Clinical significance of RBM3 expression in surgically treated colorectal lung metastases and paired primary tumors

Effect of perioperative chemotherapy on resection of isolated pulmonary metastases from colorectal cancer: A single center experience

BACKGROUND

Numerous studies have assessed surgical resection as a standard treatment option for patients with colorectal cancer (CRC) and resectable pulmonary metastases (PM). However, the role of perioperative chemotherapy after complete resection of isolated PM from patients with CRC patients remains controversial. We hypothesize that perioperative chemotherapy does not provide significant survival benefits for patients undergoing resection of PM from CRC.

AIM

To determine whether perioperative chemotherapy affects survival after radical resection of isolated PM from CRC.

METHODS

We retrospectively collected demographic, clinical, and pathologic data on patients who underwent radical surgery for isolated PM from CRC. Cancer-specific survival (CSS) and disease-free survival were calculated using Kaplan-Meier analysis. Inter-group differences were compared using the log-rank test. For multivariate analysis, Cox regression was utilized when indicated.

RESULTS

This study included 120 patients with a median age of 61.6 years. The 5-year CSS rate was 78.2%, with 36.7% experiencing recurrence. Surgical resection for isolated PM resulted in a 5-year CSS rate of 50.0% for second metastases. Perioperative chemotherapy (P = 0.079) did not enhance survival post-resection. Factors associated with improved survival included fewer metastatic lesions [hazard ratio (HR): 2.51, P = 0.045], longer disease-free intervals (HR: 0.35, P = 0.016), and wedge lung resections (HR: 0.42, P = 0.035). Multiple PM predicted higher recurrence risk (HR: 2.22, P = 0.022). The log-rank test showed no significant difference in CSS between single and repeated metastasectomy (P = 0.92).

CONCLUSION

Perioperative chemotherapy shows no survival benefit post-PM resection in CRC. Disease-free intervals and fewer metastatic lesions predict better survival. Repeated metastasectomy is warranted for eligible patients.

Preoperative prognostic factors for 5-year survival following pulmonary metastasectomy from colorectal cancer: a systematic review and meta-analysis

OBJECTIVES

We seek to identify preoperative prognostic factors and measure their effect on 5-year survival following pulmonary metastasectomy (PM) for Colorectal Cancer (CRC).

METHODS

We systematically reviewed the databases of Cochrane Library, MEDLINE, Embase and Google Scholar from January 2000 to April 2021 to identify preoperative factors that have been investigated for their prognostic effect on survival following PM. Quality assessment was performed using the QUIPS tool. The prognostic effect of each identified factor on 5-year survival post-PM was estimated using random-effects meta-analyses.

RESULTS

We identified 115 eligible articles which included 13 294 patients who underwent PM from CRC. The overall 5-year survival after resection of the lung metastasis was 54.1%. The risk of bias of the included studies was at least moderate in 93% (107/115). Seventy-seven preoperative factors had been investigated for their prognostic effect. Our analysis showed that 11 factors had favourable and statistically significant prognostic effect on 5-year survival post-PM. These included solitary metastasis, size <2 cm, unilateral location, N0 thoracic disease, no history of extra-thoracic or liver metastasis, normal carcinoembryonic antigen levels both before PM and CRC excision, no neo-adjuvant chemotherapy before PM, CRC T-stage < T4 and no p53 mutations on CRC. Disease-free interval at 24 months did not appear to affect 5-year survival.

CONCLUSIONS

Despite the considerable risk of bias in the literature, our study consolidates the available evidence on preoperative prognostic factors for PM from CRC. These findings can complement both clinical practice and the design of future research on the field of PM.

Pulmonary Metastasectomy in Colorectal Cancer (PulMiCC) randomised controlled trial: a systematic review of published responses

OBJECTIVES

The objective of this review was to assess the nature and tone of the published responses to the Pulmonary Metastasectomy in Colorectal Cancer (PulMiCC) randomized controlled trial.

METHODS

Published articles that cited the PulMiCC trial were identified from Clarivate Web of Science (©. Duplicates and self-citations were excluded and relevant text extracted. Four independent researchers rated the extracts independently using agreed scales for the representativeness of trial data and the textual tone. The ratings were aggregated and summarized. Two PulMiCC authors carried out a thematic analysis of the extracts.

RESULTS

Sixty-four citations were identified and relevant text was extracted and examined. The consensus rating for data inclusion was a median of 0.25 out of 6 (range 0 to 5.25, IQR 0-1.5) and for textual tone the median rating was 1.87 out of 6 (range 0 to 5.75, IQR 1-3.5). The majority of citations did not provide adequate representation of the PulMiCC data and the overall the textual tone was dismissive. Although some were supportive, many discounted the findings because the trial closed early and was underpowered to show non-inferiority. Two misinterpreted the authors' conclusions but there was acceptance that five-year survival was much higher than widely assumed.

CONCLUSIONS

Published comments reveal a widespread reluctance to consider seriously the results of a carefully conducted randomized trial. This may be because the results challenge accepted practice because of 'motivated reasoning'. But there is a widespread misunderstanding of the fact that though PulMiCC with 93 patients was underpowered to test non-inferiority, it still provides reliable evidence to undermine the widespread belief in a major survival benefit from metastasectomy.

Delineating the intra-patient heterogeneity of molecular alterations in treatment-naïve colorectal cancer with peritoneal carcinomatosis

In a non-negligible number of patients with metastatic colorectal cancer (mCRC), the peritoneum is the predominant site of dissemination. Cure can be achieved by cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), but this procedure is associated with long-term morbidity and high relapse rates. Thus, there is a pressing need for improved therapeutic strategies and complementary biomarkers. The present study explored the molecular heterogeneity in mCRC with peritoneal carcinomatosis (PC), and the potential clinical implications thereof. Multi-region immunohistochemical profiling and deep targeted DNA-sequencing was performed on chemotherapy-naïve tumours from seven patients with synchronous colorectal PC who underwent CRS and HIPEC. In total, 88 samples (5-19 per patient) were analysed, representing primary tumour, lymph node metastases, tumour deposits, PC and liver metastases. Expression of special AT-rich sequence-binding protein 2 (SATB2), a marker of colorectal lineage, was lacking in the majority of cases, and a conspicuous intra-patient heterogeneity was denoted for expression of the proposed prognostic and predictive biomarker RNA-binding motif protein 3 (RBM3). Loss of mismatch repair proteins MLH1 and PSM2, observed in one case, was concordant with microsatellite instability and the highest tumour mutational burden. When present in a patient, mutations in key CRC driver genes, i.e., KRAS, APC and TP53, were homogenously distributed across all samples, while less common mutations were more heterogenous. On the same note, copy number variations showed intra-patient as well inter-patient heterogeneity. In two out of seven cases, hierarchical clustering revealed that samples from the PC and lymph node metastases were more similar to each other than to the primary tumour. In summary, these findings should encourage additional studies addressing the potential distinctiveness of mCRC with PC, which might pave the way for improved personalized treatment of these patients.