Evolution and Management of Treatment-Related Toxicity in Anal Cancer

Preclinical Models of Anal Cancer Combined-Modality Therapy

INTRODUCTION

There have been no significant changes in anal cancer treatment options in 4 decades. In this study, we highlight two preclinical models designed to assess anal cancer treatments.

MATERIALS AND METHODS

Transgenic K14E6/E7 mice were treated with 7, 12-dimethylbenz(a)anthracene until anal tumors developed. Mice were treated with localized radiation in addition to chemotherapy (combined-modality therapy [CMT]) and compared to no treatment control (NTC). K14E6/E7 mouse anal spheroids with and without Pik3ca mutations were isolated and treated with vehicle, LY3023414 (LY3) (a drug previously shown to be effective in cancer prevention), CMT, or CMT + LY3.

RESULTS

In the in vivo model, there was a significant increase in survival in the CMT group compared to the NTC group (P = 0.0392). In the ex vivo model, there was a significant decrease in the mean diameter of CMT and CMT + LY3-treated spheroids compared to vehicle (P ≤ 0.0001). For LY3 alone compared to vehicle, there was a statistically significant decrease in spheroid size in the K14E6/E7 group without mutation (P = 0.0004).

CONCLUSIONS

We have provided proof of concept for two preclinical anal cancer treatment models that allow for the future testing of novel therapies for anal cancer.

Anal cancer: a 20-year retrospective study from Australia

BACKGROUNDS

Anal cancer is an uncommon condition, occurring at higher rates in specific subpopulations. Clinical experience is limited and substantial changes have recently occurred in our understanding of this condition. We, therefore, set out to characterize patients presenting with anal cancer and investigate whether there have been any changes over the past 20 years.

METHODS

Retrospective audit of cases identified from pathology and clinical databases during the period 1 January 2000 to 31 December 2019.

RESULTS

Two hundred and sixteen patients had anal squamous cell carcinomas, comprising 160 (74%) males and 56 (26%) females. Mean age at initial diagnosis was 55.1 ± 11.20 for males and 60.6 ± 15.18 for females (P = 0.02). At initial diagnosis, HIV-positive cases were significantly younger than HIV negative cases (mean 52.2 ± 9.35 vs. 62.8 ± 11.61, P < 0.001); 46% of cases were classified as intra-anal, 29% perianal and 25% both; 52% were > 2 cm at diagnosis. At presentation, intra-anal cases were larger and more advanced than perianal cases (P = 0.049). Compared with the period 2000-2009, anal cancers presented more commonly in 2010-2019 (148 vs. 76), were more likely to occur in HIV-negative people and to be diagnosed at a similar stage.

CONCLUSION

The number of anal cancer cases almost doubled over the study period and people living with HIV presented 10 years younger than others. Perianal cases presented earlier than those originating in intra-anal locations. Together with the large size at diagnosis, this suggests the potential value of screening, particularly for intra-anal cancers in those at high risk.

Follow-up imaging of anal cancer after treatment

Anal cancer treatment response assessment can be challenging with both magnetic resonance imaging (MRI) and clinical evaluation considered essential. MRI, in particular, has shown to be useful for the assessment of treatment response, the detection of recurrent disease in follow up and surveillance, and the evaluation of possible post-treatment complications as well as complications from the tumor itself. In this review, we focus on the role of imaging, mainly MRI, in anal cancer treatment response assessment. We also describe the treatment complications that can occur, and the imaging findings associated with those complications.

Chemoradiation vs. local excision in the management of early squamous cell carcinoma of the anus: a systematic review

PURPOSE

Squamous cell carcinoma of the anus (SCCA) suffers a constant increase each year in the last decades. Recent studies suggested the possibility of local excision (LE) as an option for early-stage SCAC patients. This systematic review aims to summarize the available evidence on the comparison of LE vs. chemoradiotherapy (CRT) in the treatment of early SCCA patients.

METHODS

We conducted a literature review including MEDLINE/PubMed, EMBASE, SCOPUS, clinicaltrials.gov, and the Cochrane Database of Systematic Reviews through June 2022. MOOSE guidelines were followed. We used the methodological index for non-randomized studies (MINORS) tool to assess quality. Data on survival and procedure-associated costs were extracted.

RESULTS

Four retrospective studies including 3323 patients were included. They were all comparative retrospective cohort studies (three were registry-based studies, either NCDB or SEER) with a MINORS score of 16-19 points. Overall survival (OS) was comparable between LE and CRT patients in three studies, with a 5-year OS of 85.3-100% in LE patients and 85-91.6% in CRT patients. One study investigated cancer-specific survival (CSS) and reported similar 5-year CSS in LE (98%) and CRT patients (96%). One investigated progression-free survival (PFS) and did not report any statistically significant difference in 5-year PFS between LE (91%) and CRT patients (83%). Only one study considered the mean costs associated with the two approaches (29,210 USD with LE and 46,350 USD with CRT).

CONCLUSIONS

LE may potentially be considered a valid alternative to CRT for patients with early-stage SCAA. Results of prospective randomized long-term trials comparing LE with CRT are warranted to draw definitive conclusions and consider LE as a true cost-effective strategy for T1N0 SCCA with similar oncologic results offered by CRT, which-to date-remains the "gold standard."

PROSPERO REGISTRATION

CRD42022338750.

Radiodermatitis: severity, predictive factors and discontinuation of radiotherapy in patients with anal and rectal cancer

OBJECTIVE

to determine the prevalence of radiodermatitis, severity grades and predictive factors of its occurrence in patients with anal and rectal cancer followed up by the nursing consultation, and to analyze the association of severity grades of radiodermatitis with temporary radiotherapy interruption.

METHOD

a quantitative, cross-sectional and retrospective study, carried out with 112 medical records of patients with anal and rectal cancer undergoing curative radiotherapy followed up in the nursing consultation. Data were collected using a form and analyzed using analytical and inferential statistics.

RESULTS

99.1% of patients had radiodermatitis, 34.8% of which were severe. The predictive factors were female sex, age greater than 65 years, anal canal tumor, treatment with cobalt device and IMRT technique. Treatment interruption occurred in 13% of patients, associated with severe radiodermatitis.

CONCLUSION

there was a high prevalence of radiodermatitis, mainly severe, which resulted in treatment interruption.

Treatment of Anal High-Grade Squamous Intraepithelial Lesions to Prevent Anal Cancer

BACKGROUND

The incidence of anal cancer is substantially higher among persons living with the human immunodeficiency virus (HIV) than in the general population. Similar to cervical cancer, anal cancer is preceded by high-grade squamous intraepithelial lesions (HSILs). Treatment for cervical HSIL reduces progression to cervical cancer; however, data from prospective studies of treatment for anal HSIL to prevent anal cancer are lacking.

METHODS

We conducted a phase 3 trial at 25 U.S. sites. Persons living with HIV who were 35 years of age or older and who had biopsy-proven anal HSIL were randomly assigned, in a 1:1 ratio, to receive either HSIL treatment or active monitoring without treatment. Treatment included office-based ablative procedures, ablation or excision under anesthesia, or the administration of topical fluorouracil or imiquimod. The primary outcome was progression to anal cancer in a time-to-event analysis. Participants in the treatment group were treated until HSIL was completely resolved. All the participants underwent high-resolution anoscopy at least every 6 months; biopsy was also performed for suspected ongoing HSIL in the treatment group, annually in the active-monitoring group, or any time there was concern for cancer.

RESULTS

Of 4459 participants who underwent randomization, 4446 (99.7%) were included in the analysis of the time to progression to cancer. With a median follow-up of 25.8 months, 9 cases were diagnosed in the treatment group (173 per 100,000 person-years; 95% confidence interval [CI], 90 to 332) and 21 cases in the active-monitoring group (402 per 100,000 person-years; 95% CI, 262 to 616). The rate of progression to anal cancer was lower in the treatment group than in the active-monitoring group by 57% (95% CI, 6 to 80; P = 0.03 by log-rank test).

CONCLUSIONS

Among participants with biopsy-proven anal HSIL, the risk of anal cancer was significantly lower with treatment for anal HSIL than with active monitoring. (Funded by the National Cancer Institute; ClinicalTrials.gov number, NCT02135419.).

Photobiomodulation as a treatment for dermatitis caused by chemoradiotherapy for squamous cell anal carcinoma: case report and literature review

In-field dermatitis is a severe and common adverse effect of radiation therapy, that can cause significant pain and treatment interruptions in patients with squamous cell anal carcinoma (SCAC) being treated with radical chemoradiation protocols. There are no established therapies for the treatment of radiation induced dermatitis. Photobiomodulation (PBM) is an effective and low-cost treatment for radiation induced mucositis, but have recently been explored to treat in-field dermatitis. We present a case report of the successful use of PBM for the treatment of dermatitis in the anal area in a patient with SCAC treated with concomitant chemoradiation with curative intent and follow with a literature review of the recent advances and possibilities of the use of PBM as a promising strategy. PBM therapy proved to be efficient in the radiodermatitis treatment, both in relieving the symptoms and controlling dermatitis, in addition to improving the patient's quality of life.

Radiodermatite: severidade, fatores preditivos e interrupção da radioterapia em pacientes com câncer anal e de reto

RESUMO Objetivo: determinar a prevalência da radiodermatite, os graus de severidade e os fatores preditivos da sua ocorrência em pacientes com câncer de canal anal e reto acompanhados pela consulta de enfermagem, e analisar a associação dos graus de severidade da radiodermatite com a interrupção temporária da radioterapia. Método: pesquisa quantitativa, seccional e retrospectiva, realizada com 112 prontuários de pacientes com câncer de canal anal e reto submetidos à radioterapia curativa acompanhados na consulta de enfermagem. Dados foram coletados por formulário e analisados empregando-se estatística analítica e inferencial. Resultados: 99,1% dos pacientes apresentaram radiodermatite, sendo 34,8% graus severos. Os fatores preditivos foram sexo feminino, idade maior que 65 anos, tumor de canal anal, tratamento com aparelho de cobalto e técnica IMRT. A interrupção do tratamento ocorreu em 13% dos pacientes, associada à radiodermatite severa. Conclusão: houve alta prevalência de radiodermatite, principalmente grau severo, que resultou em interrupção do tratamento.

The association between protease inhibitors and anal cancer outcomes in veterans living with HIV treated with definitive chemoradiation: a retrospective study

BACKGROUND

The incidence of anal squamous cell carcinoma has been increasing, particularly in people living with HIV (PLWH). There is concern that radiosensitizing drugs, such as protease inhibitors, commonly used in the management of HIV, may increase toxicities in patients undergoing chemoradiation. This study examines treatment outcomes and toxicities in PLWH managed with and without protease inhibitors who are receiving chemoradiation for anal cancer.

METHODS

Patient demographic, HIV management, and cancer treatment information were extracted from multiple Veterans Affairs databases. Patients were also manually chart reviewed. Among PLWH undergoing chemoradiation for anal carcinoma, therapy outcomes and toxicities were compared between those treated with and without protease inhibitors at time of cancer treatment. Statistical analysis was performed using chi-square, Cox regression analysis, and logistic regression.

RESULTS

A total of 219 PLWH taking anti-retroviral therapy undergoing chemoradiation for anal cancer were identified and included in the final analysis. The use of protease inhibitors was not associated with any survival outcome including colostomy-free survival, progression-free survival, or overall survival (all adjusted hazard ratio p-values> 0.05). Regarding toxicity, protease inhibitor use was not associated with an increased odds of hospitalizations or non-hematologic toxicities; however, protease inhibitor use was associated with increased hospitalizations for hematologic toxicities, including febrile neutropenia (p < 0.01).

CONCLUSION

The use of protease inhibitors during chemoradiation for anal carcinoma was not associated with any clinical outcome or increase in non-hematologic toxicity. Their use was associated with increased hospitalizations for hematologic toxicities. Further prospective research is needed to evaluate the safety and efficacy of protease inhibitors for patients undergoing chemoradiation.

Volumetric Modulated Arc Therapy Improves Outcomes in Definitive Radiochemotherapy for Anal Cancer Whilst Reducing Acute Toxicities and Increasing Treatment Compliance

Simple Summary

Intensity-modulated radiotherapy (IMRT) is the standard of care in definitive chemoradiotherapy (CRT) for anal cancer. Only a limited number of studies have analyzed the clinical results with VMAT (volumetric modulated arc therapy, the advanced form of IMRT). We conducted a retrospective study on patients treated at our institution. We compared the outcomes of VMAT-treated and 3DCRT (3D conformal radiotherapy)-treated patients. VMAT reduced acute toxicities (i.e., primarily dermatitis and enteritis) to a great extent. Additionally, VMAT relevantly improved treatment compliance (i.e., less CRT interruptions/delays, shorter overall treatment time, and higher absolute 5-fluorouracil dose applied). Finally, we found improved cancer-specific survival and distant control in VMAT-treated patients. The present study underlines the great progress that has been achieved with IMRT/VMAT in the CRT of anal cancer. Our study is the first to demonstrate an improvement in treatment compliance and outcomes with VMAT. Future studies could address whether VMAT is advantageous when compared to conventional IMRT.

Abstract

Background: Intensity-modulated radiotherapy (IMRT) is the standard of care in chemoradiotherapy (CRT) for anal cancer. Until now, only a limited number of studies have analyzed the results with VMAT (volumetric modulated arc therapy). We conducted a retrospective study on patients treated at our institution. Patients and Methods: We included patients who received curative CRT for anal cancer. We compared VMAT-treated and 3DCRT (3D conformal radiotherapy)-treated patients. We analyzed toxicities (acute: CTCAE criteria; late: LENT/SOMA criteria), treatment compliance, overall survival, cancer-specific survival (CSS), distant control (DC), and locoregional control. Results: A total of 149 patients (3DCRT: n = 87, VMAT: n = 62) were included. The median follow-up was longer in 3DCRT-treated patients (3DCRT: 61.3 months; VMAT: 39.1 months; p < 0.05). VMAT-treated patients had more G3 tumors (3DCRT: 12/87 (13.8%); VMAT: 18/62 (29.0%), p < 0.001). VMAT reduced acute toxicities ≥grade 3 (3DCRT: n = 48/87 (55.2%); VMAT: n = 11/62 (17.7%), p < 0.001). VMAT improved treatment compliance (less interruptions/delays) (3DCRT: 37/87, 42.5%; VMAT: 4/62, 6.5%; p < 0.001), provided a shorter median overall treatment time (3DCRT: 41 days; VMAT: 38 days; p = 0.02), and gave a higher median absolute 5-fluorouracil dose (3DCRT: 13,700 mg; VMAT: 14,400 mg; p = 0.001). Finally, we found improved CSS (p = 0.02; 3DCRT: 81.9% at 3 years; VMAT: 94.1% at 3 years) and DC (p = 0.01; 3DCRT: 89.4% at 3 years; VMAT: 100.0% at 3 years) with VMAT. Summary: Our study is the first to demonstrate improved treatment compliance and outcomes with VMAT for anal cancer. Previous studies have indicated that organs at risk sparing might be more improved with the use of VMAT vs. with conventional IMRT. Future studies should address whether these advantages lead to a further reduction in CRT-associated morbidity.

Evolution of the Role of Radiotherapy for Anal Cancer

Prior to the 1980s, the primary management of localized anal cancer was surgical resection. Dr. Norman Nigro and colleagues introduced neoadjuvant chemoradiotherapy prior to abdominoperineal resection. Chemoradiotherapy 5-fluorouracil and mitomycin C afforded patients complete pathologic response and obviated the need for upfront surgery. More recent studies have attempted to alter or exclude chemotherapy used in the Nigro regimen to mitigate toxicity, often with worse outcomes. Reductions in acute adverse effects have been associated with marked advancements in radiotherapy delivery using intensity-modulated radiation therapy (IMRT) and image-guidance radiation delivery, resulting in increased tolerance to greater radiation doses. Ongoing trials are attempting to improve IMRT-based treatment of locally advanced disease with efforts to increase personalized treatment. Studies are also examining the role of newer treatment modalities such as proton therapy in treating anal cancer. Here we review the evolution of radiotherapy for anal cancer and describe recent advances. We also elaborate on radiotherapy's role in locally persistent or recurrent anal cancer.

Chemoradiation versus local excision in treatment of stage I anal squamous cell carcinoma: A population-based analysis

INTRODUCTION

Chemoradiation therapy (CRT) is the standard treatment for anal squamous cell carcinoma (ASCC) but can have significant treatment related toxicities. Recent studies have demonstrated the effectiveness of local excision (LE) for stage I ASCC with comparable oncologic outcomes to CRT. We aimed to evaluate this finding in a large population-based database.

METHODS

Patients diagnosed with stage I (T1N0M0) ASCC were identified from the Surveillance, Epidemiology, and End Results database, 2004-2015. Treatment approach was categorized as CRT or LE. Factors associated with treatment approach and cause-specific survival (CSS) were analyzed for the entire cohort and after stratification by tumor size (≤1 cm and 1-2 cm).

RESULTS

Among 883 patients, 56% had ASCCs 1-2 cm in size and 77% received CRT. Mean age was 60 years, 65% were female, and 90% were White. Factors independently associated with receiving CRT were, being female, higher tumor grade, and tumor size 1-2 cm. Unadjusted 5-year CSS for CRT was 96% while for LE it was 98% (p = 0.048). After adjusting for available confounders, treatment approach was not associated with worse CSS, however being Black (HR = 8.7) and uninsured (HR = 13.7) were independently associated with worse prognosis. After stratification by tumor size, there was still no significant difference in 5-year CSS by treatment approach.

CONCLUSIONS

LE was performed in a significant proportion of patients but was not independently associated with worse CSS compared to CRT. In appropriately selected patients with well differentiated ASCCs ≤1 cm, LE could be an acceptable management option but studies measuring outcomes such as local recurrence are needed.

Sarcopenia is associated with worse overall survival in patients with anal squamous cell cancer

BACKGROUND AND OBJECTIVES

Sarcopenia is associated with poor long-term outcomes in many gastrointestinal cancers, but its role in anal squamous cell carcinoma (ASCC) is not defined. We hypothesized that patients with sarcopenic ASCC experience worse long-term outcomes.

METHODS

A retrospective review of patients with ASCC treated at an academic medical center from 2006 to 2017 was performed. Of 104 patients with ASCC, 64 underwent PET/computed tomography before chemoradiation and were included in the analysis. The skeletal muscle index was calculated as total L3 skeletal muscle divided by height squared. Sarcopenia thresholds were 52.4 cm² /m² for men and 38.5 cm² /m² for women. Cox regression analysis was performed to assess overall and progression-free survival.

RESULTS

Twenty-five percent of the patients were sarcopenic (n = 16). Demographics were similar between groups. There was no difference in the clinical stage or comorbidities between groups. On multivariate analysis, factors associated with worse overall survival were male gender (hazard ratio [HR] 3.7, P = .022) and sarcopenia (HR 3.6, P = .019). Male gender was associated with worse progression-free survival (HR 2.6, P = .016).

CONCLUSIONS

Sarcopenia is associated with worse overall survival in patients with anal cancer. Further studies are indicated to determine if survival can be improved with increased attention to nutritional status in sarcopenic patients.

Local excision for patients with stage I anal canal squamous cell carcinoma can be curative

Background

Definitive concurrent chemoradiation is the current standard of care for all stage I anal canal squamous cell carcinoma. Local excision as primary treatment for selected stage I lesions has been reported in the literature but is not currently recommended by major guidelines. We herein compared the oncologic outcomes of patients with stage I anal canal squamous cell carcinoma treated with local excision alone versus chemoradiation to determine if there are any significant differences in outcomes including disease free survival, overall survival (OS) and local failure rate.

Methods

A retrospective review of all patients treated for stage I anal canal squamous cell carcinoma between 1990 and 2016 was conducted. Data collected included baseline demographics, staging studies, pathology, treatment received, relapse pattern and survival.

Results

A total of 57 patients were treated for stage I anal canal squamous cell carcinoma between 1990 and 2016; 13 were treated with local excision alone and 44 were treated with chemoradiation therapy. Baseline characteristics in both cohorts of patients were comparable. Median follow-up duration of the local excision and the chemoradiation cohorts were 106 and 70 months, respectively. Of the 13 patients in local excision cohort, two patients had disease recurrence, at 21 and 97 months from the diagnosis. Both patients were long term survivors with salvage treatment. In chemoradiation cohort, 1 out of 44 patients had a local recurrence at 1 year who underwent curative resection. Five-year progression free survival (PFS) of subjects in local excision cohort and chemoradiation cohort were 91% and 83%, respectively (P=0.57).

Conclusions

Local excision as primary treatment may be safe and effective for a selected group of stage I anal canal squamous cell carcinoma patients.

The Role of Multiagent Chemoradiation in the Management and Prognosis of Anal Squamous Cell Carcinoma

INTRODUCTION

The standard treatment for anal squamous cell carcinoma (ASCC) is multiagent chemotherapy with radiation (CRT). This is based on several randomized trials demonstrating lower recurrence and colostomy-free survival rates with multiagent CRT; however, these studies could not confirm an overall survival (OS) benefit. We hypothesized that the lack of improved OS was due to limited sample sizes and follow-up, and that multiagent CRT is associated with higher OS.

METHODS

The National Cancer Database was queried for patients diagnosed with stages I, II, and II ASCC and received between 45 and 59.4 Gy of radiation between 2004 and 2015. OS of patients receiving multiagent CRT compared to monoagent CRT and radiation alone was analyzed across stages.

RESULTS

A total of 10,438 patients received multiagent CRT, 1163 had monoagent CRT and 446 received radiation alone. Compared to the other two groups, patients receiving multiagent CRT were younger, had fewer comorbidities, and more advanced disease (all p < 0.001). After adjusting for available confounders, multiagent CRT remained independently associated with higher OS for stages II and III ASCC. A subset analysis of patients ≥ 70 years demonstrated similar survival between monoagent versus multiagent CRT across all stages.

CONCLUSION

Multiagent CRT is associated with an OS benefit compared to monoagent CRT or radiation alone for stages II and III, but not stage I ASCC. Monoagent CRT may represent an adequate treatment for selected patients ≥ 70 years. The benefit of multiagent CRT should be balanced against treatment-related toxicities depending on disease stage and patient physiology.