Daisuke Kotani

Background: HER2 amplification is demonstrated to influence response to therapy and outcomes in metastatic colorectal cancer (mCRC), but its role in resectable CRC remains unclear. This study investigated the prognostic impact of WES-defined ERBB2 amplification and its association with adjuvant chemotherapy (ACT) efficacy and circulating tumor DNA (ctDNA) in resectable CRC. Methods: Data from 3607 patients with resectable CRC from the GALAXY study were analyzed. HER2 amplification was defined using ERBB2 copy number alterations based on whole exome sequencing of tumor specimens. We analyzed disease-free survival (DFS) in WES-defined ERBB2 amplified CRC, evaluating ACT benefit and the correlation between ERBB2 copy number and ctDNA status. Results: No significant difference in DFS was observed between those with and without WES-defined ERBB2 amplification in a univariate ( P = 0.0659) or a multivariate analysis ( P = 0.2300). Among patients with pathological stage III, ACT was associated with improved DFS in the non-amplified subgroup (HR 0.67, P = 0.0002), particularly in the subgroup of patients with early post-operative (2–10 weeks following surgical resection) ctDNA-positivity (HR 0.27, P < 0.0001), whereas no clear association was detected in the small amplified subgroup; however, the ACT-by- ERBB2 amplification interaction was not statistically significant. While WES-defined ERBB2 amplification correlated with higher early post-operative ctDNA positivity ( P = 0.0486), ERBB2 copy number did not associate with recurrence or levels. However, early post-operative ctDNA positivity strongly predicted poor DFS in patients with WES-defined ERBB2 amplification (HR 15.26, P < 0.0001). Conclusions: WES-defined ERBB2 amplification was not identified as a significant adverse prognostic factor in resectable CRC, unlike early post-operative ctDNA status. The limited number of amplified cases precluded a reliable assessment of whether WES-defined ERBB2 amplification modifies the association between ACT and DFS.

Tumor-informed circulating tumor DNA (ctDNA) enables detection of molecular residual disease (MRD) after curative resection of colorectal cancer (CRC), but whether early intervention improves outcomes remains uncertain. ALTAIR was a randomized, double-blind, phase 3 trial embedded in the CIRCULATE-Japan platform evaluating a post-adjuvant ctDNA surveillance strategy with treatment initiation upon molecular recurrence. Patients with resected stage 0-IV CRC who became ctDNA positive after completion of standard-of-care therapy and had no radiological evidence of disease were randomly assigned (1:1) to receive trifluridine/tipiracil (FTD/TPI) or placebo for 6 months. The primary endpoint was investigator-assessed disease-free survival (DFS). Between July 2020 and June 2023, 243 patients were randomized to FTD/TPI (n = 122) or placebo (n = 121). Median DFS was 9.30 months with FTD/TPI and 5.55 months with placebo (hazard ratio = 0.79, 95% confidence interval: 0.60-1.05, P = 0.107), and the primary endpoint was not met. FTD/TPI increased grade 3 or higher hematologic adverse events (73.0% versus 3.3%) without new safety signals. These findings indicate that post-adjuvant intervention with FTD/TPI did not significantly improve DFS in ctDNA-positive patients without radiological disease. ClinicalTrials.gov identifier: NCT04457297 .

Objective: To evaluate the prognostic utility of postoperative circulating tumor DNA (ctDNA) for recurrence and treatment response in patients with rectal cancer undergoing upfront surgery. Background: ctDNA-based molecular residual disease (MRD) testing shows promise in colorectal cancer, but its role in patients with rectal cancer not receiving neoadjuvant therapy is unclear. This study evaluates whether postoperative ctDNA predicts disease-free survival (DFS) and guides adjuvant chemotherapy (ACT) decisions. Methods: We analyzed ctDNA from patients with stage II to III rectal cancer (N=250) enrolled in the GALAXY study, a multicenter registry in Japan. A clinically validated, personalized, tumor-informed 16-plex PCR next-generation sequencing assay (Signatera) was used to detect and quantify ctDNA. The primary outcome was DFS, defined as the time from landmark to recurrence, death, or the latest radiologic assessment. Results: In the MRD window (2–10 wk postsurgery, before ACT), 14.2% (35/246) of patients were ctDNA-positive and had significantly shorter DFS (HR: 9.96, 95% CI: 5.76–17.2, P P =0.031), whereas no benefit was seen in ctDNA-negative patients (HR: 0.59, 95% CI: 0.26–1.35, P =0.211). When analyzing ctDNA dynamics from the MRD window to 6 months postsurgery, recurrence risk was higher in patients who converted from ctDNA-negative to positive (HR: 8.22, 95% CI: 1.86–36.32, P =0.0055) and who remained ctDNA-positive (HR: 45.48, 95% CI: 14.31–144.57, P <0.0001) compared with serially ctDNA-negative patients. Conclusions: Postoperative ctDNA status is a robust biomarker predicting recurrence risk and ACT benefit in patients with rectal cancer undergoing upfront surgery.

Background: In the phase 3 FRESCO-2 study, fruquintinib plus best supportive care (BSC) significantly improved overall survival (OS) versus placebo plus BSC in patients with refractory metastatic colorectal cancer (mCRC). We present the results of a FRESCO-2 post hoc subgroup analysis evaluating outcomes of patients enrolled in Japan. Methods: In FRESCO-2, patients had previously received all standard chemotherapies, anti-VEGF and anti-EGFR therapies if indicated, and had progressed on, or were intolerant to trifluridine-tipiracil and/or regorafenib. Patients were randomized 2:1 to receive fruquintinib 5 mg or matching placebo by mouth once daily on days 1–21 in 28-day cycles, plus BSC. The primary endpoint was OS; secondary endpoints included progression-free survival (PFS) and safety. Results: Of the 56 patients enrolled in Japan, 40 (71.4%) and 16 (28.6%) were randomized to fruquintinib and placebo, respectively. OS was improved with fruquintinib versus placebo (median 6.9 vs. 5.6 months; hazard ratio [HR], 0.42; 95% confidence interval [CI] 0.19 − 0.92). PFS was also improved with fruquintinib versus placebo (median 3.6 vs. 1.8 months; HR, 0.27; 95% CI 0.13 − 0.56). The incidence of grade ≥ 3 treatment-emergent adverse events (TEAEs) with fruquintinib versus placebo was 71.8% versus 29.4%; the most common grade ≥ 3 TEAEs with fruquintinib were hypertension (23.1%) and palmar-plantar erythrodysesthesia (17.9%). Conclusions: Fruquintinib improved OS and PFS versus placebo in FRESCO-2 patients enrolled in Japan and demonstrated a manageable safety profile. Results from the Japan subgroup were consistent with the global FRESCO-2 population, thus supporting fruquintinib as a novel treatment option for patients in Japan with refractory mCRC. Clinical trial details: ClinicalTrials.gov; NCT04322539.

Although surgical resection is the standard therapy for stage II/III colorectal cancer, recurrence rates exceed 30%. Circulating tumor DNA (ctNDA) detects molecular residual disease (MRD), but lacks spatial and tumor microenvironment information. Here, we develop a deep learning (DL) model to predict disease-free survival from hematoxylin & eosin stained whole slide images in stage II-IV colorectal cancer. The model is trained on the DACHS cohort (n = 1766) and validated on the GALAXY cohort (n = 1404). In GALAXY, the DL model categorizes 304 patients as DL high-risk and 1100 as low-risk (HR 2.31; p < 0.005). Combining DL scores with MRD status improves prognostic stratification in both MRD-positive (HR 1.58; p < 0.005) and MRD-negative groups (HR 2.1; p < 0.005). Notably, MRD-negative patients predicted as DL high-risk benefit from adjuvant chemotherapy (HR 0.49; p = 0.01) vs. DL low-risk (HR = 0.92; p = 0.64). Combining ctDNA with DL-based histology analysis significantly improves risk stratification, with the potential to improve follow-up and personalized adjuvant therapy decisions.

Objective: To investigate the association between perioperative ctDNA status and prognosis in patients with esophageal squamous cell carcinoma (ESCC). Background: Circulating tumor DNA (ctDNA) has emerged as a promising biomarker for assessing molecular residual disease (MRD) in various malignancies. However, there are limited studies evaluating the utility of ctDNA for predicting recurrence risk in patients with ESCC. Methods: We prospectively enrolled patients with locally advanced ESCC who were scheduled to receive neoadjuvant chemotherapy (NAC) followed by surgery. This report retrospectively analyzed ctDNA with a personalized, tumor-informed 16-plex mPCR-NGS assay at multiple time points: pre-NAC, post-NAC but before surgery, postoperatively, and longitudinally during follow-up. Results: A total of 28 patients who underwent curative surgery and had successful whole-exome sequencing analyses of tumor tissue samples were included in this report. At the pre-NAC time point, ctDNA was detected in 50% of patients with stage I and 100% of those with stages II, III, and IV. Post-NAC but before surgery, ctDNA was detected in 33.3% of patients. The recurrence rate was 77.8% in ctDNA-positive patients compared to 27.8% in ctDNA-negative patients, with significantly worse recurrence-free survival (RFS) for ctDNA-positive patients vs. ctDNA-negative patients (HR: 4.56, P =0.01). In patients analyzed during the MRD window (2-16 weeks post-surgery), the recurrence rate was 100% in ctDNA-positive patients compared with 30.4% in ctDNA-negative patients, with significantly worse RFS (HR: 30.99, P 16 weeks postsurgery), detectable ctDNA was significantly associated with poor RFS (HR: 27.34, P =0.003). Conclusions: This study suggests that ctDNA-based MRD assessment may be valuable for evaluating patients with ESCC, particularly in post-NAC and postsurgical settings.