Chemoradiotherapy for squamous cell anal carcinoma: a review of prognostic factors

A Population-Level Validation of the New 9th Edition of the American Joint Commission on Cancer Staging System for Anal Squamous Cell Carcinoma

BACKGROUND AND OBJECTIVES

The staging system for anal squamous cell carcinoma (ASCC) was recently revised, downstaging selected node-positive patients and upstaging some with larger tumors. We aimed to validate this staging system using a population-based cohort.

METHODS

The Surveillance, Epidemiology, and End Results database was analyzed to identify adult ASCC patients. Patients were staged according to the American Joint Committee on Cancer (AJCC) 8th and 9th edition systems. Survival probabilities were estimated using Kaplan-Meier curves. Cox regression models were utilized to estimate the effect of stage on overall (OS) and cancer-specific survival (CSS).

RESULTS

A total of 2117 patients were identified and staged based on the two AJCC classifications. At 24 months when comparing stage IIB versus stage IIIA, the 8th edition revealed an improved OS (79% vs. 88%) and CSS (84% vs. 91%) for stage IIIA disease, while the 9th edition restored the hierarchical OS (IIB 88% vs. IIIA 78%) and CSS (91% vs. 82%) order.

CONCLUSIONS

The hierarchical increase of the OS HRs, and nearly all CSS HRs, across disease stages validated the updated edition of the AJCC classification. Although this change may not have significant implication on the management of ASCC, it does provide better prognostication.

Competing-risks analysis for evaluating the prognosis of patients with microinvasive cutaneous squamous cell carcinoma based on the SEER database

BACKGROUND

Utilizing the traditional Cox regression model to identify the factors affecting the risk of mortality due to microinvasive cutaneous squamous cell carcinoma (micSCC) may produce skewed results. Since cause-specific mortality can guide clinical decision-making, this study employed the Fine-Gray model based on the Surveillance, Epidemiology, and End Results (SEER) database to identify significant predictive variables for the risk of micSCC-related mortality.

METHODS

This study used the information of patients with micSCC who were listed in the SEER database during 2000-2015. Cox regression and Fine-Gray models were utilized for the multivariable analysis, and Gray's test and the cumulative incidence function were used for the univariable analyses.

RESULTS

There were 100 patients who died from other reasons and 38 who died from micSCC among the 1259 qualified patients with micSCC. Most were female, white, married, had localized metastasis, etc. According to the univariable Gray's test (P < 0.05), the cumulative incidence rate for events of interest was strongly associated with age, sex, marital status, American Joint Committee on Cancer staging, radiation status, summary stage, chemotherapy status, surgery status, and tumor size. Multivariable Cox regression analysis and multivariable competing-risks analysis indicated that age, tumor size, and income were independent risk variables for the prognosis of patients with micSCC. In both age and tumor size variables, the competing-risks model showed a slight decrease in the hazard ratio and a slight narrowing of the 95% confidence interval compared with the Cox regression model. However, this pattern is not evident in the income variable.

CONCLUSIONS

This study established a Fine-Gray model for identifying the independent risk factors that influence the risk of mortality among patients with micSCC. This study uncovers that, in the context of competing risks, age, tumor size, and income serve as independent risk factors influencing the risk of mortality due to micSCC among patients. Our findings have the potential to provide more accurate risk assessments for patient outcomes and contribute to the development of individualized treatment plans.

Estimating Risk of Locoregional Failure and Overall Survival in Anal Cancer Following Chemoradiation: A Machine Learning Approach

BACKGROUND

Optimal treatment of anal squamous cell carcinoma (ASCC) is definitive chemoradiation. Patients with persistent or recurrent disease require abdominoperineal resection (APR). Current models for predicting need for APR and overall survival are limited by low accuracy or small datasets. This study sought to use machine learning (ML) to develop more accurate models for locoregional failure and overall survival for ASCC.

METHODS

This study used the National Cancer Database from 2004-2018, divided into training, validation, and test sets. We included patients with stage I-III ASCC who underwent chemoradiation. Our primary outcomes were need for APR and 3-year overall survival. Random forest (RF), gradient boosting (XGB), and neural network (NN) ML-based models were developed and compared with logistic regression (LR). Accuracy was assessed using area under the receiver operating characteristic curve (AUROC).

RESULTS

APR was required in 5.3% (1,015/18,978) of patients. XGB performed best with AUROC of 0.813, compared with 0.691 for LR. Tumor size, lymphovascular invasion, and tumor grade showed the strongest influence on model predictions. Mortality was 23.6% (7,988/33,834). AUROC for XGB and LR were similar at 0.766 and 0.748, respectively. For this model, age, radiation dose, sex, and insurance status were the most influential variables.

CONCLUSIONS

We developed and internally validated machine learning-based models for predicting outcomes in ASCC and showed higher accuracy versus LR for locoregional failure, but not overall survival. After external validation, these models may assist clinicians with identifying patients with ASCC at high risk of treatment failure.

Impact of Time From Diagnosis to Treatment Start on the Outcomes of Patients With Nonmetastatic Anal Squamous Cell Carcinoma

OBJECTIVE

To assess the impact of time from diagnosis to treatment on the survival outcomes of patients with nonmetastatic anal squamous cell carcinoma, controlling for other clinicopathological features.

METHODS

Surveillance, Epidemiology, and End Results research plus database was accessed, and patients with nonmetastatic anal squamous cell carcinoma were reviewed. Factors associated with longer time to treatment were evaluated through multivariable logistic regression analysis. Kaplan-Meier survival estimates were used to examine survival differences according to time to treatment (≤2 vs. >2 mo), and multivariable Cox regression analysis was used to examine factors associated with worse overall and cancer-specific survival.

RESULTS

A total of 13,032 patients were considered eligible and they were included in this study. The following factors were associated with longer time to treatment (>2 mo): male sex (odds ratio [OR]: 1.503; 95% CI, 1.292 to 1.749), and non-White race (OR for Black vs. White patients: 1.846; 95% CI, 1.488 to 2.290; OR for American Indian vs. White patients: 2.414; 95% CI, 1.197 to 4.872; OR for Asian-Pacific Islanders vs. White patients: 2.182; 95% CI, 1.440 to 3.309). Using Kaplan-Meier survival estimates, longer time to treatment was associated with worse overall survival (median OS for >2 mo=109 mo; for ≤2 mo=164 mo P <0.0001). Using multivariable Cox regression analysis, the following factors were associated with worse overall survival: older age (hazard ratio [HR]: 1.037; 95% CI, 1.034 to 1.039), male sex (HR: 1.650; 95% CI, 1.548 to 1.758), Black race (HR: 1.341; 95% CI, 1.210 to 1.487), advanced stage (HR for regional vs. localized stage: 1.596; 95% CI, 1.500 to 1.698), and longer time to treatment (HR: 1.385; 95% CI, 1.222 to 1.571).

CONCLUSIONS

Time from diagnosis to treatment longer than 2 months is associated with worse survival outcomes among patients with nonmetastatic anal squamous cell carcinoma.

A population-based analysis of chemoradiation versus radiation alone in the definitive treatment of patients with stage I-II squamous cell carcinoma of the anus

BACKGROUND

The optimal management of patients with stage I-II squamous cell carcinoma (SCC) of the anus is controversial. The current study evaluates the efficacy of combined chemotherapy and radiation therapy (CRT) versus radiation therapy (RT) alone in the treatment of these patients using the Surveillance, Epidemiology, and End Results (SEER) registries.

METHODS

SEER 18 Custom Data registries were queried for patients with stage I-II SCC of the anus. Univariate analysis (UVA) and multivariable analysis (MVA) using Kaplan-Meier and Cox proportional hazards regression modeling were performed. Propensity-score matched analysis with inverse probability of treatment weighting (IPTW) was used to account for indication bias.

RESULTS

A total of 4,288 patients with stage I-II disease were identified, of whom 3,982 (93%) underwent CRT and 306 (7%) underwent RT. Median follow-up was 42 months. Approximately 30.8% had T1 disease and 69.2% had T2-T3 disease. The IPTW-adjusted 5-year overall survival (OS) was 76.7%, with no significant differences between the CRT and RT groups (77% vs. 73.5%, P=0.33). On multivariate IPTW-adjusted analysis, the lack of association between CRT use and OS was upheld (HR, 0.84, 95% CI, 0.65-1.08, P=0.2). On subgroup analyses, 5-year OS was 86% with CRT (n=1,216) and 84.2% with RT (n=103) (P=0.74) in stage I (T1N0) patients, while 5-year OS was 72.8% with CRT (n=2,766) and 66.4% with RT (n=203) (P=0.13) in stage II (T2-3N0) patients. CRT was associated with improved median OS in stage II patients (119 months vs. not reached, P=0.04).

CONCLUSIONS

The current study suggests that omission of concurrent chemotherapy is not associated with inferior OS in patients with stage I SCC of the anus. However, combined chemoradiation was superior to radiation alone in patients with stage II disease. Prospective evidence is needed to optimize clinical decision-making in this patient population.

The Prognostic Value of the New Combined Hemo-Eosinophil Inflammation Index (HEI Index): A Multicenter Analysis of Anal Cancer Patients Treated with Concurrent Chemo-Radiation

Anal squamous cell carcinoma (SCC) is a rare tumor, and bio-humoral predictors of response to chemo-radiation (CT-RT) are lacking. We developed a prognostic score system based on laboratory inflammation parameters. We investigated the correlation between baseline clinical and laboratory variables and disease-free (DFS) and overall (OS) survival in anal SCC patients treated with CT-RT in five institutions. The bio-humoral parameters of significance were included in a new scoring system, which was tested with other significant variables in a Cox's proportional hazard model. A total of 308 patients was included. We devised a prognostic model by combining baseline hemoglobin level, SII, and eosinophil count: the Hemo-Eosinophils Inflammation (HEI) Index. We stratified patients according to the HEI index into low- and high-risk groups. Median DFS for low-risk patients was not reached, and it was found to be 79.5 months for high-risk cases (Hazard Ratio 3.22; 95% CI: 2.04-5.10; p < 0.0001). Following adjustment for clinical covariates found significant at univariate analysis, multivariate analysis confirmed the HEI index as an independent prognostic factor for DFS and OS. The HEI index was shown to be a prognostic parameter for DFS and OS in anal cancer patients treated with CT-RT. An external validation of the HEI index is mandatory for its use in clinical practice.

The effect of anaemia on normal tissue toxicity and survival outcomes in prostate cancer treated with radical radiotherapy and neo-adjuvant androgen deprivation

OBJECTIVE

It has been established that survival and toxicity outcomes in some cancer types could be influenced by haemoglobin (Hb) levels. This study aims to determine if pre-treatment Hb is associated with late toxicity or survival outcomes in prostate cancer.

METHODS

Data from one Phase III randomised controlled trial and one single arm translational trial were analysed. Patients had localized prostate cancer and received ≥70 Gy radiotherapy and neo-adjuvant androgen deprivation between 1997 and 2013.

RESULTS

302 males were included. Median follow-up was 6.8 years for toxicity and 10.3 years for survival outcomes. Patients with Hb below the reference range were more likely to experience Grade 2-3 late gastrointestinal toxicity than patients with Hb within the range (p = 0.050). Neither late genitourinary toxicity, erectile function toxicity, prostate-specific antigen relapse free survival nor overall survival of patients were statistically significantly different between groups.

CONCLUSION

Anaemia in prostate cancer is found in the minority of patients and is usually mild. Prostate cancer patients undergoing radiotherapy with low Hb were more likely to experience Grade 2-3 late gastrointestinal toxicity.

ADVANCES IN KNOWLEDGE

This study is one of the first in the published literature to investigate the role of Hb in prostate cancer toxicity and survival. We have found an association between Hb below the reference range and late GI toxicity. Consideration should be given to further investigating patients with iron deficiency anaemia to guide management options and outrule underlying GI pathology before proceeding with radiotherapy treatment.

Survival benefits and predictors of use of chemoradiation compared with radiation alone for early stage (T1-T2N0) anal squamous cell carcinoma

Background

Standard of care treatment for anal squamous cell carcinoma (SCC) is concurrent chemoradiation (CRT). However, the necessity of CRT over radiation alone for T1-2N0 disease is less certain.

Methods

The National Cancer Database (NCDB) was queried to identify patients who received CRT, defined as initiation of chemo and RT within 14 days of each other, or RT alone (without any chemo during initial treatment phase) for cT1-2N0M0 SCC of the anus. The cohort was limited to patients less than 70 years old with Charlson-Deyo Comorbidity Index of 0, receiving a radiation dose range of 4,500-5,940 cGy. Univariable and multivariable logistic regression were performed to assess for predictors of CRT usage. Five-year overall survival (OS) was analyzed using the Kaplan-Meier method with the log rank test both for the full cohort and then on the subsets of T1 and T2 patients.

Results

We identified 4,564 patients, of whom 4,371 (95.8%) received CRT and 193 (4.2%) received RT alone. Median follow up was 49.8 months. About 33.5% of patients had cT1N0 disease, while 66.5% of patients had cT2N0 disease. On multivariable logistic regression, patients were more likely to receive CRT if they had T2 disease [OR 2.318 (1.732-3.102), P<0.0001]. Five-year OS was 86.6% for CRT and 79.1% for RT (P=0.001). For T1 patients, 5-year OS was 90.3% with CRT and 84.7% with RT (P=0.114). For T2 patients, 5-year OS was 84.7% with CRT and 72.8% with RT (P<0.0001). Multivariable Cox regression analysis confirmed association between OS and CRT use [HR 0.588 (95% CI: 0.430-0.804), P=0.001].

Conclusions

The vast majority of patients under age 70 without significant comorbidities are treated with CRT over radiation alone for early stage anal SCC, with better survival associated with CRT.

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.

The prognostic role of hemoglobin levels in patients undergoing concurrent chemo-radiation for anal cancer

BACKGROUND

Concurrent chemo-radiation (CT-RT) is a standard therapy for squamous cell carcinoma of anal canal. Different clinical and biological factors may potentially affect outcome. We investigated the prognostic role of baseline hemoglobin (Hb) in a cohort of anal cancer patients submitted to CT-RT with 5-fluorouracil and mitomycin C.

METHODS

Up to 161 patients with clinical stage T1-T4/N0-N3/M0 were treated. Response was assessed at 6 weeks and thereafter at 3, 6 and 12 months. Two different approaches were used:a)simultaneous integrated boost following RTOG 05-29 indications;b)first sequence of 45Gy/25 fractions to the pelvis followed by 9-14.4 Gy/5-8 fractions to the macroscopic disease. Primary endpoints were progression-free survival (PFS) and overall survival (OS).

RESULTS

On multivariate analysis, pre-treatment Hb level had a significant correlation to OS (HR:0.53;95% CI:0.33-0.87; p = 0.001), but not to PFS (HR:0.78;95% CI:0.53-1.15; p = 0.12) Patients with pre-treatment Hb ≥ 12 g/dl had 5-year PFS and OS of 82.2%, compared to 29.3% and 32.8% for those below the threshold. The likelihood to achieve a complete remission increased by 5.6% for every single-unit (g/dl) increase in baseline Hb level over 11 g/dl. On multivariate analysis, response to treatment had a significant correlation to PFS (incomplete vs complete response - HR:5.43;95% CI:2.75-10.7; p < 0.0001) and OS (HR: 6.96;95% CI:2.96-16.5; p < 0.0001).

CONCLUSIONS

We showed that baseline Hb level is a strong indicator for poor response to RT-CT in anal cancer patients. A close clinical monitoring for incomplete response to treatment should be advised in patients with low pre-treatment Hb. The hypothesis that the preservation of adequate Hb level during treatment may lead to a better outcome needs prospective evaluation.

Analysis of outcomes achieved with squamous cell carcinomas of the anus in a single university hospital over the last two decades: Clinical response rate, relapse and survival of 190 patients

BACKGROUND AND OBJECTIVES

We reviewed our series of anal squamous cell carcinomas (ASCC) treated over the last two decades.

METHODS

ASCC patients undergoing treatment at the Leicester Royal Infirmary between 1998 and 2016 were selected. Age, gender, pathological tumor characteristics, treatment adopted, the overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS) at 5-year follow-up were recorded and calculated.

RESULTS

A total of 190 ASCC were reviewed, of these 64.2% (n = 122) received primary radical chemoradiotherapy. Complete response rate was 92.6% (n = 113) and four patients with residual disease underwent a salvage APER. Twenty-eight patients experienced recurrent disease (23.0%) either systemic (n = 8), local (n = 14), or both (n = 6); six had a salvage APER. Complete follow-up data are available for 63.1% patients (77/122). Overall, the locoregional failure rate of primary chemoradiotherapy (residual + recurrent disease) was present in 29 patients (29/122; 23.8%). OS was 41.6% CSS was 69.2% and DFS 60.0% at 5 years follow-up.

CONCLUSIONS

In our series of ASCC primary chemoradiotherapy had achieved significant initial complete response rates, however, long term-follow ups still present systemic and local recurrences. APR is able to treat 30% of the pelvic recurrences (6/20), the others are either associated with systemic disease or locally inoperable masses.

Image-guided IMRT with simultaneous integrated boost as per RTOG 0529 for the treatment of anal cancer

AIM

To report on clinical outcomes of simultaneous integrated boost intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy as per Radiation Therapy Oncology Group (RTOG) 0529 protocol in anal cancer patients.

METHODS

Clinical stage T1-T4 N0-N3 anal cancer patients were submitted to concomitant chemoradiation. Patients with cT2N0 disease were prescribed 50.4 Gy/28 fractions to the gross tumor planning target volume (PTV) and 42 Gy/28 fractions to the elective nodal PTV. Patients staged as cT3-T4/N0-N3 were given 54 Gy/30 fractions to the macroscopic anal PTV, while clinical nodes were prescribed 50.4 Gy/30 fractions if <3 cm or 54 Gy/30 fractions if ≥3 cm; elective nodal PTV was prescribed 45 Gy/30 fractions. Two cycles of concomitant 5-fluorouracil and mitomycin C were planned for all patients. Oncological outcomes, acute and late toxicity profiles and pattern of failure were reported.

RESULTS

The 3-year colostomy-free survival rate was 64% (95% CI 0.52-0.75). The 3-year local control, disease-free and overall survival rates were 69% (95% CI 0.57-0.79), 71% (95% CI 0.59-0.80) and 79% (95% CI 0.66-0.87), respectively. The cumulative incidence of colostomies was 15.1% (95% CI 8.15-23.88) at 24 months. The cumulative incidence of cancer-specific deaths was 16.4% (95% CI 8.60-26.47) at 36 months. Major acute toxicity consisted of hematological (G3-G4: 26%) and cutaneous (G3-G4: 16%) events. Only one case of ≥G3 late toxicity was documented.

CONCLUSIONS

Simultaneous integrated boost IMRT and concurrent chemotherapy as per RTOG 0529 protocol seems to be safe and feasible with consistent oncological outcomes and a mild acute and late toxicity profile in anal cancer patients.