Long-Term Locoregional Treatment Benefits Observed in Patients With Oligometastatic CRC

San Francisco—Findings from a pooled analysis of 2 randomized phase 3 studies (TRIBE 1 and TRIBE 2) presented at the 2020 American Society of Clinical Oncology Gastrointestinal Cancers Symposium better defined the prognostic implications of tumor load, locoregional treatments (LRTS), and first-line therapy intensification in patients with oligometastatic colorectal cancer.

Currently, there are no available data from clinical trials adopting the European Society for Medical Oncology guidelines for defining oligometastatic disease. Thus, Gemma Zuchelli, MD, Azienda Ospedaliera Universitaria Pisana, Pisa, Italy, and co-investigators sought to assess the efficacy of FOLFOXIRI plus bevacizumab versus doublets FOLFOX or FOLFIRI plus bevacizumab and the impact of locoregional treatments based on whether a patient has oligometastaticor non-oligometastaticdisease.

Subgroup analyses were performed on pooled data from 2 clinical trials according to tumor load at baseline, with oligometastatic disease defined as having up to 5 metastases, up to 3 metastases in 1 organ, up to 3 affected organs, metastases size ≤3 cm, and absence of ascites and peritoneal, bone, and central nervous system metastases.

Of 1158 classifiable patients, 126 (11%) had oligometastatic disease and 1032 (89%) had non-oligometastatic disease.

The primary end points were progression-free survival (PFS), overall response rate (ORR), and overall survival (OS). 

The PFS was found to be longer in patients with oligometastatic versus non-oligometastatic disease(14.3 months vs 10.5 months, respectively). Furthermore, patients with oligometastatic diseasehad a longer OS than did those with non-oligometastatic disease(44.3 months vs 24.0 months).

Among 35 patients with oligometastatic diseaseat baseline (n = 202) who underwent locoregional treatmentswith curative intent during first-line therapy, the OS was 59.6 months compared with 50.6 months in patients with non-oligometastatic disease.

In addition, the oligometastatic disease subgroup had clinical benefit from FOLFOXIRI plus bevacizumab compared with the doublets FOLFOX or FOLFIRI plus bevacizumab, with no interaction effect between treatment arm and tumor load in terms of ORR, PFS, and OS.

“OMD [oligometastatic disease] is confirmed as a positive prognostic factor and is associated with a higher magnitude of long-term benefit from locoregional treatments than non-OMD. The positive impact of the intensification of the upfront CT [chemotherapy] is independent of tumor load,” Dr Zuchelli et al concluded.—Kaitlyn Manasterski

Zucchelli G, Moretto R, Rossini D, et al. Oligometastatic colorectal cancer: Prognostic implications of tumor load, role of locoregional treatments, and of first-line therapy intensification—A pooled analysis of TRIBE and TRIBE2 studies by GONO. Presented at: the 2020 Gastrointestinal Cancers Symposium; January 23-25, 2020; San Francisco, CA. Abstract 12.