Situs inversus is a rare congenital anatomical variant that involves a group of anomalies regarding the arrangement of intrathoracic and intraabdominal organs. Being able to find in the abdominal region the liver, gallbladder, inferior vena cava, and head of the pancreas and ascending colon on the left side of the abdomen, while on the right side there is the spleen, the stomach, the body of the pancreas, the ligament of Treitz, descending colon among others. In this same way, the thoracic organs, lungs and heart, are changed in their position in a mirror translocation.

We systematically searched MEDLINE, Web of Science, Google Scholar, CINAHL, Scopus, and LILACS; the search strategy included a combination of the following terms: "Situs inversus," "Situs inversus totalis," "Cancer," "Neoplasm," "Abdominopelvic regions," and "clinical anatomy."

Within the 41 included studies, 46 patients with situs inversus who had cancer, in addition to being found in this organ and in these regions, we also found as a result that the majority of the studies in the research were in stage II; finally, no one study could assert the direct relationship between the situs inversus totalis and the cancer.

If our hallmarks could make us think that more exhaustive follow-up of the stomach and other organs should be carried out in these patients, there could also be other predisposing factors for cancer, which is why more studies are suggested to give future diagnostic and treatment guidelines treatment.

Situs inversus totalis (SIT) is a rare condition in which the positions of abdominal and thoracic organs present a "mirror image" of the normal ones in the median sagittal plane. Although minimally invasive surgery has evolved to achieve laparoscopic gastrectomy for gastric cancer (GC) patients with SIT, it is difficult to perform lymphadenectomy (LND) in such a transposed anatomical condition. Herein, we report the cases of two patients with SIT who successfully underwent laparoscopy-assisted gastrectomy (LAG) with D2 LND.

Case 1: A 65-year-old man was admitted for intermittent abdominal pain and distension, occasional belching, and acid reflux for 4 mo. He was diagnosed with GC (cT3N1-2M0) with SIT. Before surgery, he had undergone four cycles of neoadjuvant chemotherapy and immunotherapy. Then, the patient was evaluated as having a partial response, and laparoscopy-assisted distal gastrectomy with D2 LND and Billroth II reconstruction were performed. The operation was performed successfully within 240 min with an estimated blood loss of 50 mL and no severe complications. The patient was discharged on postoperative day (POD) 9. Case 2: A 55-year-old man was admitted for upper abdominal distension with pain and discomfort after eating for 3 mo. He was diagnosed with GC (cT3N1M0) with SIT. He had a history of hypertension for more than 10 years; however, his blood pressure was well-controlled via regular medication. We performed laparoscopy-assisted total gastrectomy with D2 LND and Roux-en-Y reconstruction. The operation was performed successfully within 168 min with an estimated blood loss of 50 mL and no severe complications. The patient was discharged on POD 10.

LAG with D2 LND could be considered an accessible, safe, and curative procedure for advanced GC patients with SIT.

Situs inversus totalis (SIT) is a rare genetic anomaly involving the mirror-image transposition of organs. This transposition can potentially make surgical treatments difficult because of the reversed anatomy and intraoperative confusion. The aim of this systematic review is to compare the perioperative outcomes and safety of robotic and laparoscopic gastrectomy in patients with SIT.

We included full-text case reports with brief reviews and standalone case studies on SIT patients age ≥21, undergoing laparoscopic or robotic gastrectomy. We excluded case studies focusing on procedures other than laparoscopic and robotic gastrectomy, namely, open gastrectomy, gastric banding, and gastric bypass. English was selected as the language and articles published in the last 10 years were selected with a date range from Jan, 2011, to Aug, 2021. We focused on intraoperative and postoperative outcomes including blood loss, vascular aberrancy, operation duration, mortality, operative complications, duration of hospitalization, and follow-up interval. Online databases included Clinical Key, Embase, ScienceDirect, Ovid, and Google Scholar. The last search was conducted on Aug 15, 2021. For all eligible articles, risk of bias assessment was carried out using JBI critical appraisal checklist (Table 1). Continuous data were analyzed using t-test with p value of 0.05.

From our search, we retained 29 case reports which reported information from 30 cases. The results reported in each study were summarized (Table 2). The laparoscopic procedure was used in 21 cases and robot-assisted surgery was used in 9 cases. Operative time was mentioned in 24 out of the 30 cases and the average operative time was 205.67 min. Blood loss was reported in 16 out of the 30 cases, with an average blood loss of 51.9 mL. Hospital stay information was provided in 26 out of the 30 cases, with an average length of stay of 8.5 days. A statistically significant difference was not found for the operative time, length of hospitalization, or age of the patient. However, intraoperative blood loss in robot-assisted gastrectomy was lower compared to laparoscopic gastrectomy, with a p value of 0.0293. Perioperative death was not reported in any of the cases. Only three cases of postoperative complications were reported in laparoscopic surgery. Only one of the three cases suggested that the complication was due to an anomaly, whereas the other two of them reported complications due to procedural errors.

Laparoscopic and robotic gastrectomy can be safely used for SIT patients if performed cautiously. Some precautions include thoroughly assessing anatomical aberrations using preoperative imaging, adjusting the operative set up, and having experienced surgeons. The robotic approach may have a few advantages over laparoscopic procedures that may enhance the surgical safety for SIT patients and need to be further explored in future research. Advantages of the robotic approach may include improved surgical safety with better visualization of the surgical field, promoting the stability of surgical instruments and perhaps allowing ease of surgical orientation and positioning when operating on patients with SIT. Further research in this field is merited.