Abstract 515P
Background
Comprehensive molecular profiling (CMP) has evolved over the last decade and now is increasingly used in low-middle-income countries. It can affect the course of treatment of patients (pts) with most solid tumors. Here we describe data on pts with gastrointestinal (GI) cancers who underwent CPM in Russia.
Methods
We conducted a multicenter, retrospective study in adult pts with advanced GI cancers who underwent a CMP with minimum 160 genes tested. Clinical benefit of testing was considered if the pt received a molecularly-matched therapy (MMT) ≥ 6 months or if PFS2/PFS1 ratio was ≥ 1,3. The analysis also included disease control rate (DCR), objective response rate (ORR), PFS and OS according to MMT.
Results
During 2018 - 2024, 235 pts with available CMP reports were included in the study. Pts were diagnosed with colorectal (CRC, 145; 62%), gastric (35; 15%), pancreatic (22; 9,5%), cholangiocellular (21; 9%), small intestine (8; 3,5%) and esophageal cancers (4; 1%). Median age was 56 years (17- 87), males - 51,5% and ECOG 0-1 - 65%. Pts received a median of 2 (0-7) lines of prior systemic therapy with mPFS1 (before CMP) 4 months. MMT could be recommended in 136 (58%, ESCAT I-II - 23,6%, III - 56,7%, IV-X - 19,7%) cases on the CMP basis, but only 35 pts (15%; ESCAT I-II - 37,2%, III - 48,6%, IV-X - 14,2%) received MMT. Table: 515P
Treatment results after CMP
| Criteria | MMT (n=35) | non-MMT (n=138) | p-value |
| Therapy ≥ 6 months,% | 38 | 18 | 0,035 |
| PFS2/1 ≥ 1,3,% | 46 | 13 | <0,001 |
| DCR,% | 60 | 29 | 0,007 |
| ORR,% | 24 | 8 | 0,037 |
| mPFS, m | 5 | 2 | 0,009 |
| mOS, m | 6 | 5 | 0,007 |
In multivariate analysis such factors as availability of molecular tumor board (HR 0,12; 95 % CI 0,04 - 0,38) and ESCAT I-II findings (HR 0,11; 95 % CI 0,03 - 0,36) were positive predictors for receiving MMT. Significant negative predictor was CRC (HR 2,78, 95% CI 1,024 - 7,58). Reasons for non-MMT were: low targetability of alteration as of MTB decision (40%), unavailability of the drugs or clinical trials (30%), deterioration of clinical condition (23%), clinician’s choice (7%).
Conclusions
We observed that in a middle-income country setting only 15% of pts with GI cancers received MMT after CMP. MMT was associated with clinical benefit in comparison with non-MMT group.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.