Immune checkpoint inhibitors for POLE or POLD1 proofreading-deficient metastatic colorectal cancer.

BACKGROUND: POLE and POLD1 proofreading deficiency (POLE/D1pd) define a rare subtype of ultramutated metastatic colorectal cancer (mCRC; over 100 mut/Mb). Disease-specific data about the activity and efficacy of immune checkpoint inhibitors (ICIs) in POLE/D1pd mCRC are lacking and it is unknown whether outcomes may be different from mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) mCRCs treated with ICIs. PATIENTS AND METHODS: In this global study, we collected 27 patients with mCRC harboring POLE/D1 mutations leading to proofreading deficiency and treated with anti-programmed cell death-ligand 1 alone +/- anti-cytotoxic T-lymphocyte antigen-4 agents. We collected clinicopathological and genomic characteristics, response, and survival outcomes after ICIs of POLE/D1pd mCRC and compared them with a cohort of 610 dMMR/MSI-H mCRC patients treated with ICIs. Further genomic analyses were carried out in an independent cohort of 7241 CRCs to define POLE and POLD1pd molecular profiles and mutational signatures. RESULTS: POLE/D1pd was associated with younger age, male sex, fewer RAS/BRAF driver mutations, and predominance of right-sided colon cancers. Patients with POLE/D1pd mCRC showed a significantly higher overall response rate (ORR) compared to dMMR/MSI-H mCRC (89% versus 54%; P = 0.01). After a median follow-up of 24.9 months (interquartile range: 11.3-43.0 months), patients with POLE/D1pd showed a significantly superior progression-free survival (PFS) compared to dMMR/MSI-H mCRC [hazard ratio (HR) = 0.24, 95% confidence interval (CI) 0.08-0.74, P = 0.01] and superior overall survival (OS) (HR = 0.38, 95% CI 0.12-1.18, P = 0.09). In multivariable analyses including the type of DNA repair defect, POLE/D1pd was associated with significantly improved PFS (HR = 0.17, 95% CI 0.04-0.69, P = 0.013) and OS (HR = 0.24, 95% CI 0.06-0.98, P = 0.047). Molecular profiling showed that POLE/D1pd tumors have higher tumor mutational burden (TMB). Responses were observed in both subtypes and were associated with the intensity of POLE/D1pd signature. CONCLUSIONS: Patients with POLE/D1pd mCRC showed more favorable outcomes compared to dMMR/MSI-H mCRC to treatment with ICIs in terms of tumor response and survival.

FOLFOX4 plus cetuximab administered weekly or every second week in the first-line treatment of patients with KRAS wild-type metastatic colorectal cancer: a randomized phase II CECOG study.

BACKGROUND: This randomized phase II study investigated first-line chemotherapy plus cetuximab administered every second week in KRAS wild-type metastatic colorectal cancer. PATIENTS AND METHODS: Patients received FOLFOX4 plus either standard weekly cetuximab (arm 1) or cetuximab (500 mg/m(2)) every second week (arm 2), until disease progression or unacceptable toxicity. Primary end point was the objective response rate (ORR). Progression-free survival (PFS), overall survival (OS), disease control rate (DCR) and safety were also investigated. The study was not powered to establish non-inferiority, but aimed at the estimation of treatment differences. RESULTS: Of 152 randomized eligible patients, 75 were treated in arm 1 and 77 in arm 2; ORRs [53% versus 62%, odds ratio 1.40, 95% confidence interval (CI) 0.74-2.66], PFS [median 9.5 versus 9.2 months, hazard ratio (HR) 0.92, 95% CI 0.63-1.34], OS (median 25.8 versus 23.0 months, HR 0.86, 95% CI 0.56-1.30) and DCR (87%) were comparable. HRs adjusted for baseline factors were 1.01 and 0.99 for PFS and OS, respectively. Frequencies of grade 3/4 adverse events in arms 1 versus 2 were similar: most common were neutropenia (28% versus 34%) and rash (15% versus 17%). CONCLUSIONS: Activity and safety of FOLFOX4 plus either cetuximab administered weekly or every second week were similar.

Impact of "critical lesions" on outcomes following cytoreductive surgery and hyperthermic intra-peritoneal chemotherapy.

BACKGROUND: Peritoneal Cancer Index (PCI) and complete cytoreduction are the best outcome predictors following cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC). Lesions in critical areas, regardless of PCI, complicate surgery and impact oncological outcomes. We prospectively defined "Critical lesions" (CL) as penetrating the hepatic hilum, diaphragm at hepatic outflow, major blood vessels, pancreas, or urinary tract. METHODS: Retrospective analysis of a prospective database of 352 CRS + HIPEC patients from 2015 to 2019. Excluded patients with aborted/redo operation (n = 112), or incomplete data (n = 19). Patients categorized by CL status and compared: operative time, estimated blood loss (EBL), PCI, transfusions, hospital stay, post-operative complications and mortality, overall survival (OS) and disease-free survival (DFS). RESULTS: Included 221 patients (78 CL; 143 no-CL). No difference in patients' characteristics: age, BMI, gender or co-morbidities noted. Operative time longer (5.3 h vs 4.3 h, p < 0.01), EBL higher (769 ml vs 405 ml, p < 0.01), transfusions higher (1.9 vs 0.7 Units, p < 0.001) and PCI higher (15.5 vs 9.5, p < 0.01) in CL. No difference in major complications. Postoperative complications, CL, OR-time and transfusions were predictive of OS in univariate analysis, while only complications remained on multivariate analysis. Median follow up of 21.4 months, 3-year DFS/OS was 22% vs 30% (p < 0.037) and 73% vs 87% (p < 0.014) in CL and non-CL, respectively. Despite CL complete resection, 17/38 patients (44.7%) that recurred had recurrence at previous CL site. CONCLUSIONS: Critical lesions complicate surgery and may be associated with poor oncological outcomes with high local recurrence rate, despite no significant difference in complications. Utilizing adjuvant or intra-operative radiation may be beneficial.

Number of retrieved lymph nodes and survival in node-negative patients undergoing laparoscopic colorectal surgery for cancer.

BACKGROUND: The number of retrieved lymph nodes in colorectal cancer resection may have an impact on staging and survival. Examination of at least 12 nodes has become a quality measure for adequate surgical practice. To evaluate the impact of the number of retrieved lymph nodes in laparoscopic colorectal surgery for cancer on node-negative patients' survival. METHODS: Evaluation of our prospective in-hospital collected data of patients that underwent laparoscopic surgery for curable colorectal cancer over a 5-year period. Long-term data were collected from our outpatient's clinic data and personal contact when necessary. RESULTS: During a 5-year period since September 2003,173 patients were operated laparoscopically for curable colorectal cancer. Of the 117 patients who were node negative, 85 node-negative patients (72%) had 12 or more evaluated lymph nodes (mean, 18.3 + 2.4), while 32 node-negative patients had less than 12 (mean, 8.3 + 6.2). Patients with fewer than 12 nodes evaluated had significantly more left-sided tumors, while patients with 12 nodes or more had more right-sided tumors. A comparison of 5-year disease free and overall Kaplan-Meier survival curves revealed no statistically significant difference between the two groups. CONCLUSIONS: Evaluation of less than 12 nodes may not necessarily impact patients' survival in node-negative patients undergoing laparoscopic resection for curable colorectal cancer. A lower number of nodes may be sufficient.

A randomized phase III study comparing adjuvant 5-fluorouracil/folinic acid with FOLFIRI in patients following complete resection of liver metastases from colorectal cancer.

BACKGROUND: Studies indicate that adjuvant 5-fluorouracil (5-FU) with folinic acid (FA) in colorectal cancer patients with completely resectable liver-limited metastases (LMCRC) offers clinical benefit over surgery alone. This phase III trial compared FOLFIRI with simplified 5-FU/FA in this setting. PATIENTS AND METHODS: LMCRC patients were randomized to receive every 14 days, FA, 400 mg/m2 infused over 2 h, followed by 5-FU as a 400 mg/m2 i.v. bolus, followed by continuous 5-FU infusion, 2400 mg/m2 over 46 h (LV5FUs) with or without irinotecan: 180 mg/m2 infusion (FOLFIRI). The primary end point was disease-free survival (DFS); secondary end points included overall survival (OS) and safety. RESULTS: Treated patients (n = 306) were balanced for critical prognostic factors in each arm. Median DFS in patients receiving LV5FUs was 21.6 versus 24.7 months for FOLFIRI [hazard ratio (HR) 0.89, log-rank P = 0.44]. No significant differences were found in OS. A trend was observed for improved DFS in patients receiving FOLFIRI within 42 days of surgery (HR 0.75, P = 0.17). Grade 3/4 toxic effects were more common in patients treated with FOLFIRI versus LV5FUs (47% versus 30%) with neutropenia being most common (23% versus 7%). CONCLUSION: FOLFIRI in the adjuvant treatment of LMCRC showed no significant improvement in DFS compared with LV5FUs.