Search

Metastatic colorectal cancer (mCRC) is a heterogeneous disease that can evoke discordant responses to therapy among different lesions in individual patients. The Response Evaluation Criteria in Solid Tumors (RECIST) criteria do not take into consideration response heterogeneity. We explored and developed lesion-based measurement response criteria to evaluate their prognostic effect on overall survival (OS)., Patients and Methods: Patients enrolled in 17 first-line clinical trials, who had mCRC with ≥ 2 lesions at baseline, and a restaging scan by 12 weeks were included. For each patient, lesions were categorized as a progressing lesion (PL: > 20% increase in the longest diameter (LD)), responding lesion (RL: > 30% decrease in LD), or stable lesion (SL: neither PL nor RL) based on the 12-week scan. Lesion-based response criteria were defined for each patient as follows: PL only, SL only, RL only, and varied responses (mixture of RL, SL, and PL). Lesion-based response criteria and OS were correlated using stratified multivariable Cox models. The concordance between OS and classifications was measured using the C statistic., Results: Among 10,551 patients with mCRC from 17 first-line studies, varied responses were noted in 51.6% of patients, among whom, 3.3% had RL/PL at 12 weeks. Among patients with RL/SL, 52% had stable disease (SD) by RECIST 1.1, and they had a longer OS (median OS (mOS) = 19.9 months) than those with SL only (mOS = 16.8 months, HR (95% CI) = 0.81 (0.76, 0.85), p < 0.001), although a shorter OS than those with RL only (mOS = 25.8 months, HR (95% CI) = 1.42 (1.32, 1.53), p < 0.001). Among patients with SL/PL, 74% had SD by RECIST 1.1, and they had a longer OS (mOS = 9.0 months) than those with PL only (mOS = 8.0 months, HR (95% CI) = 0.75 (0.57, 0.98), p = 0.040), yet a shorter OS than those with SL only (mOS = 16.8 months, HR (95% CI) = 1.98 (1.80, 2.18), p < 0.001). These associations were consistent across treatment regimen subgroups. The lesion-based response criteria showed slightly higher concordance than RECIST 1.1, although it was not statistically significant., Conclusion: Varied responses at first restaging are common among patients receiving first-line therapy for mCRC. Our lesion-based measurement criteria allowed for better mortality discrimination, which could potentially be informative for treatment decision-making and influence patient outcomes.

Background/aim: In patients with advanced platinum-resistant ovarian cancer we prospectively evaluated whether trabectedin could resensitize the tumor cells to platinum rechallenge., Patients and Methods: Upon progression to platinum-based chemotherapy, trabectedin was administered as a 3-hour infusion every three weeks and subsequently crossed over to carboplatin/carboplatin-based combinations. The primary endpoints comprised objective response rate (ORR) and time to progression after trabectedin (TTP Trab). Secondary endpoints included ORR following platinum post-trabectedin, the growth modulation index (GMI) assessed as the ratio of successive TTP to platinum, given after (TTP2) and before (TTP1) trabectedin, quality of life (QoL), and ancillary translational studies., Results: Ten patients with platinum-resistant ovarian cancer from a single institution were treated with trabectedin, one of whom achieved a partial response (PR) reaching the ORR of 10% and six had stable disease (SD) for a disease control rate (DCR) of 70%. After the treatment with platinum post-trabectedin, one patient achieved a PR and two had SD, attaining a rate of resensitization to platinum of 37.5%. The median TTP with trabectedin treatment was 15.0 weeks, while eight patients who received platinum post-trabectedin had the median TTP2 of 19.9 weeks. One patient reached the threshold of GMI >1 (12.5%) as indicator of clinical benefit. QoL of patients was not deteriorated with trabectedin. Predictive biomarkers of response to trabectedin and/or re-exposure to platinum could not be identified., Conclusion: Although trabectedin did not achieve a wide resensitization to platinum in this heavily pretreated platinum-resistant population, a significant number of patients attained disease control., Competing Interests: The Authors declare that they have no conflicts of interest in relation to this study., (Copyright 2023, International Institute of Anticancer Research.)