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Background: In metastatic colorectal cancer (mCRC), the prognostic relevance of the human epidermal growth factor receptor-2 (HER2) remains controversial. We evaluated the impact of HER2 overexpression on outcomes of standard chemotherapy in patients with mCRC. Methods: This retrospective study included patients with mCRC who received standard chemotherapy for mCRC and were tested for HER2 expression at Samsung Medical Center, Seoul, Korea, between January 15, 2017, and February 05, 2022. The HER2 test was performed using immunohistochemistry. We assessed the objective response rate (ORR), overall survival (OS), and progression-free survival (PFS) according to HER2 status. All statistical analyses were performed using SPSS® version 25 (IBM, Armonk, NY, USA). Results: In total, 108 patients were included; 10 (9.3%) had HER2-positive tumors. The ORR for patients with mCRC receiving standard chemotherapy did not differ for HER2-positive and HER2-negative tumors. The median PFS for patients with mCRC with HER2-positive or HER2-tumors after receiving first-line chemotherapy was 18.52 months [95% confidence interval (CI): 4.355-32.695] or 10.95 months (95% CI: 9.317-12.585; P=0.417), respectively, and that after second-line chemotherapy was 7.08 months (95% CI: 6.801-7.363) or 5.34 months (95% CI: 4.433-6.255; P=0.837), respectively. Likewise, OS did not differ according to HER2 expression (median OS: HER2-positive tumors, 49.1 months (95% CI: 0.000-98.365); HER2-negative tumors, 37.7 months (95% CI: 27.111-48.366; P=0.410). Conclusions: The tumor response and survival of patients with mCRC after standard chemotherapy did not differ by HER2 expression. These findings suggest that the status of HER2 expression need not be considered when choosing regimens as the current first- and second-line treatments.
RESUMEN
BACKGROUND AND PURPOSE: Administration of pegylated granulocyte-colony-stimulating factor (peg-GCSF) 24 to 72 hours after chemotherapy is usually recommended. Next-day administration (after 24 hours) resulted in fewer duration of grade (Gr) 4 chemotherapy-induced neutropenia (CIN) and decreased severity of CIN than same-day (within 4 hours). However, patients sometimes receive same-day Peg-GCSF for the sake of convenience. In addition, a few prior studies showed that the same-day method is comparable or superior to the next-day method in preventing CIN, especially in chemotherapy regimens that include day 1 myelosuppressive agents. Thus, we aim to verify the hypothesis that same-day administration of pegteograstim, a new formulation of peg-GCSF, is non-inferior to next-day administration in terms of Gr4 CIN duration. METHODS: This study is a randomized, multicenter, open-label, investigator-initiated phase 3 study. Patients with adjuvant/neoadjuvant or first-line palliative chemotherapy comprising intensively myelosuppressive agents on day 1 (mFOLFIRINOX, ECb, EP, FOLFIRI, and FOLFOX) are enrolled. The patients are assigned to the same-day arm or the next-day arm in a 1:1 ratio. The randomizations are stratified according to number of patient CIN risk factors (1 vs ≥2), chemotherapy setting (perioperative vs palliative), and interval (2-week vs 3-week). In the same-day arm, pegteograstim 6 mg is subcutaneously injected within 4 hours after completion of chemotherapy. In the next-day arm, pegetograstim is injected at 24 to 36 hours post-chemotherapy. A complete blood count test is performed daily from day 5 to 9 during the cycle 1. The primary endpoint is duration of Gr4 CIN (cycle 1), and secondary endpoints include incidence of Gr 3 to 4 CIN (cycle 1), severity of CIN (cycle 1), time to recovery absolute neutrophil count 1000/µL (cycle 1), incidence of febrile neutropenia, incidence of CIN-related dose delay, and dose intensity. In order to verify non-inferiority of 0.6 days, we estimated a significance level of 5%, power of 80%, and drop-out rate of 15%. This results in the need for a total of 160 patients, 80 in each group.