Extensive molecular profiling of squamous cell anal carcinoma in a phase 2 trial population: Translational analyses of the "CARACAS" study

Emerging advances and future opportunities in the molecular and therapeutic landscape of anal cancer

Anal squamous cell carcinoma (ASCC) is a rare malignancy with an increasing incidence. Primary chemoradiotherapy (CRT) is the standard-of-care treatment for patients with localized ASCC. In the metastatic setting, trials testing immune-checkpoint inhibitor monotherapy have demonstrated outcomes similar to those of patients receiving chemotherapy. Conversely, adding the anti-PD-1 antibody retifanlimab to chemotherapy in patients with recurrent or metastatic ASCC has been shown to significantly improve outcomes. Despite considerable efforts to develop personalized therapy, treatment guidance and prognosis remain reliant on baseline clinical characteristics. An improved understanding of the molecular characteristics of ASCC has provided insights into the mechanisms that mediate tumour progression and response to CRT. For example, human papillomavirus (HPV) infection is known to have an aetiological role in most ASCCs and can modulate cellular responses to CRT via several distinct mechanisms. In this Review, we summarize emerging advances in the molecular and therapeutic landscape of ASCC, including the implementation of biomarkers for treatment guidance and translation into new therapeutic approaches, with HPV infection constituting a global determinant of both tumour biology and clinical outcome. We also discuss the rationale for combining immune-checkpoint inhibitors with CRT in patients with HPV+ tumours.

Clinical characteristics and treatment outcome in p16 negative anal cancer

BACKGROUND

Anal squamous cell carcinoma (ASCC) is linked to human papillomavirus infection with p16 being positive in about 85% of cases. Overall survival (OS) of ASCC is 60%-80%. Prognosis in p16 negative (p16-) ASCC is worse with an OS of 30%-60%. It is important to elucidate differences in p16+ and p16- ASCC characteristics and outcome.

METHODS

Consecutive ASCC patients (n = 380) treated with curative intent in Uppsala 2017-2022 were reviewed and analyzed retrospectively. A cohort of p16- patients (n = 30) from Gothenburg was included as a validation cohort.

RESULTS

Ninety-one per cent (n = 347) were p16+ and 9% (n = 33) p16-. Median follow-up was 33 months (range 4-78). p16- status was associated with higher age (≥65 years; p = 0.03), comorbidity (p = 0.03), male sex (p = 0.001) and perianal localization (p < 0.001). At 3 years progression free survival was 50% and 81% (p <0.0001) and OS 60% and 89% (p < 0.0001) for p16- and p16+ patients, respectively. Male sex, advanced T-stage (T3-4), N+ disease, advance treatment and p16- status were associated with inferior OS (p = 0.01 - p < 0.0001). In the p16- subgroup, advanced T-stage and intensive treatment were negative prognostic factors for OS (p = 0.007 and 0.009, respectively) but no clinical characteristic predicted persistent disease. The p16- validation cohort essentially confirmed the findings from the main cohort.

INTERPRETATION

p16- ASCC is a disease subset with specific clinical features and poor prognosis in need of improved treatment.

Prognostic value of PD-L1 expression in patients with anal cancer: a meta-analysis

Background: The present meta-analysis was performed to evaluate the prognostic and clinicopathological significance of PD-L1 in anal cancer (AC). Methods: Hazard ratios (HRs) and 95% CIs regarding overall survival (OS) and progression-free survival (PFS) were calculated based on PD-L1 levels. Results: According to the combined data, PD-L1 showed no significant relationship with OS (HR = 0.76; 95% CI = 0.35-1.67; p = 0.502) or PFS (HR = 0.88; 95% CI = 0.35-2.33; p = 0.789) in patients with AC. Based on subgroup analysis, PD-L1 overexpression significantly predicted prolonged OS (HR = 0.38; 95% CI = 0.17-0.84; p = 0.017) in tumor node metastasis stages I-III and inferior PFS (HR = 2.73; 95% CI = 1.32-5.65; p = 0.007) in patients with stage I-IV AC. Conclusion: PD-L1 level assessed by immunohistochemistry did not significantly predict survival outcomes in AC cases.

Unraveling Emerging Anal Cancer Clinical Biomarkers from Current Immuno-Oncogenomics Advances

Anal squamous cell carcinoma (ASCC) is a rare gastrointestinal malignancy associated with high-risk human papillomavirus (HPV) and is currently one of the fastest-growing causes of cancer incidence and mortality in developed countries. Although next-generation sequencing technologies (NGS) have revolutionized cancer and immuno-genomic research in various tumor types, a limited amount of clinical research has been developed to investigate the expression and the functional characterization of genomic data in ASCC. Herein, we comprehensively assess recent advancements in "omics" research, including a systematic analysis of genome-based studies, aiming to identify the most relevant ASCC cancer driver gene expressions and their associated signaling pathways. We also highlight the most significant biomarkers associated with anal cancer progression, gene expression of potential diagnostic biomarkers, expression of therapeutic drug targets, and emerging treatment opportunities. This review stresses the urgent need for developing target-specific therapies in ASCC. By illuminating the molecular characteristics and drug-target expression in ASCC, this study aims to provide insights for the development of precision medicine in anal cancer.

Recent Advances in the Management of Anal Cancer

The incidence and mortality of squamous cell carcinoma of the anus (SCCA) is on the rise, which highlights the unmet need for advances in treatment options. The landscape of treatment for this cancer is rapidly evolving with novel combination strategies including immunotherapy, radiation therapy and biomarker-guided therapy. This review article features an overview of recent advancements in both locoregional and metastatic SCCA. The recent focus on locoregional SCCA management is to tailor treatment according to tumor burden and minimize treatment-related toxicities. Mitomycin plus either infusional 5-fluorouracil (5-FU) or capecitabine is used for first-line chemoradiotherapy (CRT), and intensity-modulated radiotherapy (IMRT) is the preferred modality for radiation for locoregional anal cancer. Locally recurrent disease is managed with surgical resection. Systemic treatment is first-line for metastatic SCCA and immunotherapy with nivolumab and pembrolizumab being included as second-line agents. Current and future clinical trials are evaluating treatments for SCCA including immunotherapy alone or in combination regimens, radiotherapies, targeted treatments and novel agents. Another critical aspect of current research in SCCA is the personalization of CRT and immunotherapies based on molecular characterization and biomarkers such as the programmed death-ligand 1 (PD-L1), epidermal growth factor receptor (EGFR) and circulating tumor DNA.