Canadian Oncology Today

Treatment of dMMR Metastatic Colorectal Cancer in 2025

Renata D’Alpino Peixoto, MD, PhD, Thiago Miranda do Amaral, MD — Wed, 05 Nov 2025 00:00:00 +0000

Deficient mismatch repair (dMMR) or microsatellite instability-high (MSI-H) metastatic colorectal cancer (mCRC), accounting for approximately 4–5% of cases, represents a distinct molecular subgroup with unique therapeutic implications. These malignancies are characterized by a high mutational burden and increased immune cell infiltration, making them particularly responsive to immune checkpoint inhibitors (ICI). Conversely, this subgroup tends to be less sensitive to traditional chemotherapy.

First-line Treatment Selection for Advanced Unresectable Biliary Tract Cancer

Arwa Ahmed Abdelrahim, MD, Rachel Goodwin, MD — Wed, 05 Nov 2025 00:00:00 +0000

Biliary tract cancer (BTC) comprises a group of heterogenous malignancies that arise from the bile ducts (intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma) and the gallbladder (gallbladder cancer). Collectively, these malignancies carry a poor prognosis, which is attributed to the advanced stage at presentation. Historically, advanced BTC had a reputation of being less responsive to chemotherapy, a theory that was changed in the last decade, likely due to improved biliary drainage techniques that consequently improve liver function. Few advances have been made in the treatment of advanced and unresectable BTC in the past couple of years.

Original Research: Biomarker Testing in a Canadian Centre for Patients with Non‑small Cell Lung Cancer: Assessing Residual Risks

Wed, 05 Nov 2025 00:00:00 +0000

Biomarker testing is critical for guiding treatment decisions and clinical management in patients with non-small cell lung cancer (NSCLC). Although the clinical utility of comprehensive testing for point mutations and gene rearrangements is well established, access to next-generation sequencing (NGS)‑based assays in Ontario has historically been limited due to provincial funding constraints.

We conducted a retrospective chart review of 215 patients diagnosed with lung adenocarcinoma over a five-year period (2016-2021) and report the observed biomarker testing practice. Testing primarily comprised polymerase chain reaction (PCR)-based detection of common epidermal growth factor receptor (EGFR) mutations and immunohistochemistry (IHC) for anaplastic lymphoma kinase (ALK) overexpression, with or without confirmatory fluorescence in situ hybridization (FISH), and programmed death-ligand 1 (PD-L1) IHC. IHC for ROS1 overexpression, as a surrogate for ROS1 fusion, was observed in the first quarter of 2020. Routine panel-based NGS testing was implemented in the first quarter of 2021. Noting the differences between PCR- and NGS-based EGFR assessment, risks of “false negative” were estimated based on Bayesian analyses. Given the limited scope of PCR tests in terms of variants detected, the post-test, residual risk of “false negative” EGFR was estimated to range ~1:90 in white, Caucasian patients, to ~1:9 in Asian patients.

We observed consistent implementation of EGFR, ALK, and PD-L1 testing during the study period, which was in alignment with 2017 National Comprehensive Cancer Network (NCCN) guideline recommendations. However, the delayed adoption of ROS1 testing and NGS-based profiling, including assays for MET and RET alterations, reflects broader limitations in provincial funding policy and highlights the need for equitable access to comprehensive biomarker testing in Ontario.

Current Issues in the Management of Sporadic Non-clear Cell Renal Cell Carcinoma (Non-ccRCC)

Mariam Jafri, MBChB (Hons), MRCP(UK), BMedSc, MSc, Ph.D — Wed, 05 Nov 2025 00:00:00 +0000

Renal cell carcinoma (RCC) is the 10^th most common cancer type in Canada. Numerous developments in the management of RCC over the last decade have led to improved outcomes, though these have mostly focused on the ~80% of patients with clear cell renal cell carcinoma (ccRCC). The remaining 20% of cases are labelled non-clear cell renal cell carcinoma (non‑ccRCC) and represent a biologically and clinically heterogeneous group of diseases that are rare entities. Historically, non-ccRCC has been managed similarly to clear cell tumours. Localized non-ccRCC has better outcomes than ccRCC; however, survival of metastatic non-ccRCC is inferior to ccRCC (median overall survival [OS] of metastatic non-ccRCC reported as 39.2 months compared to 81.1 months for ccRCC).

This has led to interest within the RCC scientific and patient communities to further improve outcomes for patients with non-ccRCC. This article describes the current management of patients with non-ccRCC and discusses future areas of interest in the field.