Significance of HPV16 Viral Load Testing in Anal Cancer

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.

Development of a touchdown droplet digital PCR assay for the detection and quantitation of human papillomavirus 16 and 18 from self-collected anal samples

IMPORTANCE

The quantity of the human papillomavirus (HPV) is associated with disease outcome. We designed an accurate and precise digital PCR assay for quantitating HPV in anal samples, a sample type that is typically problematic due to the presence of PCR inhibitors.

Evaluation of the validity of the HPV viral load compared to conventional techniques for the detection of high-grade anal intraepithelial lesions in men with HIV who have sex with men

Background

The incidence of high-grade anal intraepithelial lesions (HSILs) has increased in recent years among men who have sex with men with human immunodeficiency virus (HIV). This work evaluated the validity of the human papilloma virus viral load (HPV-VL) versus cytological and qualitative HPV results to detect HSILs.

Methods

From May 2017 to January 2020, 93 men who have sex with men and HIV were included in an anal cancer screening program from the Infectious Diseases Unit at a tertiary-care hospital in Alicante (Spain). The gold-standard for the screening of anal HSILs is the anal biopsy using high-resolution anoscopy. The diagnostic methods compared against gold-standard were HPV-16-VL, HPV-18-VL, and HPV-16-18-VL co-testing, anal cytology, and qualitative HPV detection. The receiver operating characteristic (ROC) curve and cut-off points for HPV-VL were calculated. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Cohen's Kappa coefficient (κ) were also calculated.

Results

The mean patient age was 44.6 ± 9.5 years. All of them received antiretroviral treatment, 96.8% had an HIV viral load of <50 copies/mL and 17.2% had a previous diagnosis of AIDS. The diagnosis of the anal biopsies were: 19.4% (n = 18) HSIL, 29.1% (n = 27) LSIL, and 51.6% (n = 48) negative. An HPV-16-VL >6.2 copies/cell was detected in the HSIL biopsy samples (p = 0.007), showing a sensitivity of 100% and a specificity of 46.2%. HPV-18-VL and HPV16-18-VL co-testing showed a sensitivity of 75% and 76.9% and a specificity of 72.7% and 61.3%, respectively. The highest PPV was 50% obtained with the cytology and HPV-18-VL. The HPV-16-VL showed a NPV of 100%, followed by 88.9% in the HPV-18-VL and 87% in the abnormal cytology. Cohen's Kappa coefficient were: HPV-18-VL (κ = 0.412), abnormal cytology (κ = 0.353) and HPV-16-VL (κ = 0.338).

Conclusions

HPV-VL testing improved the detection sensitivity but not the specificity for HSIL biopsies compared to anal cytology and the qualitative detection of HPV. In men who have sex with men and HIV the HPV-VL could be an useful tool for diagnosis of HSILs in anal cancer screening programs. Further studies will be needed to evaluate the clinical implications of HPV-VL in these programs.

Circulating HPV16 DNA in Blood Plasma as Prognosticator and Early Indicator of Cancer Recurrence in Radio-Chemotherapy for Anal Cancer

BACKGROUND

Implementation of anal squamous cell carcinoma (ASCC) treatment modifications requires reliable patient risk stratification. The circulating tumor-related human papillomavirus type 16 (ctHPV16) may play a role in predicting survival or assessing treatment response.

METHODS

The study included 62 ASCC patients treated with chemoradiotherapy. A threshold of 2.5 was used to determine the maximum standardized uptake value (SUVmax). The ctHPV16 viral load (VL) was quantified by qPCR.

RESULTS

In the multivariate Cox analysis, lower SUVmax (p = 0.047) and ctHPV16-positive (p = 0.054) proved to be independent prognostic factors for favorable overall survival (OS). In the subgroup with the higher SUVmax, ctHPV16 and nodal (N) status were independent prognostic factors with p = 0.022 for ctHPV16 and p = 0.053 for N. The best survival rate (95%) presented ctHPV16-positive/N-negative patients. High ctHPV16 VL tended to be slightly specific for patients younger than 63 years (p = 0.152). The decrease in ctHPV16 VL to undetectable level after the end of treatment correlated with the overall clinical response.

CONCLUSIONS

A prognostic stratification by SUVmax, ctHPV16 and N-positive status allows consideration of more aggressive treatment in high-risk patients (those with high SUVmax, ctHPV16-negative, and N-positive) or de-intensification of therapy in low-risk patients (those with low SUVmax, ctHPV16-positive and N-negative). However, prospective clinical trials on a large group are needed.

Screening Women for Anal Cancers: Guidance for Health Care Professionals

Anal cancer is rare in the general population but is steadily increasing in incidence over the past decade especially in women. Identification and screening of women with high risk facilitates detection of anal precancer and early-stage cancer, improves survival, and potentially uses less invasive therapies compared with the conventional chemoradiation treatments used for advanced cancers. No recently published guidelines currently describe details about screening women for anal squamous cell cancer (ASCC). The available evidence supports the existence of groups of women with higher prevalence of ASCC (e.g., women with human immunodeficiency virus, immune suppression, or previous lower-genital high-grade lesion or cancer) who would likely benefit from screening with some combination of anal cytology and human papillomavirus testing. Additional research is needed to establish the cost-effectiveness and the influence of screening on ASCC mortality rates.

Viruses in Cancers of the Digestive System: Active Contributors or Idle Bystanders?

The human virome, which is a collection of all the viruses that are present in the human body, is increasingly being recognized as an essential part of the human microbiota. The human gastrointestinal tract and related organs (e.g., liver, pancreas, and gallbladder)-composing the gastrointestinal (or digestive) system-contain a huge number of viral particles which contribute to maintaining tissue homeostasis and keeping our body healthy. However, perturbations of the virome steady-state may, both directly and indirectly, ignite/sustain oncogenic mechanisms contributing to the initiation of a dysplastic process and/or cancer progression. In this review, we summarize and discuss the available evidence on the association and role of viruses in the development of cancers of the digestive system.