Abstract 18P
Background
T4 is one of the most important and independent prognostic factors in adjuvant setting for CC patients. However, the optimal management in stage II (pT4N0) as well as the impact of DNA mismatch repair deficiency (dMMR) in this subset of patients remain unclear. Here, we present a large, multicenter, real-world analysis of pT4N0 CC patients.
Methods
A real-world database including pts treated at 9 Italian institutions from April 2010 to November 2023 was queried. Clinico-pathological characteristics of pts diagnosed with a stage II pT4N0 CC were analyzed. Pts were stratified according to duration of treatment, DNA mismatch repair (MMR) status, type of adjuvant chemotherapy (ACT). Primary endpoints were median relapse-free survival (RFS) and overall survival (OS).
Results
A total of 382 pts was included, and outcomes data were available for 306 pts. Median age 72 yrs, 51% male. 51 pts (23%) had dMMR CC; Lynch Syndrome was found in 15% of them. After a median follow-up of 48.6 mo (40.7-50.4), 3-yr RFS and 5-yr RFS were 67% and 53%, respectively; 3-yr OS was 81% and 5-yr OS 68%. 160 pts (52%) received ACT: oxaliplatin (oxa)-based CT was given to 107 pts (67%). 6-mo ACT was given to 37 pts (71%) and 77 pts (72%) in the monotherapy and oxa-based group, respectively. Pts receiving 6-mo ACT had a significant longer OS compared to those who did not (HR 0.19; 0.10-0.35; p <.001). A trend towards improved OS was observed in 6-mo vs 3-mo ACT (HR 0.45; 0.19-1.06; p 0.060). Similar results were observed in terms of RFS: 6-mo ACT showed a longer RFS compared to 3-mo ACT (HR 0.57; 0.32-1.00; p .047) and to no-ACT (HR 0.45; 0.30-0.68; p <.001). Oxa-based ACT was associated with a significant improvement in OS compared to monotherapy (HR 0.21; 0.09-0.52; p <.001). Overall, pts with dMMR CC did not show a statistically significant difference in terms of OS (p .23), while RFS was significantly longer (HR 0.57; 0.33-1.00; p .047) compared to proficient pts.
Conclusions
In this large real-world dataset, T4 was confirmed as a poor prognostic factor, independently to MMR status. ACT provides large benefit in this population, and oxa-based ACT may be better than monotherapy. In addition, 6-mo oxa-based ACT showed a trend towards a better outcome compared to 3-mo ACT.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.