Treatment outcomes and prognostic factors after chemoradiotherapy for anal cancer

Improving our understanding of the quality of life of patients with metastatic or recurrent/persistent anal cancer: a systematic review

PURPOSE

Chemoradiation (CRT) is used to treat anal carcinomas which, for most patients with loco-regional disease, results in a cure but is associated with acute and chronic complications impairing quality of life (QoL). Patients with metastatic disease or recurrence are likely to experience additional QoL concerns. This paper identifies the QoL issues of these patients and determines whether the EORTC QLQ-ANL27 (QLQ-ANL27), a measure of QoL of patients treated with CRT for anal cancer used alongside the core EORTC QLQ-C30 (QLQ-C30), is suitable or needs adapting.

METHODS

A systematic review was conducted of studies published between 2014 and 2024 reporting QoL of patients with metastatic or recurrent/persistent anal cancer or follow-up data of patients treated with CRT for anal cancer.

RESULTS

This review included 23 papers, only three focused exclusively on metastatic and/or recurrent anal cancer. Most of the 53 reported symptoms related to bowel, urinary, and sexual functioning, with 60% covered by the QLQ-ANL27 or the QLQ-C30. Issues not captured include, for example, neuropathy, hair loss, musculoskeletal problems, urinary incontinence, and embarrassment.

CONCLUSION

There is a paucity of research looking specifically at QoL outcomes of patients with metastatic or recurrent anal cancer. Whilst the QLQ-ANL27 captures most QoL issues affecting these patients, it might require adapting to improve its sensitivity.

Elective clinical target volume in early squamous cell anal canal cancer: A systematic review and meta-analysis of the risk of recurrence in untreated upper pelvic and external iliac lymph nodes

BACKGROUND

For squamous-cell carcinoma of the anal canal, most delineation guidelines recommend elective irradiation of the external iliac lymph nodes (LNS) and the upper pelvic LNS (located above the inferior aspect of the sacroiliac joints), regardless of clinical stage. However, neither of these regions is the first-echelon nodal station for anal primaries, and there is no conclusive evidence on the risk of microscopic involvement of these LNS in patients with cT1-2N0 disease. The recommendation to include these regions in the elective CTV for early anal canal cancer is based on historical practice, reflecting lymph node regions in earlier AP-PA fields, rather than conclusive evidence.

PATIENTS AND METHODS

A systematic review of the literature and a meta-analysis were performed to determine the rates of regional recurrence in the upper pelvic and external iliac LNS in patients with early anal canal cancer (cT1-2N0) treated with radio(chemo)therapy without elective nodal irradiation (ENI) of these LNS.

RESULTS

One prospective and eight retrospective studies were included in the meta-analysis. The pooled weighted rate of regional recurrence in the upper pelvic LNS was 0.9 % (95 % confidence interval [CI]: 0.1-1.8 %) among 495 cT1-2N0 patients treated with ENI not covering these LNS. None of 233 patients treated with ENI not covering external iliac LNS had a recurrence in this region after radio(chemo)therapy.

CONCLUSION

Low risk of regional recurrence in the untreated upper pelvic and external iliac LNS suggests they can be confidently excluded from the elective nodal CTV for patients with early squamous cell anal canal cancer.

Barriers and facilitators to anal cancer screening among men who have sex with men: a systematic review with narrative synthesis

BACKGROUND

Increasing trends of anal cancer among men who have sex with men (MSM) highlight the importance of anal cancer screening. However, the screening rate of anal cancer among MSM remains relatively low. This systematic review aims to identify and critically evaluate studies examining barriers and facilitators influencing MSM's participation in anal cancer screening.

METHODS

Systematic searches were performed in five databases (Web of Science, Medline, Embase, PsycINFO, and CINAHL). Evidence from qualitative, quantitative, and mixed methods studies was extracted and synthesized. Mixed Methods Appraisal Tool (MMAT) was used for quality assessment. Two researchers underwent selection and appraisal independently. PROSPERO registration number: CRD42024601449.

RESULTS

305 studies were identified with a total of 32 studies included, including 11 qualitative studies, 18 quantitative studies, and 3 mixed methods studies. The barriers and facilitators to anal cancer screening were categorized into four domains: individual factors, healthcare system factors, healthcare provider factors, and screen-related factors. Among the four domains, the most frequently reported barriers and facilitators to anal cancer screening were individual factors. A lack of knowledge about the risks of HPV, anal cancer, and anal screening (n = 16) was the most significant barrier. In contrast, a greater perceived understanding of anal cancer and screening (n = 6) was identified as the primary facilitator.

CONCLUSIONS

This systematic review provided a comprehensive assessment of barriers and facilitators to anal cancer screening among MSM, highlighting the need for targeted comprehensive intervention programs to enhance acceptance of screening. Implementing effective strategies to address potential barriers and promote facilitators across all domains of public health could significantly increase screening uptake.

Is the omission of the external iliac or upper pelvic lymph nodes from elective irradiation safe in selected anal canal squamous cell cancers?

BACKGROUND

Guidelines recommend elective irradiation of the external iliac and upper pelvic lymph nodes (LNs) regardless of clinical stage, but the supporting evidence for this recommendation is limited.

METHODS

We conducted a retrospective analysis of 68 consecutive patients with squamous cell carcinoma of the anal canal who underwent volumetric modulated arc therapy chemoradiation, excluding external iliac LNs from elective irradiation. In patients with negative bilateral inguinal LNs, both external iliac regions were omitted, while in those with unilateral positive inguinal LNs, only the ipsilateral external iliac region was included and the contralateral side was omitted. For patients with early-stage tumours, the cranial border of elective irradiation was located in the inferior aspect of the sacroiliac joints.

RESULTS

The median follow-up was 4.0 years. Six patients (9 %) experienced recurrence of the primary tumour and three (4 %) developed distant metastases. No isolated nodal recurrences were seen in the LNs that were positive at baseline, or in or outside electively irradiated regions. Notably, no recurrences were seen in any of the 124 external iliac regions omitted from elective irradiation across the 68 patients, or in the upper pelvic region among the subgroup of 33 patients where the cranial irradiation border was at the bottom of the sacroiliac joint. Reducing the elective irradiation volume significantly decreased the dose-volume parameters for organs-at-risk.

CONCLUSIONS

The present findings suggest that omitting the external iliac and upper pelvic LNs from elective irradiation is safe for selected patients and allows dose reduction in organs-at-risk.

Diffusion-weighted magnetic resonance imaging as an early prognostic marker of chemoradiotherapy response in squamous cell carcinoma of the anus: An individual patient data meta-analysis

Background and purpose

Squamous cell carcinoma of the anus (SCCA) can recur after chemoradiotherapy (CRT). Early prediction of treatment response is crucial for individualising treatment. Existing data on radiological biomarkers is limited and contradictory. We performed an individual patient data meta-analysis (IPM) of four prospective trials investigating whether diffusion-weighted (DW) magnetic resonance imaging (MRI) in weeks two to three of CRT predicts treatment failure in SCCA.

Material and methods

Individual patient data from four trials, including paired DW-MRI at baseline and during CRT, were combined into one dataset. The association between ADC volume histogram parameters and treatment failure (locoregional and any failure) was assessed using logistic regression. Pre-defined analysis included categorising patients into a change in the mean ADC of the delineated tumour volume above and below 20%.

Results

The study found that among all included 142 patients, 11.3 % (n = 16) had a locoregional treatment failure. An ADC mean change of <20 % and >20 % resulted in a locoregional failure rate of 16.7 % and 8.0 %, respectively. However, no other ADC-based histogram parameter was associated with locoregional or any treatment failure.

Conclusions

DW-MRI standard parameters, as an isolated biomarker, were not found to be associated with increased odds of treatment failure in SCCA in this IPM. Radiological biomarker investigations involve multiple steps and can result in heterogeneous data. In future, it is crucial to include radiological biomarkers in large prospective trials to minimize heterogeneity and maximize learning.

Reduction of elective lymph node volume in radiotherapy of early anal squamous cell cancer: a comparative study between two Swedish university hospitals

BACKGROUND

Anal squamous cell cancer (ASCC) in early stages (T1-2N0M0) is treated with chemoradiotherapy with a 3-year overall survival (OS) exceeding 90%. In Swedish guidelines, it has been optional to include the external iliac and presacral lymph node (LN) stations in radiotherapy (RT) treatment fields in early ASCC. Two Swedish hospitals treating ASCC (SU: Sahlgrenska University Hospital; UU: Uppsala University Hospital) have chosen different approaches since 2010.

MATERIAL AND METHODS

This study included consecutive patients with early ASCC (T1-2N0M0) treated between 2010 and 2017 at both sites (SU n = 70; UU n = 46). Data were retrieved from medical records and RT charts.

RESULTS

At SU, the external iliac and presacral LN stations were included in elective LN irradiation in 96.8% (n = 60) and 95.2% (n = 59) patients compared to 2.4% (n = 1) and 29.3% (n = 12) at UU. The mean elective LN volume was 2,313 cc (interquartile range [IQR] 1,951-2,627) in the SU cohort compared to 1,317 cc (IQR 1,192-1,528) in the UU cohort, p < 0.0001. No case of regional LN recurrence was seen in either cohort. Disease specific survival (DSS) at 5 years was 95.7% (confidence interval [CI] 90.1-100.0) in the SU cohort and 97.8% (CI 93.2-100.0) in the UU cohort (p 0.55). OS at 5 years was 84.5% (CI 76.1-93.0) in the SU cohort and 82.6% (CI 69.6-89.1) in the UU cohort (p 0.8).

INTERPRETATION

We found no differences in regional recurrence, DSS or OS between the cohorts treated with different elective LN volumes. In this population-based study, reduction of RT volume in early ASCC did not lead to inferior outcome.

Outcomes of patients with anal cancer treated with definitive chemoradiation: A single centre experience

Background

Anal cancers are uncommon neoplasms that make up to <1% of all tumours globally. Concurrent chemoradiation remains the standard of care treatment for patients who present with non-metastatic anal squamous cell carcinomas (ASCCs).

Methods

We aimed to evaluate the response rate and 2-year survival outcome of the definitive chemoradiation approach in patients with non-metastatic ASCCs of our population. We conducted a cross-sectional review of these patient populations who were treated and then followed after completion of treatment at our institute during the last 10 years.

Results

A total of 17 patients were enrolled after fulfillment of the eligibility criteria. The responses were documented in 16 patients through magnetic resonance imaging or computed tomography of the pelvis, done at 3 months of treatment completion. More than 80% of the patients had complete radiological responses. Among the surviving participants, the 2-year disease-free survival rate was found to be more than two-thirds. Approximately 20% of the study participants had disease recurrence during the subsequent clinic visits following treatment completion.

Conclusion

This review emphasises the impact of definitive chemo-radiation in achieving radiological and clinical responses in patients with non-metastatic ASCCs. Moreover, to our knowledge, this is the first review to highlight anal cancer's incidence and characteristics in Pakistan.

Magnetic resonance imaging of anal cancer: tumor characteristics and early prediction of treatment outcome

PURPOSE

To analyze tumor characteristics derived from pelvic magnetic resonance imaging (MRI) of patients with squamous cell carcinoma of the anus (SCCA) before and during chemoradiotherapy (CRT), and to compare the changes in these characteristics between scans of responders vs. nonresponders to CRT.

METHODS

We included 52 patients with a pelvic 3T MRI scan prior to CRT (baseline scan); 39 of these patients received an additional scan during week 2 of CRT (second scan). Volume, diameter, extramural tumor depth (EMTD), and external anal sphincter infiltration (EASI) of the tumor were assessed. Mean, kurtosis, skewness, standard deviation (SD), and entropy values were extracted from apparent diffusion coefficient (ADC) histograms. The main outcome was locoregional treatment failure. Correlations were evaluated with Wilcoxon's signed rank-sum test and Pearson's correlation coefficient, quantile regression, univariate logistic regression, and area under the ROC curve (AUC) analyses.

RESULTS

In isolated analyses of the baseline and second MRI scans, none of the characteristics were associated with outcome. Comparison between the scans showed significant changes in several characteristics: volume, diameter, EMTD, and ADC skewness decreased in the second scan, although the mean ADC increased. Small decreases in volume and diameter were associated with treatment failure, and these variables had the highest AUC values (0.73 and 0.76, respectively) among the analyzed characteristics.

CONCLUSION

Changes in tumor volume and diameter in an early scan during CRT could represent easily assessable imaging-based biomarkers to eliminate the need for analysis of more complex MRI characteristics.

A common [18F]-FDG PET radiomic signature to predict survival in patients with HPV-induced cancers

Locally advanced cervical cancer (LACC) and anal and oropharyngeal squamous cell carcinoma (ASCC and OPSCC) are mostly caused by oncogenic human papillomaviruses (HPV). In this paper, we developed machine learning (ML) models based on clinical, biological, and radiomic features extracted from pre-treatment fluorine-18-fluorodeoxyglucose positron emission tomography ([18F]-FDG PET) images to predict the survival of patients with HPV-induced cancers. For this purpose, cohorts from five institutions were used: two cohorts of patients treated for LACC including 104 patients from Gustave Roussy Campus Cancer (Center 1) and 90 patients from Leeds Teaching Hospitals NHS Trust (Center 2), two datasets of patients treated for ASCC composed of 66 patients from Institut du Cancer de Montpellier (Center 3) and 67 patients from Oslo University Hospital (Center 4), and one dataset of 45 OPSCC patients from the University Hospital of Zurich (Center 5). Radiomic features were extracted from baseline [18F]-FDG PET images. The ComBat technique was applied to mitigate intra-scanner variability. A modified consensus nested cross-validation for feature selection and hyperparameter tuning was applied on four ML models to predict progression-free survival (PFS) and overall survival (OS) using harmonized imaging features and/or clinical and biological variables as inputs. Each model was trained and optimized on Center 1 and Center 3 cohorts and tested on Center 2, Center 4, and Center 5 cohorts. The radiomic-based CoxNet model achieved C-index values of 0.75 and 0.78 for PFS and 0.76, 0.74, and 0.75 for OS on the test sets. Radiomic feature-based models had superior performance compared to the bioclinical ones, and combining radiomic and bioclinical variables did not improve the performances. Metabolic tumor volume (MTV)-based models obtained lower C-index values for a majority of the tested configurations but quite equivalent performance in terms of time-dependent AUCs (td-AUC). The results demonstrate the possibility of identifying common PET-based image signatures for predicting the response of patients with induced HPV pathology, validated on multi-center multiconstructor data.

Stability of metabolic tumor volume may enable radiotherapy dose painting in anal cancer

PURPOSE

To evaluate the variability of the 18F-FDG-PET/CT-based metabolic tumor volume (MTV) in anal cancers during fractionated chemoradiotherapy (CRT), and assess the impact of this variability on dosimetric accuracy in MTV-targeted dose painting.

METHODS

Eleven patients with anal squamous cell carcinoma who received fractionated chemoradiotherapy with curative intent were included. 18F-FDG PET/CT images were acquired at pre- and mid-treatment. Target volumes and organs at risk (OARs) were contoured manually on both image series. The MTV was generated from the PET images by thresholding. Treatment plans were retrospectively optimized for both image series using volumetric modulated arc therapy (VMAT). Standard plans prescribed 48.6 Gy, 54 Gy and 57.5 Gy in 27 fractions to elective regions, lymph node metastases and primary tumor, respectively. Dose painting plans included an extra dose level of 65 Gy to the MTV. Pre-treatment plans were transferred and re-calculated at mid-treatment basis.

RESULTS

MTV decreased from pre- to mid-treatment in 10 of the 11 patients. On average, 71 % of MTVmid overlapped with MTVpre. The median and mean doses to the MTV were robust against anatomical changes, but the transferred dose painting plans had lower D98% values than the original and re-optimized plans. No major differences were found between standard and dose painting plans for OARs.

CONCLUSIONS

Despite volumetric changes in the MTV, adequate dose coverage was observed in most dose painting plans. The findings indicate little or no need for adaptive dose painting at mid-treatment. Dose painting appears to be a safe treatment alternative with similar dose sparing of OARs.

Nordic anal cancer (NOAC) group consensus guidelines for risk-adapted delineation of the elective clinical target volume in anal cancer

Background: To date, anal cancer patients are treated with radiotherapy to similar volumes despite a marked difference in risk profile based on tumor location and stage. A more individualized approach to delineation of the elective clinical target volume (CTVe) could potentially provide better oncological outcomes as well as improved quality of life. The aim of the present work was to establish Nordic Anal Cancer (NOAC) group guidelines for delineation of the CTVe in anal cancer.Methods: First, 12 radiation oncologists reviewed the literature in one of the following four areas: (1) previous delineation guidelines; (2) patterns of recurrence; (3) anatomical studies; (4) common iliac and para-aortic recurrences and delineation guidelines. Second, areas of controversy were identified and discussed with the aim of reaching consensus.Results: We present consensus-based recommendations for CTVe delineation in anal cancer regarding (a) which regions to include, and (b) how the regions should be delineated. Some of our recommendations deviate from current international guidelines. For instance, the posterolateral part of the inguinal region is excluded, decreasing the volume of irradiated normal tissue. For the external iliac region and the cranial border of the CTVe, we agreed on specifying two different recommendations, both considered acceptable. One of these recommendations is novel and risk-adapted; the external iliac region is omitted for low-risk patients, and several different cranial borders are used depending on the individual level of risk.Conclusion: We present NOAC consensus guidelines for delineation of the CTVe in anal cancer, including a risk-adapted strategy.

Long-term survival after treatment for primary anal cancer- results from the Swedish national ANCA cohort study

BACKGROUND

Squamous cell carcinoma of the anus is increasing in incidence but remains a rare disease with good 3- and 5-year recurrence free and overall survival rates of 63%-86%. The treatment includes chemoradiotherapy, mainly with 5-fluoruracil (5FU) and mitomycin. The aim of this study was to describe long-term (up to 9 years after treatment) oncological outcome and the types of treatments given, in a Swedish national cohort of patients diagnosed with anal cancer between 2011 and 2013.

METHOD

Patients were identified in the Swedish Cancer Registry. Patients still alive were contacted and asked for consent. Clinical data were retrieved from National Patient Register at the Swedish National Board of Health and Welfare and from medical records. Unadjusted and adjusted analyses were performed for overall survival.

RESULTS

Three hundred and eighty-eight patients were included in the study of which 338 patients (87%) received treatment with a curative intent. Follow up was 85 months (0-113 months) for patients treated with curative intent (information missing in one patient) 7.5 months (0-55) for patients with treated with a palliative intent. Curative treatment varied and consisted of both chemoradiotherapy and radiotherapy (46-64 Gy) alone. 5-FU, mitomycin and cisplatin were the most used chemotherapy agents. Five-year overall survival for patients treated with curative intent was 73%. In an adjusted analysis 5-FU and mitomycin is associated with a lower mortality than 5-FU and cisplatin but the association was weaker (HR 1.61 (95% CI: 0.904; 2.85) than in the unadjusted analysis.

CONCLUSIONS

In this national cohort overall five-year survival was 73% for patients treated with curative intent. As reported by others our results indicate that 5-FU and mitomycin C should be the preferred chemotherapy in treatment for cure.

Deep learning-based automatic delineation of anal cancer gross tumour volume: a multimodality comparison of CT, PET and MRI

BACKGROUND

Accurate target volume delineation is a prerequisite for high-precision radiotherapy. However, manual delineation is resource-demanding and prone to interobserver variation. An automatic delineation approach could potentially save time and increase delineation consistency. In this study, the applicability of deep learning for fully automatic delineation of the gross tumour volume (GTV) in patients with anal squamous cell carcinoma (ASCC) was evaluated for the first time. An extensive comparison of the effects single modality and multimodality combinations of computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI) have on automatic delineation quality was conducted.

MATERIAL AND METHODS

18F-fluorodeoxyglucose PET/CT and contrast-enhanced CT (ceCT) images were collected for 86 patients with ASCC. A subset of 36 patients also underwent a study-specific 3T MRI examination including T2- and diffusion-weighted imaging. The resulting two datasets were analysed separately. A two-dimensional U-Net convolutional neural network (CNN) was trained to delineate the GTV in axial image slices based on single or multimodality image input. Manual GTV delineations constituted the ground truth for CNN model training and evaluation. Models were evaluated using the Dice similarity coefficient (Dice) and surface distance metrics computed from five-fold cross-validation.

RESULTS

CNN-generated automatic delineations demonstrated good agreement with the ground truth, resulting in mean Dice scores of 0.65-0.76 and 0.74-0.83 for the 86 and 36-patient datasets, respectively. For both datasets, the highest mean Dice scores were obtained using a multimodal combination of PET and ceCT (0.76-0.83). However, models based on single modality ceCT performed comparably well (0.74-0.81). T2W-only models performed acceptably but were somewhat inferior to the PET/ceCT and ceCT-based models.

CONCLUSION

CNNs provided high-quality automatic GTV delineations for both single and multimodality image input, indicating that deep learning may prove a versatile tool for target volume delineation in future patients with ASCC.

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

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