Novel Application of Iterative Hyperthermic Intraperitoneal Chemotherapy for Unresectable Peritoneal Metastases from High-Grade Appendiceal Ex-Goblet Adenocarcinoma

Mutational Features and Tumor Microenvironment Alterations in High-Grade Appendiceal Cancers Treated With Iterative Hyperthermic Intraperitoneal Chemotherapy

PURPOSE

High-grade appendiceal adenocarcinomas (HGAA) with peritoneal metastases (PMs) are associated with poor survival. Hyperthermic intraperitoneal chemotherapy (HIPEC) is a novel treatment approach for unresectable HGAA-PM. However, its influence on immunogenomic profiles has not yet been fully explored.

MATERIALS AND METHODS

We obtained 79 samples of metastatic peritoneal tumor deposits from patients diagnosed with HGAA and performed whole-exome sequencing, RNA sequencing, and immunoprofiling before and after HIPEC. Tumor biopsies were subjected to immunogenomic profiling to detect mutational signatures and immune populations associated with oncologic outcomes.

RESULTS

Fifteen patients with HGAA-PMs were included in the study. The median progression-free survival (PFS) was 6.7 months (2.7-25.3) and the median overall survival was 11.4 months (4.7-42). Mucin-associated genes (MUC16, MUC3A, and MUC5AC) and titin (TTN) had the highest mutation frequencies. Mutational signatures such as single-base substitution 29 and doublet-base substitution 11 were present in >50% of single-base and double-base mutations. Higher PD-L1 coexpression on CD8+ T cells demonstrated a higher PFS both intratumorally (P = .019) and at the margin (P = .025).

CONCLUSION

HIPEC-associated mutational signatures were identified in HGAA-PMs. Elevated PD-L1+ cytotoxic T-cell populations after HIPEC had better PFS, offering valuable insights for prognostication in the context of HIPEC treatment.

PI3K Pathway Alterations in Peritoneal Metastases are Associated with Earlier Recurrence in Patients with Colorectal Cancer Undergoing Optimal Cytoreductive Surgery

BACKGROUND

Colorectal cancer with peritoneal metastasis (CRC-PM) represents a biologically heterogeneous disease; yet little is known regarding the impact of tumor biology on survival outcomes following optimal cytoreductive surgery (CRS). We analyzed the frequency of alterations in cancer signaling pathways in patients with CRC-PM and their impact on recurrence-free survival (RFS) following optimal CRS.

METHODS

Thirty-five consecutive CRC-PM patients who underwent optimal CRS/HIPEC and next generation sequencing of peritoneal metastases were included in the study. Alterations in eight cancer-related signaling pathways were analyzed: Wnt/APC, p53, RTK-RAS, PI3K, TGF-B, Notch, Myc, and cell cycle. The association of pathway alterations with RFS and OS following optimal cytoreduction was estimated using Cox proportional hazard modeling.

RESULTS

The most frequently altered pathways were Wnt/APC (63%), p53 (63%), RTK-RAS (60%), and PI3K (23%). Among optimally cytoreduced patients with CRC-PM, PI3K pathway alterations were an independent predictor of worse RFS (hazard ratio 3.2, 95% confidence interval CI 1.3-8.3, p = 0.01) with a clinically meaningful impact on median months to recurrence (5 vs. 13 months, p = 0.02). Alterations in p53, Wnt, and RTK-RAS pathways were not significantly associated with a difference in RFS following CRS. Alterations in the four pathways were not associated with differences in OS following CRS (median OS was 50 (interquartile range 23-80) months).

CONCLUSIONS

In patients with CRC-PM, PI3K pathway alterations are associated with earlier recurrence following optimal CRS, which may represent a distinct molecular subtype. This novel finding can tailor clinical trials by using PIK3CA-directed interventions to reduce risk of recurrence after optimal CRS.

Goblet Cell Adenocarcinoma of the Appendix: A Systematic Review and Incidence and Survival of 1,225 Cases From an English Cancer Registry

Background

Goblet cell adenocarcinoma (GCA) of the appendix is a rare and aggressive tumour with varying nomenclature and classification systems. This has led to heterogeneity in published data, and there is a lack of consensus on incidence, survival, and management.

Methods

We provide an overview of GCA with a comprehensive systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology and a retrospective analysis of all cases recorded in the English National Cancer Registration and Analysis Service database between 1995 and 2018. The Kaplan–Meier estimator was used to calculate overall survival, and Cox proportional hazards regression was used to identify prognostic factors.

Results

The systematic review demonstrated an incidence of 0.05–0.3 per 100,000 per year among North American registry studies. The 1-, 3-, and 5-year survival rate was 95.5%, 85.9%–87.6%, and 76.0%–80.6%, respectively. Age, stage, and grade were identified as prognostic factors for survival. Our analysis included 1,225 cases. Age-standardised incidence was 0.0335 per year in 1995 and gradually rose to 0.158 per year in 2018. The 1-, 3-, and 5-year survival rate was 90.0% [95% confidence interval (95% CI): 85.4–94.0], 76.0% (95% CI: 73.8–80.9), and 68.6% (95% CI: 65.9–72.2), respectively. On univariate Cox regression analyses, female sex, stage, and grade were associated with worse overall survival. On multivariate analysis, only stage remained a statistically significant prognostic factor.

Conclusions

GCA of the appendix is rare, but incidence is increasing. We report a lower incidence and survival than North American registry studies. Higher stage was associated with decreased survival. Further prospective studies are required to establish optimal management.

Direct Comparison of In-Person Versus Virtual Interviews for Complex General Surgical Oncology Fellowship in the COVID-19 Era

BACKGROUND

In the era of coronavirus disease 2019 (COVID-19), many Complex General Surgical Oncology (CGSO) fellowship programs implemented virtual interviews (VI) during the 2020 interview season. At our institution, we had the unique opportunity to conduct an in-person interview (IPI) prior to the pandemic-related travel restrictions, and a VI after the restrictions were in place.

OBJECTIVE

The goal of this study was to understand how the VI model compares with the traditional IPI approach.

METHODS

Online surveys were distributed to both groups, collecting feedback on their interview experience. Responses were evaluated using a two-sample t test assuming equal variances.

RESULTS

Twenty-three of 26 (88%) applicants completed the survey. Most applicants reported that the interview gave them a satisfactory understanding of the CGSO fellowship (100% IPI, 92% VI) and the majority in both groups felt that the interview experience allowed them to accurately represent themselves (92% and 82%, respectively). All participants in the IPI group felt they were able to get an adequate understanding of the culture of the program, while only 64% in the VI group agreed with that statement (p = 0.02). IPI applicants were more likely to agree that the interview experience was sufficient to allow them to make a ranking decision (92% vs. 54%; p = 0.04).

CONCLUSIONS

While the VI modality offers several advantages over the IPI, it still falls short in conveying some of the more subjective aspects of the programs, including program culture. Strategies to provide applicants with better insight into these areas during the VI will be important moving forward.