Clinicopathologic Features Associated With Human Papillomavirus/p16 in Patients With Metastatic Squamous Cell Carcinoma of the Anal Canal

Understanding the HPV associated cancers: A comprehensive review

Human papillomavirus (HPV), a common cause of sexually transmitted diseases, may cause warts and lead to various types of cancers, which makes it important to understand the risk factors associated with it. HPV is the leading risk factor and plays a crucial role in the progression of cervical cancer. Viral oncoproteins E6 and E7 play a pivotal role in this process. Beyond cervical cancer, HPV-associated cancers of the mouth and throat are also increasing. HPV can also contribute to other malignancies like penile, vulvar, and vaginal cancers. Emerging evidence links HPV to these cancers. Research on the oncogenic effect of HPV is still ongoing and explorations of screening techniques, vaccination, immunotherapy and targeted therapeutics are all in progress. The present review offers valuable insight into the current understanding of the role of HPV in cancer and its potential implications for treatment and prevention in the future.

POD1UM-303/InterAACT 2: A phase III, global, randomized, double-blind study of retifanlimab or placebo plus carboplatin–paclitaxel in patients with locally advanced or metastatic squamous cell anal carcinoma

Background

Squamous carcinoma of the anal canal (SCAC) is a human papillomavirus (HPV)-driven cancer with poor prognosis in locally advanced or recurrent settings. Carboplatin–paclitaxel is the preferred first-line regimen for unresectable locally advanced or metastatic SCAC, with the reported median progression-free survival (PFS) and overall survival (OS) of 8.1 and 20.0 months, respectively. Immune checkpoint blockade (ICB) demonstrates improved survival in HPV-driven cervical and head and neck cancers. Retifanlimab (INCMGA00012) is an investigational humanized, hinge-stabilized, immunoglobulin G4κ monoclonal antibody targeting programmed cell death-1 (PD-1), with characteristics common to the ICB class. In POD1UM-202, retifanlimab showed substantial clinical activity and an expected safety profile in patients with advanced SCAC who progressed on platinum-based chemotherapy. Based on these encouraging results, POD1UM-303/InterAACT 2 (NCT04472429), a phase III, double-blind, randomized, multiregional study, investigates the addition of retifanlimab to the standard of care (SOC) carboplatin–paclitaxel in patients with inoperable locally recurrent or metastatic SCAC not previously treated with systemic chemotherapy.

Methods and analysis

Patients ≥18 years with inoperable locally recurrent or metastatic SCAC, measurable disease per RECIST v1.1, and no prior systemic chemotherapy or PD-(L)1-directed therapy will be enrolled and stratified by PD-L1 expression, region, and extent of disease. Patients with well-controlled human immunodeficiency virus infection are eligible. Planned enrollment is approximately 300 patients worldwide, with a 1:1 randomization to retifanlimab or placebo. Patients will receive up to six induction cycles (24 weeks) of carboplatin (area-under-the-curve 5 on day 1) and paclitaxel (80 mg/m² on days 1, 8, and 15) every 28 days per SOC. Concurrently, retifanlimab 500 mg or placebo will be administered intravenously in a blinded fashion on day 1 of each 28-day cycle for up to 13 cycles (1 year) in the absence of unacceptable toxicity, disease progression, withdrawal of consent, loss to follow-up, or premature discontinuation. Crossover to open-label retifanlimab will be allowed for patients assigned to placebo upon verification of progression by blinded independent central radiographic review (BICR). The primary study endpoint is PFS per RECIST v1.1 by BICR. Secondary endpoints are OS, objective response rate, duration of response, disease control rate, safety, and retifanlimab pharmacokinetics. The study is currently recruiting.

Clinical Trial Registration

https://clinicaltrials.gov/ct2/show/NCT04472429; https://clinicaltrialsregister.eu/ctr-search/search?query=2020-000826-24

Sex-dependent development of Kras-induced anal squamous cell carcinoma in mice

Anal squamous cell carcinoma (SCC) will be diagnosed in an estimated 9,080 adults in the United States this year, and rates have been rising over the last several decades. Most people that develop anal SCC have associated human papillomavirus (HPV) infection (~85-95%), with approximately 5-15% of anal SCC cases occurring in HPV-negative patients from unknown etiology. This study identified and characterized the Kras-driven, female sex hormone-dependent development of anal squamous cell carcinoma (SCC) in the LSL-KrasG12D; Pdx1-Cre (KC) mouse model that is not dependent on papillomavirus infection. One hundred percent of female KC mice develop anal SCC, while no male KC mice develop tumors. Both male and female KC anal tissue express Pdx1 and Cre-recombinase mRNA, and the activated mutant KrasG12D gene. Although the driver gene mutation KrasG12D is present in anus of both sexes, only female KC mice develop Kras-mutant induced anal SCC. To understand the sex-dependent differences, KC male mice were castrated and KC female mice were ovariectomized. Castrated KC males displayed an unchanged phenotype with no anal tumor formation. In contrast, ovariectomized KC females demonstrated a marked reduction in anal SCC development, with only 15% developing anal SCC. Finally, exogenous administration of estrogen rescued the tumor development in ovariectomized KC female mice and induced tumor development in castrated KC males. These results confirm that the anal SCC is estrogen mediated. The delineation of the role of female sex hormones in mediating mutant Kras to drive anal SCC pathogenesis highlights a subtype of anal SCC that is independent of papillomavirus infection. These findings may have clinical applicability for the papillomavirus-negative subset of anal SCC patients that typically respond poorly to standard of care chemoradiation.

The impact of gender and HPV status on anal squamous cell carcinoma survival

BACKGROUND

Anal cancer is a rare entity and the effect of gender and HPV status on survival is controversial. We aimed to evaluate the difference in overall survival (OS) according to gender and analyzed the effect of HPV status on OS.

PATIENTS AND METHODS

The National Cancer Database (NCDB) was queried for patients with anal squamous cell carcinoma between 2004 and 2016. We evaluated the OS based on gender and HPV status using Kaplan-Meier estimates and we used multivariate Cox regression analyses to evaluate factors associated with overall survival.

RESULTS

A total of 6133 patients with known HPV status were included for analysis. In the non-metastatic group, male gender was associated with worse OS (HR 1.50, 95% CI 1.32-1.70; P<0.001) whereas HPV status did not affect the OS (HR 1.08, 95% CI 0.96-1.22; P=0.213). In the metastatic group, there was no difference in OS based on gender (HR 1.29, 95% CI 0.91-1.82; P=0.148), whereas HPV-negative status was associated with worse OS (HR 1.52, 95% CI 1.09-2.12; P=0.014).

CONCLUSION

Females had better OS only in non-metastatic anal squamous cell carcinoma (ASCC). HPV-negative status was associated with worse OS only in metastatic ASCC.

CEA as a blood-based biomarker in anal cancer

BACKGROUND

The clinical utility of a blood-based biomarker in squamous cell carcinoma of the anus (SCCA) is unknown. We analyzed carcinoembryonic antigen (CEA), a commonly employed assay for patients with colorectal adenocarcinoma, as a serum biomarker for patients with biopsy-proven SCCA.

MATERIALS AND METHODS

Medical records from 219 patients with biopsy-proven SCCA at the University of Texas MD Anderson Cancer Center were reviewed under an IRB-approved protocol from 2013 to 2020 to assess for correlations between CEA levels and corresponding clinical and pathologic characteristics.

RESULTS

The mean CEA among subgroups by clinical status at the time of presentation to our institution was highest among those patients with metastatic SCCA to visceral organs (M-V, 20.7 ng/mL), however this finding was not statistically significant by ANOVA (p = .74). By clinical subgroup, the percentage of patients with an abnormally elevated CEA was highest in those patients with metastatic disease to lymph nodes (M-L, 41.2%) followed by recurrent/unresectable SCCA (36.8%), and metastatic SCCA to visceral organs (M-V, 35.2%), and was statistically significant between groups (Fisher's exact test p = .02). Using RECIST criteria for tumor progression and disease response, the mean change in CEA for patients with progression was an increase in 19 ng/mL, compared to a change of -7.3 ng/mL in those with disease response (p = .004). We likewise assessed whether CEA levels were associated with survival outcomes for all patients with metastatic SCCA, and found no correlation between CEA and likelihood for survival in a ROC analysis (multivariate, age-adjusted analysis for CEA cutoff of 8, HR = 1.01, 95% CI 0.52-1.96).

CONCLUSIONS

Despite interesting patterns of abnormally high CEA in SCCA patients with advanced disease, and correlation of increased CEA with disease progression (and conversely decreased CEA with disease response), CEA is not associated with survival outcomes in SCCA, and is not a clinically relevant biomarker in this disease.

Molecular and immunophenotypic characterization of anal squamous cell carcinoma reveals distinct clinicopathologic groups associated with HPV and TP53 mutation status

Squamous cell carcinoma (SqCC) is the most common malignancy of the anal canal, where it is strongly associated with HPV infection. Characteristic genomic alterations have been identified in anal SqCC, but their clinical significance and correlation with HPV status, pathologic features, and immunohistochemical markers are not well established. We examined the molecular and clinicopathologic features of 96 HPV-positive and 20 HPV-negative anal SqCC. HPV types included 89 with HPV16, 2 combined HPV16/HPV18, and 5 HPV33. HPV-positive cases demonstrated frequent mutations or amplifications in PIK3CA (30%; p = 0.027) or FBXW7 mutations (10%). HPV-negativity was associated with frequent TP53 (53%; p = 0.00001) and CDKN2A (21%; p = 0.0045) mutations. P16 immunohistochemistry was positive in all HPV-positive cases and 3/20 HPV-negative cases (p < 0.0001; sensitivity: 100%; specificity: 85%) and was associated with basaloid morphology (p = 0.0031). Aberrant p53 immunohistochemical staining was 100% sensitive and specific for TP53 mutation (p < 0.0001). By the Kaplan-Meier method, HPV-negativity, aberrant p53 staining, and TP53 mutation were associated with inferior overall survival (OS) (p < 0.0001, p = 0.0103, p = 0.0103, respectively) and inferior recurrence-free survival (p = 0.133, p = 0.0064, and p = 0.0064, respectively). TP53/p53 status stratified survival probability by HPV status (p = 0.013), with HPV-negative/aberrant p53 staining associated with the worst OS, HPV-positive/wild-type p53 with best OS, and HPV-positive/aberrant p53 or HPV-negative/wild-type p53 with intermediate OS. On multivariate analysis HPV status (p = 0.0063), patient age (p = 0.0054), T stage (p = 0.039), and lymph node involvement (p = 0.044) were independently associated with OS. PD-L1 expression (CPS ≥ 1) was seen in 30% of HPV-positive and 40% of HPV-negative cases, and PD-L1 positivity was associated with a trend toward inferior OS within the HPV-negative group (p = 0.064). Our findings suggest that anal SqCC can be subclassified into clinically, pathologically, and molecularly distinct groups based on HPV and TP53 mutation status, and p16 and p53 immunohistochemistry represent a clinically useful method of predicting these prognostic groups.

Safety considerations with new treatment regimens for anal cancer

Introduction: Anal cancer is a rare malignancy, but incidence rates are rising. Primary chemoradiation is the standard of care for early disease with surgery reserved for salvage. Despite success in terms of survival, patients suffer significant morbidity. Research is underway to advance the field and improve outcomes for these patients.Areas covered: This review aims to discuss the safety and efficacy of new approaches to treat anal cancer. A literature search was performed from January 1950 through November 2020 via PubMed and ClinicalTrials.gov databases to obtain data from ongoing or published studies examining new regimens for the treatment of anal cancers. Pertinent topics covered include miniature drug conjugates, epidermal growth factor receptor inhibitors, checkpoint inhibitor combinations, and novel immunomodulators.Expert opinion: Based on emerging clinical data, the treatment paradigm for anal cancer is likely to shift in the upcoming years. One of the largest areas of investigation is the field of immunotherapy, which may emerge as an integral component of anal cancer for all treatment settings.

Clinical characteristics and prognosis of anal squamous cell carcinoma: a retrospective audit of 144 patients from 11 cancer hospitals in southern China

Background

The incidence of anal squamous cell carcinoma (SCC) has been steadily growing globally in the past decade. Clinical data on anal SCC from China are rare. We conducted this study to describe the clinical and epidemiological characteristics of anal SCC in China and explore prognostic factors of outcomes among patients with anal SCC.

Methods

We audited demographic characteristics, relevant symptoms, risk factors, treatment modalities and outcomes for patients diagnosed with anal SCC at 11 medical institutions in China between January 2007 and July 2018.

Results

A total of 144 patients (109 females) were diagnosed with SCC during this period. Median age at initial diagnosis was 52.0 (interquartile range: 46.0–61.8) years. The most common symptoms were bleeding (n = 93, 64.6%), noticing a lump (n = 49, 34.0%), and pain (n = 47, 32.6%). The proportion of patients at the American Joint Committee on Cancer (AJCC) stages I-IV were 10 (6.9%), 22 (15.3%), 61 (42.4%) and 8 (5.6%), respectively, and AJCC stages in 43 (29.9%) patients were unknown. Thirty-six patients (25.0%) underwent abdominoperineal resection initially. Univariable analysis showed that T stage predicted recurrence-free survival (RFS) (Hazard ratio [HR] = 3.03, 95% Confidence interval [CI]: 1.10–8.37, p = 0.032), and age group (HR = 2.90, 95% CI: 1.12–7.49, p = 0.028), AJCC stage (HR = 4.56, 95% CI: 1.02–20.35, p = 0.046), and N stage (HR = 3.05, 95% CI: 1.07–8.74, p = 0.038) predicted overall survival (OS).

Conclusions

T stage was identified as prognostic factor of RFS, and age, AJCC stage, and N stage were identified as prognostic factors of OS. Improving symptom awareness and earlier presentation among patients potentially at risk for anal SCC should be encouraged. Familiarity with the standard treatment among health care providers in China should be further improved.

Immunotherapy in Anal Cancer

PURPOSE OF REVIEW

Standard treatment for early-stage squamous cell cancer of the anal canal (SCCA) includes concurrent chemotherapy and radiation to achieve curative intent. Treatment options are limited, however, especially with locoregional disease relapse occurring in 20-30% of patients and about 10-30% of patients presenting with metastatic disease. With more than 90% of SCCAs occurring in the setting of HPV, immune-based therapies are now the target of possible new treatments for this rare disease. This review highlights the role of immunotherapy in HPV-associated SCCA.

RECENT FINDINGS

Immunotherapy has been shown to extend progression-free survival and overall survival in various solid malignancies, including SCCA. So far, single-agent monotherapy with either nivolumab or pembrolizumab has shown durable clinical response with a tolerable side effect profile. The 2018 NCCN guidelines now advise nivolumab or pembrolizumab monotherapy as second-line treatment in the management of metastatic SCCA. Further investigation with immunotherapy continues to be critical for such a rare malignancy with few treatment options.

A phase II study of axalimogene filolisbac for patients with previously treated, unresectable, persistent/recurrent loco-regional or metastatic anal cancer

Squamous cell carcinoma of the anorectal canal (SCCA) is a rare HPV-related malignancy that is steadily increasing in incidence. A high unmet need exists for patients with persistent loco-regional and metastatic disease. Axalimogene filolisbac (ADXS11-001) is an investigational immunotherapy that stimulates tumor-specific responses against HPV-associated cancers, and has demonstrated benefit in metastatic cervical cancer. We conducted this single-arm, multicenter, phase 2 trial in patients with persistent/recurrent, loco-regional or metastatic SCCA. Patients received ADXS11-001, 1 × 10⁹ colony-forming units intravenously every 3 weeks. A Simon 2-stage design was used to test primary co-endpoints of overall response rate (ORR) and 6-month progression-free survival (PFS) rate. Study would proceed to full enrollment if ORR ≥ 10% or 6-month PFS rate ≥ 20%. Thirty-six patients were treated; 29 patients were evaluable for response. One patient had a prolonged partial response (3.4% ORR). The 6-month PFS rate was 15.5%. Grade 3 adverse event were noted in 10 patients, with the majority being cytokine-release symptoms; one grade 4 adverse event was noted. No grade 5 adverse events occurred. ADXS11-001 was safe and well-tolerated in patients with SCCA. However, this study did not meet either primary endpoint. ADXS11-001 may be more beneficial when administered in combination with other cytotoxic or targeted agents.

Prognostic Significance of HPV DNA and p16INK4a in Anal Cancer: A Systematic Review and Meta-Analysis

We conducted a systematic review and meta-analysis of observational studies evaluating survival in patients with anal cancer, according to human papillomavirus (HPV) DNA, p16^INK4a, and combined HPV DNA/p16^INK4a status. We systematically searched PubMed, EMBASE, and Cochrane Library databases to identify studies published in English until July 25, 2018, directly providing or allowing estimation of survival of patients with anal cancer according to the presence of HPV DNA and/or overexpression of p16^INK4a We estimated pooled HRs and 95% confidence intervals (CI) for overall survival (OS) using a random-effects model. We included 16 studies, comprising 1,724 patients with anal cancer tested for HPV DNA (65% positive), and 567 patients tested for p16^INK4a (87% positive). The pooled HR for OS was 0.54 (95% CI, 0.33-0.89) for HPV DNA positive versus negative, 0.37 (95% CI, 0.24-0.57) for p16^INK4a positive versus negative, and 0.36 (95% CI, 0.22-0.58) for HPV DNA positive/p16^INK4a positive versus HPV DNA positive/p16^INK4a negative patients with anal cancer. Patients with HPV DNA or p16^INK4a positive anal cancer have significantly better OS compared with HPV DNA or p16^INK4a negative. This points to the possible value of HPV DNA and/or p16^INK4a testing when planning the management and follow-up strategy for patients diagnosed with anal cancer.

MR staging of anal cancer: what the radiologist needs to know

Anal canal cancer is a rare disease and squamous cell carcinoma is the most common histologic subtype. Traditionally, anal cancer is imaged with CT and PET/CT for purposes of TNM staging. With the increased popularity of MRI for rectal cancer evaluation, MRI has become increasingly utilized for local staging of anal cancer. In this review, we focus on the necessary information radiologists need to know to understand this rare and unique disease and to be familiar with staging of anal cancer on MRI.

Pharmacotherapy of Anal Cancer

Anal squamous cell carcinoma (SCCA), among other malignancies, is associated with the human papillomavirus (HPV) and its incidence continues to rise. Anal SCCA will likely remain an existing healthcare concern given compliance issues with the HPV vaccination seen in the US. Localized disease is predominantly treated with standard of care (SOC) definitive chemoradiation that has remained unchanged for decades. Clinical and molecular prognostic factors have emerged to characterize patients unresponsive to SOC, revealing the need for an alternate approach. Metastatic disease is an extremely small subset and understudied population due to its rarity. Recent prospective trials and mutational analysis have opened treatment options for this subset in need. Our review details the pharmacotherapeutic treatment in localized and metastatic anal SCCA chronologically, while also describing future outlooks.

New Insights into the Role of Human Papillomavirus in Anal Cancer and Anal Wart Development

Human papillomavirus is associated with several anogenital and oropharyngeal lesions, including warts, premalignant lesions, and cancer. There are specific groups that were identified as high-risk groups for anal squamous cell carcinoma and anal human papillomavirus infection, namely HIV-positive patients, men who have sex with men, women with genital tract neoplasia, and solid organ transplant recipients. Condylomas have classically been considered to be a benign lesion, with an exception made for the Buschke-Loewenstein tumor, but several publications have shown that a high percentage of condylomas harbor high-grade lesions. Due to the similarities between anal and cervical carcinogenesis, anal cancer screening based on anal cytology and referral to high-resolution anoscopy, in case of abnormalities, have been advocated. Testing for anal human papillomavirus is not routinely done in anal cancer screening, because of the very high prevalence in high-risk populations. The large majority of anal cancers are squamous cell carcinomas (SCC), and around 90% are attributed to human papillomavirus. Human papillomavirus positivity in anal SCC seems to have a prognostic value, with better survival in those patients with positive tumors. Prophylactic vaccination has been shown to be important for prevention of anal human papillomavirus-related lesions.

Epidemiology of Anal Canal Cancer

Anal cancer is a rare malignancy, although its incidence has been increasingly in recent decades. This article discusses risk factors for anal cancer and how these risk factors affect the changing demographics of this disease.

Metastatic Anal Cancer and Novel Agents

Squamous cell carcinoma of the anal canal (SCCA) represents an orphan disease. Although prior infection with human papilloma virus is associated with the development of SCCA, knowledge of this relationship has proven ineffective in identifying therapeutic agents that have activity in the management of metastatic SCCA. Combination chemotherapy with traditional cytotoxic agents has demonstrated efficacy in multiple small series. However, immune checkpoint blockade agents have demonstrated efficacy for patients with refractory metastatic SCCA; these agents hold promise in the horizon for patients with metastatic SCCA. Clinical trials should be considered for oncologists to manage patients with metastatic SCCA.

A viral map of gastrointestinal cancers

Cancers of the gastrointestinal tract (GIT) are expected to account for approximately 20% of all cancers in 2017. Apart from their high incidence, GIT cancers show high mortality rates, placing these malignancies among the most prominent public health issues of our time. Cancers of the GIT are the result of a complex interplay between host genetic factors and environmental factors and frequently arise in the context of a continued active inflammatory response. Several tumor viruses are able to elicit such chronic inflammatory responses. In fact, several viruses have an impact on GIT tumor initiation and progression, as well as on patients' response to therapy and prognosis, through direct and indirect mechanisms. In this review, we have gathered information on different viruses' rates of infection, viral-driven specific carcinogenesis mechanisms and viral-related impact on the prognosis of cancers of the GIT (specifically in organs that have an interface with the environment - esophagus, stomach, intestines and anus). Overall, while some viral infections show a strong causal relation with specific gastrointestinal cancers, these represent a relatively small fraction of GIT malignancies. Other types of cancer, like Esophageal Squamous Cell Carcinoma, require further studies to confirm the carcinogenic role of some viral agents.

Radiation generates an abscopal response and complete resolution of metastatic squamous cell carcinoma of the anal canal: a case report

The abscopal effect is a rare phenomenon in the setting of radiation therapy (RT) for metastatic cancer where tumor regression occurs distant from the site of treatment. A proposed mechanism of the abscopal effect is the activation of a systemic antitumor immune response by localized RT. We report the first case, to our knowledge, of the abscopal effect in squamous carcinoma of the anal canal with metastases to pelvic lymph nodes, liver and bone. After palliative RT to the pelvis with sensitizing chemotherapy, complete response was observed not only in the primary tumor but also in bone and multiple liver metastases at 4 months after treatment, an effect that remained durable at 4-year follow-up. Understanding of the abscopal effect and the immune mechanisms associated with anal cancer may lead to new avenues of research to improve outcome for patients with this rare disease.

Racial Disparity in Gastrointestinal Cancer Risk

Cancer from the gastrointestinal tract and its associated excretory organs will occur in more than 300,000 Americans in 2017, with colorectal cancer responsible for >40% of that burden; there will be more than 150,000 deaths from this group of cancers in the same time period. Disparities among subgroups related to the incidence and mortality of these cancers exist. The epidemiology and risk factors associated with each cancer bear out differences for racial groups in the United States. Esophageal adenocarcinoma is more frequent in non-Hispanic whites, whereas esophageal squamous cell carcinoma with risk factors of tobacco and alcohol is more frequent among blacks. Liver cancer has been most frequent among Asian/Pacific Islanders, chiefly due to hepatitis B vertical transmission, but other racial groups show increasing rates due to hepatitis C and emergence of cirrhosis from non-alcoholic fatty liver disease. Gastric cancer incidence remains highest among Asian/Pacific Islanders likely due to gene-environment interaction. In addition to esophageal squamous cell carcinoma, cancers of the small bowel, pancreas, and colorectum show the highest rates among blacks, where the explanations for the disparity are not as obvious and are likely multifactorial, including socioeconomic and health care access, treatment, and prevention (vaccination and screening) differences, dietary and composition of the gut microbiome, as well as biologic and genetic influences. Cognizance of these disparities in gastrointestinal cancer risk, as well as approaches that apply precision medicine methods to populations with the increased risk, may reduce the observed disparities for digestive cancers.

Randomized Clinical Trials in Localized Anal Cancer

Management of anal carcinoma began as abdominoperineal resection and has evolved to combined chemotherapy and radiation. Early randomized trials demonstrated superior clinical outcomes of combined modality therapy over radiotherapy alone. Subsequent trials investigated alterations in the standard backbone of radiotherapy concurrent with 5-fluorouracil and mitomycin C with intent to maintain clinical outcomes while reducing treatment-related morbidity. The addition of intensity-modulated radiotherapy to radiation planning and delivery has subsequently reduced acute toxicity and detrimental treatment breaks. Ongoing and future trials are aimed at reducing therapy in favorable patient populations to decrease morbidity while intensifying treatment in patients with negative prognostic factors.

Targeting phosphorylation of STAT3 delays tumor growth in HPV-negative anal squamous cell carcinoma mouse model

Although conventional chemoradiotherapy is effective for most anal squamous cell carcinoma (ASCC) patients, HPV-negative ASCC patients respond poorly to this treatment and new therapeutic approach is required. Our group has previously established an HPV-negative ASCC mouse model and demonstrated that signal transducer and activation of transcription 3 (STAT3) is hyper-activated in the model. Here, we show that in vivo inhibition of STAT3 by S3I-201 effectively delays tumor growth in ASCC mouse model indicated by significantly smaller tumor size and burden in the treatment group compared with control group at the same point. Further analysis shows that survivin and Ki67, important biomarkers for tumor cell survival and proliferation, are significantly reduced after S3I-201 treatment. Additionally, flow cytometry and immunohistofluorescent assays reveal decreased Myeloid-derived suppressor cell (MDSC) and tumor-associated macrophage (TAM) populations in the S3I-201 treatment group, which indicates a reversion of the immunosuppressive environment, unraveling the potential role for S3I-201 in immunosuppression in ASCC. Together these results for the first time demonstrated the anti-tumor effects of STAT3 inhibitor S3I-201 in HPV-negative ASCC mouse model and its multiple effects on cancer cells and immune system. Thus we conclude that S3I-201 may be a novel therapeutic approach for HPV-negative ASCC patients.

Nivolumab for previously treated unresectable metastatic anal cancer (NCI9673): a multicentre, single-arm, phase 2 study

BACKGROUND

Squamous cell carcinoma of the anal canal (SCCA) is a rare malignancy associated with infection by human papillomavirus (HPV). No consensus treatment approach exists for the treatment of metastatic disease. Because intratumoral HPV oncoproteins upregulate immune checkpoint proteins such as PD-1 to evade immune-mediated cytotoxicity, we did a trial of the anti-PD-1 antibody nivolumab for patients with metastatic SCCA.

METHODS

We did this single-arm, multicentre, phase 2 trial at ten academic centres in the USA. We enrolled patients with treatment-refractory metastatic SCCA, who were given nivolumab every 2 weeks (3 mg/kg). The primary endpoint was response according to Response Evaluation Criteria in Solid Tumors, version 1.1, in the intention-to-treat population. At the time of data cutoff, the study was ongoing, with patients continuing to receive treatment. The study is registered with ClinicalTrials.gov, number NCT02314169.

RESULTS

We screened 39 patients, of whom 37 were enrolled and received at least one dose of nivolumab. Among the 37 patients, nine (24% [95% CI 15-33]) had responses. There were two complete responses and seven partial responses. Grade 3 adverse events were anaemia (n=2), fatigue (n=1), rash (n=1), and hypothyroidism (n=1). No serious adverse events were reported.

INTERPRETATION

To our knowledge, this is the first completed phase 2 trial of immunotherapy for SCCA. Nivolumab is well tolerated and effective as a monotherapy for patients with metastatic SCCA. Immune checkpoint blockade appears to be a promising approach for patients with this orphan disease.

FUNDING

National Cancer Institute/Cancer Therapy Evaluation Program, the HPV and Anal Cancer Foundation, the E B Anal Cancer Fund, The University of Texas MD Anderson Moon Shots Program, and an anonymous philanthropic donor.

Summary of emerging targets in anal cancer: the case for an immunotherapy based-approach

Squamous cell carcinoma of the anal canal (SCCA) remains a less common gastrointestinal malignancy despite a continued increase in the annual incidence in the United States and globally. The vast majority of all cases are attributed to persistent infection and integration into host cell DNA by human papillomavirus (HPV). For patients with metastatic anal cancer, there is currently no accepted consensus standard of care. Given the viral etiology associated with the oncogenesis of this tumor, great interest exists for the development of immunotherapy as a novel approach to improving clinical outcomes for patients afflicted with this disease. This review highlights various immunotherapies under investigation in the treatment of advanced human malignancies and discusses their potential as future treatments for metastatic anal cancer.

Comprehensive genomic profiling of anal squamous cell carcinoma reveals distinct genomically defined classes

BACKGROUND

Squamous cell cancers of the anal canal (ASCC) are increasing in frequency and lack effective therapies for advanced disease. Although an association with human papillomavirus (HPV) has been established, little is known about the molecular characterization of ASCC. A comprehensive genomic analysis of ASCC was undertaken to identify novel genomic alterations (GAs) that will inform therapeutic choices for patients with advanced disease.

PATIENTS AND METHODS

Hybrid-capture-based next-generation sequencing of exons from 236 cancer-related genes and intronic regions from 19 genes commonly rearranged in cancer was performed on 70 patients with ASCC. HPV status was assessed by aligning tumor sequencing reads to HPV viral genomes. GAs were identified using an established algorithm and correlated with HPV status.

RESULTS

Sixty-one samples (87%) were HPV-positive. A mean of 3.5 GAs per sample was identified. Recurrent alterations in phosphoinositol-3-kinase pathway (PI3K/AKT/mTOR) genes including amplifications and homozygous deletions were present in 63% of cases. Clinically relevant GAs in genes involved in DNA repair, chromatin remodeling, or receptor tyrosine kinase signaling were observed in 30% of cases. Loss-of-function mutations in TP53 and CDKN2A were significantly enhanced in HPV-negative cases (P < 0.0001).

CONCLUSIONS

This is the first comprehensive genomic analysis of ASCC, and the results suggest new therapeutic approaches. Differing genomic profiles between HPV-associated and HPV-negative ASCC warrants further investigation and may require novel therapeutic and preventive strategies.