is likely to have areas of atrophy and metaplasia, and hence, coexisting gastric cancer may be present. In this paper, we have reviewed the prevalence, characteristics, and predictors of synchronous neoplasm in patients with gastric cancer. Data on synchronous gastric neoplasms (SGNs) are mainly available from two types of studies, those detected on surgically resected specimens and those detected endoscopically. The prevalence of SGN cancer generally ranges between 5%-12% although the number may vary. Most of the synchronous lesions are noted in the distal stomach and are well differentiated on histology. Increasing age, male gender, well-differentiated histology of primary cancer, early stage of the primary cancer, and presence of atrophy and intestinal metaplasia in the background gastric mucosa increase the risk of synchronous neoplasm. SGN cancers may be missed in about one-third of cases during initial endoscopy. Overall, there is an urgent need to improve awareness of SGN cancer and improve its detection by using appropriate endoscopic evaluation. This would lead to a greater chance of curative treatment and better patient outcomes.

Key Words: Gastric cancer; Synchronous neoplasia; Detection; Prevalence; Endoscopy; Risk factors

Core Tip: Gastric cancer is among the top causes of cancer globally. Approximately one in ten patients with gastric cancer has a coexisting neoplastic lesion in the stomach. In most instances, these synchronous lesions are at an early and curable stage. However, one-third of them are not detected at the time of diagnosis of the primary cancer. This can adversely affect the overall outcome. This minireview highlights the characteristics and risk factors of synchronous gastric neoplasms. Advances in endoscopic techniques, such as magnification and digital chromoendoscopy, facilitate better visualisation of gastrointestinal mucosa and detection of lesions. Utilization of these techniques and improved awareness about synchronous lesions may improve the detection rate and clinical outcome.

INTRODUCTION

Gastric cancer is among the leading cancers globally, both in terms of incidence and mortality[1]. The highest burden of gastric cancer is noted in Asia, especially East Asian countries like Japan and South Korea (> 5 per 100000 person-years)[2]. The incidence is also high in some of the East African nations. In several European nations and in North America and Australia, the incidence ranges from 2 to 3.9 per 100000 person-years[2]. The reported incidence is low in many of the North and West African nations[2]. Patients with symptoms usually have the disease at an advanced stage, where curative resection may not be possible[3]. Identification of cancer at an early stage results in better outcomes but needs screening and better detection, as shown by data from countries like Japan and South Korea[3]. Most gastric cancers follow the pathway from Helicobacter pylori infection to atrophic gastritis, intestinal metaplasia, dysplasia, and subsequently cancer[4]. This pathway may lead to the development of cancer at more than one site in the stomach at the same time (synchronous cancer), as the background atrophic/metaplastic mucosa is conducive to carcinogenesis. In addition, the environmental and genetic risk factors that contribute to carcinogenesis are already present in these patients.

Synchronous gastric neoplasm (SGN) has been variably defined and includes cancer in the stomach at another location noted up to 12 months after detection of the primary lesion. The Moertel criteria, which are frequently cited, include the following conditions: (1) Malignancy confirmed histologically at more than one site of the stomach; (2) Lesions must be clearly separate from each other; and (3) The second lesion should not represent a metastatic lesion[5]. There are ample studies showing both the presence of synchronous gastric cancer as well as the frequency of missing these lesions on initial endoscopy. A recent meta-analysis showed that the risk of gastric cancer is the same in high and low incidence regions of gastric cancer once intestinal metaplasia develops[6]. Hence, the problem of synchronous cancer is relevant in both high and low-incidence gastric cancer regions across the world and needs proper attention. Detection of synchronous gastric cancer will lead to two key benefits. SGN are usually small and operable, which provides an opportunity for curative resection. The treatment can be done at the same time as treating the primary cancer, thereby reducing the need for repeat hospital admission and cost of care. In this minireview, we discuss the epidemiology, characteristics, risk factors, and methods to detect synchronous gastric cancer.

PREVALENCE OF SGN

The prevalence of SGN usually ranges between 5%-12% although some studies report a higher rate[7-9]. Apart from true differences, other factors also contribute to this variability. These include the mode of detection (endoscopy vs histopathology of surgical specimen), definitions of synchronous neoplasia, and time interval from the detection of primary cancer[9-12]. A number of studies in the past reported synchronous lesions during pathological examination of the resected stomach[12,13]. Most of them are from the time when endoscopic detection of early gastric cancer (EGC) was less common, and endoscopic submucosal dissection (ESD)/endoscopic mucosal resection (EMR) were infrequently done. Several studies done later are from endoscopic detection among patients undergoing EMR/ESD[7,9,14]. The use of image enhancement during endoscopy, which increases the chance of detection, may also influence prevalence[7,9,14]. The definition of neoplasia is not uniform, with some considering only cases with cancer while others also include dysplasia[10,15]. The presence of a second cancer at the time of evaluation of the index cancer or during the next 6 to 12 months has all been considered as synchronous, and longer follow-up may affect the prevalence[8,16].

Table 1 summarizes the prevalence of SGN primarily based on endoscopic detection. All the studies are from Japan or South Korea and have been done in patients undergoing ESD or EMR for gastric neoplasia[7-10,14,15,17-20]. Most reports have considered both dysplasia and cancer as SGN. The frequency of SGN varied from 5.7% to 20.1% although it was generally below 12%[7-10,14,15,17-20]. The largest study reported 9.1% SGN in 3018 patients undergoing ESD[9]. In the only prospective study, among the 802 cases undergoing ESD, the prevalence of synchronous EGC was 16.2%[10]. The highest prevalence of 20.2% was reported by Park et al[15], likely due to the inclusion of low-grade dysplasia as SGN. There was no clear trend between the use of image-enhanced endoscopy and a higher prevalence of SGN, although this may be confounded by other factors[9,14,20]. As there is a lack of endoscopic data outside of Japan and South Korea, it may affect the generalizability of these findings to other regions. There is a need for information from other parts of the world. Since Helicobacter pylori is the key risk factor of gastric cancer across the globe, synchronous lesions must be present in other regions as well, although the frequency may vary. This is further supported by data from surgical series discussed below.

Table 1 Prevalence and features of synchronous gastric neoplasms detected endoscopically.

Ref.	Country	Study design	Setting and number of patients	Frequency and type of SGN, n (%)	Characteristics of synchronous neoplasm
Asonuma et al[10], 2024	Japan	Prospective multicenter	Patients undergoing ESD, 802	130 (16.2), EGC	Males: 81.5%
Shin et al[20], 2020	South Korea	Retrospective	Patients undergoing ESD/EMR, 1569	182 (11.6), cancer, adenoma	Age: 66.1 ± 8.0 years; males: 75.8%; location: Lower third 61.5%, middle third 34.6%, upper third 3.9%
Lim et al[19], 2015	South Korea	Retrospective	Patients undergoing ESD/EMR, 971	56 (5.8), EGC, HGD	Age: 64.5 (7.8) years; males: 78.6%. Location: Lower third 67.9%, middle third 28.6%, upper third 3.6%. Undifferentiated 7.1%
Gweon et al[14], 2015	South Korea	Retrospective	Patients undergoing EMR/ESD, 678	41 (6), cancer, dysplasia	Location: Upper third 7.3%, middle third 36.6%, lower third 56.1%. Morphology: Elevated 51.3%, flat 34.1%, depressed 14.6%
Park et al[15], 2014	South Korea	Retrospective	Patients undergoing ESD/EMR, 228	46 (20.1), EGC, HGD, LGD	Age: 66.1 ± 7.1 years; males: 71.7%. Morphology: Elevated 87%, protruding 8.7%, flat depressed 4.3%. Location: Lower third 61.4%, middle third 35.1%. Undifferentiated 2.2%
Kim et al[18], 2013	South Korea	Retrospective	Patients undergoing ESD, 602	38 (6.3), cancer, adenoma
Kim et al[9], 2013	South Korea	Retrospective multicenter	Patients undergoing ESD, 3018	275 (9.1), cancer, adenoma	Age: 67.4 years; males: 73.8%. Morphology: Elevated 53.1%, depressed 37.8%
Jang et al[17], 2013	South Korea	Retrospective	Patients who underwent ESD/EMR, 512	66 (12.9), EGC, adenoma
Kato et al[8], 2013	Japan	Retrospective multicenter	Patients who underwent ESD, 1258	110 (8.7)
Kasuga et al[7], 2013	Japan	Retrospective	Patients undergoing ESD, 851	62 (7.3), EGC	Age: 70.6 years; males: 71%. Location: Upper third 20%, middle third 40%, lower third 40%. Differentiated 96.8%

ESD: Endoscopic submucosal dissection; EMR: Endoscopic mucosal resection; EGC: Early gastric cancer; HGD: High-grade dysplasia; LGD: Low-grade dysplasia; SGN: Synchronous gastric neoplasm.

Table 2 contains the prevalence and characteristics of SGNs detected in surgically resected specimens for gastric cancer. These studies, which are all retrospective, outnumber the number of papers reporting endoscopic detection, and most were published more than two decades ago[11-13,16,21-33]. However, they are a source of valuable information on the profile of SGNs. While the bulk of the data is from Japan and South Korea, there is also information from Brazil, France, Germany, and China, thereby providing less skewed data than the endoscopic series[12,21,28,31-33]. The overall prevalence ranges between 3%-12%. The prevalence in the Japanese population was 5.1%-11.7% and 5.1%-5.7% in South Korean subjects[11,13,16,22-27,29,30]. The largest study was from China, which included 4107 patients undergoing radical gastrectomy, and 3.2% had SGN[12]. Lee et al[16] included both surgically resected specimens and patients undergoing ESD/EMR and noted a prevalence of 5.17%. The prevalence was 3.4% in the study from Germany and 3.7% in the paper from Brazil[28,31]. Overall, the prevalence outside of Japan and South Korea appears to be lower, with the exception of a study from France, which reported a frequency of 9.9%[21]. Interestingly, five of the surgical series included only patients with EGC, and the prevalence of SGN in them ranged from 5.1%-11.7%[11,21,27,30,33]. Patients with gastric cancer also have an increased risk of synchronous cancer at other sites such as the colon, pancreas, esophagus, and non-gastrointestinal organs. Kaibara et al[23] showed the presence of extragastric synchronous tumours in 5.9% cases of single gastric lesions and in 12.1% cases with multiple gastric cancers (P < 0.05).

Table 2 Prevalence and features of synchronous gastric neoplasms detected on surgically resected specimens.

Ref.	Country	Study design	Setting and number of patients	Frequency and type of SGN, n (%)	Characteristics of synchronous neoplasm
Zhao et al[32], 2020	China	Retrospective	Gastric cancer, 364	26 (7.1)	Age > 60 years: 53.8%. Males: 73.1%. Location: Lower third 76.9%, middle third 19.2%, upper third 3.8%. Morphology: Elevated/flat: 23.8%, depressed: 76.9%. Differentiated: 26.9%. Undifferentiated: 73.1%
Zhu et al[33], 2020	China	Retrospective	Early gastric cancer, HGIN, 644	44 (6.8)
Lin et al[12], 2019	China	Retrospective	Gastric cancer, 4107	133 (3.2)
Isobe et al[11], 2013	Japan	Retrospective	Early gastric cancer, 1340	146 (10.9)	Age: 68 years. Males: 81.5%. Differentiated: 80.8%
Kim et al[24], 2012	South Korea	Retrospective	Gastric cancer, 3320	188 (5.7)	Age: 57.5 ± 10.7 years. Males: 71.8%
Lee et al[27], 2012	South Korea	Retrospective	Early gastric cancer, 2299	117 (5.1)	Age: 56.5 years. Male: 63%. Location: Upper third 10.3%, middle third 20.3%, lower third 69.1%. Morphology: Elevated 14.3%, flat 26.3%, depressed 50.9%, others 9%. Well differentiated: 42.1%. Poorly differentiated: 57.9%
Lee et al[16], 2010	South Korea	Retrospective	Surgery, ESD/EMR for gastric neoplastic lesions, 986	51 (5.17)	Age: 63.25 ± 8.11 years. Males: 84.3%
Fujita et al[22], 2009	Japan	Retrospective	Gastric cancer, 2120	153 (7.2)	Age: 63.2 years. Males: 71.4%. Location: Upper third 6.5%, middle third 51%, lower third 42.5%. Differentiated: 59.4%
Ribeiro et al[28], 2007	Brazil	Retrospective	Gastric cancer, 553	19 (3.43)	Age: 66.8 years. Males: 68.4%
Otsuji et al[13], 2005	Japan	Retrospective	Gastric cancer, 1481	76 (5.1)	Age: 63.1 years. Male: 74%. Location: Upper third 17%, middle third 42%, lower third 41%
Borie et al[21], 2003	France	Retrospective multicenter	Early gastric cancer, 333	33 (9.9)	Males: 51.5%. Morphology: Elevated 21.2%, depressed 66.7%, flat 12.1%. Location: Upper third 15.2%, middle third 30.3%, lower third 54.5%. Differentiated: 54.5%. Undifferentiated 45.5%
Wittekind et al[31], 1997	Germany	Retrospective	Gastric cancer, 1664	61 (3.7)	Age: 67.7 years. Males: 69%
Takeshita et al[30], 1997	Japan	Retrospective	Early gastric cancer, 521	61(11.7)	Age: 64 years. Males: 78.7%. Differentiated: 64%
Seto et al[29], 1996	Japan	Retrospective	Gastric cancer, 911	82 (9)	Age: 61.3 years. Male: 81.7%. Location: Upper third 4.1%, middle third 49.5%, lower third 46.4%. Morphology: Elevated 33%, depressed 67%. Differentiated: 83%. Undifferentiated: 17%
Kodama et al[25], 1996	Japan	Retrospective	Gastric cancer, 1563	107 (6.8)	Age > 49 years: 84.1%. Males: 74.8%. Morphology: Elevated 31.8%. Differentiated 38.9%
Kaibara et al[23], 1993	Japan	Retrospective	Gastric cancer, 1606	132 (8.2)
Kosaka et al[26], 1990	Japan	Retrospective	Gastric cancer, 852	49 (5.8)

SGN: Synchronous gastric neoplasm; HGIN: High grade intraepithelial neoplasia; ESD: Endoscopic submucosal dissection; EMR: Endoscopic mucosal resection.

CHARACTERISTICS OF SGN

Endoscopically detected lesions

The SGN is located most commonly in the distal stomach, with about 50%-70% cases noted in the lower third[9,14,15,19,20]. The middle third of the stomach is the next common site, and SGN in the upper third of the stomach is infrequent[9,14,15,19,20]. The gross appearance of SGN may be flat, elevated, or depressed. Among these, the elevated type of lesion appears to be most common, accounting for 50%-80% cases[9,14,15]. Depressed lesions are less frequent, although it was reported in 37.8% of the patients in the large series by Kim et al[9]. Synchronous lesions on endoscopy are often small (< 15 mm) in size, and on histopathology, the majority of them (> 70%-80%) are well-differentiated[7,14,15,19]. Figure 1 shows the main characteristics of SGN detected on endoscopy.

Figure 1 Key features of synchronous gastric neoplasm detected on upper gastrointestinal endoscopy.

SGN detected on surgically resected stomach

The location of SGN is similar to that noted on endoscopic series, with most occurring in the lower and middle third of the stomach[12,13,21,22,27,29,30,32]. On gross appearance, most studies reported the depressed type lesion to be most common, in contrast to the endoscopy studies[11,21,25,29,30,32]. SGNs tended to be well differentiated, although some papers reported more undifferentiated cases[11,21,22,25,27-30,32]. There may be more than two neoplastic lesions in the same patient. In the study by Lee et al[27], among the 117 cases with SGN, 17 (14.5% of SGN) had more than two lesions. Seto et al[29] reported more than two lesions in 27% of cases with SGN, and Isobe et al[11] had more than two lesions in 17.8%. In the French study, out of 33 SGNS, five were triple lesions, nine were quadruple lesions, and one was a quintuple lesion[21]. Hence, the search for SGN should not stop after finding one additional lesion. The background mucosa often had atrophy and intestinal metaplasia in cases with SGN[31,33].

RISK STRATIFICATION OF PATIENTS FOR SGN

The presence of gastric cancer in itself is perhaps the strongest risk factor for the occurrence of SGN. Several other factors have been evaluated in both endoscopic and surgical series as predisposing to SGN. These are summarized in Table 3.

Table 3 Risk factors for synchronous gastric neoplasms.

Ref.	Older age	Male gender	Well differentiated PN	Lower stage of PN	AG/IM in background mucosa
Zhao et al[32], 2020					1
Zhu et al[33], 2020		1			1
Isobe et al[11], 2013	1	1
Jang et al[17], 2013	1
Lee et al[27], 2012		1	1		1
Fujita et al[44], 2010	1		1
Ribeiro et al[28], 2007			1	1
Otsuji et al[13], 2005	1		1	1
Arai et al[34], 2004	1	1	1
Lee et al[35], 2001	1	1		1
Takeshita et al[30], 1997	1	1	1
Seto et al[29], 1996	1	1	1
Kodama et al[25], 1996	1		1
Kosaka et al[26], 1990	1	1	1

1: Represent a positive relationship of the factor with synchronous gastric neoplasm; PN: Primary neoplasm; AG: Atrophic gastritis; IM: Intestinal metaplasia.

Age and gender

One of the most consistent observations across various studies is the higher risk of SGN with increasing age (Table 3)[11,13,17,25,26,34]. The age cut-offs evaluated have ranged from 50-65 years in different studies, and an age above 65 years almost doubles the risk[11]. The next well-established risk factor is male gender[11,26,27,29,33,34]. Males have a two to five times higher risk of SGN[11,33].

Tumour differentiation and lymph node status

SGN is more likely present in patients with well-differentiated primary gastric cancer. This has been confirmed by a number of studies[25,26,29,30,34]. Absent or lower stage of lymph node involvement and early stage of tumour are more frequent in SGN, although this is less frequently reported[13,28,35]. Conversely, when the tumour histology is unfavourable and the disease is in an advanced stage, SGN is less frequent. This observation makes it more imperative to look for SGNs, as failure to detect them may adversely affect the prognosis in an otherwise well-differentiated and early-stage primary cancer.

Atrophic gastritis and intestinal metaplasia

The presence of gastric atrophy and gastric intestinal metaplasia in the background mucosa facilitates the development of SGN[4]. The risk almost doubles in the presence of atrophy and becomes up to eight times in the presence of intestinal metaplasia[27,32,33]. This is not surprising, as atrophic gastritis and intestinal metaplasia are well-established gastric preneoplastic conditions[36].

Other factors

Other factors which have been reported, although less frequently and inconsistently, include a smaller size of the primary lesion, smoking, family history of gastric cancer, and elevated morphology of the primary lesion[13,19,27,32]. Park et al[15] found a lower level of pepsinogen I (< 30 ng/mL) to be present in 71.7% of cases with SGN and 25.6% cases with single neoplasm (P < 0.001). Low pepsinogen I is a marker of gastric atrophy. A multicenter study from Japan on 802 cases with EGC found alcohol dehydrogenase 1B Arg and acetaldehyde dehydrogenase 2 Lys genotypes to be associated with increased risk of SGN[10]. These polymorphisms affect ethanol metabolism and the accumulation of acetaldehyde, which may promote carcinogenesis. Further, in the same study, the presence of additional risk factors (smoking, low pepsinogen I, and low pepsinogen I/pepsinogen II ratio) further increased the risk of gastric cancer.

MISSED SGN DURING DETECTION OF PRIMARY NEOPLASM

Another aspect of SGN, which is quite concerning, is the frequency of missed lesions during the diagnosis of the primary lesion. A large retrospective multicenter study from South Korea, with 3018 subjects undergoing ESD for gastric lesions, identified 275 cases with SGN[9]. 141 synchronous lesions were missed among 123 patients in this group at initial assessment. The miss rates of SGN were 38.8% by Jang et al[17], 35% by Takeshita et al[30], and 27.6% by Lee et al[16]. The missed lesions usually tend to be subcentimeter in size[9,16,30]. The location of missed lesions is not consistent, although some have found the posterior wall of the stomach and the proximal stomach to harbour missed lesions more commonly[8,9,21]. Inexperience of the endoscopist is another factor for failure to detect SGN[8]. Overall, the proportion of lesions missed appears to be quite significant and calls for more efforts to detect SGN.

IMPROVING THE DETECTION OF SGN

The discussion above brings out a couple of important messages: First, SGNs are not infrequent, and second, a number of them are being missed at the initial diagnosis of the primary lesion. This calls for improved awareness of this entity and better endoscopic detection practices. The endoscopy techniques available in the current era are more advanced than two decades ago, and the appropriate use of these tools will help further improve the lesion pick-up rate.

Patients with gastric cancer should undergo detailed endoscopic evaluation to look for synchronous lesions in the stomach. They should be fasting for an adequate duration to ensure there is no food residue or fluids in the stomach. Patients who have symptoms of vomiting can have obstructive lesions and may require a longer duration of fasting prior to endoscopy. Use of pharmacological agents may further help in improving the visibility of mucosal lesions by removing the surface mucus and defoaming luminal contents. A meta-analysis of 13 studies with 11086 patients showed significant improvement in total mucosal visibility score with the use of agents such as pronase, simethicone, dimethicone, and N-acetylcysteine[37]. The use of these agents was not associated with more adverse effects.

Spending adequate time examining the gastric mucosa is paramount to detecting lesions that may be subtle in appearance in the early stage. A large retrospective study from China with 18357 upper gastrointestinal endoscopies evaluated the procedure time with detection of lesions[38]. Fast endoscopists spent about five minutes for each case, while slow endoscopists spent about seven minutes. The detection of lesions was 50%-80% higher among the slow endoscopists. As the stomach is a large, voluminous structure with some blind areas, it is essential to adequately insufflate the stomach and ensure that all the areas are examined properly and from a close distance. Photodocumentation may further help to ensure that all the areas have been properly examined. In this regard, following a systematic protocol to examine the stomach can be useful. For example, the systematic screening protocol from Japan requires endoscopic examination of the antrum, lower body, and mid-upper body in forward view and fundus, incisura, and mid-upper body in retroflexed view and capture of a total of 22 images from these areas[39]. This ensures examination of all the areas of the stomach.

The availability of image enhancement techniques enables the inspection of the mucosal surface in much more detail than conventional white light endoscopy. These include digital chromoendoscopy techniques such as narrow band imaging, blue light imaging, etc. In digital chromoendoscopy, the wavelength of light is manipulated to provide better contrast, and these endoscopes are usually equipped with higher resolution and greater magnification capabilities. Multiple studies have shown improved detection of gastric neoplastic lesions with the use of digital chromoendoscopy[40]. Another chromoendoscopy technique is based on the spray of dye during endoscopy (dye-spray chromoendoscopy). Examples include methylene blue and indigocarmine. As with digital chromoendoscopy, the spray of dye improves the contrast, and areas of abnormality are easier to detect. Their superiority over conventional white light endoscopy in detecting gastric lesions has been confirmed in a meta-analysis[41]. Hence, in patients with gastric cancer, detection of synchronous lesions should be done preferably by using digital or dye-spray chromoendoscopy. Their application requires training of endoscopists for translation into improved detection[36]. Another promising technique is the probe-based confocal laser endomicroscopy. This technique provides a highly magnified image and makes the cellular and tissue architecture visible real time (virtual biopsy). The confocal probe is passed through the channel of the endoscope to obtain the images. The interpretation of images needs training and experience, and the equipment is quite expensive. A systematic review and meta-analysis of seven studies found a sensitivity of 87.9% in detecting gastric cancer[42].

Artificial intelligence is being actively evaluated to help with the detection of lesions during endoscopy[43]. A meta-analysis on the detection of EGC with the assistance of artificial intelligence included 15 studies[43]. The area under the curve was 0.94 with a sensitivity of 0.87 (95% confidence interval: 0.87-0.88) and specificity of 0.88 (95% confidence interval: 0.87-0.88). While artificial intelligence has demonstrated encouraging results in early studies, large-scale prospective validation is still required before its routine clinical use can be recommended.

CLINICAL IMPLICATIONS AND FUTURE DIRECTION

In patients with gastric cancer, every effort should be made to look for SGN, as these are not infrequent. These can be present in any part of the stomach, with a predeliction for the distal and middle parts of the stomach. Adequate time should be spent on endoscopic evaluation of the stomach, and the use of the chromoendoscopy technique should be considered. The incremental yield of advanced endoscopic techniques in this specific setting needs to be prospectively evaluated. There is also a need for data from different regions of the world on the prevalence of SGN to estimate the burden of disease and guide treatment recommendations.

CONCLUSION

Synchronous gastric cancers are noted in 5%-12% of patients with gastric cancer. These are generally located in the lower and mid third of the stomach and are usually well differentiated in histology. Synchronous gastric cancers are missed in a significant proportion of cases during initial evaluation. There is a need for better awareness of this condition and the use of appropriate endoscopic tools and techniques for improving detection. This, in turn, would improve outcomes in patients with synchronous gastric cancers.