Molecular Marker Identification for Relapse Prediction in 5-FU-Based Adjuvant Chemotherapy in Gastric and Colorectal Cancers

3536 Background: Microsatellite instability (MSI) phenotype is found in approximately 12% of colorectal cancers (CRC). MSI CRC is associated with a low recurrence rate and 5-fluorouracil chemoresistance in adjuvant setting. Clinical and pathological prognostic factors of recurrence are well-identified after surgery of CRC but not in the subgroup of MSI CRC. Methods: This multicenter retrospective study included patients with stage I, II and III MSI CRC. The following prognostic factors were studied: age, sex, perforation, occlusion, tumor location, tumor differentiation, T4 stage, lymph node invasion, VELIPI criteria (vascular emboli, lymphatic invasion and perinervous invasion), BRAF mutation and adjuvant chemotherapy. Disease-free survival (DFS) was calculated using the Kaplan-Meier method. Prognostic factors of DFS were analyzed in multivariate analysis using Cox model. Results: A total of 294 MSI CRC patients were analyzed, including 10%, 49% and 41% stage I, II and III, respectively. Mean age was 67.2 ± 16.0 years. Occlusion was observed in 10% of cases. VELIPI criteria were found in 39%, including 26% with vascular emboli. BRAF mutation was detected in 27% of cases. All in all, 40% of patients received adjuvant chemotherapy, predominantly stage III (74%). Mean follow-up was 39.2 ± 33.2 months. The disease recurrence rate was 3%, 8% and 21% in stage I, II and III patients, respectively. The 3-year DFS rate was 85%. In univariate analysis, age, occlusion, lymph node invasion, T4 stage, vascular emboli and perinervous invasion were associated with decreased DFS (p<0.05). In multivariate analysis, only occlusion (RR=3.0; 95% CI 1.2-7.7, p=0.02) and vascular emboli (RR=4.5; 95% CI 1.6-12.7, p<0.01) were associated with decreased DFS. Recurrence rates for MSI CRC with and without vascular emboli were respectively, 22% versus 5% for stage II and 33% versus 15% for stage III. Conclusions: Occlusion and vascular emboli were independently associated with recurrence of MSI CRC but not lymph node invasion. We advocate vascular emboli analysis in routine clinical practice to facilitate adjuvant chemotherapy decision-making in MSI CRC.

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Quality indicators of colorectal cancer care in a public healthcare institution in Uruguay: Results from a retrospective population-based study.

Journal of Clinical Oncology ◽

10.1200/jco.2020.38.29_suppl.234 ◽

2020 ◽

Vol 38 (29_suppl) ◽

pp. 234-234

Author(s):

Santiago Fontes ◽

Mauricio Cuello ◽

Ana Marín-Jiménez ◽

Juan Carlos Sánchez ◽

Megan Berry ◽

...

Keyword(s):

Colorectal Cancer ◽

Latin America ◽

Adjuvant Chemotherapy ◽

Quality Indicators ◽

Cancer Care ◽

Definitive Treatment ◽

Colorectal Cancers ◽

Public Healthcare ◽

Target Values ◽

Rectal Cancers

234 Background: There is an urgent need to assess quality of cancer care in Latin America, especially amongst the most prevalent tumors, such as colorectal cancer. The main aim of this study was to assess adherence to previously validated quality indicators (QIs) for colorectal cancer in the context of a public healthcare provider in Uruguay. Methods: Data regarding all colorectal cancers registered between January 1, 2008 and December 31, 2019 at the National Cancer Institute of Montevideo was collected through retrospective analysis of medical records. We used 12 QIs (4 diagnostic, 7 treatment,1 surveillance) validated in previous publications. Each QI was analyzed as a proportion (%) and compared to target values with 95% confidence interval. Results: A total of 808 colorectal cancers were identified; only 10.1% were diagnosed by screening, 87% were diagnosed after reporting symptoms and 29.5% underwent emergency surgery. A complete preoperative colonoscopy was performed in 47% of patients, 64% had a CT-TAP scan and 63% of locally advanced rectal cancers had staging MRI prior to definitive treatment. Surgical resection with tumor free margins was obtained in 97% of cases, and for 68% at least 12 lymph nodes were examined. Neoadjuvant radiotherapy plus chemotherapy as first therapeutic strategy was implemented in 79% of rectal cancers. High risk stage II and III colon cancer received adjuvant chemotherapy within 16 weeks of surgery in 72,9% of cases. Postoperative follow up with CEA was registered in 97% of our series. Most patients ≤ 75 years of age with metastatic unresectable colorectal cancer at diagnosis underwent first-line chemotherapy or bio-chemotherapy. A low level of adherence was identified in micro-satellite and RAS status testing, 16 and 22 patients respectively. Conclusions: This study is a pioneer study in Latin America. The standardization of QI definition to achieve interregional comparative goals remains an unmet need.Our data indicates there is much to improve in early diagnosis, preoperative staging, neoadjuvant therapy and molecular testing. QI indicators in surgery and adjuvant chemotherapy prescription are similar to those reported in international studies.

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