Chemoradiotherapy for squamous cell cancer of the anal canal: a systematic review

Rectal squamous cell carcinoma treated with neoadjuvant fluorouracil, oxaliplatin, cetuximab, and radiation: A case report of pathological complete response

RATIONALE

Treatment strategies for rectal squamous cell carcinoma (rSCC) are yet to be established, given its rarity. Although squamous cell carcinoma has been reported to be highly sensitive to cetuximab and radiation, there is no report of combination therapy of cetuximab and radiation for rSCC. In this study, we firstly reported a case of rSCC in which a complete response was achieved with the original chemoradiotherapy comprising oxaliplatin, S-1, cetuximab, and simultaneous radiation.

PATIENT CONCERNS

A 46-year-old women presented to our hospital with lower abdominal pain and fatigue.

DIAGNOSES

Based on tumor marker analyses, histological examination of biopsy specimens, and comprehensive imaging, the patient was diagnosed with rSCC.

INTERVENTIONS

Neoadjuvant chemoradiotherapy (50.4 Gy) was administered in 28 fractions, along with concurrent chemotherapy comprising SOX (S-1: 80 mg/m2, days 1-5 and 8-12, oxaliplatin: 85 mg/m2, day 1) and cetuximab (400 mg/m2, day 1, 250 mg/m2, after day 8).

OUTCOMES

Five weeks after chemoradiation, the patient underwent laparoscopic partial intersphincteric resection, achieving a complete pathological response.

LESSONS

This case firstly highlights the usefulness of SOX plus cetuximab combined with radiation in the treatment of locally advanced rSCC. However, a large-scale study is required to establish safe and effective treatment regimens.

Concurrent Chemo-radiotherapy in Anal Squamous Cell Carcinoma: A Retrospective Review of a Tertiary Centre Experience

PURPOSE

Anal cancer is a rare form of gastrointestinal malignancy, and treatment is often confined to specialist centres. It has a high cure rate with non-surgical approach resulting in organ preservation. The current accepted schedule is chemo-radiotherapy (CRT) with 5-fluorouracil and mitomycin with radiotherapy doses between 50.4 and 53.2 Gray in 28 fractions.

METHODS

This study included patients who had histological confirmation of squamous cell carcinoma and had completed the full CRT course for anal cancer between 2008 and 2018 in our centre. Data was collected retrospectively assessing demographics, staging, surgery, relapse, latest follow-up, date of death, CRT regimen and TNM stage. Outcome data and stoma reversal rate were analysed.

RESULTS

Overall, 87 patients were included in the study. At diagnosis 94.3% of patients had T2-T4 disease, and 44.8% had involvement of positive loco-regional lymph nodes. Overall survival (OS) probability at 1, 3 and 5 years were 98.8%, 87.4% and 83.7%, respectively. Results also revealed a statistically significant effect of time from diagnosis to the start of radiotherapy on OS (p = 0.039). Sixty-nine (79.3%) patients achieved complete remission at last follow-up. Twenty-one patients (24%) underwent surgery for a de-functioning stoma, and only five of these patients subsequently received stoma reversal surgery.

CONCLUSIONS

Our data reflects the efficacy of CRT as the primary modality of treatment in the management of anal squamous cell carcinoma with effective organ preservation and disease control. Early stoma reversal may also enhance quality of life.

Definitive Radiotherapy for Patients With Anal Squamous Cell Carcinoma: A Retrospective Cohort Study

Background

Anal squamous cell carcinoma accounts for less than 2-3% of all digestive system carcinomas. The present study aimed to determine the clinical characteristics, treatment patterns, and treatment outcomes of patients at our institution.

Methodology

We reviewed the clinical data of all consecutive patients with anal squamous cell carcinoma who were treated with definitive radiotherapy in our department between July 2009 and July 2020. Radiotherapy was delivered in 1.8-2 Gy daily fractions to a whole pelvic dose ranging from 45 to 50 Gy, followed by boost radiotherapy of 10-15 Gy, resulting in a total dose of approximately 60 Gy. Concurrent chemotherapy with radiotherapy included 5-fluorouracil/mitomycin C or 5-fluorouracil/cisplatin.

Results

A total of 14 patients with a median age of 61.5 years (range: 45-85 years) were analyzed. There were nine women and five men. The clinical T stage was T1 in two patients, T2 in six patients, T3 in two patients, and T4 in four patients. The clinical N stage was N0 in four patients and N1 in 10 patients. Patients with clinical stage III disease comprised 79% of the entire study population. For the entire cohort, the five-year overall survival rate was 83.3% and the five-year progression-free survival rate was 48.5%. One patient experienced grade 3 fecal incontinence, and the others experienced no radiation-induced severe delayed adverse events.

Conclusions

The results of our study demonstrated that definitive radiotherapy with or without chemotherapy for patients with anal squamous cell carcinoma is an effective and feasible treatment.

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.

Anal canal squamous carcinoma

Background Anal canal carcinoma is a rare neoplasm, representing 2% of the digestive tumors, and the most common is squamous cell carcinoma, with an increasing incidence.

Objective The study aims to elucidate the pathogenesis of an increasingly prevalent disease, as well as to update treatment and prognosis.

Methods A literature search in Pubmed database, including articles from 2005 to 2015 and cross-research articles with the initial research.

Results Several studies prove the role of HPV as a major risk factor in the development of squamous cell carcinoma of anal canal, as well as a greater prevalence of this neoplasia in HIV-positive people and in those who practice receptive anal intercourse. In the last two decades chemoradiotherapy remains the treatment of choice, and abdominoperineal resection is reserved for those cases of treatment failure or recurrence. Evidence advances in order to adapt the treatment to each patient, taking into account individual prognostic factors and biological tumor characteristics.

Conclusions Squamous cell carcinoma of the anal canal is a neoplasm associated with HPV; therefore, screening and vaccination programs of male individuals, by way of prevention, should be started. Many studies are needed in order to achieve development in the treatment as well as in the evaluation of the biological characteristics of the tumor.

Oncological therapy to Swedish men with metastatic penile cancer 2000-2015

BACKGROUND

Penile cancer is an uncommon disease with poor prognosis when spread to more than one inguinal lymph node. Recommendations on chemo- and radiotherapy in treatment guidelines are based on low-grade evidence. There are to our knowledge no described population-based cohort with detailed information on given oncological treatment and survival data. The aim of this study is to investigate in detail how men with metastatic penile cancer have been treated with chemotherapy and radiotherapy over time, and how survival varies with N-stage and given treatment.

MATERIAL AND METHODS

For this observational cohort study all men in Sweden diagnosed with penile cancer with lymph node- or distant metastases 2000-2015 were identified through the Swedish National Penile Cancer Register (NPECR). Medical records were retrieved and 325 men were confirmed to have metastatic penile cancer (T_any, c or pN1-3 and/or M1). Information on treatments was collected. Causes of death were retrieved from the National Cause of Death Register (CDR).

RESULTS

Chemotherapy and/or radiotherapy were given to 172 (53%) of all men. The use of oncological treatments with curative intent increased significantly during the study period, from 30% of men with c/pN2-3 diagnosed 2000-2003 compared with 57% of men diagnosed 2012-2015. Ninety-three (29%) men received oncological treatments with curative intent of whom 85/93 (91%) had stage c/pN2-3M0. Survival decreased with higher N-stage, M1-stage, and absence of oncological treatment with curative intent. For men with c/pN3-stage, the engagement of pelvic lymph nodes was entailed with lower survival than pN3 based on extra-nodal extension (ENE).

CONCLUSION

The use of oncological treatment was below recommendations in guidelines but increased during the study period. Treatment was given predominantly to men with c/pN2-3 and M1-disease. Survival was higher among men treated with curative intent; this could be due to patient selection bias.

Pooled Analysis of external-beam RADiotherapy parameters in phase II and phase III trials in radiochemotherapy in Anal Cancer (PARADAC)

PURPOSE

Concomitant external-beam radiochemotherapy (5-fluorouracil-mitomycin C) has become the standard of care in anal cancer since the '90s. A pooled analysis of individual patient data from 7 major trials was performed quantifying the effect of radiation therapy (RT)-related parameters on the outcome of patients with anal cancer.

MATERIALS AND METHODS

Pooling databases from combined modality trials, the impact of RT parameters (total dose, gap duration, OTT: overall treatment time) on outcome including locoregional failure (LRF), 5-year progression free survival (PFS) and toxicities were investigated. Individual patient data were received for 10/13 identified published studies conducted from 1987 to 2008 (n = 3031). A Cox regression model was used (landmark = 3 months after RT for first follow-up).

RESULTS

After data inspection indicating severe heterogeneity between trials, only 1343 patients from 7/10 studies received were analysed (the most recent ones, since 1994; median follow-up = 4.1 years). A higher overall 5-year LRF rate [22.8% (95% confidence interval [CI] 22.3-27.3%)] significantly correlated with longer OTT (p = 0.03), larger tumour size (p < 0.001) and male gender (p = 0.045). Although significant differences were not observed, subset analyses for LRF (dose range: 50.4-59 Gy) seemed to favour lower doses (p = 0.412), and when comparing a 2-week gap versus 3 (dose: 59.4 Gy), results suggested 3 weeks might be detrimental (p = 0.245). For a 2-week gap versus none (dose range: 55-59.4 Gy), no difference was observed (p = 0.89). Five-year PFS was 65.7% (95% CI: 62.8-68.5%). Higher PFS rates were observed in women (p < 0.001), smaller tumour sizes (p < 0.001) and shorter OTT (p = 0.025). Five-year overall survival [76.7% (95% CI: 73.9%-79.3%)] correlated positively with female gender (p < 0.001), small tumour size (p = 0.027) and short OTT (p = 0.026). Descriptive toxicity data are presented.

CONCLUSION

For patients receiving concurrent external-beam doublet chemoradiation, a longer OTT seems detrimental to outcome. Further trials involving modern techniques may better define optimal OTT and total dose.

A novel tumor spheroid model identifies selective enhancement of radiation by an inhibitor of oxidative phosphorylation

There is a need for preclinical models that can enable identification of novel radiosensitizing drugs in clinically relevant high-throughput experiments. We used a new high-throughput compatible total cell kill spheroid assay to study the interaction between drugs and radiation in order to identify compounds with radiosensitizing activity. Experimental drugs were compared to known radiosensitizers and cytotoxic drugs clinically used in combination with radiotherapy. VLX600, a novel iron-chelating inhibitor of oxidative phosphorylation, potentiated the effect of radiation in tumor spheroids in a synergistic manner. This effect was specific to spheroids and not observed in monolayer cell cultures. In conclusion, the total cell kill spheroid assay is a feasible high-throughput method in the search for novel radiosensitizers. VLX600 shows encouraging characteristics for development as a novel radiosensitizer.

MRI heterogeneity analysis for prediction of recurrence and disease free survival in anal cancer

BACKGROUND

The aim of this study was to evaluate the role of image heterogeneity analysis of standard care magnetic resonance imaging (MRI) in patients with anal squamous cell carcinoma (ASCC) to predict chemoradiotherapy (CRT) outcome. The ability to predict disease recurrence following CRT has the potential to inform personalized radiotherapy approaches currently being explored in novel clinical trials.

METHODS

An IRB waiver was obtained for retrospective analysis of standard care MRIs from ASCC patients presenting between 2010 and 2014. Whole tumor 3D volume-of-interest (VOI) was outlined on T2-weighted (T2w) and diffusion weighted imaging (DWI) of the pre- and post-treatment scans. Independent imaging features most predictive of disease recurrence were added to the baseline clinico-pathological model and the predictive value of respective extended models was calculated using net reclassification improvement (NRI) algorithm. Cross-validation analysis was carried out to determine percentage error reduction with inclusion of imaging features to the baseline model for both endpoints.

RESULTS

Forty patients who underwent 1.5 T pelvic MRI at baseline and following completion of CRT were included. A combination of two baseline MR heterogeneity features (baseline T2w energy and DWI coefficient of variation) was most predictive of disease recurrence resulting in significant NRI (p = 0 < 0.001). This was confirmed in cross-validation analysis with 34.8% percentage error reduction for the primary endpoint and 18.1% reduction for the secondary endpoint with addition of imaging variables to baseline model.

CONCLUSION

MRI heterogeneity analysis offers complementary information, in addition to clinical staging, in predicting outcome of CRT in anal SCC, warranting validation in larger datasets.

Toxicity, Tolerability, and Compliance of Concurrent Capecitabine or 5-Fluorouracil in Radical Management of Anal Cancer With Single-dose Mitomycin-C and Intensity Modulated Radiation Therapy: Evaluation of a National Cohort

PURPOSE

Chemoradiation therapy (CRT) with mitomycin C (MMC) and 5-fluorouracil (5-FU) is established as the standard of care for the radical treatment of patients with anal squamous cell carcinoma (ASCC). The use of the oral fluoropyrimidine-derivative capecitabine is emerging as an alternative to 5-FU despite limited evidence of its tolerability and toxicity.

METHODS AND MATERIALS

A national cohort evaluation of ASCC management within the United Kingdom National Health Service was undertaken from February to July 2015. The toxicity rates were prospectively recorded. For the present analysis, we report data from ASCC patients who underwent intensity modulated RT and a single dose of MMC with either 5-FU (5-FU/MMC) or capecitabine (capecitabine/MMC). All were treated with radical intent and intensity modulated radiation therapy (IMRT) was delivered in accordance with UK guidance.

RESULTS

Of the 242 patients received from 40 centers across the United Kingdom, 147 met the inclusion criteria; 52 of whom were treated with capecitabine/MMC and 95 with 5-FU/MMC. No treatment-related deaths and no overall difference were found in the proportion of patients experiencing any grade ≥3 toxicity between the capecitabine and 5-FU groups (45% vs 55%; P = .35). However, significantly fewer patients in the capecitabine/MMC group experienced grade 3 hematologic toxicity (4% vs 27%; P = .001). A lower proportion of patients completed their planned chemotherapy course in the capecitabine cohort, although this did not reach statistical significance (81% vs 90%; P = .21). The median RT duration was 38 days (interquartile range 38-39) for both groups. No difference was found in the 1-year oncologic outcomes.

CONCLUSIONS

Capecitabine/MMC resulted in similar levels of grade 3/4 toxicity overall compared with 5-FU/MMC as CRT for ASCC, although differences were found in the patterns of observed toxicities, with less hematologic toxicity with capecitabine. Further studies of capecitabine/MMC are required to understand the acute toxicity profile and long-term oncologic outcomes of this combination with intensity modulated RT for ASCC.

Feasibility of preference-driven radiotherapy dose treatment planning to support shared decision making in anal cancer

PURPOSE/OBJECTIVE

Chemo-radiotherapy is an established primary curative treatment for anal cancer, but clinically equal rationale for different target doses exists. If joint preferences (physician and patient) are used to determine acceptable tradeoffs in radiotherapy treatment planning, multiple dose plans must be simultaneously explored. We quantified the degree to which different toxicity priorities might be incorporated into treatment plan selection, to elucidate the feasible decision space for shared decision making in anal cancer radiotherapy.

MATERIAL AND METHODS

Retrospective plans were generated for 22 anal cancer patients. Multi-criteria optimization handles dynamically changing priorities between clinical objectives while meeting fixed clinical constraints. Four unique dose distributions were designed to represent a wide span of clinically relevant objectives: high-dose preference (60.2 Gy tumor boost and 50.4 Gy to elective nodes with physician-defined order of priorities), low-dose preference (53.75 Gy tumor boost, 45 Gy to elective nodes, physician-defined priorities), bowel sparing preference (lower dose levels and priority for bowel avoidance) and bladder sparing preference (lower dose levels and priority for bladder avoidance).

RESULTS

Plans satisfied constraints for target coverage. A senior oncologist approved a random subset of plans for quality assurance. Compared to a high-dose preference, bowel sparing was clinically meaningful at the lower prescribed dose [median change in V_45Gy: 234 cm³; inter-quartile range (66; 247); p < .01] and for a bowel sparing preference [median change in V_45Gy: 281 cm³; (73; 488); p < .01]. Compared to a high-dose preference, bladder sparing was clinically meaningful at the lower prescribed dose [median change in V_35Gy: 13.7%-points; (0.3; 30.6); p < .01] and for a bladder sparing preference [median change in V_35Gy: 30.3%-points; (12.4; 43.1); p < .01].

CONCLUSIONS

There is decision space available in anal cancer radiotherapy to incorporate preferences, although tradeoffs are highly patient-dependent. This study demonstrates that preference-informed dose planning is feasible for clinical studies utilizing shared decision making.

Chemoradiotherapy with Brachytherapy or Electron Therapy Boost for Locally Advanced Squamous Cell Carcinoma of the Anus-Reducing the Colostomy Rate

Purpose

The aim of this study is to determine overall survival, disease-specific survival and stoma-free survival after treatment of squamous cell carcinoma of the anus with chemoradiotherapy followed by brachytherapy or electron boost in a recent cohort of patients.

Methods

Fifty-two patients (median age 62 years) were treated with radical chemoradiotherapy (mitomycin C, infusional 5-fluorouracil concurrently with conformal radical radiotherapy 45 Gy in 25 fractions over 5 weeks) followed by a radiotherapy boost between 1 December 2000 and 30 April 2011. Follow-up was to 30 November 2014. Thirty-six patients received a boost (15–20 Gy) over 2 days with ¹⁹²Ir needle brachytherapy for anal canal tumours, and 16 patients received electron beam therapy (20 Gy in 10 fractions in 2 weeks) for anal margin tumours. A defunctioning stoma was only created prior to chemoradiotherapy for fistula or severe anal pain.

Results

The overall survival for the 36 patients treated with chemoradiotherapy followed by brachytherapy was 75 % (95 % CI, 61–89) at 5 years, the disease-specific survival was 91 % (95 % CI, 81–101 %), and the stoma-free survival was 97 % (95 % CI, 91–103 %) all at 5 years. For the 16 patients treated with an electron boost for anal margin tumours, the 5-year overall survival, disease-specific survival and stoma-free survival were 68 % (95 % CI, 44–92 %), 78 % (95 % CI, 56–100 %) and 80 % (95 % CI, 60–100 %), respectively.

Conclusions

A very low stoma formation rate can be obtained with radical chemoradiotherapy followed by a brachytherapy boost for squamous cell carcinoma of the anal canal but not with an electron boost for anal margin tumours.

Biomarkers in anal cancer: from biological understanding to stratified treatment

Squamous cell carcinomas of the anus and anal canal represent a model of a cancer and perhaps the first where level 1 evidence supported primary chemoradiotherapy (CRT) in treating locoregional disease with curative intent. The majority of tumours are associated with infection with oncogenic subtypes of human papilloma virus and this plays a significant role in their sensitivity to treatment. However, not all tumours are cured with CRT and there remain opportunities to improve outcomes in terms of oncological control and also reducing late toxicities. Understanding the biology of ASCC promises to allow a more personalised approach to treatment, with the development and validation of a range of biomarkers and associated techniques that are the focus of this review.

Squamous-cell carcinoma of the anus: progress in radiotherapy treatment

Chemoradiotherapy is the standard-of-care treatment of squamous-cell carcinoma of the anus (SCCA), and this has not changed in decades. Radiation doses of 50-60 Gy, as used in many phase III trials, result in substantial late morbidities and fail to control larger and node-positive tumours. Technological advances in radiation therapy are improving patient outcomes and quality of life, and should be applied to patients with SCCA. Modern techniques such as intensity-modulated radiotherapy (IMRT), rotational IMRT, image-guided radiotherapy using cone-beam CT, and stereotactic techniques have enabled smaller margins and highly conformal plans, resulting in decreased radiation doses to the organs at risk and ensuring a shorter overall treatment time. In this Perspectives article, the use of novel approaches to target delineation, optimized radiotherapy techniques, adaptive radiotherapy, dose-escalation with external-beam radiotherapy (EBRT) or brachytherapy, and the potential for modified fractionation are discussed in the context of SCCA.