The standard approach for stage IV gastric cancer is palliative chemotherapy. However, despite the advancements in various chemotherapy regimens, the prognosis remains poor, highlighting the urgent need to develop more effective treatment strategies. The controversy persists regarding the integration of a local therapy including surgery in the management of unresectable stage IV gastric cancer. This randomized phase III trial aims to confirm the additional benefit of conversion surgery following palliative chemotherapy compared with palliative chemotherapy alone with respect to overall survival in patients initially diagnosed with unresectable clinical stage IVB or pathological stage IV gastric cancer after a remarkable response to chemotherapy. This study plans to enroll 126 patients from 63 institutions in Japan for 5 years, and it has been registered in the Japan Registry of Clinical Trials as jRCTs031240340 (https://jrct.niph.go.jp/latest-detail/jRCTs031240340).

The concept of oligometastasis is not yet fully established in the field of gastric cancer. However, metastatic lesions that are localized, technically resectable at diagnosis, present a certain response to preoperative chemotherapy, and present favorable survival outcomes with local treatments, sometimes in combination with chemotherapy, are recognized as oligometastasis in the field of gastric cancer. Oligometastasis is noted in European Society for Medical Oncology guidelines and Japanese gastric cancer treatment guidelines, and local treatment is mentioned as one of the pivotal treatment options for oligometastasis. Solitary liver metastasis or a small number of liver metastases; retroperitoneal lymph node metastasis, especially localized para-aortic lymph node metastasis; localized peritoneal dissemination; and Krukenberg tumor are representative types of oligometastasis in gastric cancer. The AIO-FLOT3 trial prospectively evaluated the efficacy of multimodal treatments for gastric cancer with oligometastasis, including surgical resection of primary and metastatic lesions combined with chemotherapy, confirming favorable survival outcomes. Two phase 3 studies are ongoing to investigate the efficacy of surgical resection combined with perioperative chemotherapy compared with palliative chemotherapy. Thus far, the evidence suggests that multimodal treatment for oligometastasis of gastric cancer is promising.

Colorectal cancer (CRC) is the third most common cancer, and nearly half of CRC patients experience metastases. Oligometastatic CRC represents a distinct clinical state characterized by limited metastatic involvement, demonstrating a less aggressive nature and potentially improved survival with multidisciplinary treatment. However, the varied clinical scenarios giving rise to oligometastases necessitate a precise definition, considering primary tumor status and oncological factors, to optimize treatment strategies. This review delineates the concepts of oligometastatic CRC, encompassing oligo-recurrence, where the primary tumor is under control, resulting in a more favorable prognosis. A comprehensive examination of multidisciplinary treatment with local treatments and systemic therapy is provided. The overarching objective in managing oligometastatic CRC is the complete eradication of metastases, offering prospects of a cure. Essential to this management approach are local treatments, with surgical resection serving as the standard of care. Percutaneous ablation and stereotactic body radiotherapy present less invasive alternatives for lesions unsuitable for surgery, demonstrating efficacy in select cases. Perioperative systemic therapy, aiming to control micrometastatic disease and enhance local treatment effectiveness, has shown improvements in progression-free survival through clinical trials. However, the extension of overall survival remains variable. The review emphasizes the need for further prospective trials to establish a cohesive definition and an optimized treatment strategy for oligometastatic CRC.

Background: The nematode Caenorhabditis elegans (C. elegans) possesses a sophisticated sense of smell and is used for a novel cancer screening test that utilizes the chemotaxis index. We designed a single-institution, prospective study to confirm the ability of Nematode Nose (N-NOSE) to determine preoperative chemotherapy’s efficacy for esophageal cancer patients. Patients and Methods: We investigated the predictability of N-NOSE screening for the clinical effects of preoperative chemotherapy for esophageal cancer patients receiving radical surgery. The index reduction score (IRS) was calculated via the chemotaxis of C. elegans at three points: before treatment, before surgery, and after surgery, and its clinical relevance was examined. Result: Thirty-nine patients with esophageal cancer were enrolled from August 2020 to December 2021, and 30 patients receiving radical surgery were examined. Complete response or partial response was achieved in 23 cases (76.7%). When the target of the treatment effect was complete response only, the prediction accuracies of the IRS calculated by area under the curve was 0.85 (95% Confidence interval: 0.62–1) in clinically achieving complete response group, and the sensitivity and specificity were 1 and 0.63, respectively. Conclusion: Index reduction score using N-NOSE screening may reflect the efficacy of chemotherapy for esophageal cancer patients. A large-scale prospective study at multiple centers is desired in the future.

Purpose The clinical significance of longitudinal cachexia-related status during first-line therapy for advanced gastric cancer remains unclear in the era of nivolumab-containing chemotherapy. We evaluated its association with outcomes according to nivolumab use. Methods We retrospectively analyzed 121 patients with HER2-negative unresectable advanced or recurrent gastric cancer who received first-line oxaliplatin- plus fluoropyrimidine-based chemotherapy between 2017 and 2024. Modified Glasgow Prognostic Score (mGPS) 2 status and modified European Palliative Care Research Collaborative (EPCRC)-defined cachexia status were assessed as time-dependent covariates. Progression-free survival (PFS) and overall survival (OS) were analyzed using time-dependent Cox proportional hazards models. Results The cohort included 69 patients in the non-nivolumab group and 52 in the nivolumab-containing group. Median age was 71 years, 76 patients (63%) were male, and baseline mGPS 2 was present in 37 patients (31%). The cumulative proportion of patients who met the mGPS 2 criterion by 6 months was 55% in the non-nivolumab group and 57% in the nivolumab-containing group. Time-dependent mGPS 2 status was not significantly associated with PFS (hazard ratio [HR], 1.49; 95% confidence interval [CI], 0.69–3.20; P = 0.30), but was associated with shorter OS (HR, 2.17; 95% CI, 1.15–4.10; P = 0.017). No statistically significant interaction between time-dependent mGPS 2 status and nivolumab use was observed for PFS or OS. Time-dependent modified EPCRC-defined cachexia status was not significantly associated with PFS or OS. Conclusions Time-dependent mGPS 2 status during first-line therapy was associated with shorter OS, but not PFS.