Long-term outcomes of chemoradiation for anal cancer patients

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.

Failure of Initial Curative Treatment for Non-Metastatic Anal Squamous Cell Carcinoma: From Prognostic Factors Analysis to Stratified Treatment

In squamous cell anal canal neoplasms, persistent disease or recurrence after initial chemoradiotherapy are not the rule, yet their occurrence deserves to be analyzed to better identify prognostics factors. The aim of our study was to describe the patterns of failures of the initial treatment, their subsequent evolution and to identify prognostic factors in these relapsed patients. All patients with non-metastatic anal squamous cell carcinoma initially treated with curative intent at the Centre Antoine Lacassagne between 1999 and 2019, and who presented persistent disease or recurrence were analyzed. The median follow-up was 44 months. Univariate and multivariate analyses were performed to identify prognostic factors. From our database of 528 patients, 77 patients were eligible: 25 with persistent disease and 52 with recurrence after complete response. The median overall survival was 39 months (95% CI: 25.5-52.3 months) from the date of treatment failure. In univariate analysis, prognostic factors were gender, initial lymph node status, type of failure, response to treatment's failure. In multivariate analysis, only female gender remained statistically significant (HR 0.43- P=0.016). 32% of patients with persistent disease had metastatic status. 17.3% and 5.8% of recurrences respectively occurred after three and five years of follow-up. Systematic imaging could be performed after initial treatment because of distant lesions in one third of patients with persistent disease. The follow-up should not be interrupted before five years, given the significant frequency of late recurrences. In multivariate analysis, only female gender was statistically significant. Stratified treatment based on prognostic factors could be envisaged, the details of which remain to be defined.

Outcomes following local excision of early anal squamous cell carcinomas of the anal canal and perianal margin

AIM

There is a paucity of data on outcomes from local excision (LE) of early anal squamous cell carcinomas (ASCCs). This study aimed to assess survival outcomes according to tumour location, perianal (PAT) or anal canal (ACT), and to determine factors associated with R1 excision and outcomes according to T-category.

METHODS

This was a retrospective cohort study of consecutive patients with early ASCC treated by LE from 2007 to 2019. Data were collected on baseline demographics, tumour location, staging, excision histology, adjuvant treatment, site and timing of recurrence. The main outcome measures were R1 resection, locoregional recurrence (LRR), disease-free survival and overall survival.

RESULTS

Of 367 patients treated for ASCC, 39 (10.6%) patients with complete follow-up data underwent LE: 15 ACTs and 24 PATs. R1 resections were obtained in 27 patients (69.2%) and occurred more frequently in ACTs than PATs (93.3% vs. 54.2%, P = 0.006). Eighteen of 27 patients (66.7%) received adjuvant therapy (chemoradiotherapy [n = 11], radiotherapy alone [n = 7]) for R1 excision or re-excision, following which LRR developed in one of 10 (10.0%) patients in the ACT cohort and one of eight (12.5%) patients in the PAT cohort. There was no difference in 5-year LRR-free survival (82.0% vs. 70.1%, P = 0.252), disease-free survival (58.2% vs. 78.4%, P = 0.200) or overall survival (86.2% vs. 95.7%, P = 0.607) between the ACT and PAT cohorts.

CONCLUSIONS

LE is a feasible treatment option for early ASCCs of the perianal margin but not the anal canal. Acceptable long-term outcomes can still be achieved with adjuvant therapy in the presence of a positive margin. Larger prospective studies to assess LE as a treatment strategy, such as the ACT3 trial, are warranted.

Racial/Ethnic Disparities in Survival Among Women Diagnosed with Invasive Cancer of the Anal Canal: an Analysis of Surveillance, Epidemiology, and End Results (SEER) Data

OBJECTIVE

To identify differences in survival among women diagnosed with cancer of the anal canal from varying racial and ethnic backgrounds.

METHODS

Data from the Surveillance, Epidemiology and End Results (SEER) registry between the years of 1975 and 2016 were analyzed, which included 19,048 women with cancer of the anal canal. Multivariable Cox proportional hazard regression (HRs) was performed to examine the relative risk of dying among women with anal cancer. Multivariable odds ratios (ORs) with 95% confidence intervals (CIs) were used to examine odds of highly fatal disease (death within 12 months from diagnosis).

RESULTS

Non-Hispanic Black women (n = 1694) had greater risk of dying when compared with non-Hispanic White women (n = 15,821) with anal cancer (HR = 1.26, CI: 1.17-1.35), independent of other prognostic indicators. Stratifying by age at diagnosis, risk of death was highest for non-Hispanic Black women diagnosed younger than age 50 years compared with non-Hispanic White women of similar age (HR = 1.60, CI: 1.34-1.89), and lowest for Hispanic women (n = 1533) older than 74 years at diagnosis (HR = 0.80, CI: 0.69-0.92). Stratifying by stage at diagnosis, disparities were not observed. When comparing across years of diagnoses, non-Hispanic Black women consistently had poorer survival compared with non-Hispanic White women diagnosed in the same year intervals. Finally, non-Hispanic Black women had greater odds of highly fatal disease (OR = 1.23, CI: 1.08-1.40) compared with non-Hispanic White women.

CONCLUSION

Non-Hispanic Black women with anal cancer continue to experience poorer survival compared with non-Hispanic White women, whereas disparities were not identified for Hispanic women.

Temporal improvements in loco-regional failure and survival in patients with anal cancer treated with chemo-radiotherapy: treatment cohort study (1990-2014)

Background

We evaluated oncological changes in patients with squamous cell carcinoma of the anus (SCCA) treated by chemoradiotherapy (CRT) from a large UK institute, to derive estimates of contemporary outcomes.

Methods

We performed a treatment-cohort analysis in 560 patients with non-metastatic SCCA treated with CRT over 25 years. The primary outcomes were 3-year loco-regional failure (LRF), 5-year overall survival (OS), and 5-year cancer-specific survival (CSS). We developed prediction models; and overlaid estimates on published results from historic trials.

Results

Age distributions, proportions by gender and cT stage remained stable over time. The median follow-up was 61 (IQR: 36–79) months. Comparing the first period (1990–1994) with the last period (2010–2014), 3-year LRF declined from 33 to 16% (P_trends < 0.001); 5-year OS increased from 60% to 76% (P_trends = 0.001); and 5-year CCS increased from 62% in to 80% (P_trends = 0.001). For 2020, the models predicted a 3-year LRF of 14.7% (95% CIs: 0–31.3); 5-year OS of 74.7% (95% CIs: 54.6–94.9); and 5-year CSS of 85.7% (95% CIs: 75.3–96.0). Reported oncological outcomes from historic trials generally underestimated contemporary outcomes.

Conclusions

Current and predicted rates for 3-year LRF and 5-year survivals are considerably improved compared with those in historic trials.

Nodal stage migration and prognosis in anal cancer: a systematic review, meta-regression, and simulation study

BACKGROUND

In patients with squamous cell carcinoma of the anus (SCCA), lymph node positivity (LNP) indicates poor prognosis for survival and is central to radiotherapy planning. Over the past three decades, LNP proportion has increased, mainly reflecting enhanced detection with newer imaging modalities; a process known as nodal stage migration. If accompanied by constant T stage distributions, prognosis for both lymph node-positive and lymph node-negative groups may improve without any increase in overall survival for individual patients; a paradox termed the Will Rogers phenomenon. Here, we aim to systematically evaluate the impact of nodal stage migration on survival in SCCA and address a novel hypothesis that this phenomenon results in reduced prognostic discrimination.

METHODS

We did a systematic review and meta-regression to quantify changes in LNP over time and the impact of this change on survival and prognostic discrimination. We searched MEDLINE, Embase, and the Cochrane Library to identify randomised trials and observational studies in patients with SCCA published between Jan 1, 1970, and Oct 11, 2016. Studies were eligible if patients received chemoradiotherapy or radiotherapy as the main treatment, reported LNP proportions (all studies), and reported overall survival (not necessarily present in all studies). We excluded studies with fewer than 50 patients. We extracted study-level data with a standardised, piloted form. The primary outcome measure was 5-year overall survival. To investigate scenarios in which reduced prognostic discrimination might occur, we simulated varying true LNP proportions and true overall survival, and compared these with expected observed outcomes for varying levels of misclassification of true nodal state.

FINDINGS

We identified 62 studies reporting LNP proportions, which included 10 569 patients. From these, we included 45 studies (6302 patients) with whole cohort 5-year overall survival, 11 studies with 5-year survival stratified by nodal status, and 20 studies with hazard ratios in our analyses of temporal changes. In 62 studies, the LNP proportions increased from a mean estimate of 15·3% (95% CI 10·5-20·1) in 1980 to 37·1% (34·0-41·3) in 2012 (p<0·0001). In 11 studies with prognostic data, increasing LNP was associated with improved overall survival in both lymph node-positive and lymph node-negative categories, whereas the proportions with combined tumour stage T3 and T4 remained constant. In 20 studies, across a range of LNP proportions from 15% to 40%, the hazard ratios for overall survival of lymph node-positive versus lymph node-negative patients decreased significantly from 2·5 (95% CI 1·8-3·3) at 15% LNP to 1·3 (1·2-1·9; p=0·014) at 40% LNP. The simulated scenarios reproduced this effect if the true LNP proportions were 20% or 25%, but not if the true LNP proportions were 30% or greater.

INTERPRETATION

We describe a consequence of staging misclassification in anal cancer that we have termed reduced prognostic discrimination. We used this new observation to infer that the LNP proportions of more than 30% seen in modern clinical series (11 out of 15 studies with a median year since 2007) are higher than the true LNP proportion. The introduction of new staging technologies in oncology might misclassify true disease stage, spuriously informing disease management and ultimately increasing the risk of overtreatment.

FUNDING

Bowel Disease Research Foundation.

Radiochemotherapy in Anal Cancer: cCR, clinical outcomes and quality of life using two different treatment schedules

AIM

Main endpoint was a response rate to therapy; secondary endpoints were disease-free survival, overall survival, acute and late toxicities, specially in terms of anorectal and urinary continence.

BACKGROUND

Radiochemotherapy for anal cancer achieves a good clinical response, locoregional control, anal function preservation. However, oncologic outcomes can differ using radiotherapy plus fluorouracil and mytomicin vs. cisplatin and fluorouracil.

METHODS

Between 2000 and 2012, 27 anal cancer patients receiving radiotherapy combined with two different radiochemotherapy schedules, fluorouracil and mytomicin (group A) and cisplatin plus fluorouracil (group B). The Kaplan-Meier method was also used to estimate local control, overall survival and disease free survival. Statistical significance between curves was evaluated using the Log-rank test.

RESULTS

Complete pathological response was found in 85.2% of patients, with higher rates of response in the group A (100% vs. 63.6%, p = 0.039). No significantly difference was found between the two groups for the other endpoints. Low rates of both acute and late toxicities were recorded.

CONCLUSION

Radiotherapy plus fluorouracil and mytomicin provide a better complete pathological response than radiotherapy plus cisplatin and fluorouracil and a greater rate of anal sphincter function preservation. Globally, radiochemotherapy of the anal cancer provides excellent clinical outcomes with a good profile of acute and late toxicity, without difference between the two groups studied.