Definition, diagnosis and treatment of oligometastatic oesophagogastric cancer: A Delphi consensus study in Europe

Dose prescription for stereotactic body radiotherapy: general and organ-specific consensus statement from the DEGRO/DGMP Working Group Stereotactic Radiotherapy and Radiosurgery

PURPOSE AND OBJECTIVE

To develop expert consensus statements on multiparametric dose prescriptions for stereotactic body radiotherapy (SBRT) aligning with ICRU report 91. These statements serve as a foundational step towards harmonizing current SBRT practices and refining dose prescription and documentation requirements for clinical trial designs.

MATERIALS AND METHODS

Based on the results of a literature review by the working group, a two-tier Delphi consensus process was conducted among 24 physicians and physics experts from three European countries. The degree of consensus was predefined for overarching (OA) and organ-specific (OS) statements (≥ 80%, 60-79%, < 60% for high, intermediate, and poor consensus, respectively). Post-first round statements were refined in a live discussion for the second round of the Delphi process.

RESULTS

Experts consented on a total of 14 OA and 17 OS statements regarding SBRT of primary and secondary lung, liver, pancreatic, adrenal, and kidney tumors regarding dose prescription, target coverage, and organ at risk dose limitations. Degree of consent was ≥ 80% in 79% and 41% of OA and OS statements, respectively, with higher consensus for lung compared to the upper abdomen. In round 2, the degree of consent was ≥ 80 to 100% for OA and 88% in OS statements. No consensus was reached for dose escalation to liver metastases after chemotherapy (47%) or single-fraction SBRT for kidney primaries (13%). In round 2, no statement had 60-79% consensus.

CONCLUSION

In 29 of 31 statements a high consensus was achieved after a two-tier Delphi process and one statement (kidney) was clearly refused. The Delphi process was able to achieve a high degree of consensus for SBRT dose prescription. In summary, clear recommendations for both OA and OS could be defined. This contributes significantly to harmonization of SBRT practice and facilitates dose prescription and reporting in clinical trials investigating SBRT.

Toripalimab plus chemotherapy and radiotherapy for treatment-naive advanced esophageal squamous cell carcinoma: a single-arm phase 2 trial

This single-arm phase 2 trial (ChiCTR2100046715) examined previously untreated patients with advanced esophageal squamous cell carcinoma (ESCC) who received four cycles of paclitaxel with carboplatin every 3 weeks. Toripalimab was infused intravenously every 3 weeks for 12 months, or until disease progression or intolerable toxicity. Radiotherapy that encompassed the primary lesions and metastases commenced in the third cycle. The median progression-free survival time was 9.8 months (95% confidence interval [CI]: 6.8-not estimable) in the intent-to-treat population, failing to meet the pre-specified primary endpoints. Secondary endpoints included an objective response rate of 45.5%, a disease control rate of 57.6%, and a median duration of response of 11.5 months (interquartile range, 6.4-15.0). The 1-year progression-free survival and overall survival rates were 41.9% (95% CI: 27.7-63.5) and 69.7% (95% CI: 55.7-87.3), respectively. Lymphopenia was the most frequent grade ≥3 adverse event (82%), and an esophageal fistula developed in three patients (9.1%). No treatment-related deaths occurred. In prespecified exploratory biomarker analysis, higher densities of CD8 + T cells, CD11c+ dendritic cells, and CD68+ macrophages correlated with improved tumor response and prognosis. Radiotherapy supplementation to first-line chemo-immunotherapy for treatment-naive advanced ESCC demonstrated some antitumor activity and manageable safety profiles, warranting further randomized controlled trials.

Esophagectomy in patients with esophageal squamous cell carcinoma and distant nodal metastasis

The role of surgery in oligometastatic esophageal squamous cell carcinoma (ESCC) remains controversial. This study evaluated the oncological outcomes after esophagectomy in patients with ESCC with distant lymph node (LN) metastasis. Patients with ESCC and nodal metastasis treated with chemoradiotherapy or chemotherapy followed by esophagectomy between 2010 and 2020 were included. Overall survival (OS) and recurrence-free survival (RFS) were compared between patients with distant LN metastasis (dLN+) and exclusively regional LN metastasis (dLN-). The cohort comprised 69 dLN+ and 111 dLN- patients. Survival was significantly better in the dLN- group than in the dLN+ group (5-year OS, 51.9% vs. 25.5%, P < 0.001; RFS, 47.2% vs. 18.1%, P < 0.001). Stratified by the yp stage, 49 (44.1%) dLN- and 30 (43.5%) dLN+ patients achieved a pathological complete response (pCR). In the dLN- and dLN+ groups, the OS rates were significantly higher in the pCR group than in the non-pCR group (dLN-: 76.7% vs. 32.4%, P < 0.001; dLN+: 39.6% vs. 14.2%; P = 0.002). The dLN-/pCR group had the best OS, significantly outperforming the dLN-/non-pCR and dLN+/pCR groups. OS did not differ between the dLN-/non-pCR and dLN+/pCR groups. The dLN+/non-pCR group had the worst OS. The RFS analysis paralleled the OS findings. Patients with dLN+ disease had worse outcomes than their dLN- counterparts, irrespective of the pCR status. The survival rates were poor but comparable between the dLN+/pCR and dLN-/non-pCR groups. Adjuvant therapy may be required for dLN+ patients following systemic treatment and surgery, even after achieving pCR.

European clinical practice guidelines for the definition, diagnosis, and treatment of oligometastatic esophagogastric cancer (OMEC-4)

INTRODUCTION

The OligoMetastatic Esophagogastric Cancer (OMEC) project aims to provide clinical practice guidelines for the definition, diagnosis, and treatment of esophagogastric oligometastatic disease (OMD).

METHODS

Guidelines were developed according to AGREE II and GRADE principles. Guidelines were based on a systematic review (OMEC-1), clinical case discussions (OMEC-2), and a Delphi consensus study (OMEC-3) by 49 European expert centers for esophagogastric cancer. OMEC identified patients for whom the term OMD is considered or could be considered. Disease-free interval (DFI) was defined as the time between primary tumor treatment and detection of OMD.

RESULTS

Moderate to high quality of evidence was found (i.e. 1 randomized and 4 non-randomized phase II trials) resulting in moderate recommendations. OMD is considered in esophagogastric cancer patients with 1 organ with ≤ 3 metastases or 1 involved extra-regional lymph node station. In addition, OMD continues to be considered in patients with OMD without progression in number of metastases after systemic therapy. 18F-FDG PET/CT imaging is recommended for baseline staging and for restaging after systemic therapy when local treatment is considered. For patients with synchronous OMD or metachronous OMD and a DFI ≤ 2 years, recommended treatment consists of systemic therapy followed by restaging to assess suitability for local treatment. For patients with metachronous OMD and DFI > 2 years, upfront local treatment is additionally recommended.

DISCUSSION

These multidisciplinary European clinical practice guidelines for the uniform definition, diagnosis and treatment of esophagogastric OMD can be used to standardize inclusion criteria in future clinical trials and to reduce variation in treatment.

Surgical and multimodal treatment of metastatic oesophageal cancer: retrospective cohort study

BACKGROUND

In contrast to the well-established multimodal therapy for localized oesophageal cancer, the metastatic stage is commonly treated only with systemic therapy as current international guidelines recommend. However, evidence suggesting that multimodal therapy including surgery could benefit selected patients with metastasized oesophageal cancer is increasing. The aim of this study was to investigate the survival of patients diagnosed with metastatic oesophageal cancer after different treatment regimens.

METHODS

This was a retrospective single-centre study of patients with adenocarcinoma or squamous cell carcinoma of the oesophagus with synchronous or metachronous metastases who underwent Ivor Lewis oesophagectomy between 2010 and 2021. Each patient received an individual treatment for their metastatic burden based on an interdisciplinary tumour board conference. Survival differences between different treatments were assessed using the Kaplan-Meier method, as well as univariable and multivariable Cox regression models.

RESULTS

Out of 1791 patients undergoing Ivor Lewis oesophagectomy, 235 patients diagnosed with metastases were included. Of all of the included patients, 42 (17.9%) only underwent surgical resection of their metastatic disease, 37 (15.7%) underwent multimodal therapy including surgery, 78 (33.2%) received chemotherapy alone, 49 (20.9%) received other therapies, and 29 (12.3%) received best supportive care. Patients who underwent resection or multimodal therapy including surgery of their metastatic burden showed superior overall survival compared with chemotherapy alone (median overall survival of 19.0, 18.0, and 11.0 months respectively) (P < 0.001). This was confirmed in subcohorts of patients with metachronous solid-organ metastases and with a single metastasis. In multivariable analyses, resection with or without multimodal therapy was an independent factor for favourable survival.

CONCLUSION

Surgical resection could be a feasible treatment option for metastasized oesophageal cancer, improving survival in selected patients. Further prospective randomized studies are needed to confirm these findings and define reliable selection criteria.

[Tailored surgery in the treatment of gastroesophageal cancer]

The surgical options and particularly perioperative treatment, have significantly advanced in the case of gastroesophageal cancer. This progress enables a 5-year survival rate of nearly 50% to be achieved through curative multimodal treatment concepts for locally advanced cancer. Therefore, in tumor boards and surgical case discussions the question increasingly arises regarding the type of treatment that provides optimal oncological and functional outcomes for individual patients with pre-existing diseases. It is therefore essential to carefully assess whether organ-preserving treatment might also be considered in the future or in what way minimally invasive or robotic surgery can offer advantages. Simultaneously, the boundaries of surgical and oncological treatment are currently being shifted in order to enable curative forms of treatment for patients with pre-existing conditions or those with oligometastatic diseases. With the integration of artificial intelligence into decision-making processes, new possibilities for information processing are increasingly becoming available to incorporate even more data into making decisions in the future.

Significance of Surgery for Resectable M1 Lymph Node Metastases Without Organ Metastasis in Esophageal Carcinoma in the Era of Neoadjuvant Treatment

BACKGROUND

M1 esophageal carcinoma goes beyond localized disease and requires treatment with systemic therapy. M1 status is primarily divided into two categories: M1 lymph node metastasis and distant organ metastasis. Oligometastasis is defined as a state of limited metastatic disease, and surgery for oligometastasis of distant organs is reported to be beneficial in limited conditions. The aim of this study was to investigate resected cases of M1 lymph node metastases as the only metastatic site in stage IVB esophageal carcinoma.

PATIENTS AND METHODS

This study was a single-center retrospective cohort study. Patients with esophageal carcinoma who underwent esophagectomy with curative intent between April 2017 and December 2021 were examined. Neoadjuvant chemotherapy was our standard therapy and administered in almost all cases. We hypothesized that four sites of metastatic M1LN (supraclavicular (no. 104), pretracheal (no. 106pre), posterior thoracic para-aortic (no. 112aoP), and abdominal para-aortic (no. 16a2lat) LNs) were potentially resectable M1LN (rM1LN) metastases with curative intent and compared the prognosis of patients with and without rM1LN metastasis.

RESULTS

Six hundred eight-two patients were included in the study. Among these patients, 80 had rM1LN metastasis and received surgery for curative intent. Short-term safety outcomes were equivalent between patients with and without rM1LN metastases. After propensity score matching, there were no significant differences in overall survival between patients with and without rM1LN metastasis. Multivariate analyses revealed that the only independent prognostic factor was ypN status.

CONCLUSION

The present study suggests the feasibility and favorable OS in the patients with resection of rM1LN metastasis.

Outcomes after Surgical Treatment of Oesophagogastric Cancer with Synchronous Liver Metastases: A Multicentre Retrospective Cohort Study

Approximately 10-12% of patients with oesophageal or gastric cancer (OGC) present with oligometastatic disease at diagnosis. It remains unclear if there is a role for radical surgery in these patients. We aimed to assess the outcomes of OGC patients who underwent simultaneous treatment for the primary tumour and synchronous liver metastases. Patients with OGC who underwent surgical treatment between 2008 and 2020 for the primary tumour and up to five synchronous liver metastases aiming for complete tumour removal or ablation (i.e., no residual tumour) were identified from four institutional databases. The primary outcome was overall survival (OS), calculated with the Kaplan-Meier method. Secondary outcomes were disease-free survival and postoperative outcomes. Thirty-one patients were included, with complete follow-up data for 30 patients. Twenty-six patients (84%) received neoadjuvant therapy followed by response evaluation. Median OS was 21 months [IQR 9-36] with 2- and 5-year survival rates of 43% and 30%, respectively. While disease recurred in 80% of patients (20 of 25 patients) after radical resection, patients with a solitary liver metastasis had a median OS of 34 months. The number of liver metastases was a prognostic factor for OS (solitary metastasis aHR 0.330; p-value = 0.025). Thirty-day mortality was zero and complications occurred in 55% of patients. Long-term survival can be achieved in well-selected patients who undergo surgical resection of the primary tumour and local treatment of synchronous liver metastases. In particular, patients with a solitary liver metastasis seem to have a favourable prognosis.

Oligometastasis of Gastric Cancer: A Review

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.

Treatment strategy for successful conversion surgery in clinical stage IVB gastric cancer

INTRODUCTION

Recent advances in chemotherapy have resulted in successful conversion surgery (CS) for clinical stage (cStage) IVB gastric cancer (GC). This study aimed to evaluate the success rate of CS in clinical practice and determine optimal treatment strategies.

METHODS

Totally, 166 patients with cStage IVB gastric and gastroesophageal junction adenocarcinoma, who underwent chemotherapy at Hyogo Medical University Hospital between January 2017 and June 2022, were included. CS was performed after confirming tumor to be M0 based on imaging and/or staging laparoscopy, except for resectable liver metastases. Preoperative chemotherapy was continued for at least 6 months provided that adverse events were manageable.

RESULTS

Of 125 eligible patients, 23 were treated with CS, achieving a conversion rate of 18.4% and an R0 resection rate of 91.3%. The median duration of preoperative chemotherapy was 8.5 months; the median number of cycles was eight. The highest conversion rate was observed in patients receiving first-line treatment (14.4%), followed by those receiving second and third lines (5.8% and 2.3%, respectively). The median survival time in patients who received CS was significantly longer than that in patients who continued chemotherapy alone (56.7 versus 16 months, respectively, P < 0.0001). There was no significant difference in the 3-year overall survival between the patients who achieved CS after first-line treatment (63.2%, n = 18) and those who achieved CS after second- or third-line treatment (66.7%, n = 5).

CONCLUSION

Consistent chemotherapy strategies could lead to successful CS and improved prognosis in a greater number of patients with cStage IVB GC, regardless of line of treatment.

Treatment of Oligometastatic GI Cancers

Oligometastatic state is believed to potentially represent a transitional stage between early, locoregional state disease and widely metastatic disease. Historically, locoregional approaches, particularly in advanced colorectal cancers, have demonstrated efficacy in select patients with limited burden of metastatic disease. Recent strides in systemic therapies, including biomarker-based treatments and immunotherapy, alongside innovations in surgical techniques and novel locoregional approaches such as stereotactic radiotherapy and ablation, have ushered in a new era of therapeutic possibilities across all oligometastatic GI cancers. Despite these advancements, there remains a significant gap in high-quality prospective evidence guiding patient selection and treatment decisions across various disease types. Ongoing clinical trials are anticipated to provide crucial insights into oligometastatic states, fostering the refinement of disease-specific oligometastatic state definitions and treatment algorithms. This article reviews existing data on the management of oligometastatic GI cancer, summarizes current state of knowledge for each disease state, and provides updates on ongoing studies in this space.

Oligometastatic Gastric Cancer: Clinical Data from the Meta-Gastro Prospective Register of the Italian Research Group on Gastric Cancer

BACKGROUND

Interest in the field of metastatic gastric cancer has grown in recent years, and the identification of oligometastatic patients plays a critical role as it consents to their inclusion in multimodal treatment strategies, which include systemic therapy but also surgery with curative intent. To collect sound clinical data on this subject, The Italian Research Group on Gastric Cancer developed a prospective multicentric observational register of metastatic gastric cancer patients called META-GASTRO.

METHODS

Data on 383 patients in Meta-Gastro were mined to help our understanding of oligometastatic, according to its double definition: quantitative/anatomical and dynamic.

RESULTS

the quantitative/anatomical definition applies to single-site metastases independently from the metastatic site (p < 0.001) to peritoneal metastases with PCI ≤ 12 (p = 0.009), to 1 or 2 hepatic metastases (p = 0.024) and nodal metastases in station 16 (p = 0.002). The dynamic definition applies to a percentage of cases variable according to the metastatic site: 8%, 13.5 and 23.8% for hepatic, lymphatic and peritoneal sites, respectively. In all cases, the OS of patients benefitting from conversion therapy was similar to those of cases deemed operable at diagnosis and operated after neoadjuvant chemotherapy.

CONCLUSIONS

META-GASTRO supports the two-fold definition of oligometastatic gastric cancer: the quantitative/anatomical one, which accounts for 30% of our population, and the dynamic one, observed in 16% of our cases.

Commentary: The Prognostic Value of Oligo-Recurrence Following Esophagectomy for Esophageal Cancer

See Article page 403.

Definitive Chemoradiation Associated with Improved Survival Outcomes in Patients with Synchronous Oligometastatic Esophageal Cancer

BACKGROUND

The study of oligometastatic esophageal cancer (EC) is relatively new. Preliminary data suggests that more aggressive treatment regimens in select patients may improve survival rates in oligometastatic EC. However, the consensus recommends palliative treatment. We hypothesized that oligometastatic esophageal cancer patients treated with a definitive approach (chemoradiotherapy [CRT]) would have improved overall survival (OS) compared to those treated with a purely palliative intent and historical controls.

METHODS

Patients diagnosed with synchronous oligometastatic (any histology, ≤5 metastatic foci) esophageal cancer treated in a single academic hospital were retrospectively analyzed and divided into definitive and palliative treatment groups. Definitive CRT was defined as radiation therapy to the primary site with ≥40 Gy and ≥2 cycles of chemotherapy.

RESULTS

Of 78 Stage IVB (AJCC 8th ed.) patients, 36 met the pre-specified oligometastatic definition. Of these, 19 received definitive CRT, and 17 received palliative treatment. With a median follow-up of 16.5 months (Range: 2.3-95.0 months), median OS for definitive CRT and palliative groups were 90.2 and 8.1 months (p < 0.01), translating into 5-year OS of 50.5% (95%CI: 32.0-79.8%) vs. 7.5% (95%CI: 1.7-48.9%), respectively.

CONCLUSIONS

Oligometastatic EC patients treated with definitive CRT benefited from that approach with survival rates (50.5%) that vastly exceeded historical standards of 5% at 5 years for metastatic EC. Oligometastatic EC patients treated with definitive CRT had significantly improved OS compared to those treated with palliative-only intent within our cohort. Notably, definitively treated patients were generally younger and with better performance status versus those palliatively treated. Further prospective evaluation of definitive CRT for oligometastatic EC is warranted.