A clinical and molecular portrait of non-metastatic anal squamous cell carcinoma

Clinical outcomes and prognostic factors of concurrent chemoradiotherapy for anal squamous cell carcinoma in Japan

BACKGROUND

Concurrent chemoradiotherapy (CCRT) is the standard treatment for locoregional anal squamous cell carcinoma (ASCC) in western countries. However, there have been few reports on the clinical outcomes of CCRT in Japan. This study aimed to evaluate the clinical outcomes of CCRT, prognostic factors, and the clinical impact of programmed cell death-ligand 1 (PD-L1) expression of ASCC in Japan.

METHODS

Patients with locoregional ASCC were enrolled between 2007 and 2017. All patients received CCRT consisting of ≥ 45 Gy of radiation, 5-fluorouracil, and mitomycin C. Disease-free survival (DFS), overall survival (OS), and adverse events (AEs) were estimated. Expression of p16 and PD-L1 were assessed by immunohistochemical staining (IHC).

RESULTS

This study included 36 patients, of whom 30 (83.3%) were female. Among the participants, 32 (88.9%) achieved complete clinical remission, while six (16.7%) experienced recurrence. The five-year DFS and five-year OS were 72.2% and 84.7%, respectively. Grades ≥ 3 serious AEs included neutropenia in 10 (27.7%) and perianal dermatitis in eight (22.2%). In a univariate analysis, male sex, lymph node metastasis, and large tumor size were significantly associated with worse outcome. In a multivariate analysis, tumor size was an independent factor associated with short DFS. Of the 30 patients whose biopsy specimens were available for IHC, 29 (96.7%) were positive for p16, and 13 (43.3%) were positive for PD-L1. However, PD-L1 expression did not show any clinical impact.

CONCLUSIONS

The comparative etiology, clinical outcomes, and prognostic factors of CCRT observed in Japanese patients with locoregional ASCC were consistent with western data.

HPV status and immunohistochemical analysis of p16, p53 and PD‑L1 expression as prognostic biomarkers in patients with squamous cell anal cancer receiving definitive radiotherapy/chemoradiotherapy

Anal squamous cell carcinoma (SCC) treated with definitive radiotherapy (RT)/chemoradiotherapy (CRT) has shown high success rates, yet challenges such as treatment resistance and recurrence persist. The present study aimed to investigate the associations between immunohistochemical (IHC) evaluation, treatment response and prognosis in anal SCC. A retrospective cohort analysis included 42 patients with anal SCC treated at a single institution between 2006 and 2022. Human papillomavirus (HPV) status was determined, and the IHC analysis of p16, p53 and PD-L1 expression was conducted using formalin-fixed, paraffin-embedded biopsies. A complete response to RT/CRT was observed in 71.4% of patients. Recurrence occurred in 38.1% of cases, of which 7.1% had local-regional recurrence (LRR), 14.3% had distant recurrence (DR), and 16.7% had both LRR and DR. HPV positivity (71.4%) was significantly associated with p16 positivity. Lack of complete response was associated with HPV-negative status, p16-negative status, increased recurrence and DR. In addition, recurrence was significantly associated with p53-positive status, and p53 positivity was significantly associated with increased LRR. PD-L1 positivity, defined as a combined positive score (CPS) ≥1% was found in 73.8% of the patients, and exhibited significant associations with HPV positivity and p16 positivity. PD-L1 CPS ≥ 1% was also associated with an increased LRR. Univariate analysis revealed that age <65 years, a complete response and HPV positivity were associated with increased 5-year overall survival (OS), while a complete response, HPV positivity and p53-negative status were associated with increased 5-year disease-free survival (DFS). Multivariate analysis identified that age <65 years and HPV positivity are independent prognostic factors for 5-year OS, and a complete response and p53-negative status are independent prognostic factors for 5-year DFS. In conclusion, these findings suggust that the identification of HPV status and poor prognostic biomarkers at diagnosis may be used to guide personalized treatment strategies, with the combination of immunotherapy with standard CRT potentially providing improved outcomes.

Transcriptome and microbiome-immune changes across preinvasive and invasive anal cancer lesions

Anal squamous cell carcinoma (ASCC) is a rare gastrointestinal malignancy linked to high-risk human papillomavirus (HPV) infection, which develops from precursor lesions like low-grade squamous intraepithelial lesions and high-grade squamous intraepithelial lesions (HGSILs). ASCC incidence varies across populations and poses increased risk for people living with HIV. Our investigation focused on transcriptomic and metatranscriptomic changes from squamous intraepithelial lesions to ASCC. Metatranscriptomic analysis highlighted specific bacterial species (e.g., Fusobacterium nucleatum, Bacteroides fragilis) more prevalent in ASCC than precancerous lesions. These species correlated with gene-encoding enzymes (Acca, glyQ, eno, pgk, por) and oncoproteins (FadA, dnaK), presenting potential diagnostic or treatment markers. Unsupervised transcriptomic analysis identified distinct sample clusters reflecting histological diagnosis, immune infiltrate, HIV/HPV status, and pathway activities, recapitulating anal cancer progression's natural history. Our study unveiled molecular mechanisms in anal cancer progression, aiding in stratifying HGSIL cases based on low or high risk of progression to malignancy.

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

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

Inflammatory pathways confer resistance to chemoradiotherapy in anal squamous cell carcinoma

Anal squamous cell carcinoma (ASCC) is associated with immunosuppression and infection with human papillomavirus (HPV). Response to standard chemoradiotherapy (CRT) varies considerably. A comprehensive molecular characterization of CRT resistance is lacking, and little is known about the interplay between tumor immune contexture, host immunity, and immunosuppressive and/or immune activating effects of CRT. Patients with localized ASCC, treated with CRT at three different sites of the German Cancer Consortium (DKTK) were included. Patient cohorts for molecular analysis included baseline formalin fixed paraffin embedded biopsies for immunohistochemistry (n = 130), baseline RNA sequencing (n = 98), peripheral blood immune profiling (n = 47), and serum cytokine measurement (n = 35). Gene set enrichment analysis showed that pathways for IFNγ, IFNα, inflammatory response, TNFα signaling via NF-κB, and EMT were significantly enriched in poor responders (all p < 0.001). Expression of interferon-induced transmembrane protein 1 (IFITM1), both on mRNA and protein levels, was associated with reduced Freedom from locoregional failure (FFLF, p = 0.037) and freedom from distant metastasis (FFDM, p = 0.014). An increase of PD-L1 expression on CD4+ T-cells (p < 0.001) and an increase in HLA-DR expression on T-cells (p < 0.001) was observed in the peripheral blood after CRT. Elevated levels of regulatory T-cells and CXCL2 were associated with reduced FFLF (p = 0.0044 and p = 0.004, respectively). Inflammatory pathways in tissue in line with elevated levels of regulatory T-cells and CXCL2 in peripheral blood are associated with resistance to CRT. To counteract this resistance mechanism, the RADIANCE randomized phase-2 trial currently tests the addition of the immune checkpoint inhibitor durvalumab to standard CRT in locally advanced ASCC.

Integrated genomic and transcriptomic analysis reveals the activation of PI3K signaling pathway in HPV-independent cervical cancers

BACKGROUND

HPV-independent cervical cancers (HPV-ind CCs) are uncommon with worse prognosis and poorly understood. This study investigated the molecular characteristics of HPV-ind CCs, aiming to explore new strategies for HPV-ind CCs.

METHODS

HPV status of 1010 cervical cancer patients were detected by RT-PCR, PCR and RNA-sequencing (RNA-seq). Whole exome sequencing (WES) and RNA-seq were performed in identified HPV-ind CCs. The efficacy of PI3Kα inhibitor BYL719 in HPV-ind CCs was evaluated in cell lines, patient-derived organoids (PDOs) and patient-derived xenografts (PDXs).

RESULTS

Twenty-five CCs were identified as HPV-ind, which were more common seen in older, adenocarcinoma patients and exhibited poorer prognosis as well as higher tumor mutation burden compared to HPV-associated CCs. HPV-ind CCs were featured with highly activated PI3K/AKT signaling pathway, particularly, PIK3CA being the most predominant genomic alteration (36%). BYL719 demonstrated superior tumor suppression in vitro and in vivo. Furthermore, HPV-ind CCs were classified into two subtypes according to distinct prognosis by gene expression profiles, the metabolism subtype and immune subtype.

CONCLUSIONS

This study reveals the prevalence, clinicopathology, and molecular features of HPV-ind CCs and emphasizes the importance of PIK3CA mutations and PI3K pathway activation in tumorigenesis, which suggests the potential significance of PI3Kα inhibitors in HPV-ind CC patients.

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

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

Pathogenic alterations in PIK3CA and KMT2C are frequent and independent prognostic factors in anal squamous cell carcinoma treated with salvage abdominoperineal resection

The management of anal squamous cell carcinoma (ASCC) has yet to experience the transformative impact of precision medicine. Conducting genomic analyses may uncover novel prognostic biomarkers and offer potential directions for the development of targeted therapies. To that end, we assessed the prognostic and theragnostic implications of pathogenic variants identified in 571 cancer-related genes from surgical samples collected from a homogeneous, multicentric French cohort of 158 ASCC patients who underwent abdominoperineal resection treatment. Alterations in PI3K/AKT/mTOR, chromatin remodeling, and Notch pathways were frequent in HPV-positive tumors, while HPV-negative tumors often harbored variants in cell cycle regulation and genome integrity maintenance genes (e.g., frequent TP53 and TERT promoter mutations). In patients with HPV-positive tumors, KMT2C and PIK3CA exon 9/20 pathogenic variants were associated with worse overall survival in multivariate analysis (Hazard ratio (HR)KMT2C  = 2.54, 95%CI = [1.25,5.17], P value = .010; HRPIK3CA  = 2.43, 95%CI = [1.3,4.56], P value = .006). Alterations with theragnostic value in another cancer type was detected in 43% of patients. These results suggest that PIK3CA and KMT2C pathogenic variants are independent prognostic factors in patients with ASCC with HPV-positive tumors treated by abdominoperineal resection. And, importantly, the high prevalence of alterations bearing potential theragnostic value strongly supports the use of genomic profiling to allow patient enrollment in precision medicine clinical trials.

Recent Advances in the Management of Anal Cancer

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

Prognostic Factors of Long-Term Outcomes after Primary Chemo-Radiotherapy in Non-Metastatic Anal Squamous Cell Carcinoma: An International Bicentric Cohort

Anal squamous cell carcinoma (ASCC) is a rare malignancy with a rising incidence associated with human papillomavirus (HPV) infection. The locally advanced disease is associated with a 30% rate of treatment failure after standard chemoradiotherapy (CRT). We aimed to elucidate the prognostic factors for ASCC after curative CRT. A retrospective multicenter study of 176 consecutive patients with ASCC having completed CRT treated between 2010 and 2017 at two centers was performed. Complete response (CR), disease-free survival (DFS), and overall survival (OS) were analyzed by Kaplan–Meier estimates with log-rank tests. The hierarchical clustering on principal components (HCPC) method was employed in an unsupervised and multivariate approach. The CR rate was 70% and was predictive of DFS (p < 0.0001) and OS (p < 0.0001), where non-CR cases were associated with shorter DFS (HR = 16.5, 95% CI 8.19–33.21) and OS (HR = 8.42, 95% CI 3.77–18.81) in a univariate analysis. The median follow-up was 38 months, with a 3-year DFS of 71%. The prognostic factors for DFS were cT1-T2 (p = 0.0002), N0 (p = 0.035), HIV-positive (p = 0.047), HIV-HPV coinfection (p = 0.018), and well-differentiated tumors (p = 0.037). The three-year OS was 81.6%. Female sex (p = 0.05), cT1-T2 (p = 0.02) and well-differentiated tumors (p = 0.003) were associated with better OS. The unsupervised analysis demonstrated a clear segregation of patients in three clusters, identifying that poor prognosis clusters associated with shorter DFS (HR = 1.74 95% CI = 1.25–2.42, p = 0.0008) were enriched with the locally advanced disease, anal canal location, HIV-HPV coinfection, and non-CR. In conclusion, our results reinforce the prognostic value of T stage, N stage, sex, differentiation status, tumor location, and HIV-HPV coinfection in ASCC after CRT.

The prognostic impact of PD-L1 and CD8 expression in anal cancer patients treated with chemoradiotherapy

Background

Programmed death-ligand 1 (PD-L1) expression has been shown to be prognostic in many cancer types and used in consideration of checkpoint inhibitor immunotherapy. However, there are very limited and conflicting data on the prognostic impact of PD-L1 in patients with anal squamous cell carcinoma (ASCC). The objectives of this study were to measure the expression of PD-L1 and CD8 in patients with ASCC treated with radical chemoradiotherapy (CRT) and to correlate tumor expression with progression-free survival (PFS) and overall survival (OS).

Methods

Ninety-nine patients with ASCC treated with primary CRT at two tertiary care cancer centers between 2000 and 2013, with available pre-treatment tumors, were included. Tissue microarrays (TMAs) from pre-treatment tumor specimens were stained for PD-L1 and CD8. PD-L1 expression in the tumor and stroma was quantified using HALO image analysis software, and results were interpreted using quantitative methods. The density of CD8 cells within the tumor was interpreted by a trained pathologist semi-quantitatively, using a 0-4 scoring system. Kaplan-Meier analysis with log-rank was used to determine the significance in the association of tumor markers with PFS and OS. Cox multivariate analysis was used to explore independent predictors of PFS and OS.

Results

Of the 99 patients, 63 (64%) had sufficient tumor samples available for full analysis. CD8 high status was documented in 32 of 63 (50.8%) % of cases. PD-L1 expression was positive in 88.9% of cases. Approximately half the patients had tumor PD-L1 ≥ 5%. Patients with tumor PD-L1 ≥ 5% had better OS vs those with lower expression, HR=0.32 (95% CI 0.11-0.87), p=0.027; 10 years OS: 84% for tumor PD-L1 ≥ 5% vs 49% for PD-L1 < 5%. PD-L1 expression was not associated with PFS. On multivariate analysis, tumor PD-L1 ≥ 5% showed a trend to statistical significance for better OS, HR=0.55 (95% CI 0.12- 1.00), p=0.052.

Conclusions

Tumor PD-L1≥5% is associated with OS in patients with ASCC treated with CRT. PD-L1 expression status using this unique cut-point warrants further validation for prognostication in patients with this disease. Future studies are required to determine the benefit of alternative treatment strategies based on PD-L1 status.

PD-L1 evaluation in the gastrointestinal tract: from biological rationale to its clinical application

Immune-checkpoint inhibitors targeting the PD-1/PD-L1 axis have brought significant clinical benefit in many solid cancer types, including gastrointestinal malignancies. However, it has been estimated that only 20-40% of patients respond to treatment. The pattern of expression and potential predictive value of PD-L1 as an immunohistochemical biomarker has been extensively studied in gastrointestinal neoplasms. Until now, its predictive value has been demonstrated, and is currently in use only in upper gastrointestinal malignancies (gastroesophageal adenocarcinoma and esophageal squamous cell carcinoma).

In this Review, we describe the technical aspects and challenges related to PD-L1 immunohistochemical assays, the current role of PD-L1 as a biomarker in clinical practice and we outline the main studies and clinical trials analyzing the prognostic and predictive value of PD-L1 in gastrointestinal cancers.

Biomarkers in Anal Cancer: Current Status in Diagnosis, Disease Progression and Therapeutic Strategies

Squamous cell carcinoma of the anal canal (SCCA) is a rare neoplasm, but with rising incidence rates in the past few decades; it is etiologically linked with the human papillomavirus (HPV) infection and is especially prevalent in immunocompromised patients, mainly those infected with HIV. Fluoropyrimidine-based chemoradiotherapy remains the cornerstone of the treatment of non-metastatic disease, but the locally advanced disease still presents high rates of disease recurrence and systemic therapy of SCCA is an unmet clinical need. Despite sharing common molecular aspects with other HPV-related malignancies, such as cervical and head and neck cancers, SCCA presents specific epigenomic, genomic, and transcriptomic abnormalities, which suggest that genome-guided personalized therapies should be specifically designed for this disease. Actionable mutations are rare in SCCA and immune checkpoint inhibition has not yet been proven useful in an unselected population of patients. Therefore, advances in systemic therapy of SCCA will only be possible with the identification of predictive biomarkers and the subsequent development of targeted therapies or immunotherapeutic approaches that consider the unique tumor microenvironment and the intra- and inter-tumoral heterogeneity. In the present review, we address the molecular characterization of SCCA and discuss potential diagnostic, predictive and prognostic biomarkers of this complex and challenging disease.

Simultaneous and Spatially-Resolved Analysis of T-Lymphocytes, Macrophages and PD-L1 Immune Checkpoint in Rare Cancers

Penile, vulvar and anal neoplasms show an incidence lower than 0.5% of the population per year and therefore can be considered as rare cancers but with a dramatic impact on quality of life and survival. This work describes the experience of a Chilean cancer center using multiplexed immunofluorescence to study a case series of four penile cancers, two anal cancers and one vulvar cancer and simultaneous detection of CD8, CD68, PD-L1, Cytokeratin and Ki-67 in FFPE samples. Fluorescent image analyses were performed using open sources for automated tissue segmentation and cell phenotyping. Our results showed an objective and reliable counting of objects with a single or combined labeling or within a specific tissue compartment. The variability was below 10%, and the correlation between analytical events was 0.92-0.97. Critical cell phenotypes, such as TILs, PD-L1+ or proliferative tumor cells were detected in a supervised and unsupervised manner with a limit of detection of less than 1% of relative abundance. Finally, the observed diversity and abundance of the different cell phenotypes within the tumor microenvironment for the three studied tumor types confirmed that our methodology is useful and robust to be applicable for many other solid tumors.

Neoadjuvant PD-1 Blockade Combined With Chemotherapy Followed by Concurrent Immunoradiotherapy in Locally Advanced Anal Canal Squamous Cell Carcinoma Patients: Antitumor Efficacy, Safety and Biomarker Analysis

Background

Anal canal squamous cell carcinoma (ACSCC) is an exceedingly rare malignant neoplasm with challenges in sphincter preservation, treatment toxicities and long-term survival. Little is known concerning the activity of PD-1 antibodies in locally advanced ACSCC. This study reports on the efficacy and toxicities of a neoadjuvant PD-1 blockade combined with chemotherapy followed by concurrent immunoradiotherapy in ACSCC patients, and describes biomarkers expression and mutation signatures.

Methods

In this cohort study, patients were treated as planned, including four cycles of neoadjuvant PD-1 antibody toripalimab combined with docetaxol and cisplatin, followed by radiotherapy and two cycles of concurrent toripalimab. Multiplex immunofluorescence staining (mIHC) with PD-L1, CD8, CD163, Pan-Keratin and DAPI was performed with the pretreatment tumor tissue. Whole exome sequencing was performed for the primary tumor and peripheral blood mononuclear cells. The primary endpoint was the complete clinical response (cCR) rate at 3 months after overall treatment. Acute and late toxicities graded were assessed prospectively.

Results

Five female patients with a median age of 50 years old (range, 43-65 years old), finished treatment as planned. One patient had grade 3 immune related dermatitis. Two patients had grade 3 myelosuppression during neoadjuvant treatment. No severe radiation-related toxicities were noted. Four patients with PD-L1 expression >1% achieved a cCR after neoadjuvant treatment. and the other patient with negative PD-L1 expression also achieved a cCR at 3 months after radiotherapy. All the patients were alive and free from disease and had a normal quality of life, with 19.6-24 months follow up. Inconsistent expression of PD-L1 and CD163 was detected in 3 and 5 patients, respectively. TTN, POLE, MGAM2 were the top mutation frequencies, and 80 significant driver genes were identified. Pathway analysis showed enrichment of apoptosis, Rap1, Ras, and pathways in cancer signaling pathways. Eight significantly deleted regions were identified.

Conclusions

This small cohort of locally advanced ACSCC patients had quite satisfactory cCR and sphincter preservation rate, after neoadjuvant PD-1 antibody toripalimab combined with chemotherapy followed by concurrent immunoradiotherapy, with mild acute and long-term toxicities.

Programmed Death Ligand-1 Expression Is Associated With Poorer Survival in Anal Squamous Cell Carcinoma

Context.—

Upregulation of programmed death ligand-1 (PD-L1), an immunoregulatory protein, is associated with an adverse outcome in several malignancies. Very few studies have evaluated PD-L1 expression in invasive anal squamous cell carcinoma (ASCC).

Objective.—

To assess PD-L1 expression in patients with ASCC and correlate it with clinicopathologic factors and clinical outcomes.

Design.—

Fifty-one cases of ASCC were immunostained for PD-L1. PD-L1 expression by combined positive score and tumor proportion score was correlated with age, gender, HIV status, HIV viral load, CD4 count, stage, and outcomes. Kaplan-Meier curves for overall survival were plotted and compared using the log-rank test. Cox regression analysis was performed to identify significant prognostic factors (2-tailed P &lt; .05 was considered statistically significant).

Results.—

PD-L1 was positive in 24 of 51 cases (47%) by combined positive score and in 18 of 51 (35%) by tumor proportion score. The median cancer-specific survival and 5-year overall survival were significantly lower in PD-L1+ patients. Age, gender, HIV status, HIV viral load, stage, and cancer progression were not significantly different between the two groups. CD4 count of more than 200/μL was significantly higher in PD-L1+ patients. PD-L1+ status remained statistically significant for worse overall survival on multivariate analysis.

Conclusions.—

PD-L1+ status is an independent adverse prognostic factor for overall survival in ASCC. This study highlights the potential of PD-L1 targeted therapy in better management of ASCC.

Prognostic impact of lymphopenia and neutrophil-lymphocyte ratio for patients with anal squamous cell carcinoma

Background

Outcomes after definitive chemoradiation for squamous cell carcinoma are generally favorable. However, biomarkers to further yield prognostic information are desired. Treatment-related lymphopenia as well as an elevated baseline neutrophil-lymphocyte ratio have been associated with worse survival in several cancer types. We evaluated absolute lymphocyte count and neutrophil-lymphocyte ratio at baseline and at treatment-related nadir in patients with anal cancer for associations with oncologic endpoints.

Methods

We conducted a retrospective analysis of 428 consecutive patients with non-metastatic anal cancer treated with definitive, intensity-modulated radiation therapy-based chemoradiation. We analyzed absolute neutrophil and lymphocyte counts at several timepoints: pretreatment, weekly during treatment, and in the six weeks following treatment completion. Neutrophil-lymphocyte ratio was calculated at baseline and treatment-related nadir. We estimated oncologic endpoints using life tables and compared them using the log-rank test. We conducted univariate and multivariable time-to-event analyses using Cox proportional hazards.

Results

Median absolute lymphocyte count at baseline and nadir were 1.80 [interquartile range (IQR), 1.45-2.32] k/µL and 0.26 (IQR, 0.18-0.36) k/µL, respectively, and 31% developed treatment-related grade 4 lymphopenia. Median neutrophil-lymphocyte ratio at baseline and nadir were 2.34 (IQR, 1.68-3.30) and 8.80 (IQR, 5.86-12.68), respectively. Estimates of overall survival, local failure-free survival, distant metastasis-free survival (DMFS), and freedom from colostomy at 5 years were 87%, 86%, 82%, and 88%, respectively. Baseline and nadir absolute lymphocyte count were not associated with selected outcomes on univariate analysis. On multivariable analysis, factors independently associated with death included T3-T4 disease, HIV-positive status, treatment break, and baseline neutrophil-lymphocyte ratio >3. Baseline neutrophil-lymphocyte ratio showed a trend toward association with distant progression or death (P=0.07). The 5-year overall survival estimates for patients with baseline neutrophil-lymphocyte ratios ≤3 and >3 were 92.3% and 80.6%, respectively.

Conclusions

Lymphopenia during and after chemoradiation for anal cancer is common but does not appear to be associated with worse survival, recurrence, or metastases. However, elevated baseline neutrophil-lymphocyte ratio was independently associated with overall survival, local recurrence-free survival, and DMFS. Further studies are needed to determine the clinical utility of baseline neutrophil-lymphocyte ratio to guide treatment and follow-up.