EGFR and K-ras gene mutation status in squamous cell anal carcinoma: a role for concurrent radiation and EGFR inhibitors?

Efficacy and tolerance of cetuximab in combination with 5 FU plus irinotecan based chemotherapy in metastatic squamous cell anal carcinoma

BACKGROUND

Squamous cell anal carcinoma (SCAC) is an uncommon neoplasia often cured by surgery and/or chemo-adiation therapy at the localized stage. Although the first-line treatment for metastatic anal canal cancer is now better codified with two validated treatment regimens, carboplatin-paclitaxel and modified docetaxel-cisplatin-5FU (DCF), there is little data and no consensus regarding subsequent lines [1-5]. In this study, we report the safety and efficacy of cetuximab (an epidermal growth factor receptor inhibitor) in combination with 5-FU plus irinotecan based chemotherapy.

METHOD

A retrospective analysis of patients with metastatic SCAC (mSCAC), who failed on at least one prior line of treatment, before being treated with the combination FOLFIRI and cetuximab between March 2015 and February 2022 at Gustave Roussy cancer center, was performed.

RESULTS

A total of 33 patients with a pre-treated mSCAC were analyzed. The combination of FOLFIRI and cetuximab provided a disease control rate (DCR) of 73%, and response rate of 30%. With a median follow-up of 38 months, the median progression free survival was 5.5 months, and the median overall survival was 13.7 months. Fourteen patients (42%) experienced grade III/IV adverse events that remained manageable.

CONCLUSION

Our study suggests that FOLFIRI and cetuximab is a promising combination in the management of mSCAC with a very good DCR and a manageable toxicity profile. Further prospective trials would be needed to confirm our results.

Molecular characterization of squamous cell carcinoma of the anal canal

Background

Squamous cell carcinoma of the anal canal (SCCA) is an uncommon malignancy with limited therapeutic options. Nivolumab and pembrolizumab show promising results in patients with SCCA. Human papillomavirus (HPV)-negative tumors are frequently TP53-mutated (TP53-MT) and often resistant to therapy.

Methods

We present a large molecularly-profiled cohort of SCCA, exploring the underlying biology of SCCA, differences between TP53-wild type (TP53-WT) and TP53-MT tumors, and differences between local and metastatic tumors. SCCA specimens (n=311) underwent multiplatform testing with immunohistochemistry (IHC), in situ hybridization (ISH) and next-generation sequencing (NGS). Tumor mutational burden (TMB) was calculated using only somatic nonsynonymous missense mutations. Chi-square testing was used for comparative analyses.

Results

The most frequently mutated genes included PIK3CA (28.1%), KMT2D (19.5%), FBXW7 (12%), TP53 (12%) and PTEN (10.8%). The expression of PD-1 was seen in 68.8% and PD-L1 in 40.5% of tumors. High TMB was present in 6.7% of specimens. HER2 IHC was positive in 0.9%, amplification by chromogenic in situ hybridization (CISH) was seen 1.3%, and mutations in ERBB2 were present in 1.8% of tumors. The latter mutation has not been previously described in SCCA. When compared with TP53-WT tumors, TP53-MT tumors had higher rates of CDKN2A, EWSR1, JAK1, FGFR1 and BRAF mutations. PD-1 and PD-L1 expression were similar, and high TMB did not correlate with PD-1 (P=0.50) or PD-L1 (P=0.52) expression.

Conclusions

Molecular profiling differences between TP53-MT and TP53-WT SCCA indicate different carcinogenic pathways which may influence response to therapy. Low frequency mutations in several druggable genes may provide therapeutic opportunities for patients with SCCA.

A Prospective Cohort Study of Biomarkers in Squamous Cell Carcinoma of the Anal Canal (SCCAC) and their Influence on Treatment Outcomes

Background: Although Chemoradiation (CRT) is the curative treatment for SCCAC, many patients present primary resistance. Since it is a rare tumor, response predictors remain unknown.

Methods: We performed a prospective cohort study to evaluate biomarkers associated with CRT response, progression-free survival (PFS), and overall survival (OS). The primary endpoint was response at 6 months (m). Tumor DNA and HPV were analyzed by next-generation sequencing, while KI-67 and PD-L1 by immunohistochemistry in tumor tissue.

Results: Seventy-eight patients were recruited between October/2011 and December/2015, and 75 were response evaluable. The median age was 57 years, 65% (n=49) were stage III and 12% (n=9) were HIV positive (HIV+). At 6m, 62.7% (n=47) presented CR. On multivariate analyses, stage II patients were 4.7 more likely to achieve response than stage III (OR, 4.70; 95%CI, 1.36-16.30; p=0.015). HIV+ was associated with a worse response (OR, 5.72; 95%CI, 2.5-13.0; p<0.001). 5-year PFS and OS rates were 63.3% and 76.4%, respectively, with a median follow up of 66m. On multivariate analyses, older age (HR 1.06, p=0.022, 95%IC 1.01-1.11) and absence of CR at 6m (HR 3.36, p=0.007, 95%IC 1.39-8.09) were associated with inferior OS. The 5-year OS rate was 62.5% in HIV+ group compared to 78% among HIV- pts, although this difference was not statistically significant (p=0.4). PIK3CA, MET and TP53 mutations, HPV, Ki-67 expression, and PD-L1 expression, were not associated with PFS and OS.

Conclusions: Clinical stage III and HIV+ were associated with worse response to CRT at 6m. The absence of CR was the main factor associated with poor 5-year OS.

Treatment of Squamous Cell Carcinoma of the Anus, Unresolved Areas and Future Perspectives for Research: Perspectives of Research Needs in Anal Cancer

Anal cancer is a relatively rare, mostly HPV-related cancer. The curative treatment consists of concurrent chemoradiation delivered with modern radiotherapy techniques. The prognosis for most patients with early localized disease is very favourable; however patients with locally advanced disease and/or HPV negative tumours are at higher risk of locoregional and distant treatment failure. Tailored approaches are presently being investigated to determine the most suitable regimen in terms of radiotherapy dose prescription, target volume selection, normal tissue avoidance, and combination therapy. Metastatic anal cancer is treated with chemotherapy aiming at prolonged survival. The role of immune therapy in the clinical setting is being investigated. There is little knowledge on the biology of anal cancer, and an urgent need for more clinical and translational research dedicated to this disease. In this article, the evidence-base for the current treatment is briefly reviewed, and perspectives on future research needs are high-lighted.

Chemoradiation for Anal Cancer: Clinical Outcomes and Strategies to Optimize the Therapeutic Ratio According to HPV Status

The incidence of anal cancer in the United States has increased in recent years, primarily related to the increasing incidence of HPV-associated anal squamous cell carcinoma, which is estimated to represent 80%-95% of anal cancers. Similar to head and neck cancer, HPV association has been demonstrated to be a strong positive prognostic factor in patients with anal cancer. Encouraging results from a number of studies investigating treatment de-escalation for HPV-associated oropharyngeal cancer support the notion that similar attempts may be feasible in HPV-associated anal cancer; however, the data to support this hypothesis are currently lacking. Studies are needed to determine how, if at all, HPV status should impact the management of patients with anal cancer. This review summarizes the relationship between HPV association and outcomes for patients with anal cancer, and how HPV status may impact the treatment of patients with anal cancer going forward.

Research on Anal Squamous Cell Carcinoma: Systemic Therapy Strategies for Anal Cancer

Simple Summary

Anal cancer is rare with an estimated 9000 new cases predicted to occur in the United States in 2021. However, rates of new anal cancer cases and deaths from the disease are increasing by about 2% and 3% per year respectively. In light of these trends it is critical to better understand the nature of this disease and progress in its management. The present review focuses on the history and development of the role of systemic therapy in the treatment of anal cancer. Major trials establishing the role of chemotherapy in the management of locoregional and metastatic anal cancer are summarized. In addition, the rapidly evolving role of immunotherapy is discussed. Finally, major insights into the molecular pathobiology of anal cancer and opportunities for advancement in precision medicine in treatment of the disease.

Abstract

Anal squamous cell carcinoma (ASCC) is a rare malignancy, with most cases associated with human papilloma virus and an increased incidence in immunocompromised patients. Progress in management of ASCC has been limited not only due to its rarity, but also the associated lack of research funding and social stigma. Historically, standard of care for invasive ASCC has been highly morbid surgical resection, requiring a permanent colostomy. Surgery was associated with disease recurrence in approximately half of the patients. However, the use of chemotherapy (5-fluorouracil and mitomycin C) concomitantly with radiation in the 1970s resulted in disease regression, curing a subset of patients and sparing them from morbid surgery. Validation of the use of systemic therapy in prospective trials was not achieved until approximately 20 years later. In this review, advancements and shortcomings in the use of systemic therapy in the management of ASCC will be discussed. Not only will standard-of-care systemic therapies for locoregional and metastatic disease be reviewed, but the evolving role of novel treatment strategies such as immune checkpoint inhibitors, HPV-based vaccines, and molecularly targeted therapies will also be covered. While advances in ASCC treatment have remained largely incremental, with increased biological insight, an increasing number of promising systemic treatment modalities are being explored.

Signal transduction pathway mutations in gastrointestinal (GI) cancers: a systematic review and meta-analysis

The present study was conducted to evaluate the prevalence of the signaling pathways mutation rate in the Gastrointestinal (GI) tract cancers in a systematic review and meta-analysis study. The study was performed based on the PRISMA criteria. Random models by confidence interval (CI: 95%) were used to calculate the pooled estimate of prevalence via Metaprop command. The pooled prevalence indices of signal transduction pathway mutations in gastric cancer, liver cancer, colorectal cancer, and pancreatic cancer were 5% (95% CI: 3-8%), 12% (95% CI: 8-18%), 17% (95% CI: 14-20%), and 20% (95% CI: 5-41%), respectively. Also, the mutation rates for Wnt pathway and MAPK pathway were calculated to be 23% (95% CI, 14-33%) and 20% (95% CI, 17-24%), respectively. Moreover, the most popular genes were APC (in Wnt pathway), KRAS (in MAPK pathway) and PIK3CA (in PI3K pathway) in the colorectal cancer, pancreatic cancer, and gastric cancer while they were beta-catenin and CTNNB1 in liver cancer. The most altered pathway was Wnt pathway followed by the MAPK pathway. In addition, pancreatic cancer was found to be higher under the pressure of mutation compared with others based on pooled prevalence analysis. Finally, APC mutations in colorectal cancer, KRAS in gastric cancer, and pancreatic cancer were mostly associated gene alterations.

[Metastatic squamous cell carcinomas of the anal canal: Current management and prospects]

Anal canal cancer is a rare disease that accounts for 2.5% of digestive cancers. Squamous cell carcinomas are the most common histological form. Their incidence is in progression, probably due to the increase in Human Papilloma Virus infections. Metastatic forms account for 20% of anal canal cancers considering synchronous forms or metastatic recurrence of an initially localised disease. Their prognosis remains poor with an estimated 5-year survival rate of 30%. The first-line therapeutic standard based on the combination of cisplatin with 5-Fluorouracil has recently been challenged by carboplatin - paclitaxel and docetaxel, cisplatin and 5-Fluorouracil regimens which are becoming new treatment options. In second-line setting, there is no international consensus. Anti-EGFRs and immunotherapy in combination or not with other molecules are promising but these results need to be confirmed. In this review, we report current and future data in the management of squamous cell carcinomas of the anal canal in unresectable locoregional recurrence or at metastatic stage.

VITAL phase 2 study: Upfront 5-fluorouracil, mitomycin-C, panitumumab and radiotherapy treatment in nonmetastatic squamous cell carcinomas of the anal canal (GEMCAD 09-02)

Aim

VITAL, a phase II single‐arm study, aimed to evaluate efficacy and safety of panitumumab addition to 5‐fluorouracil (5‐FU), mitomycin‐C (MMC) and radiotherapy (RT) in patients with localized squamous cell carcinoma of the anal canal (SCCAC).

Methods

Adult, treatment‐naïve SCCAC patients (Stage T2‐T4, any N, M0) and ECOG‐PS ≤2, received panitumumab (6 mg/kg, day 1 and Q2W; 8 weeks), 5‐FU (1000 mg/m²/d, days 1‐4 and 29‐32), MMC (10 mg/m², days 1 and 29) and RT 45 Gy (1.8 Gy/fraction) to the primary tumor and mesorectal, iliac and inguinal lymph nodes, plus 10‐15 Gy boost dose to the primary tumor and affected lymph nodes. The primary objective was disease free survival rate (DFS) at 3‐years (expected 3‐year DFS rate: 73.7 ± 12%).

Results

Fifty‐eight patients (31 women; median age: 59 years; ECOG‐PS 0‐1:98%; TNM II [29%] (T2 or T3/N0/M0)/IIIA (T1‐T3/N1/M0 or T4/N0/M0) [21%]/IIIB (T4/N1/M0 or any T/N2 or N3/M0) [47%]/nonevaluable [4%]) were included. The median follow‐up was 45 months. The 3‐year DFS rate was 61.1% (95% CI: 47.1, 72.4). The 3‐year overall survival rate was 78.4% (95% CI: 65.1, 87.1). Eighteen patients (31.0%) required a colostomy within 2 years posttreatment. Grade 3‐4 toxicities were experienced by 53 (91%) patients. Most common grade 3‐4 treatment‐related events were radiation skin injury (40%) and neutropenia (24%). No toxic deaths occurred. Improved efficacy in colostomy‐free survival and complete response rate was observed in human papilloma virus positive patients.

Conclusions

Panitumumab addition to MMC‐5FU regimen in SCCAC patients increases toxicity and does not improve patients’ outcomes. RT plus MMC‐5FU remains the standard of care for localized SCCAC patients.

Expression and role of EGFR, cyclin D1 and KRAS in laryngocarcinoma tissues

Epidermal growth factor receptor (EGFR), cyclin D1 and KRAS proto-oncogene, GTPase (KRAS) genes serve roles in the occurrence and development of tumors. The aim of the current study was to investigate the expression levels of EGFR, cyclin D1 and KRAS in laryngocarcinoma tissues and their association with clinical features. In addition, correlation between the expression levels of EGFR, cyclin D1 and KRAS was analyzed in laryngocarcinoma tissues. The expression levels of EGFR, cyclin D1 and KRAS in 46 patients with laryngocarcinoma and 20 patients with vocal cord polyps as the control group were determined using Super Vision immunohistochemical staining assay kits. The differences in clinical and pathological parameters between groups were statistically analyzed using SPSS software version 16.0. The expression rates of EGFR, cyclin D1 and KRAS were 71.7, 52.2 and 39.1%, respectively in laryngocarcinoma tissues, and 10.0, 5.0 and 10.0%, respectively in vocal cord polyps. There was a positive correlation between the expression levels of EGFR, cyclin D1 and KRAS. The expression of these genes was also closely associated with the clinical stage, treatment response and prognosis of patients with laryngocarcinoma. Multivariate analysis of prognosis using the Cox regression model indicated that EGFR expression in laryngocarcinoma tissues and the clinical stage of patients with laryngocarcinoma were closely associated with patient prognosis. The results of the current study indicated that EGFR, cyclin D1 and KRAS were synergistically involved in the occurrence and development of laryngocarcinoma, directly affecting the prognosis of patients. Additionally, high expression of EGFR, cyclin D1 and KRAS facilitated the invasion and metastasis of laryngocarcinoma cells. The expression of EGFR in laryngocarcinoma tissues and clinical stage were two independent risk factors affecting the prognosis of patients.

Experimental and investigational drugs for the treatment of anal cancer

INTRODUCTION

Squamous cell carcinoma of the anal canal (SCCA) is a rare malignancy, but its incidence rates have been increasing in the last decade. Studies have demonstrated that up to 47% of patients with locally advanced disease have high-risk features for treatment failure. The potential high rates of recurrence after standard chemoradiotherapy for locally advanced disease and the lack of established care for metastatic disease have created an urgent need for the evaluation of new drugs that will ultimately improve the efficacy of treatment.

AREAS COVERED

This review presents results of recent phase-I and -II clinical trials which evaluate novel therapeutic modalities. The review also describes the findings of comprehensive genomic profiling studies which provide insights for promising therapeutics.

EXPERT OPINION

HPV vaccination is underutilized in the United States and as a result, HPV-associated malignancies are likely to continue for several decades; however, pivotal breakthroughs may create a foundation for distinctive treatment approaches for other HPV-associated malignancies for which no other standard of care exists.

Management of locally advanced anal canal carcinoma with intensity-modulated radiotherapy and concurrent chemotherapy

The best curative option for locally advanced (stages II-III) squamous-cell carcinomas of the anal canal (SCCAC) is concurrent chemo-radiotherapy delivering 36-45 Gy to the prophylactic planning target volume with an additional boost of 14-20 Gy to the gross tumor volume with or without a gap-period between these two sequences. Although 3-dimensional conformal radiotherapy led to suboptimal tumor coverage because of field junctions, this modality remains a standard of care. Recently, intensity-modulated radiotherapy (IMRT) techniques improved tumor coverage while decreasing doses delivered to organs at risk. Sparing healthy tissues results in fewer severe acute toxicities. Consequently, IMRT could potentially avoid a gap-period that may increase the risk of local failure. Furthermore, these modalities reduce severe late toxicities of the gastrointestinal tract as well as better functional conservation of anorectal sphincter. This report aims to critically review contemporary trends in the management of locally advanced SCCAC using IMRT and concurrent chemotherapy.

Systemic Therapies for Advanced Squamous Cell Anal Cancer

PURPOSE OF REVIEW

We aim to summarise the available evidence on systemic therapies for advanced anal cancer.

RECENT FINDINGS

There is no universal consensus on the management of this condition and the prognosis remains poor. Nevertheless, significant progress has been recently made including completion of the first, ever-conducted, randomised trial in the first-line setting, investigation of immunotherapy in the refractory setting and use of comprehensive genomic profiling for a better molecular characterisation of this disease and the identification of novel potential targets. The combination of a platinum agent and a fluoropyrimidine is generally considered the standard first-line treatment. Other cytotoxic agents, especially docetaxel and paclitaxel, have shown activity in both the chemotherapy-naive and chemo-refractory setting and are currently being investigated in clinical trials. Finally, further to the promising results of early clinical trials, immunotherapy with checkpoint inhibitors (i.e. nivolumab and pembrolizumab) is likely to become a standard second-line treatment option.

Human Immunodeficiency Virus/AIDS, Human Papillomavirus, and Anal Cancer

Anal cancer is an increasingly common non-AIDS-defining cancer among individuals infected with the human immunodeficiency virus (HIV). It is associated with human papillomavirus (HPV). HPV16 is the most common genotype detected in anal cancers. The HPV types detected in anal cancer are included in the 9-valent vaccine. HPV vaccines have demonstrated efficacy in reducing anal precancerous lesions in HIV-infected individuals. Standard treatment has been fluorouracil and mitomycin (or cisplatin) plus radiation. Continued studies are needed to test new treatment strategies in HIV-infected patients with anal cancer to determine which treatment protocols provide the best therapeutic index.

Whole-exome sequencing identified mutational profiles of squamous cell carcinomas of anus

Anal squamous cell carcinoma (ASCC), either with human papillomavirus (+) or (-), is a neoplastic disease with frequent recurrence and metastasis. To characterize ASCC genomes, we attempted to disclose novel alterations of ASCC genomes and other genetic features including mutation signatures. We performed whole-exome sequencing and copy number alteration (CNA) profiling for 8 ASCC samples from 6 patients (2 cases with primary and recurrent/metastatic tumors). We found known ASCC mutations (TP53, CDKN2A, and PIK3CA) and CNAs (gains on 3q and 19q and losses on 11q and 13q). In addition, we discovered novel mutations in HRAS and ARID1A and CNAs (gain on 8q and losses 5q, 9p, 10q, and 19p) that had not been reported in ASCCs. We identified 4 signature patterns of the mutations (signatures 1 and 2 with deamination of 5-methyl-cytosin, signature 3 with APOBEC, and signature 4 with mismatch repair) in the ASCCs. Although signatures 1 to 3 have been detected in other SCCs, signature 4 was first identified in ASCCs. In addition, we first found that ASCCs harbored chromothripsis, copy-neutral losses of heterozygosity, and focal amplification of KLF5 super-enhancer. Analyses of primary and recurrent/metastatic pair genomes revealed that driver events in development and progression of ASCC might not be uniform. Our data indicate that ASCCs may have similar mutation and CNA profiles to other SCCs, but that there are unique genomic features of ASCCs as well. Our data may provide useful information for ASCC pathogenesis and for developing clinical strategies for ASCC.

Survival rate variation with different histological subtypes of poor prognostic male anal squamous cell carcinoma: a population-based study

Background and objective

The prognosis of male anal squamous cell carcinoma (MASCC) and female anal squamous cell carcinoma (FASCC) is variable. The influence of tumor subtype on the survival rate and gender is poorly known. Our study is the largest population-based study and aims to outline the difference in survival between MASCC and FASCC patients.

Methods

A retrospective population-based study was performed to compare the disease-specific mortalities (DSMs) between genders related to the tumor subtypes. The Surveillance, Epidemiology, and End Results (SEER) program database was employed to obtain the data from January 1988 to December 2014.

Results

A total of 4,516, (3,249 males and 1,267 females), patients with anal squamous cell carcinomas (ASCC) were investigated. The 5-year DSMs were 24.18% and 18.08% for men and women, respectively. The univariate analysis of the male basaloid squamous cell carcinoma (BSCC) and cloacogenic carcinoma (CC) patients demonstrated higher DSMs (P <0.001). Moreover, in the multivariate analysis, BSCC and CC were associated with soaring DSMs in male patients (P < 0.05).

Conclusions

In the cohort of BSCC and CC patients, male patients demonstrated a considerable decrease in survival rate compared to females. A more precise classification of ASCC and individualized management for MASCC are warranted.

Significance of Co-expression of Epidermal Growth Factor Receptor and Ki67 on Clinical Outcome in Patients With Anal Cancer Treated With Chemoradiotherapy: An Analysis of NRG Oncology RTOG 9811

PURPOSE

To measure co-expression of EGFR and Ki67 proteins in pretreatment tumor biopsies of anal cancer patients enrolled on NRG Oncology RTOG 9811, a phase III trial comparing 5-fluorouracil/mitomycin-C/radiation therapy (Arm A) versus 5-fluorouracil/cisplatin/radiation therapy (Arm B), and to correlate expression with clinical outcome.

METHODS AND MATERIALS

EGFR and Ki67 co-expression was measured after constructing a tissue microarray using fluorescence immunohistochemistry and automated quantitative image analysis. The Ki67 score within EGFR high versus low areas (Ki67ratio in EGFRhigh:low) in each tumor core was analyzed at the median, quartiles, and as a continuous variable. Associations between the tumor markers and clinical endpoints (overall and disease-free survival, locoregional and colostomy failure, and distant metastases) were explored.

RESULTS

A total of 282 pretreatment tumors were analyzed from NRG Oncology RTOG 9811. Of evaluated specimens, 183 (65%, n=89, Arm A; n=94, Arm B) were eligible and analyzable. There were no significant differences in baseline characteristics or outcomes between analyzable and unanalyzable patient cases. Median follow-up was 6.0 years. On multivariate analysis, after adjusting for gender, patients with Ki67ratio in EGFRhigh:low ≥median had worse overall survival (hazard ratio 2.41, 95% confidence interval 1.38-4.19, P=.0019). After adjusting for N stage and largest tumor dimension, patients with Ki67ratio in EGFRhigh:low ≥ median had a higher risk of a disease-free failure (hazard ratio 1.85, 95% confidence interval 1.18-2.92, P=.0078). Technical validation with an independent anal cancer patient cohort was performed and shows a very similar biomarker score distribution.

CONCLUSIONS

High Ki67ratio in EGFRhigh:low is associated with worse clinical outcome in this subset of patients with anal cancer treated with chemoradiation on NRG Oncology RTOG 9811. Evaluation within a clinical trial will be required to determine whether patients with these tumor characteristics may specifically benefit from an EGFR-targeted therapeutic agent.

Unravelling the pharmacologic opportunities and future directions for targeted therapies in gastro-intestinal cancers Part 1: GI carcinomas

Until the 1990s, cytotoxic chemotherapy has been the cornerstone of medical therapy for gastrointestinal (GI) cancers. Better understanding of the molecular biology of cancer cell has led to the therapeutic revolution of targeted therapies, i.e. monoclonal antibodies or small molecule inhibitors directed against proteins that are specifically overexpressed or mutated in cancer cells. These agents being more specific to cancer cells were expected to be less toxic than cytotoxic agents. Targeted agents have provided clinical benefit in many GI cancer types. For example, antiangiogenics and anti-EGFR therapies have significantly improved survival of patients affected by metastatic colorectal cancer and have deeply changed the therapeutic strategy in this disease. However, their effects have sometimes been disappointing, due to intrinsic or acquired resistance mechanisms (e.g., RAS mutation for anti-EGFR therapies), or to an activity restricted to some tumour settings (e.g., lack of activity in other cancer types, or on the microscopic residual disease in adjuvant setting). Many studies are negative in overall population but positive in some specific patient subgroups (e.g., trastuzumab in HER2-positive gastric cancer), illustrating the importance of patient selection and early identification of predictive biomarkers of response to these therapies. We propose a comprehensive two-part review providing a panoramic approach of the successes and failures of targeted agents in GI cancers to unravel the pharmacologic opportunities and future directions for these agents in GI oncology. In this first part, we will focus on adenocarcinomas and squamous cell carcinomas, for which targeted therapies are mostly used in combination with chemotherapy.

Cetuximab Plus Chemoradiotherapy in Immunocompetent Patients With Anal Carcinoma: A Phase II Eastern Cooperative Oncology Group-American College of Radiology Imaging Network Cancer Research Group Trial (E3205)

Purpose Squamous cell carcinoma of the anal canal (SCCAC) is characterized by high locoregional failure (LRF) rates after sphincter-preserving definitive chemoradiation (CRT) and is typically associated with anogenital human papilloma virus infection. Because cetuximab enhances the effect of radiation therapy in human papilloma virus-associated oropharyngeal squamous cell carcinoma, we hypothesized that adding cetuximab to CRT would reduce LRF in SCCAC. Methods Sixty-one patients with stage I to III SCCAC received CRT including cisplatin, fluorouracil, and radiation therapy to the primary tumor and regional lymph nodes (45 to 54 Gy) plus eight once-weekly doses of concurrent cetuximab. The study was designed to detect at least a 50% reduction in 3-year LRF rate (one-sided α, 0.10; power 90%), assuming a 35% LRF rate from historical data. Results Poor risk features included stage III disease in 64% and male sex in 20%. The 3-year LRF rate was 23% (95% CI, 13% to 36%; one-sided P = .03) by binomial proportional estimate using the prespecified end point and 21% (95% CI, 7% to 26%) by Kaplan-Meier estimate in a post hoc analysis using methods consistent with historical data. Three-year rates were 68% (95% CI, 55% to 79%) for progression-free survival and 83% (95% CI, 71% to 91%) for overall survival. Grade 4 toxicity occurred in 32%, and 5% had treatment-associated deaths. Conclusion Although the addition of cetuximab to chemoradiation for SCCAC was associated with lower LRF rates than historical data with CRT alone, toxicity was substantial, and LRF still occurs in approximately 20%, indicating the continued need for more effective and less toxic therapies.

Cetuximab Plus Chemoradiotherapy for HIV-Associated Anal Carcinoma: A Phase II AIDS Malignancy Consortium Trial

Purpose Squamous cell carcinoma of the anal canal (SCCAC) is characterized by high locoregional failure (LRF) rates after definitive chemoradiation (CRT), associated with anogenital human papilloma virus, and often appears in HIV infection. Because cetuximab enhances the effect of radiation therapy in human papilloma virus-associated oropharyngeal SCC, we hypothesized that adding cetuximab to CRT would reduce LRF in SCCAC. Methods Forty-five patients with stage I to III SCCAC and HIV infection received CRT: 45 to 54 Gy radiation therapy to the primary tumor and regional lymph nodes plus eight once-weekly doses of concurrent cetuximab and two cycles of cisplatin and fluorouracil. The study was designed to detect at least a 50% reduction in 3-year LRF rate (one-sided α, 0.10; power, 90%), assuming a 35% LRF rate from historical data. Results The 3-year LRF rate was 42% (95% CI, 28% to 56%; one-sided P = .9) by binomial proportional estimate using the prespecified end point (LRF or alive without LRF and followed < 3 years), and 20% (95% CI, 10% to 37%) by Kaplan-Meier estimate in post hoc analysis using definitions and methods consistent with historical data. Three-year rates by Kaplan-Meier estimate were 72% (95% CI, 56% to 84%) for progression-free survival and 79% (95% CI, 63% to 89%) for overall survival. Grade 4 toxicity occurred in 26%, and 4% had treatment-associated deaths. Conclusion HIV-associated SCCAC is potentially curable with definitive CRT. Although addition of cetuximab may result in less LRF, the 20% recurrence and 26% grade 4 toxicity rates indicate the continued need for more-effective and less-toxic therapies.

No evidence of NRAS mutation in squamous cell anal carcinoma (SCAC)

Epidermal growth factor receptor (EGFR) is usually expressed in squamous cell anal carcinoma (SCAC) and anti-EGFR agents could represent a valid treatment strategy, also considering that KRAS and BRAF mutations are rare events in this type of cancer. However, no data are available on NRAS status in SCAC. In this study we analyzed NRAS status (exons 2–4) by Pyrosequencing in a case series of 50 SCAC patients previously characterized in our laboratory for KRAS, BRAF, PIK3CA mutations and HPV and HIV infections. We found no mutation in NRAS gene. These results confirm that since the principal anti-EGFR resistance mechanisms are almost absent in SCAC, anti-EGFR agents should be considered for the treatment of this type of cancer.

Low mutation percentage of KRAS and BRAF genes in Brazilian anal tumors

Anal cancer is a rare type of digestive tract disease, which has had a crescent incidence in a number of regions. Carcinomas are most frequently found, with squamous cell carcinoma (SCC) comprising ~95% of all anal tumors. The major risk factor for development of this type of tumor is human papillomavirus (HPV) infection. However, previous studies have identified patients with anal cancer that are HPV‑/p16‑and observed that they have a poorer outcome compared with HPV+/p16+ patients. This suggests that molecular profile may drive anal cancer progression. The aim of the present study was to evaluate the mutational status of two important oncogenes, KRAS and BRAF, in a series of anal cancer lesions. Resected tumors of the anal canal (n=43) were evaluated, nine of these were high‑grade squamous intra‑epithelial lesion cases (HSIL), 11 were adenocarcinomas, and 23 SCCs. Direct sequencing of KRAS proto‑oncogene, GTPase (KRAS; codons 12 and 13) and B‑Raf proto‑oncogene, serine/threonine kinase (BRAF; codon 600) was performed and associated with patient clinicopathological and molecular features. There was a trend of poorer prognosis of adenocarcinoma compared with HSIL and SCC. Analysis indicated one SCC patient (2.3%) exhibited a KRAS p.G13D mutation, and one adenocarcinoma patient (2.3%) exhibited a BRAF p.V600E mutation. It was observed that, these mutations are rare in anal tumors, and certain patients may be at a disadvantage using targeted therapies based on KRAS and BRAF mutational status. As there is a low mutation percentage in SCCs, adenocarcinomas and HSIL, there may exist other underlying molecular alterations that result in anal cancer development, which require further elucidation.

Background and Current Treatment of Squamous Cell Carcinoma of the Anus

In this review, a summary of our current understanding of squamous cell carcinoma of the anus (SCCA) and the advances in our knowledge of SCCA regarding screening, prevention, the role of the immune system, current treatment and the potential for novel targets are discussed. The present standard of care in terms of treatment is 5-fluorouracil (5-FU) and mitomycin C (MMC) concurrently with radiation, which results in a high level of disease control for small early cancers. Preservation of the anal sphincter is achieved in the majority, although anorectal function is often impaired. Although evidence from prospective studies to support a change in the treatment strategy is lacking, patients with HPV-negative SCCA appear to be less responsive to chemoradiation (CRT) and relapse more frequently. In contrast, HPV-positive tumours usually fare better, but oncological outcomes are modified by smoking and immune incompetence. There is current interest in escalating the radiotherapy dose for larger, more advanced tumours, and de-escalating treatment for HPV-positive tumours. The use of novel immunological treatments to target the underlying different molecular pathways of HPV-positive cancers is exciting.

Mutational analysis of anal cancers demonstrates frequent PIK3CA mutations associated with poor outcome after salvage abdominoperineal resection

BACKGROUND

A better understanding of the molecular profile of anal squamous cell carcinomas (ASCCs) is necessary to consider new therapeutic approaches, and the identification of prognostic and predictive factors for response to treatment.

METHODS

We retrospectively analysed tumours from ASCC patients for mutational analysis of KRAS, NRAS, HRAS, BRAF, PIK3CA, MET, TP53 and FBXW7 genes by HRM and Sanger sequencing analysis.

RESULTS

Specimens from 148 patients were analysed: 96 treatment-naive tumours and 52 recurrences after initial radiotherapy (RT) or chemoradiotherapy (CRT). Mutations of KRAS, PIK3CA, FBXW7 and TP53 genes were present in 3 (2.0%), 30 (20.3%), 9 (6.1%) and 7 tumours (4.7%), respectively. The distribution of the mutations was similar between treatment-naive tumours and recurrences, except for TP53 mutations being more frequent in recurrences (P=0.0005). In patients treated with abdominoperineal resection (APR) after relapse (n=38, median follow-up of 18.2 years), overall survival (OS) was significantly correlated with HPV16 status (P=0.048), gender (P=0.045) and PIK3CA mutation (P=0.037). The PIK3CA status retained its prognostic significance in Cox multivariate regression analysis (P=0.025).

CONCLUSIONS

Our study identified PIK3CA mutation as an independent prognostic factor in patients who underwent APR for ASCC recurrence, suggesting a potential benefit from adjuvant treatment and the evaluation of targeted therapies with PI3K/Akt/mTor inhibitors in PIK3CA-mutated patients.

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.

HER3/ErbB3, an emerging cancer therapeutic target

HER3 is a member of the HER (EGFR/ErbB) receptor family consisting of four closely related type 1 transmembrane receptors (EGFR, HER2, HER3, and HER4). HER receptors are part of a complex signaling network intertwined with the Ras/Raf/MAPK, PI3K/AKT, JAK/STAT, and PKC signaling pathways. Aberrant activation of the HER receptors and downstream signaling molecules tips the balance on cellular events, leading to various types of cancers. Monoclonal antibodies (mAbs) and small molecule inhibitors targeting EGFR and HER2 tyrosine kinase activities exhibit clinical benefits in the treatment of several types of cancers, but their clinical efficacy is limited by the occurrence of drug resistance. HER3 is the preferred dimerization partner of HER2 and it is well established that HER3 plays an important role in drug resistance to EGFR- and HER2-targeting therapies. Since HER3 has limited kinase activity, mAbs are being explored to target HER3 for cancer therapy. Currently, approximately a dozen of anti-HER3 mAbs are at different stages of clinical development. However, the lack of established biomarkers has made it more challenging to stratify cancer patients to whom HER3-targeting therapies can be more effective. In this review, we focus on the validation of HER3 as a cancer drug target, the recent development in biomarker discovery for anti-HER3 therapies, and the progress made in the clinical development of HER3-targeting mAbs.

Comprehensive multiplatform biomarker analysis of 199 anal squamous cell carcinomas

Anal squamous cell carcinoma (ASCC) is a rare, HPV-associated malignancy typically diagnosed in early stages and definitively treated with chemoradiation. In situations where patients exhibit metastatic or recurrent disease, treatment options are severely limited. In this study, molecular alterations were identified that could be used to aid in therapeutic decisions for patients with metastatic or recurrent anal squamous cell carcinoma. Specimens from patients with this cancer were tested via a multiplatform profiling service (Caris Life Sciences, Phoenix, AZ) consisting of gene sequencing, protein expression by immunohistochemistry, and gene amplification with in situ hybridization. Utilizing these techniques, novel treatment strategies that could be explored were identified, including potential benefit with anti-EGFR therapies, immune checkpoint inhibitors, topoisomerase inhibitors, and taxanes. The frequency of overexpression of proteins that mark resistance to chemotherapeutic drugs, such as MRP1 (chemotherapy efflux pump), ERCC1 (resistance to platinum-based chemotherapy), and thymidylate synthase (resistance to fluoropyrimidines) were also identified, suggesting a lack of benefit. This multiplatform strategy could be explored for its potential to generate a personalized treatment selection for patients with advanced ASCC, provide a guide for future therapeutic development for this cancer, and be extended to other rare cancer types as well.

Investigational drugs for treating anal cancer and future perspectives

INTRODUCTION

Anal cancer is a relatively rare malignancy which comprises about 2.5% of all digestive system malignancies in the United States. The majority of cases are squamous cell carcinoma which is closely related to human papilloma virus (HPV) infection. Despite high cure rates with chemoradiation alone, 10 - 20% of patients do develop metastatic disease with little data to guide their treatment.

AREAS COVERED

In this review article, the authors describe the current standard treatment of early and advanced squamous cell carcinoma of the anal canal based on published data. The authors then describe the new approaches to the disease, focusing on new radio sensitizing agents, systemic targeted drugs and immunotherapy.

EXPERT OPINION

The authors believe that current standard treatment options for squamous cell carcinoma of the anal canal are well defined with acceptable results. However the major challenge in the treatment of anal cancer is the lack of randomized or even large single arm Phase II trials due to rarity of the disease, especially in the metastatic disease. But we are slowly making progress. Currently, the most promising areas of research are immunotherapy, targeted therapy and even HPV prevention. We are eagerly anticipating the results of these studies in order to expand the treatment armamentarium.

Cetuximab in combination with cisplatin and 5-Fluorouracil induces dramatic response in metastatic refractory squamous cell carcinoma of the anal canal

Metastatic squamous cell carcinoma (SCC) of the anal canal is rare with limited data regarding treatment. Epidermal growth factor receptor (EGFR) expression has been observed in SCC of the anal canal and Kristen rat sarcoma vial oncogene (KRAS) mutations are rare. EGFR monoclonal antibodies, cetuximab and panitumumab, represent a potential option in this patient population. We report a metastatic SCC of the anal canal patient treated with cetuximab in combination with cisplatin plus 5-Fluorouracil (5-FU) that had a dramatic response.

EGFR targeted therapies and radiation: Optimizing efficacy by appropriate drug scheduling and patient selection

The epidermal growth factor receptor (EGFR) plays an important role in tumor progression and treatment resistance for many types of malignancies including head and neck, colorectal, and nonsmall cell lung cancer. Several EGFR targeted therapies are efficacious as single agents or in combination with chemotherapy. Given the toxicity associated with chemoradiation and poor outcomes seen in several types of cancers, combinations of EGFR targeted agents with or without chemotherapy have been tested in patients receiving radiation. To date, the only FDA approved use of an anti-EGFR therapy in combination with radiation therapy is for locally advanced head and neck cancer. Given the important role EGFR plays in lung and colorectal cancer and the benefit of EGFR inhibition combined with chemotherapy in these disease sites, it is perplexing why EGFR targeted therapies in combination with radiation or chemoradiation have not been more successful. In this review we summarize the clinical findings of EGFR targeted therapies combined with radiation and chemoradiation regimens. We then discuss the interaction between EGFR and radiation including radiation induced EGFR signaling, the effect of EGFR on DNA damage repair, and potential mechanisms of radiosensitization. Finally, we examine the potential pitfalls with scheduling EGFR targeted therapies with chemoradiation and the use of predictive biomarkers to improve patient selection.

Cancers of the anal canal: diagnosis, treatment and future strategies

Anal cancer is an uncommon cancer; however, it is rising in incidence. There is confusion regarding nomenclature and the distinction between anal canal cancer and anal margin cancer. This article discusses the modern definition, etiology and staging of anal canal and anal margin cancers. Modern chemotherapy and radiotherapy regimens are discussed, in addition to modern imaging and radiotherapy techniques. Future preventative strategies and potential novel treatments are discussed.

Anal cancer treatment: Current status and future perspectives

Anal cancers (AC) are relatively rare tumors. Their incidence is increasing, particularly among men who have sex with other men due to widespread infection by human papilloma virus. The majority of anal cancers are squamous cell carcinomas, and they are treated according to stage. In local and locally advanced AC, concomitant chemoradiation therapy based on mitomycin C and 5-Fluorouracil (5-FU) is the current best treatment, while metastatic AC, chemotherapy with 5-FU and cisplatin remains the gold standard. There are no indications for induction or maintenance therapies in locally advanced tumors. Many novel strategies, such as targeted therapies, vaccination, immunotherapy and photodynamic therapy are in clinical trials for the treatment of AC, with promising results in some indications.

Anal squamous cell carcinoma: An evolution in disease and management

Anal cancer represents less than 1% of all new cancers diagnosed annually in the United States. Yet, despite the relative paucity of cases, the incidence of anal cancer has seen a steady about 2% rise each year over the last decade. As such, all healthcare providers need to be cognizant of the evaluation and treatment of anal squamous cell carcinoma. While chemoradiation remains the mainstay of therapy for most patients with anal cancer, surgery may still be required in recurrent, recalcitrant and palliative disease. In this manuscript, we will explore the diagnosis and management of squamous cell carcinoma of the anus.

KRAS and BRAF mutations in anal carcinoma

The EGF receptor (EGFR) is expressed in most cases of anal carcinomas. Anecdotal benefit from EGFR-targeted therapy has been reported in anal cancer and a negative correlation with Kirsten Ras (KRAS) mutation status has been proposed. The purpose of this retrospective study was to investigate the frequency and the prognostic value of KRAS and BRAF mutations in a large cohort of patients with anal cancer. One hundred and ninety-three patients with T1-4N0-3M0-1 anal carcinoma were included in the study. Patients were treated with curative (92%) or palliative intent (8%) between January 2000 and January 2010. KRAS mutations were detected using Therascreen(®)KRAS real-time PCR assay (Qiagen) and V600E or V600D/K BRAF mutations were uncovered using Pyrosequencing. The frequency of KRAS and BRAF mutations was low; KRAS mutations were detected in 1.6% and BRAF mutations in 4.7% of the biopsies. No impact of KRAS or BRAF status on survival was found. In conclusion, both KRAS and BRAF mutations are rare in anal cancer. The low frequency of KRAS mutations support protocols exploring EGFR-targeted therapy in patients with metastatic anal cancer, while treatment with BRAF inhibitors might be relevant for only a very few patients.

Chemoradiotherapy for anal cancer: clinical trials past, present and future

SUMMARY

Anal cancer is a rare cancer whose incidence is increasing in the UK. It is associated with human papilloma virus infection and smoking and is more common in women and immunosuppressed individuals, including those with transplants and HIV infection. The current standard of care is chemoradiotherapy (CRT) to the pelvis with surgery reserved for patients where CRT is contraindicated or as salvage treatment for residual disease or recurrence post-CRT. Radiotherapy combined with mitomycin-C and 5-fluorouracil has emerged as the standard of care following a series of six well-conducted Phase III trials. Trials have shown no benefit for cisplatin-based combination regimens either concurrently, adjuvantly or neoadjuvantly.

Efficacy and toxicity of chemoradiation in patients with anal cancer--a retrospective analysis

Background

Concurrent chemotherapy and radiation therapy is the preferred standard of care for patients with anal cancer. Several studies have suggested a benefit of intensity-modulated radiation therapy (IMRT) compared with 3D-conformal radiation (3D-CRT) regarding acute toxicity. This study evaluates outcome and toxicity of patients undergoing IMRT/Tomotherapy or 3D-CRT at our institution.

Methods

A cohort of 105 anal cancer patients was treated with chemoradiation or radiation alone (16.2%) between January 2000 and December 2011. 37 patients received 3D-CRT while 68 patients were treated with IMRT. Follow-up exams were performed every 3 to 6 months for a minimum of 3 years and then annually.

Results

Median follow-up was 41.4 months (2.8 – 158.4). Overall survival (OS), Progression-free survival (PFS) and local control (LC) at 3 years was 70.3%, 66.5%, 78.3% in the 3D-CRT group and 82.9%, 66.5%, 75.3% in the IMRT group without statistically significant difference. 3-year Colostomy-free survival (CFS) was 85.7% in the IMRT/Tomotherapy group and 91.8% in the 3D-CRT group (p = 0.48). No grade 4 toxicity was found in both groups. Severe (G2/3) acute skin toxicity (94.6% vs. 63.2%; p < 0.001) and acute gastrointestinal toxicity rate (67.6% vs. 47.1%; p = 0.03) was significantly higher with 3D-CRT compared to IMRT/Tomotherapy.

Conclusion

The use of IMRT can reduce acute severe side effects of the skin and gastrointestinal tract but did not demonstrate improved results regarding OS, PFS, LC and CFS.

KRAS, BRAF and PIK3CA status in squamous cell anal carcinoma (SCAC)

Anti-EGFR therapy appears to be a potential treatment option for squamous cell anal carcinoma (SCAC). KRAS mutation is a rare event in SCAC, indicating the absence of the principal mechanism of resistance to this type of therapy. However, no information is available from the literature regarding the status of BRAF or PIK3CA in this cancer type. We analysed KRAS, BRAF and PIK3CA status in SCAC patients in relation to the clinical-pathological characteristics of patients and to the presence of the human papilloma virus (HPV). One hundred and three patients were treated with the Nigro scheme for anal cancer from March 2001 to August 2012. Fifty patients were considered for the study as there was insufficient paraffin-embedded tumour tissue to perform molecular analysis the remaining 53. DNA was extracted from paraffin-embedded sections. KRAS, BRAF and PIK3CA gene status and HPV genotype were evaluated by pyrosequencing. KRAS and BRAF genes were wild-type in all cases. Conversely, PIK3CA gene was found to be mutated in 11 (22%) cases. In particular, 8 mutations occurred in exon 9 and 3 in exon 20 of the PIK3CA gene. These findings suggest that SCAC could potentially respond to an anti-EGFR drug. PIK3CA mutation may be involved in the process of carcinogenesis in some cases of SCAC.

Unexpected toxicity of cetuximab combined with conventional chemoradiotherapy in patients with locally advanced anal cancer: results of the UNICANCER ACCORD 16 phase II trial

BACKGROUND

The ACCORD 16 phase II trial aimed to evaluate the objective response rate after combination of conventional chemoradiotherapy (CRT) and cetuximab in locally advanced anal canal carcinoma (LAACC).

PATIENTS AND METHODS

Immunocompetent patients with histologically confirmed LAACC received CRT [45 gray (Gy)] in 25 fractions over 5 weeks, fluorouracil and cisplatin during weeks 1 and 5), in combination with weekly dose of cetuximab (250 mg/m(2) with a loading dose of 400 mg/m(2) 1 week before irradiation), and a standard dose boost (20 Gy). The trial was originally designed to include 81 patients to detect a 15% of objective response increase with the new combination in comparison with CRT.

RESULTS

The trial was prematurely stopped after the declaration of 15 serious adverse events (SAEs) in 14 out of 16 patients. Five patients received the entire planned treatment, and the compliance was higher after amendments of the protocol. Among the 15 SAEs, 6 were unexpected. Grade (G) 3/4 acute toxic effects, observed in 88% patients, were general (n = 13, 81%), digestive (n = 9, 56%), dermatological (n = 5, 31%), infectious (n = 4, 25%), haematological (n = 3, 19%), and others (n = 9); and three patients suffered from six G3/4 late toxic effects. No treatment-related death was reported. All 11 assessable patients had an objective response consisting of six complete (55%) and five partial (45%) response 2 months after the end of the treatment. Thirteen patients were followed up with a median of 22 months [95% confidence interval (CI ): 18-27] and had a 1-year colostomy-free survival, progression-free and overall survival rate of 67% (95% CI: 40%-86%), 62% (95% CI: 36%-82%), and 92% (95% CI: 67%-99%), respectively.

CONCLUSION

CRT plus cetuximab was unacceptably toxic in this population of patients. Results of others phase II trials evaluating this combination are awaited to confirm these findings.

EUDRA CT NO

2007-007029-38.

p16INK4A, p53, EGFR expression and KRAS mutation status in squamous cell cancers of the anus: correlation with outcomes following chemo-radiotherapy

BACKGROUND AND PURPOSE

Squamous cell carcinomas of the anal canal are associated with infection with Human Papilloma Viruses (HPVs). Chemo-radiotherapy (CRT) gives 70% 3-year relapse-free survival. Improved predictive markers and therapeutic options are required.

METHODS

Tumours from 153 patients treated with radical chemo-radiotherapy (50.4 Gy in 28# with concurrent Mitomycin and 5-Fluorouracil between 2004 and 2009) were retrieved and immunohistochemistry performed for p16(INK4A), p53 and EGFR and correlated with outcome. Primary and relapsed samples were analysed for mutations in KRAS.

RESULTS

137/153 (89.5%) stained moderately or strongly for p16(INK4A). p16(INK4A) correlated strongly with outcome. 37/137 patients demonstrating moderate/strong p16(INK4A) expression relapsed (27.0%), as opposed to 10/16 (62.5%) with absent/weak staining (log rank test p<0.001). p16 and p53 expression were inversely correlated. p16(INK4A) negative tumours were more frequent in men. p16(INK4A) negative patients had significantly worse overall survival (p<0.001). No mutations in KRAS were identified in primary tumours or relapses following treatment.

CONCLUSIONS

p16(INK4A) is strongly associated with relapse in SCC of the anus and identifies patients with very poor rates of relapse-free and overall survival. Primary and recurrent anal cancer expresses wild type KRAS, unaffected by treatment, supporting trials targeting EGFR in poor risk/recurrent anal cancer.

Ras and Ras mutations in cancer

Ras genes are pre-eminent genes that are frequently linked with cancer biology. The functional loss of ras protein caused by various point mutations within the gene, is established as a prognostic factor for the genesis of a constitutively active Ras-MAPK pathway leading to cancer. Ras signaling circuit follows a complex pathway, which connects many signaling molecules and cells. Several strategies have come up for targeting mutant ras proteins for cancer therapy, however, the clinical benefits remain insignificant. Targeting the Ras-MAPK pathway is extremely complicated due its intricate networks involving several upstream and downstream regulators. Blocking oncogenic Ras is still in latent stage and requires alternative approaches to screen the genes involved in Ras transformation. Understanding the mechanism of Ras induced tumorigenesis in diverse cancers and signaling networks will open a path for drug development and other therapeutic approaches.

Phase 1 study of cetuximab in combination with 5-fluorouracil, cisplatin, and radiotherapy in patients with locally advanced anal canal carcinoma

BACKGROUND

This study sought to determine the feasibility and recommended phase 2 dose (RP2D) of the combination of cetuximab with chemoradiotherapy based on 5-fluorouracil (5-FU) and cisplatin (CP) in locally advanced anal canal carcinoma.

METHODS

Cetuximab was administered on days 1, 8, 15, 29, 36, 43, and 50 (400 mg/m(2) initial dose, then 250 mg/m(2) /week) concurrent with total dose radiation of 55 to 59 Gy, both starting on day 1. Escalating doses of 5-FU (96-hour infusion) and CP (2-hour infusion), both on days 1 and 29, were administered according to the following design: starting dose level (0) 5-FU/CP = 800/60 mg/m(2) /day and up to dose level (+2) 5-FU/CP = 1000/80 mg/m(2) /day.

RESULTS

Dose-limiting toxicity (DLT) events (uncontrolled diarrhea or febrile neutropenia) occurred in 3 of 14 assessable patients receiving escalated dose of 5-FU/CP, with 1 in dose level (0) and 2 in dose level (+2). The RP2D was 5-FU/CP = 800/80 mg/m(2) /day. Because of unexpected non-DLT treatment-related grade 3 (G3) adverse events (AEs) such as thrombosis/embolism, syncope, and infection occurring in ≥ 20% of patients, a safety expansion cohort with an additional 9 patients was investigated with the RP2D. The most frequent G3/G4 AEs evaluated in 23 patients were radiation dermatitis (12 patients), diarrhea (10 patients), thrombosis/embolism (6 patients), and infection (5 patients). The study was closed due to these severe AEs, although no G5 AEs occurred. Twenty of 21 patients (95%) achieved pathological complete response at primary tumor. With a median follow-up of 43.4 months, the 3-year locoregional control rate was 64.2%.

CONCLUSIONS

Cetuximab could not be integrated with chemoradiotherapy-cisplatin-based therapy due to the high toxicity rate. However, efficacy is encouraging and further investigation of an epidermal growth factor receptor-targeted agent (other than cetuximab) concurrent with chemoradiation should be pursued.