Primary tumor resection for asymptomatic colorectal cancer patients with synchronous unresectable metastases: a meta-analysis of randomized controlled trials and case-matched studies.

PURPOSE: The value of upfront primary tumor resection (PTR) for asymptomatic unresectable metastatic colorectal cancer (mCRC) patients remains contentious. This meta-analysis aimed to assess the prognostic significance of upfront PTR for asymptomatic unresectable mCRC. METHODS: A systematic literature search was performed on June 21st, 2024. To minimize the bias and ensure robust evidence, only randomized controlled trials (RCTs) and case-matched studies (CMS) that compared PTR followed by chemotherapy to chemotherapy alone were included. The primary outcome was overall survival (OS), while cancer-specific survival (CSS) served as the secondary outcome. RESULTS: Eight studies (three RCTs and five CMS) involving 1221 patients were included. Compared to chemotherapy alone, upfront PTR followed by chemotherapy did not improve OS (hazard ratios [HR] 0.91, 95% confidence interval [CI] 0.79-1.04, P = 0.17), but was associated with slightly better CSS (HR 0.59, 95% CI 0.40-0.88, P = 0.009). CONCLUSIONS: The current limited evidence indicates that upfront PTR does not improve OS but may enhance CSS in asymptomatic unresectable mCRC patients. Ongoing trials are expected to provide more reliable evidence on this issue.

Appraising non-linear association between pre-diagnostic platelet counts and cancer survival outcomes: observational and genetic analysis.

Previous studies have reported inconsistent associations between platelet count (PLT) and cancer survival. However, whether there is linear causal effect merits in-depth investigations. We conducted a cohort study using the UK Biobank and a two-sample Mendelian randomization (MR) analysis. PLT levels were measured prior to cancer diagnosis. We adopted overall survival (OS) as the primary outcome. Cox models were utilized to estimate the effects of PLTs on survival outcomes at multiple lag times for cancer diagnosis. We employed 34 genetic variants as PLT proxies for MR analysis. Linear and non-linear effects were modeled. Prognostic effects of gene expression harboring the instrumental variants were also investigated. A total of 65 471 cancer patients were included. We identified a significant association between elevated PLTs (per 100 × 109/L) and inferior OS (HR: 1.07; 95% CI: 1.04-1.10; p < .001). Similar significant associations were observed for several cancer types. We further observed a U-shaped relationship between PLTs and cancer survival (p < .001). Our MR analysis found null evidence to support a causal association between PLTs and overall cancer survival (HR: 1.000; 95% CI: 0.998-1.001; p = .678), although non-linear MR analysis unveiled a potential greater detrimental effect at lower PLT range. Expression of eleven PLT-related genes were associated with cancer survival. Early detection of escalated PLTs indicated possible occult cancer development and inferior subsequent survival outcomes. The observed associations could potentially be non-linear. However, PLT is less likely to be a promising therapeutic target.

What is the context? Previous studies have reported inconsistent associations between platelet counts (PLTs) and cancer survival. However, it is unclear whether there is a linear causal effect, as most studies measured PLTs at the time of cancer diagnosis, which could be influenced by the cancer itself.This study aimed to investigate the association and potential causality between pre-diagnostic PLTs and cancer survival outcomes using a large prospective cohort and genetic analysis.What is new? The observational cohort study found a significant association between elevated pre-diagnostic PLTs and poorer overall and cancer-specific survival. We also identified a U-shaped relationship between PLTs and cancer survival, suggesting that both high and low PLTs may be detrimental.The Mendelian randomization analysis did not support a causal effect of PLTs on overall cancer survival, although it hinted at potential non-linear effects at lower PLT ranges.The study also identified several genes (TPM4, PDIA5, PSMD13, TMCC2, ZFPM2, BAZ2A, CDKN2A, GP1BA, TAOK1, CABLES1, and THPO) related to PLTs that were associated with cancer survival.What is the impact? The findings suggest that early detection of elevated PLTs may indicate occult cancer development and poorer subsequent survival outcomes. However, PLTs are less likely to be a promising therapeutic target for improving cancer survival, as the observed associations could be influenced by confounding factors.The study highlights the need for further research into the complex relationship between PLTs and cancer prognosis, as well as the exploration of other platelet-related traits as potential drug targets.

Total neoadjuvant therapy for locally advanced rectal cancer: a three-group propensity score matched study.

PURPOSE: Total neoadjuvant therapy (TNT) has emerged as a therapeutic approach for locally advanced rectal cancer (LARC). However, the optimal chemotherapy cycles within TNT remain uncertain. This study aimed to evaluate and compare the prognostic efficacy of varying cycles of chemotherapy during TNT for LARC. METHODS: Patients diagnosed with LARC (T3-4N0M0/T1-4N1-2M0), who underwent TNT or chemoradiotherapy followed by total mesorectal excision (TME) between 2015 and 2020, were retrospective included. Patients were categorized into three groups based on their neoadjuvant strategy: CRT (long-course chemoradiotherapy), STNT (long-course CRT with one to three cycles of chemotherapy), and LTNT (long-course CRT with four or more cycles of chemotherapy). Propensity score matching (PSM) based on gender, age, body mass index, tumor distance from the anal verge, clinical T stage, clinical N stage, and mesorectal fascia status was employed to reduce confounding bias. Primary endpoints were disease-free survival (DFS) and metastasis-free survival (MFS). RESULTS: The study comprised 372 patients, with 73 patients in each group after PSM. Compared with CRT, both STNT and LTNT demonstrated improved DFS (5-year rate: 59.7% vs. 77.8% vs. 76.5%, p = 0.027) and MFS (5-year rate: 65.1% vs. 81.3% vs. 81.4%, p = 0.030). There was no difference in DFS or MFS between STNT and LTNT. These favorable outcomes were consistent among subgroups defined by tumor distance from the anal verge ≥ 5 cm, clinical T3 stage, clinical N positive status, or involved mesorectal fascia. CONCLUSION: Compared to CRT, both STNT and LTNT demonstrated improved DFS and MFS outcomes. Notably, survival outcomes were similar between STNT and LTNT, suggesting that chemotherapy cycles in TNT may not significantly impact survival.

Primary Surgery Followed by Selective Chemoradiotherapy Versus Preoperative Chemoradiotherapy Followed by Surgery for Locally Advanced Rectal Cancer: A Randomized Clinical Trial.

PURPOSE: The aim of this work was to determine whether locally advanced rectal cancer (LARC) with negative mesorectal fascia (MRF) predicted by magnetic resonance imaging (MRI) can be excluded from preoperative radiation therapy treatment. METHODS AND MATERIALS: This multicenter, open-label, non-inferiority, randomized clinical trial enrolled patients with LARC within 6 to 12 cm from the anal verge and with negative MRI-predicted MRF. Participants were randomized to the intervention group (primary surgery, in which the patients with positive pathologic [CRM] circumferential margins were subjected to chemoradiotherapy [CRT] and those with negative CRM underwent adjuvant chemotherapy according to pathologic staging) or the control group (preoperative CRT, in which all patients underwent subsequent surgery and adjuvant chemotherapy). The primary endpoint was 3-year disease-free survival (DFS). RESULTS: A total of 275 patients were randomly assigned to the intervention (n = 140) and control (n = 135) groups, in which 33.57% and 28.15% patients were at clinical T4 stage and 85.92% and 80.45% patients were at "bad" or "ugly" risk in the intervention and control groups, respectively. There were 2 patients (1.52%) and 1 patient (0.77%) with positive CRM in the intervention and control groups, respectively (P > .05). The non-adherence rates for the intervention and control groups were 3.6% and 23.7%, respectively. After a median follow-up of 34.6 months (IQR, 18.2-45.7), 43 patients had positive events (28 patients and 15 patients in the intervention and control groups, respectively). There were 6 patients (4.4%) with local recurrence in the intervention group and none in the control group, which led to the termination of the trial. The 3-year DFS rate was 81.82% in the intervention group (95% CI, 78.18%-85.46%) and 85.37% in the control group (95% CI, 81.75%-88.99%), with a difference of -3.55% (95% CI, -3.71% to -3.39%; hazard ratio, 1.76; 95% CI, 0.94-3.30). In the per-protocol data set, the difference between 3-year DFS rates was -5.44% (95% CI, -5.63% to -5.25%; hazard ratio, 2.02; 95% CI, 1.01-4.06). CONCLUSIONS: Based on the outcomes of this trial, in patients with LARC and MRI-negative MRF, primary surgery could negatively influence their DFS rates. Therefore, primary surgery was an inferior strategy compared with preoperative CRT followed by surgery and cannot be recommended for patients with LARC.