Purpose

This was a review of circulating tumor DNA (ctDNA) in patients with peritoneal metastases from colorectal cancer.

Methods

We searched the PubMed database for studies reporting detection of ctDNA in patients with colorectal cancer (CRC) and with peritoneal metastases (PM) from colorectal cancer (CRPM). We extracted data on the population included, number of subjects, study design, type of ctDNA assay used and schedule, and the major findings from these publications.

Results

We identified 13 studies for review investigating ctDNA, using a variety of ctDNA assays, among 1787 patients with CRC without PM, as well as four eligible published and one unpublished (in press) studies, which included 255 patients with PM from any primary site and 61 patients with CRPM. Among the 13 studies investigating ctDNA among CRC without PM, posttreatment surveillance ctDNA was associated with recurrence and was generally more sensitive than imaging or tumor markers. Among the five studies including patients with PM, ctDNA was not universally able to detect the presence of PM, but when present, ctDNA predicted worse outcomes.

Conclusion

Circulating-tumor DNA is a potentially useful surveillance tool for patients with CRC. However, the sensitivity of ctDNA to detect CRPM is variable and warrants further inquiry.

Background

Primary small cell carcinoma of the pancreas (SCCP) is a rare malignant neuroendocrine carcinoma (NEC). Typically, it presents with lymphovascular invasion as well as metastasis at the time of diagnosis which portends a dismal prognosis. Treatment is typically based on therapy used for other aggressive NECs such as small cell lung cancer. Although multimodal surgery, radiation and chemotherapy may improve prognosis, the outcome generally remains poor.

Case presentation

Here we present a primary SCCP managed with neoadjuvant multi-agent chemotherapy combined with radiotherapy and surgery CONCLUSIONS: Multi-disciplinary therapy resulted in an ongoing 28 + month radiographic complete response and overall survival.

Despite progress, 2-year pancreatic cancer survival remains dismal. We evaluated a biomarker-driven, combination/N-of-one strategy in 18 patients (advanced/metastatic pancreatic cancer) (from Molecular Tumor Board). Targeted agents administered/patient = 2.5 (median) (range, 1-4); first-line therapy (N = 5); second line, (N = 13). Comparing patients (high versus low degrees of matching) (matching score ≥50% versus <50%; reflecting number of alterations matched to targeted agents divided by number of pathogenic alterations), survival was significantly longer (hazard ratio [HR] 0.24 (95% confidence interval [CI], 0.078-0.76, P = 0.016); clinical benefit rates (CBR) (stable disease ≥6 months/partial/complete response) trended higher (45.5 vs 0.0%, P = 0.10); progression-free survival, HR, 95% CI, 0.36 (0.12-1.10) (p = 0.075). First versus ≥2nd-line therapy had higher CBRs (80.0 vs 7.7%, P = 0.008). No grade 3-4 toxicities occurred. The longest responder achieved partial remission (17.5 months) by co-targeting MEK and CDK4/6 alterations (chemotherapy-free). Therefore, genomically matched targeted agent combinations were active in these advanced pancreatic cancers. Larger prospective trials are warranted.

Background

There is no agreed upon standard of care for borderline-resectable pancreatic cancer (BRPC) or locally-advanced pancreatic cancer (LAPC) patients regarding the benefit of chemotherapy or radiation alone or in combination.

Patients and methods

We completed a retrospective cohort analysis of BRPC and LAPC patients at a cancer center with expertise in multi-disciplinary pancreatic ductal adenocarcinoma (PDAC) treatment over a 5-year period from 03/01/2014 to 03/01/2019 (cut-off date). The total evaluable newly diagnosed, treatment naïve, BRPC, and LAPC patients with adequate organ function and ability to obtain treatment after multidisciplinary review was 52 patients. After analysis, patients were evaluated for rates of resection, extent of resection (R0 or R1), median progression-free survival (mPFS), and median overall survival (mOS).

Results

Patients were treated with chemotherapy alone (gemcitabine and nab-paclitaxel = 77% (20/26); FOLFIRINOX = 19% (5/26); single agent gemcitabine 3.8% (1/26)), or chemotherapy followed by chemoradiation (gemcitabine +5 Gy × 5 weeks), or chemoradiation alone prior to re-staging and potential resection. Of the 29% (15/52) of patients who went on to surgical resection, 73% (11/15) achieved R0 resection. An R0 resection was achieved in 35% (9/26) of patients treated with chemotherapy alone, 7.6% (1/13) in a patient treated with chemotherapy followed by radiation, and 7.6% (1/13) with concurrent chemoradiotherapy alone. Chemotherapy alone achieved a mPFS of 16.4 months (p  < 0.0025) and mOS of 26.2 months (p  < 0.0001), chemotherapy followed by chemoradiation was 13.0 months and 14.9 months respectively, while concurrent chemoradiotherapy was 6.9 months and 7.3 months.

Conclusions and relevance

BRPC and LAPC patients capable of surgery after only receiving neoadjuvant treatment with chemotherapy had higher rates of R0 resection with prolonged median PFS and OS compared with any patient needing combination chemotherapy with radiotherapy.

Treatment of hematologic malignancies with patient-derived anti-CD19 chimeric antigen receptor (CAR) T-cells has demonstrated long-term remissions for patients with otherwise treatment-refractory advanced leukemia and lymphoma. Conversely, CAR T-cell treatment of solid tumors, including advanced gastric cancer (GC), has proven more challenging due to on-target off-tumor toxicities, poor tumor T-cell infiltration, inefficient CAR T-cell expansion, immunosuppressive tumor microenvironments, and demanding preconditioning regimens. We report the exceptional results of autologous Claudin18.2-targeted CAR T cells (CT041) in a patient with metastatic GC, who had progressed on four lines of combined systemic chemotherapy and immunotherapy. After two CT041 infusions, the patient had target lesion complete response and sustained an 8-month overall partial response with only minimal ascites. Moreover, tumor-informed circulating tumor DNA (ctDNA) reductions coincided with rapid CAR T-cell expansion and radiologic response. No severe toxicities occurred, and the patient's quality of life significantly improved. This experience supports targeting Claudin18.2-positive GC with CAR T-cell therapy and helps to validate ctDNA as a biomarker in CAR T-cell therapy. Clinical Insight: Claudin18.2-targeted CAR T cells can safely provide complete objective and ctDNA response in salvage metastatic GC.

Purpose

Circulating tumor DNA (ctDNA) analyses allow for postoperative risk stratification in patients with curatively treated colon and breast cancers. Use of ctDNA in esophagogastric cancers (EGC) is less characterized and could identify high-risk patients who have been treated with curative intent.

Methods

In this retrospective analysis of real-world data, ctDNA levels were analyzed in the preoperative, postoperative, and surveillance settings in patients with EGC using a personalized multiplex polymerase chain reaction-based next-generation sequencing assay. Plasma samples (n = 943) from 295 patients at > 70 institutions were collected before surgery, postoperatively, and/or serially during routine clinical follow-up from September 19, 2019, to February 21, 2022. ctDNA detection was annotated to clinicopathologic features and recurrence-free survival.

Results

A total of 295 patients with EGC were analyzed, and 212 patients with stages I-III disease were further explored. Pretreatment ctDNA was detected in 96% (23/24) of patients with preoperative time points. Postoperative ctDNA was detected in 23.5% (16/68) of patients with stage I-III EGC within 16 weeks (molecular residual disease window) after surgery without receiving systemic therapy. ctDNA detection at any time point after surgery (hazard ratio [HR], 23.6; 95% CI, 10.2 to 66.0; P < .0001), within the molecular residual disease window (HR, 10.7; 95% CI, 4.3 to 29.3; P < .0001), and during the surveillance period (HR, 17.7; 95% CI, 7.3 to 50.7; P < .0001) was associated with shorter recurrence-free survival. In multivariable analysis, ctDNA status and clinical stage of disease were independently associated with outcomes.

Conclusion

Using real-world data, we demonstrate that postoperative tumor-informed ctDNA detection in EGC is feasible and allows for enhanced patient risk stratification and prognostication during curative-intent therapy.