Elective clinical target volumes for conformal therapy in anorectal cancer: a radiation therapy oncology group consensus panel contouring atlas

Prediction of pathological complete response and prognosis in locally advanced rectal cancer

BACKGROUND

Colorectal cancer is currently the third most common malignant tumor and the second leading cause of cancer-related death worldwide. Neoadjuvant chemoradiotherapy (nCRT) is standard for locally advanced rectal cancer (LARC). Except for pathological examination after resection, it is not known exactly whether LARC patients have achieved pathological complete response (pCR) before surgery. To date, there are no clear clinical indicators that can predict the efficacy of nCRT and patient outcomes.

AIM

To investigate the indicators that can predict pCR and long-term outcomes following nCRT in patients with LARC.

METHODS

Clinical data of 128 LARC patients admitted to our hospital between September 2013 and November 2022 were retrospectively analyzed. Patients were categorized into pCR and non-pCR groups. Univariate analysis (using the χ² test or Fisher’s exact test) and logistic multivariate regression analysis were used to study clinical predictors affecting pCR. The 5-year disease-free survival (DFS) and overall survival (OS) rates were calculated using Kaplan-Meier analysis, and differences in survival curves were assessed with the log-rank test.

RESULTS

Univariate analysis showed that pretreatment carcinoembryonic antigen (CEA) level, lymphocyte-monocyte ratio (LMR), time interval between neoadjuvant therapy completion and total mesorectal excision, and tumor size were correlated with pCR. Multivariate results showed that CEA ≤ 5 ng/mL (P = 0.039), LMR > 2.73 (P = 0.023), and time interval > 10 wk (P = 0.039) were independent predictors for pCR. Survival analysis demonstrated that patients in the pCR group had significantly higher 5-year DFS rates (94.7% vs 59.7%, P = 0.002) and 5-year OS rates (95.8% vs 80.1%, P = 0.019) compared to the non-pCR group. Tumor deposits (TDs) were significantly correlated with shorter DFS (P = 0.002) and OS (P < 0.001).

CONCLUSION

Pretreatment CEA, LMR, and time interval contribute to predicting nCRT efficacy in LARC patients. Achieving pCR demonstrates longer DFS and OS. TDs correlate with poor prognosis.

Prediction of pathological complete response and prognosis in locally advanced rectal cancer

BACKGROUND

Colorectal cancer is currently the third most common malignant tumor and the second leading cause of cancer-related death worldwide. Neoadjuvant chemoradiotherapy (nCRT) is standard for locally advanced rectal cancer (LARC). Except for pathological examination after resection, it is not known exactly whether LARC patients have achieved pathological complete response (pCR) before surgery. To date, there are no clear clinical indicators that can predict the efficacy of nCRT and patient outcomes.

AIM

To investigate the indicators that can predict pCR and long-term outcomes following nCRT in patients with LARC.

METHODS

Clinical data of 128 LARC patients admitted to our hospital between September 2013 and November 2022 were retrospectively analyzed. Patients were categorized into pCR and non-pCR groups. Univariate analysis (using the χ² test or Fisher’s exact test) and logistic multivariate regression analysis were used to study clinical predictors affecting pCR. The 5-year disease-free survival (DFS) and overall survival (OS) rates were calculated using Kaplan-Meier analysis, and differences in survival curves were assessed with the log-rank test.

RESULTS

Univariate analysis showed that pretreatment carcinoembryonic antigen (CEA) level, lymphocyte-monocyte ratio (LMR), time interval between neoadjuvant therapy completion and total mesorectal excision, and tumor size were correlated with pCR. Multivariate results showed that CEA ≤ 5 ng/mL (P = 0.039), LMR > 2.73 (P = 0.023), and time interval > 10 wk (P = 0.039) were independent predictors for pCR. Survival analysis demonstrated that patients in the pCR group had significantly higher 5-year DFS rates (94.7% vs 59.7%, P = 0.002) and 5-year OS rates (95.8% vs 80.1%, P = 0.019) compared to the non-pCR group. Tumor deposits (TDs) were significantly correlated with shorter DFS (P = 0.002) and OS (P < 0.001).

CONCLUSION

Pretreatment CEA, LMR, and time interval contribute to predicting nCRT efficacy in LARC patients. Achieving pCR demonstrates longer DFS and OS. TDs correlate with poor prognosis.

Pleasurable and problematic receptive anal intercourse and diseases of the colon, rectum and anus

The ability to experience pleasurable sexual activity is important for human health. Receptive anal intercourse (RAI) is a common, though frequently stigmatized, pleasurable sexual activity. Little is known about how diseases of the colon, rectum, and anus and their treatments affect RAI. Engaging in RAI with gastrointestinal disease can be difficult due to the unpredictability of symptoms and treatment-related toxic effects. Patients might experience sphincter hypertonicity, gastrointestinal symptom-specific anxiety, altered pelvic blood flow from structural disorders, decreased sensation from cancer-directed therapies or body image issues from stoma creation. These can result in problematic RAI - encompassing anodyspareunia (painful RAI), arousal dysfunction, orgasm dysfunction and decreased sexual desire. Therapeutic strategies for problematic RAI in patients living with gastrointestinal diseases and/or treatment-related dysfunction include pelvic floor muscle strengthening and stretching, psychological interventions, and restorative devices. Providing health-care professionals with a framework to discuss pleasurable RAI and diagnose problematic RAI can help improve patient outcomes. Normalizing RAI, affirming pleasure from RAI and acknowledging that the gastrointestinal system is involved in sexual pleasure, sexual function and sexual health will help transform the scientific paradigm of sexual health to one that is more just and equitable.

Nonoperative management protocol for locally advanced rectal cancer

AIM

The standard treatment for low rectal cancer is preoperative chemoradiotherapy followed by surgery with low anterior resection with diverting ileostomy or abdominoperineal resection, both of which have significant long-term effects on bowel and sexual function. Due to the high morbidity of surgery, there has been increasing interest in nonoperative management for low rectal cancer. The aim of this work is to conduct a pan-Canadian Phase II trial assessing the safety of nonoperative management for low rectal cancer.

METHOD

Patients with Stage II or III low rectal cancer completing chemoradiotherapy according to standard of care at participating centres will be assessed for complete clinical response 8-14 weeks following completion of chemoradiotherapy. Subjects achieving a clinical complete response will undergo active surveillance including endoscopy, imaging and bloodwork at regular intervals for 24 months. The primary outcome will be the rate of local regrowth 2 years after chemoradiotherapy. Nonoperative management will be considered safe (i.e. as effective as surgery to achieve local control) if the rate of local regrowth is ≤30% and surgical salvage is possible for all local regrowths. Secondary outcomes will include disease-free and overall survival.

CONCLUSION

The results will be highly clinically relevant, as it is expected that nonoperative management will be safe and lead to widespread adoption of nonoperative management in Canada. This change in practice has the potential to decrease the number of patients requiring surgery and the costs associated with surgery and long-term surgical morbidity.

Retrospective Evaluation of the Efficacy of Total Neoadjuvant Therapy and Chemoradiotherapy Neoadjuvant Treatment in Relation to Surgery in Patients with Rectal Cancer

Background and Objective: In the therapeutic strategy of rectal cancer, radiotherapy has consolidated its important position and frequent use in current practice due to its indications as neoadjuvant, adjuvant, definitive, or palliative treatment. In recent years, total neoadjuvant therapy (TNT) has been established as the preferred regimen compared to concurrent neoadjuvant chemoradiotherapy (CRT). In relation to better outcomes, the percentage of patients who achieved pathological complete response (pCR) after neoadjuvant treatment is higher in the case of TNT. This study aimed to analyze the response to TNT compared to neoadjuvant CRT regarding pCR rate and the change in staging after surgical intervention. Materials and Methods: We performed a retrospective study on 323 patients with rectal cancer and finally analyzed the data of 201 patients with neoadjuvant treatment, selected based on the inclusion and exclusion criteria. Patients received CRT neoadjuvant therapy or TNT neoadjuvant therapy with FOLFOX or CAPEOX. Results: Out of 157 patients who underwent TNT treatment, 19.74% had pathological complete response, whereas in the group with CRT (n = 44), those with pCR were 13.64%. After neoadjuvant treatment, the most frequent TNM classifications were ypT2 (40.30%) and ypN0 (79.10%). The statistical analysis of the postoperative disease stage, after neoadjuvant therapy, showed that the most frequent changes were downstaging (71.14%) and complete response (18.41%). Only four patients (1.99%) had an upstaging change. The majority of patients (88.56%) initially presented clinical evidence of nodal involvement whereas only 20.9% of the patients still presented regional disease at the time of surgical intervention. Conclusions: By using TNT, a higher rate of stage reduction is obtained compared to the neoadjuvant CRT treatment. The post-neoadjuvant-treatment imagistic evaluation fails to accurately evaluate the response. A better response to TNT was observed in young patients.

Evaluating complete response prediction rates in locally advanced rectal cancer with different radiomics segmentation approaches

Purpose

Studies examining prediction of complete response (CR) in locally advanced rectum cancer (LARC) from pre/post chemoradiotherapy (CRT) magnetic resonance imaging (MRI) are performed mostly with segmentations of the tumor, whereas only in two studies segmentation included tumor and mesorectum. Additionally, pelvic extramesorectal region, which is included in the clinical target volume (CTV) of radiotherapy, may contain information. Therefore, we aimed to compare predictive rates of radiomics analysis with features extracted from segmentations of tumor, tumor+mesorectum, and CTV.

Methods and materials

Ninety-three LARC patients who underwent CRT in our institution between 2012 and 2019 were retrospectively scanned. Patients were divided into CR and non-CR groups. Tumor, tumor+mesorectum and CTV were segmented on T2 preCRT MRI images. Extracted features were compared for best area under the curve (AUC) of CR prediction with 15 machine-learning models.

Results

CR was observed in 25 patients (26.8%), of whom 13 had pathological, and 12 had clinical complete response. For tumor, tumor+mesorectum and CTV segmentations, the best AUC were 0.84, 0.81, 0.77 in the training set and 0.85, 0.83 and 0.72 in the test set, respectively; sensitivity and specificity for the test set were 76%, 90%, 76% and 71%, 67% and 62%, respectively.

Conclusion

Although the highest AUC result is obtained from the tumor segmentation, the highest accuracy and sensitivity are detected with tumor+mesorectum segmentation and these findings align with previous studies, suggesting that the mesorectum contains valuable insights for CR. The lowest result is obtained with CTV segmentation. More studies with mesorectum and pelvic nodal regions included in segmentation are needed.

ROAR-A: re-optimization based Online Adaptive Radiotherapy of anal cancer, a prospective phase II trial protocol

BACKGROUND

Chemo-radiotherapy with curative intent for anal cancer has high complete remission rates, but acute treatment-related gastrointestinal (GI) toxicity is significant. Toxicity occurs due to irradiation of surrounding normal tissue. Current radiotherapy requires the addition of large planning margins to the radiation field to ensure target coverage regardless of the considerable organ motion in the pelvic region. This increases the irradiated volume and radiation dose to the surrounding normal tissue and thereby toxicity. Online adaptive radiotherapy uses artificial intelligence to adjust the treatment to the anatomy of the day. This allows for the reduction of planning margins, minimizing the irradiated volume and thereby radiation to the surrounding normal tissue.This study examines if cone beam computed tomography (CBCT)-guided oART with daily automated treatment re-planning can reduce acute gastrointestinal toxicity in patients with anal cancer.

METHODS/DESIGN

The study is a prospective, single-arm, phase II trial conducted at Copenhagen University Hospital, Herlev and Gentofte, Denmark. 205 patients with local only or locally advanced anal cancer, referred for radiotherapy with or without chemotherapy with curative intent, are planned for inclusion. Toxicity and quality of life are reported with Common Terminology Criteria of Adverse Events and patient-reported outcome questionnaires, before, during, and after treatment. The primary endpoint is a reduction in the incidence of acute treatment-related grade ≥ 2 diarrhea from 36 to 25% after daily online adaptive radiotherapy compared to standard radiotherapy. Secondary endpoints include all acute and late toxicity, overall survival, and reduction in treatment interruptions.

RESULTS

Accrual began in January 2022 and is expected to finish in January 2026. Primary endpoint results are expected to be available in April 2026.

DISCUSSION

This is the first study utilizing online adaptive radiotherapy to treat anal cancer. We hope to determine whether there is a clinical benefit for the patients, with significant reductions in acute GI toxicity without compromising treatment efficacy.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05438836. Danish Ethical Committee: H-21028093.

Excluding external iliac node irradiation during neoadjuvant radiotherapy decreases lower intestinal toxicity without compromising efficacy in T4b rectal cancer patients with tumours involving the anterior structures

PURPOSE

To explore the impact of excluding the external iliac node (EIN) from the clinical target volume (CTV) during preoperative radiotherapy in T4b rectal cancer with anterior structure invasion.

METHODS

We retrospectively identified 132 patients with T4b rectal cancer involving the anterior structures who received radiotherapy followed by surgery between May 2010 and June 2019. Twenty-nine patients received EIN irradiation (EIN group), and 103 did not (NEIN group). Failure patterns, survival and toxicities were compared between the two groups.

RESULTS

The most common failure was distant metastasis (23.5%). 11 (8.3%) patients developed locoregional recurrence, 10 (9.7%) patients were in the NEIN group, and 1 (3.4%) was in the EIN group (P = 0.34). The EIN region failure was rare (1/132, 0.8%). The locoregional recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), overall survival (OS) and progression-free survival (PFS) rates were 96.3% vs. 90.5%, 82.1% vs.73.7%, 75.9% vs. 78.0% and 72.4% vs. 68.3% (all P > 0.05) for the EIN group and NEIN group, respectively. The incidence of grade 3-4 acute toxicity in the lower intestine was significantly higher in the EIN group than in the NEIN group (13.8% vs. 1.9%, P = 0.02). The Dmax, V35 and V45 of the small bowel was decreased in the NEIN group compared to the EIN group.

CONCLUSIONS

Exclusion of the EIN from the CTV in T4b rectal cancer with anterior structure invasion could reduce lower intestinal toxicity without compromising oncological outcomes. These results need further evaluation in future studies.

Capecitabine/cisplatin combined with concurrent intensity-modulated radiation therapy: a feasible therapeutic strategy for anal squamous cell carcinoma

PURPOSE

To evaluate the efficacy and safety of capecitabine/cisplatin (XP) combined with intensity-modulated radiation therapy (IMRT) in patients with non-metastatic anal squamous cell carcinoma (ASCC).

METHOD AND MATERIALS

All patients with ASCC who received radical concurrent chemoradiotherapy in the past 8 years were screened. Patients who received XP or mitomycin/5-fluorouracil (MF) were selected and analyzed retrospectively.

RESULTS

ASCC is an uncommon cancer, there were 36 patients were included in our study. The XP group and MF group included 18 patients each. The clinical complete response (cCR) rates in the XP group and the MF group were 94.4% and 88.9%, respectively (P = 1). The 2-year local control (LC), disease-free survival (DFS), and colostomy-free survival (CFS) rates were higher in the XP group than in the MF group (100% vs 93.3%, P = 0.32). Hematologic toxicities, especially grade ≥ 3 leukopenia (11.1% vs 44.4%, P = 0.06) and neutropenia (5.6% vs 61.1%, P = 0.001), were lower in the XP group than MF group. As a result of fewer side effects, fewer patients in the XP group demanded the dose reduction of chemotherapy (11.1% vs 50%, P = 0.03) and radiation interruption (55.6% vs 77.8%, P = 0.289). Delayed radiotherapy was shorter in the XP group (2.5 vs 6.5 days, P = 0.042) than in the MF group.

CONCLUSION

The XP regimen was as effective as the MF regimen in non-metastatic ASCC. Compared with the standard MF regimen, XP combined with IMRT showed higher treatment completion and lower toxicities. It could be considered a feasible alternative for patients with non-metastatic ASCC.

Randomized Controlled Trial of Neoadjuvant Short-Course Radiotherapy Followed by Consolidation Chemotherapy Versus Long-Course Chemoradiotherapy in Locally Advanced Rectal Cancer: Comparison of Overall Response Rates

BACKGROUND

Management of locally advanced rectal cancer (LARC) is evolving with current emphasis on the addition of chemotherapy to short course radiotherapy (SCRT). We primarily aimed to analyse the difference in overall response rates between SCRT with sequential chemotherapy and standard long-course chemoradiotherapy (LCCRT)in LARC.

METHODS

After randomization, patients in arm A received 45 Gy in 25 fractions over 5 weeks with concurrent capecitabine while patients in arm B received 25 Gy in 5 fractions over 1 week followed by 3 cycles of CAPOX (capecitabine and oxaliplatin) chemotherapy. Clinical and radiological response assessment was made after the completion of neoadjuvant treatment, a week prior to surgery. Adjuvant chemotherapy was added to complete 6 months of peri-operative chemotherapy. Surgery was performed between 8 and 10 weeks of completion of radiation treatment in both arms.

RESULTS

Of the 33 patients recruited in this study between February 2020 to July 2021, 17 patients were randomized to arm A and 16 to arm B. The rates of complete tumour regression were 23.1% in arm A versus 35.7% in arm B (p-value = 0.683). Pathological complete response (pCR) rate was 20% arm A versus 30% in arm B (0.446). A higher number of patients in arm B experienced grade 3 diarrhoea, whereas acute skin toxicity was seen only in arm A. SCRT had fewer treatment interruptions compared to LCCRT.

CONCLUSIONS

SCRT followed by three cycles of CAPOX chemotherapy in the neoadjuvant setting is comparable to LCCRT in terms of tumour response. This may be a better alternative regimen with fewer treatment interruptions in a resource-limited setting.

Neoadjuvant short-course radiotherapy or chemoradiation plus consolidative chemotherapy followed by radical operation for locally advanced rectal cancer

Introduction

Limited evidence compares short-course radiotherapy (SCRT) and long-course chemoradiotherapy (LCCRT), both of which are followed by consolidative chemotherapy before radical rectal surgery. We conducted a retrospective cohort study to assess treatment response, survival outcomes, and toxicity in patients with locally advanced rectal cancer.

Materials and methods

Patients (cT3-4 and/or N+) treated with SCRT or LCCRT, consolidative chemotherapy, or total mesorectal excision between 2013 and 2021 were identified. the cause-specific cumulative incidence of disease-related treatment failure, locoregional recurrence, distant metastases, and overall survival were evaluated using flexible parametric competing risk analysis and Kaplan-Meier methods, adjusted for treatment regimens and clinicopathological factors. A pathological complete response (pCR), tumor downstaging, and toxicity have been reported.

Results

Among the 144 patients, 115 (80%) underwent curative rectal surgery. The LCCRT and SCRT groups achieved pCR in 10 (18%) and seven (12%) patients, respectively (odds ratio, 1.68; 95% confidence interval [CI], 0.59-4.78). The adjusted cause-specific hazard ratio for disease-related treatment failure with LCCRT versus SCRT was 0.26 (95% CI, 0.08-0.87). Three-year cumulative probability of disease-related treatment failure was 10.0% and 25.6% for LCCRT and SCRT, respectively. No significant differences in T-downstaging, N-downstaging, significant pathologic downstaging (ypT0-2N0), locoregional failure, distant metastasis, or overall survival were found. Late rectal toxicity occurred in 10 (15%) LCCRT and two (3%) SCRT patients, respectively.

Conclusion

LCCRT with consolidative chemotherapy demonstrated improved disease-related treatment failure compared with SCRT, despite higher late rectal toxicity. Further research is needed to assess the long-term oncologic outcomes and toxicity.

Is radiotherapy necessary for upper rectal cancer underwent curative resection? A retrospective study of 363 patients

BACKGROUND

To investigate the impact of radiotherapy (RT) on recurrence and survival in patients with locally advanced upper rectal cancer underwent curative resection.

METHODS

363 locally advanced upper rectal cancer cases were identified from the database of our hospital from 2010 to 2018. All patients underwent curative resection and had the lower margin of the tumor located 10-15 cm from the anal verge, among them, 69 patients received pre- or post-operative radiotherapy and 294 patients without. Local control and survivals were compared, and stratification grouping based on European Society for Medical Oncology risk factors were further compared. 1:2 propensity score matching analysis was used to reduce the impact of confounding factors.

RESULTS

There were 207 patients after 1:2 matching (RT group:non-RT group = 69:138). The 5-year overall survival (OS) of the RT group and non-RT group after matching was 84.1% and 80.9%, respectively(P = 0.440); the 5-year local recurrence-free survival (LRFS) was 96.5% and 94.7%, respectively(P = 0.364); the 5-year distant metastasis-free survival (DMFS) was 76.8% and 76.9%, respectively(P = 0.531). Subgroup analysis showed that radiotherapy could not significantly improve the overall survival, local recurrence, and distant metastasis with or without poor prognostic features. In the high-risk subgroup, the 5-year OS was 76.9% and 79.6% for patients treated with radiotherapy and without (P = 0.798), LRFS was 94.8% and 94.2%, respectively (P = 0.605), DMFS 68.7% and 74.7%, respectively (P = 0.233).

CONCLUSIONS

Our results suggest that radiotherapy could not improve local control and survival for locally advanced upper rectal cancer patients underwent curative resection, even in the cases with poor prognostic features.

Lateral Pelvic Nodal Management and Patterns of Failure in Patients Receiving Short-Course Radiation for Locally Advanced Rectal Cancer

BACKGROUND

Management of lateral pelvic lymph nodes in locally advanced rectal cancer is controversial, with limited data indicating the optimal approach. In addition, no data exist regarding the treatment of lateral nodes in the setting of short-course radiation and nonoperative intent.

OBJECTIVE

To evaluate a novel approach incorporating simultaneous integrated boost to suspicious lateral nodes.

DESIGN

A retrospective study.

SETTING

This study was conducted at a large tertiary referral center.

PATIENTS

Patients treated with radiation therapy and consolidation chemotherapy were included. All primary tumors underwent biopsy confirmation and disease staging with pelvic MRI.

INTERVENTIONS

Primary tumors were biopsy proven and staged with pelvic MRI. A subset of lateral pelvic lymph node patients received a simultaneous integrated boost of 35 Gy in 5 fractions. Then, chemotherapy was administered, with the majority receiving modified folinic acid, fluorouracil, and oxaliplatin. Clinical partial response required total mesorectal excision.

MAIN OUTCOME MEASURES

Patterns of failure and survival analyses by subgroup were assessed. Outcomes based on receipt of radiation were compared across node status.

RESULTS

Between January 2017 and January 2022, 155 patients were treated with short-course chemotherapy, with 121 included in the final analysis. Forty-nine percent of patients underwent nonoperative management. The median follow-up was 36 months and the median age was 58 years. Thirty-eight patients (26%) had positive lateral pelvic lymph nodes. Comparing lateral node status, progression-free survival was significantly worse for patients with positive disease ( p < 0.001), with a trend for worse overall survival. Receipt of nodal boost in patients with lateral nodes resulted in meaningful locoregional control. Nodal boost did not contribute to additional acute or late GI toxicity.

LIMITATIONS

Limitations include retrospective nature and lack of lateral node pathology; however, a thorough radiographic review was performed.

CONCLUSIONS

Lateral node-positive rectal cancer is correlated with worse oncologic outcomes and higher locoregional failure. Boost to clinically positive lateral nodes is a safe approach in the setting of short course radiation and in those receiving nonoperative intent. See Video Abstract.

MANEJO DE LOS GANGLIOS PLVICOS LATERALES Y PATRONES DE FALLA EN PACIENTES QUE RECIBEN RADIACIN DE CICLO CORTO PARA EL CNCER DE RECTO LOCALMENTE AVANZADO

ANTECEDENTES:El manejo de los ganglios linfáticos pélvicos laterales en el cáncer de recto localmente avanzado es controvertido, con datos limitados que indiquen el abordaje óptimo. Además, no existen datos sobre el tratamiento de los ganglios linfáticos laterales en el contexto de la radiación de curso corto y la intención no operatoria.OBJETIVO:Evaluamos un enfoque novedoso que incorpora sobreimpresión integrada simultánea (SIB) a los linfonodos laterales sospechosos.DISEÑO:Este fue un estudio retrospectivo.ESCENARIO:Este estudio se realizó en un gran centro de referencia terciario.PACIENTES:Se incluyeron pacientes tratados con radiación y quimioterapia de consolidación. Todos los tumores primarios se confirmaron mediante biopsia y la enfermedad se estadificó con resonancia magnética pélvica.INTERVENCIONES:Los tumores primarios se confirmaron mediante biopsia y se estadificaron con RM pélvica. Un subconjunto de pacientes con linfonodos pélvicos laterales (LPLN) recibió SIB a 35 Gy en 5 fracciones. Luego, se administró quimioterapia y la mayoría recibió mFOLFOX. La respuesta clínica parcial requirió la escisión total del mesorrecto.PRINCIPALES MEDIDAS DE RESULTADO:Se evaluaron los patrones de fracaso y los análisis de supervivencia por subgrupo. Los resultados basados en el esquema de radiación se compararon según el estado de los ganglios.RESULTADOS:Entre enero de 2017 y enero de 2022, 155 pacientes fueron tratados con ciclo corto y quimioterapia con 121 incluidos en el análisis final. El 49% se sometió a manejo no operatorio. La mediana de seguimiento fue de 36 meses y la mediana de edad fue de 58 años. 38 pacientes (26%) tuvieron LPLN positivos. Comparando el estado de los ganglios laterales, la supervivencia libre de progresión fue significativamente peor para los pacientes con LPLN positiva ( p < 0,001) con una tendencia a una peor supervivencia global. La recepción de refuerzo nodal en pacientes con nodos laterales dio como resultado un control locorregional significativo. La sobreimpresión ganglionar no contribuyó a la toxicidad GI aguda o tardía adicional.LIMITACIONES:Las limitaciones incluyeron la naturaleza retrospectiva y la falta de patología de los ganglios linfáticos laterales; sin embargo, se realizó una revisión radiográfica exhaustiva.CONCLUSIONES:El cáncer de recto con ganglio lateral positivo se correlaciona con peores resultados oncológicos y mayor fracaso locorregional. La sobreimpresión a los ganglios laterales clínicamente positivos es un enfoque seguro en el contexto de un curso corto y en aquellos que siguen un manejo no operatorio. (Traducción-Dr. Felipe Bellolio ).

Predictive Value of the Interaction between CEA and Hemoglobin in Neoadjuvant CCRT Outcomes in Rectal Cancer Patients

The adoption of neoadjuvant concurrent chemoradiotherapy (CCRT) has reshaped the therapeutic landscape, but response prediction remains challenging. This study investigates the interaction between pre-CCRT carcinoembryonic antigen (CEA) and post-CCRT hemoglobin (Hb) levels in predicting the response of locally advanced rectal cancer (LARC) to CCRT. Retrospective data from 93 rectal cancer patients receiving neoadjuvant CCRT were analyzed. Univariate analyses assessed clinical factors associated with tumor regression grade (TRG) and T-stage outcomes. Machine learning identified predictive biomarkers. Interaction effects between CEA and Hb were explored through subgroup analyses. Post-CCRT Hb varied between pre-CCRT CEA groups. The interaction between pre-CCRT CEA and post-CCRT Hb influenced TRG. Males with normal pre-CCRT CEA and anemia showed better treatment responses. Females with elevated pre-CCRT CEA and post-CCRT anemia exhibited poorer responses. The interaction effect between them was significant, indicating that their relationship with TRG was not additive. Inflammatory biomarkers, WBC, neutrophil count, and post-CCRT platelet level correlated with CCRT response. Contrasting with previous findings, anemia was a predictor of better treatment response in males with normal pre-CCRT CEA. The interaction between pre-CCRT CEA and post-CCRT Hb levels predicts the response of LARC to CCRT. CEA, Hb, and sex should be considered when assessing treatment response. Inflammatory biomarkers contribute to response prediction. Understanding these complex relationships can enhance personalized treatment approaches in rectal cancer patients.

Preoperative sequential short-course radiation therapy and FOLFOX chemotherapy versus long-course chemoradiotherapy for locally advanced rectal cancer: a multicenter, randomized controlled trial (SOLAR trial)

BACKGROUND

Preoperative (chemo)radiotherapy has been widely used as an effective treatment for locally advanced rectal cancer (LARC), leading to a significant reduction in pelvic recurrence rates. Because early administration of intensive chemotherapy for LARC has more advantages than adjuvant chemotherapy, total neoadjuvant therapy (TNT) has been introduced and evaluated to determine whether it can improve tumor response or treatment outcomes. This study aims to investigate whether short-course radiotherapy (SCRT) followed by intensive chemotherapy improves oncologic outcomes compared with traditional preoperative long-course chemoradiotherapy (CRT).

METHODS

A multicenter randomized phase II trial involving 364 patients with LARC (cT3-4, cN+, or presence of extramural vascular invasion) will be conducted. Patients will be randomly assigned to the experimental or control arm at a ratio of 1:1. Participants in the experimental arm will receive SCRT (25 Gy in 5 fractions, daily) followed by four cycles of FOLFOX (oxaliplatin, 5-fluorouracil, and folinic acid) as a neoadjuvant treatment, and those in the control arm will receive conventional radiotherapy (45-50.4 Gy in 25-28 fractions, 5 times a week) concurrently with capecitabine or 5-fluorouracil. As a mandatory surgical procedure, total mesorectal excision will be performed 2-5 weeks from the last cycle of chemotherapy in the experimental arm and 6-8 weeks after the last day of radiotherapy in the control arm. The primary endpoint is 3-year disease-free survival, and the secondary endpoints are tumor response, overall survival, toxicities, quality of life, and cost-effectiveness.

DISCUSSION

This is the first Korean randomized controlled study comparing SCRT-based TNT with traditional preoperative LC-CRT for LARC. The involvement of experienced colorectal surgeons ensures high-quality surgical resection. SCRT followed by FOLFOX chemotherapy is expected to improve disease-free survival compared with CRT, with potential advantages in tumor response, quality of life, and cost-effectiveness.

TRIAL REGISTRATION

This trial is registered at Clinical Research Information under the identifier Service KCT0004874 on April 02, 2020, and at Clinicaltrial.gov under the identifier NCT05673772 on January 06, 2023.

Radiological Biomarkers in MRI directed Rectal Cancer Radiotherapy Volume Delineation

Our study evaluated whether an MRI reporting system highlighting areas of contiguous and discontinuous extramural venous invasion (EMVI) can improve the accuracy of gross tumour volume (GTV) delineation. Initially, 27 consecutive patients with locally advanced rectal cancer treated between 2012 and 2014 were evaluated. We used an MRI reporting proforma that documented the position of the primary tumour, lymph nodes and EMVI. The new GTVs delineated were compared with historical radiotherapy treatment volumes to identify the frequency of GTV geographical miss. We observed that the delineation of involved nodes and areas of EMVI was more likely to represent sources of uncertainty wherein nodal GTV geographical miss was evident in 5 out of 27 patients (19%). Complete EMVI GTV geographical miss occurred in two patients (7%). We re-evaluated our radiotherapy practice in a further 27 patients after the implementation of a modified MRI reporting system. An improvement was seen; nodal miss was observed in two patients (7%) and partial EMVI miss in one patient (4%), although these areas were encompassed in the planning target volume (PTV). Our study shows that extramural venous invasion and involved nodes need to be highlighted on MRI to improve the accuracy of rectal cancer GTV delineation.

Towards deep-learning (DL) based fully automated target delineation for rectal cancer neoadjuvant radiotherapy using a divide-and-conquer strategy: a study with multicenter blind and randomized validation

PURPOSE

Manual clinical target volume (CTV) and gross tumor volume (GTV) delineation for rectal cancer neoadjuvant radiotherapy is pivotal but labor-intensive. This study aims to propose a deep learning (DL)-based workflow towards fully automated clinical target volume (CTV) and gross tumor volume (GTV) delineation for rectal cancer neoadjuvant radiotherapy.

MATERIALS & METHODS

We retrospectively included 141 patients with Stage II-III mid-low rectal cancer and randomly grouped them into training (n = 121) and testing (n = 20) cohorts. We adopted a divide-and-conquer strategy to address CTV and GTV segmentation using two separate DL models with DpuUnet as backend-one model for CTV segmentation in the CT domain, and the other for GTV in the MRI domain. The workflow was validated using a three-level multicenter-involved blind and randomized evaluation scheme. Dice similarity coefficient (DSC) and 95th percentile Hausdorff distance (95HD) metrics were calculated in Level 1, four-grade expert scoring was performed in Level 2, and head-to-head Turing test in Level 3.

RESULTS

For the DL-based CTV contours over the testing cohort, the DSC and 95HD (mean ± SD) were 0.85 ± 0.06 and 7.75 ± 6.42 mm respectively, and 96.4% cases achieved clinical viable scores (≥ 2). The positive rate in the Turing test was 52.3%. For GTV, the DSC and 95HD were 0.87 ± 0.07 and 4.07 ± 1.67 mm respectively, and 100% of the DL-based contours achieved clinical viable scores (≥ 2). The positive rate in the Turing test was 52.0%.

CONCLUSION

The proposed DL-based workflow exhibited promising accuracy and excellent clinical viability towards automated CTV and GTV delineation for rectal cancer neoadjuvant radiotherapy.

Gender-Affirming Surgery and Cancer: Considerations for Radiation Oncologists for Pelvic Radiation in Transfeminine Patients

Access to gender-affirming surgery is increasing for many transgender and nonbinary people in the United States, and radiation oncologists must be equipped to care for patients who have undergone such surgery in the region of their planned radiation treatment field. There are no guidelines for radiation treatment planning after gender-affirming surgery, and most oncologists do not receive training in the unique needs of transgender people with cancer. We review common gender-affirming genitopelvic surgeries for transfeminine people, including vaginoplasty, labiaplasty, and orchiectomy, and summarize the existing literature on the treatment of cancers of the neovagina, anus, rectum, prostate, and bladder in these patients. We also describe our systematic treatment approach and rationale for pelvic radiation treatment planning.

Evaluation of survival outcomes and prognostic factors of carcinoma anal canal at a tertiary cancer center

CONTEXT

Concurrent chemoradiotherapy is considered a standard of care for patients with carcinoma anal canal. Being an unusual malignancy, there is limited Indian data regarding survival outcomes and prognostic factors.

AIM

To evaluate survival outcomes and associated prognostic factors in patients with carcinoma anal canal treated with radical intent.

METHODS AND MATERIAL

Patients with squamous cell carcinoma of the anal canal, treated with radical intent between 2015 and 2019 were included in the study. Data regarding the baseline characteristics of the patients and treatment outcomes were collected and analyzed. Survival rates were estimated using Kaplan-Meier method. To determine survival difference between the groups, log-rank test was used. Multivariate analyses were performed with Cox proportional hazard models and P value < 0.05 was considered significant.

RESULTS

Forty-two patients were identified after applying suitable eligibility criteria. The median age was 55 years (range: 26-80 years).The median follow-up duration was 23.5 months (range: 1.9-51.9 months). The 3-year overall survival (OS), disease-free survival (DFS), and locoregional (LRC) were 78.5%, 53.1%, and 66.4%, respectively. On multivariate analysis, inferior DFS was significantly affected by lack of concurrent chemotherapy (CT) (hazard ratio [HR], 11.50; 95% confidence interval [CI], 1.92-68.78; P = 0.007) and radiotherapy (RT) dose of 45 Gy or less (HR, 35.96; 95% CI, 6.32-204.56; P = 0.000).

CONCLUSION

For patients of carcinoma anal canal, concurrent CT and RT dose are independent prognostic factors influencing DFS.

Upper limit of radiation treatment portals in rectal cancer: is it wise to keep using bony landmarks in the present era of 3D conformal treatment?

Background

This study aimed to compare the levels of L5-S1 interspace and the bifurcation of common iliac vessels on simulation images of rectal cancer patients to evaluate the adequacy of superior borders in conventional 2D planning for covering internal iliac vessels.

Materials and methods

Simulation images of 236 rectal cancer patients who received neoadjuvant chemoradiation and surgery were analyzed. The images were retrieved from the radiation treatment database and included delineations of L5-S1 interspace and common iliac vessel bifurcation. Distances between these landmarks were measured.

Results

Among the 236 patients, the majority had the common iliac artery bifurcation positioned above the L5-S1 interspace. Specifically, 78.3% of patients had the right common iliac bifurcation above L5-S1 interspace, with an average distance of 2.02 cm. For the left common iliac artery, 77.11% of patients had the bifurcation above L5-S1 interspace, with an average distance of 1.99 cm. Notably, there were cases where the bifurcations were not at the same level.

Conclusion

Using the L5-S1 junction as the upper border of the treatment portal may result in missing proximal nodes at risk of metastases. However, further research is needed to determine the significance of failures above the L5-S1 interspace for justifying the inclusion of the common iliac artery bifurcation in the treatment portal.

Radiation hematologic toxicity prediction for locally advanced rectal cancer using dosimetric and radiomics features

BACKGROUND

Hematologic toxicity (HT) is a common adverse tissue reaction during radiotherapy for rectal cancer patients, which may lead to various negative effects such as reduced therapeutic effect, prolonged treatment period and increased treatment cost. Therefore, predicting the occurrence of HT before radiotherapy is necessary but still challenging.

PURPOSE

This study proposes a hybrid machine learning model to predict the symptomatic radiation HT in rectal cancer patients using the combined demographic, clinical, dosimetric, and Radiomics features, and ascertains the most effective regions of interest (ROI) in CT images and predictive feature sets.

METHODS

A discovery dataset of 240 rectal cancer patients, including 145 patients with HT symptoms and a validation dataset of 96 patients (63 patients with HT) with different dose prescription were retrospectively enrolled. Eight ROIs were contoured on patient CT images to derive Radiomics features, which were then, respectively, combined with the demographic, clinical, and dosimetric features to classify patients with HT symptoms. Moreover, the survival analysis was performed on risky patients with HT in order to understand the HT progression.

RESULTS

The classification models in ROIs of bone marrow and femoral head exhibited relatively high accuracies (accuracy = 0.765 and 0.725) in the discovery dataset as well as comparable performances in the validation dataset (accuracy = 0.758 and 0.714). When combining the two ROIs together, the model performance was the best in both discovery and validation datasets (accuracy = 0.843 and 0.802). In the survival analysis test, only the bone marrow ROI achieved statistically significant performance in accessing risky HT (C-index = 0.658, P = 0.03). Most of the discriminative features were Radiomics features, and only gender and the mean dose in Irradvolume was involved in HT.

CONCLUSION

The results reflect that the Radiomics features of bone marrow are significantly correlated with HT occurrence and progression in rectal cancer. The proposed Radiomics-based model may help the early detection of radiotherapy induced HT in rectal cancer patients and thus improve the clinical outcome in future.

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.

Impact of dose escalation on colostomy-free survival and treatment outcome in squamous cell anal carcinoma

PURPOSE

Primary radiochemotherapy (RCT) constitutes the standard of care for early- and advanced-stage anal carcinoma. This retrospective study investigates the impact of dose escalation on colostomy-free survival (CFS), overall survival (OS), locoregional control (LRC), progression-free survival (PFS), and acute and late toxicities in patients with squamous cell anal cancer.

METHODS

Considered were the outcomes of 87 patients with anal cancer treated with radiation/RCT between May 2004 and January 2020 at our institution. Toxicities were evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE version 5.0).

RESULTS

The 87 patients received treatment with a median boost of 63 Gy to the primary tumor. With a median follow-up of 32 months, the 3‑year CFS, OS, LRC, and PFS were 79.5%, 71.4%, 83.9%, and 78.5%, respectively. Tumor relapse occurred in 13 patients (14.9%). Dose escalation to > 63 Gy (maximum 66.6 Gy) to the primary tumor in 38/87 patients revealed a nonsignificant trend for improved 3‑year CFS (82.4% vs. 97%, P = 0.092), a significantly improved CFS for T2/T3 tumors (72.6% vs. 100%, P = 0.008), and a significantly improved 3‑year PFS for T1/T2 tumors (76.7% vs. 100%, P = 0.035). While acute toxicities did not differ, dose escalation > 63 Gy led to a higher rate of chronic skin toxicities (43.8% vs. 69%, P = 0.042). Treatment with intensity-modulated radiotherapy (IMRT) showed a significant improvement in 3‑year OS (75.4% vs. 53.8%, P = 0.048). In multivariate analysis, significant improvements for T1/T2 tumors (CFS, OS, LRC, PFS), G1/2 tumors (PFS), and IMRT (OS) were shown. The nonsignificant trend for CFS improvement with dose escalation > 63 Gy was also apparent in multivariate analysis (P = 0.067).

CONCLUSION

Dose escalation > 63 Gy (maximum 66.6 Gy) may improve CFS and PFS for certain subgroups, with a concomitant increase in chronic skin toxicities. Modern IMRT seems to be associated with an improvement in OS.

Risk-adjusted chemoradiation according to human papilloma viral status for anal cancer: a pilot study

Background and purpose

HPV-associated or positive (HPV+) anal cancer patients may have better outcome compared to those with HPV negative (HPV-) disease. We report a planned interim analysis of a prospective registry study that tailors chemoradiation (CRT) for anal cancer according to HPV status.

Materials and methods

HPV+ patients received de-escalated radiation doses of 45, 50.4 and 55.8 Gy, while HPV- received 50.4, 55.8 and 63 Gy for T1, T2 and T3/T4 disease respectively. Chemotherapy consisted of a single dose of mitomycin-C and oral capecitabine on days of RT. All patients were planned by VMAT following CT, PET/CT and MR simulation. This cohort (n = 24) had a minimum 24-month follow-up. Disease free survival (DFS) and local failure rates (LFR) were compared with 180 patients managed by standard CRT (2 cycles of mitomycin-C and 5-fluorouracil, radiation doses 50.4-63 Gy based on T-category) from 2011-2018. Propensity score comparison was performed using a retrospective to prospective 2 to 1 match based on tumor size and N-category.

Results

In the HPV+ cohort (n = 20), there were 2 local failures. Two of 4 HPV- patients failed locally. The 30-month DFS and LFR were 79% and 17% respectively. Similar DFS and LFR were observed in the retrospective (80% and 15% respectively) and matched patients (76% and 16% respectively). No grade ≥3 neutropenia and febrile neutropenia were observed in the registry cohort whereas 19% and 14% respectively were seen in the retrospective patients.

Conclusion

De-escalation of CRT for HPV+ anal cancer may result in decreased acute toxicities and similar cancer outcomes compared to standard CRT.

The role of MRI after neochemoradiotherapy in predicting pathological tumor regression grade and clinical outcome in patients with locally advanced rectal adenocarcinoma

Objective

To evaluate the predictive value of tumor regression grade assessed by MRI (mr-TRG) after neoadjuvant chemoradiotherapy (neo-CRT) for postoperative pathological TRG (pTRG) and prognosis in patients with locally advanced rectal adenocarcinoma (LARC).

Materials and methods

This was a retrospective study from a single center experience. The patients who were diagnosed with LARC and received neo-CRT in our department between January 2016 and July 2021 were enrolled. The agreement between mrTRG and pTRG was assessed with the weighted κ test. Overall survival (OS), progress-free survival (PFS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were calculated by Kaplan-Meier analysis and log-rank test.

Results

From January 2016 to July 2021, 121 LARC patients received neo-CRT in our department. Among them, 54 patients had complete clinical data, including MRI of pre- and post-neo-CRT, postoperative tumor samples, and follow-up. The median follow-up time was 34.6 months (range: 4.4-70.6 months). The estimated 3-year OS, PFS, LRFS and DMFS were 78.5%, 70.7%, 89.0%, and 75.2%, respectively. The median time from the completion of neo-CRT to preoperative MRI and surgery was 7.1 weeks and 9.7 weeks, respectively. Out of 54 patients, 5 patients achieved mrTRG1 (9.3%), 37 achieved mrTRG2 (68.5%), 8 achieved mrTRG3 (14.8%), 4 achieved mrTRG4 (7.4%), and no patient achieved mrTRG5 after neo-CRT. Regarding pTRG, 12 patients achieved pTRG0 (22.2%), 10 achieved pTRG1 (18.5%), 26 achieved pTRG2 (48.1%), and 6 achieved pTRG3 (11.1%). The agreement between three-tier mrTRG (mrTRG1 vs. mrTRG2-3 vs. mrTRG4-5) and pTRG (pTRG0 vs. pTRG1-2 vs. pTRG3) was fair (weighted kappa=0.287). In a dichotomous classification, the agreement between mrTRG(mrTRG1 vs. mrTRG2-5)and pTRG(pTRG0 vs. pTRG1-3) also resulted in fair agreement (weighted kappa=0.391). The sensitivity, specificity, positive, and negative predictive values of favorable mrTRG (mrTRG 1-2) for pathological complete response (PCR) were 75.0%, 21.4%, 21.4%, and 75.0%, respectively. In univariate analysis, favorable mrTRG (mrTRG1-2) and downstaging N were significantly associated with better OS, while favorable mrTRG (mrTRG1-2), downstaging T, and downstaging N were significantly associated with superior PFS (p<0.05). In multivariate analysis, downstaging N was an independent prognostic factor for OS. Meanwhile, downstaging T and downstaging N remained independent prognostic factors for PFS.

Conclusions

Although the consistency between mrTRG and pTRG is only fair, favorable mrTRG after neo-CRT may be used as a potential prognostic factor for LARC patients.

Identification of patients with locally advanced rectal cancer eligible for neoadjuvant chemotherapy alone: Results of a retrospective study

BACKGROUND AND OBJECTIVES

Neoadjuvant chemotherapy (nCT) appears in a few clinical studies as an alternative to neoadjuvant chemoradiation (nCRT) in selected patients with locally advanced rectal cancer (LARC). We aimed to compare the clinical outcomes of nCT with or without nCRT in patients with LARC and to identify patients who may be suitable for nCT alone.

MATERIALS AND METHODS

A total of 155 patients with LARC who received neoadjuvant treatment (NT) were retrospectively analysed from January 2016 to June 2021. The patients were divided into two groups: nCRT (n = 101) and nCT (n = 54). More patients with locally advanced disease (cT4, cN+ and magnetic resonance imaging-detected mesorectal fascia [mrMRF] positive [+]) were found in the nCRT group. Patients in the nCRT group received a dose of 50 Gy/25 Fx irradiation with concurrent capecitabine, and the median number of nCT cycles was two. In the nCT group, the median number of cycles was four.

RESULTS

The median follow-up duration was 30 months. The pathologic complete response (pCR) rate in the nCRT group was significantly higher than that in the nCT group (17.5% vs. 5.6%, p = 0.047). A significant difference was observed in the locoregional recurrence rate (LRR); 6.9% in the nCRT group and 16.7% in the nCT group (p = 0.011). Among patients with initial mrMRF (+) status, the LRR in the nCRT group was significantly lower than that in the nCT group (6.1% vs. 20%, p = 0.007), but not in patients with initial mrMRF negative (-) (10.5% in each group, p = 0.647). Compared with the nCT group, a lower LRR was observed in patients in the nCRT group with initial mrMRF (+) converted to mrMRF (-) after NT (5.3% vs. 23%, p = 0.009). No significant difference was observed between the two groups regarding acute toxicity and overall and progression-free survivals. Multivariate analysis showed that nCRT and ypN stage were independent prognostic factors for the development of LRR.

CONCLUSION

Patients with initial mrMRF (-) may be suitable for nCT alone. However, patients with initial mrMRF (+) converted to mrMRF (-) after nCT are still at high risk of LRR, and radiotherapy is recommended. Prospective studies are required to confirm these findings.

The Role of MRI and PET/CT in Radiotherapy Target Volume Determination in Gastrointestinal Cancers-Review of the Literature

Positron emission tomography with computed tomography (PET/CT) and magnetic resonance imaging (MRI) could improve accuracy in target volume determination for gastrointestinal cancers. A systematic search of the PubMed database was performed, focusing on studies published within the last 20 years. Articles were considered eligible for the review if they included patients with anal canal, esophageal, rectal or pancreatic cancer, as well as PET/CT or MRI for radiotherapy treatment planning, and if they reported interobserver variability or changes in treatment planning volume due to different imaging modalities or correlation between the imaging modality and histopathologic specimen. The search of the literature retrieved 1396 articles. We retrieved six articles from an additional search of the reference lists of related articles. Forty-one studies were included in the final review. PET/CT seems indispensable for target volume determination of pathological lymph nodes in esophageal and anal canal cancer. MRI seems appropriate for the delineation of primary tumors in the pelvis as rectal and anal canal cancer. Delineation of the target volumes for radiotherapy of pancreatic cancer remains challenging, and additional studies are needed.

Comparative analysis of toxicity in patients with anal cancer undergoing definitive simultaneous integrated boost (SIB) or sequential integrated boost (SeqB) radiotherapy

PURPOSE

To compare toxicity of radiotherapy (RT) with concomitant chemotherapy (CHT) in patients (pts) with anal cancer treated with simultaneous integrated boost (SIB) versus sequential boost (SeqB).

METHODS

Sixty-six patients were treated from 2007 to 2021. Thirty patients underwent to SeqB concurrent to CHT and 37 to SIB-group. Toxicity assessment has been considered in acute and in late toxicities for gastrointestinal (GI), genitourinary (GU), cutaneous (CU) districts, according to Common Terminology Criteria for Adverse Events (CTCAE), Version 5.0. The Wexner scale among summary scoring systems has been used as a tool to measure fecal incontinence. The chi-square test for ordinal variables were used to evaluate the association between patient and treatment characteristics and acute or late severe toxicity. Univariable logistic regression models were fit to evaluate predictive factors associated with fecal incontinence.

RESULTS

Median follow-up was 61.5 months (IQR, 27.1-121.7 months) for all patients. Severe acute toxicity (≥ G2) was observed in 49 patients (74.2%). Late toxicity (≥ G2) occurred in 13 cases (19.6%). In assessment of cutaneous toxicity, there was also a significant reduction in ≥ G1 in SIB group with 29 patients (80.5%) vs SeqB group with 29 patients (96.6%) (p-value = 0.046). Of both groups 11 patients (16.6%) developed fecal incontinence, 8 (22%) in the SIB group and 3 (10%) in the SeqB.

CONCLUSION

SIB for anal cancer treatment results in reduced acute and late cutaneous toxicity compared to SeqB. According to our results the rate of other acute and late toxicities are low and comparable between the two groups.

Inguinal nodal clinical target volume delineation based on analysis of anatomical locations of normal and metastatic lymph nodes in pelvic malignant tumors

PURPOSE

To optimize inguinal nodal clinical target volume (CTV) delineation based on analysis of the anatomical locations and embryonic development of normal and metastatic inguinal lymph nodes (ILNs) in patients with pelvic malignant tumors, including cervical, vaginal, vulvar, and anal tumors.

MATERIALS AND METHODS

One hundred and eighty-one patients with pelvic malignancies and 415 involved ILNs treated with intensity-modulated radiation therapy were selected. First, the inguinal nodal CTV was divided into three fields as follows: I, horizontal superficial inguinal field; II, vertical superficial inguinal field; and III, deep inguinal field. Initial CTV delineation of each field was based on analysis of the anatomical locations and embryonic development of normal ILNs. Subsequently, the positions of metastatic ILNs relative to the proper anatomical landmarks or vessels were determined to optimally delineate the final ILN CTV contours. Eighty percent of the data acquired (n = 145) were used as test data for optimization and analysis, the remaining 20% (n = 36) were used for delineation validation.

RESULTS

In total, 252 positive ILNs in 103 cervical cancer patients, 94 positive ILNs in 41 vulvar cancer patients, 8 positive ILNs in 3 vaginal cancer patients, and 61 positive ILNs in 34 anal cancer patients were enrolled. Detailed target volume contouring guidelines for the three divisions were determined on images. All positive ILNs from the remaining 20% patients were located in the CTV boundaries delineated based on analysis of 80% of the data acquired. Importantly, the final inguinal nodal CTV field determined using our method was substantially smaller than defined by existing atlases, and the femoral vessels were excluded in the delineation.

CONCLUSIONS

This study provided anatomical, embryonic, surgical, and statistical evidence to facilitate ILN CTV delineation in radiotherapy planning for patients with pelvic malignancies.

Implications of recent neoadjuvant clinical trials on the future practice of radiotherapy in locally advanced rectal cancer

Over the last two decades, the standard treatment for locally advanced rectal cancer (LARC) has been neoadjuvant chemoradiotherapy plus total mesorectal excision followed by adjuvant chemotherapy. Total neoadjuvant treatment (TNT) and immunotherapy are two major issues in the treatment of LARC. In the two latest phase III randomized controlled trials (RAPIDO and PRODIGE23), the TNT approach achieved higher rates of pathologic complete response and distant metastasis-free survival than conventional chemoradiotherapy. Phase I/II clinical trials have reported promising response rates to neoadjuvant (chemo)-radiotherapy combined with immunotherapy. Accordingly, the treatment paradigm for LARC is shifting toward methods that increase the oncologic outcomes and organ preservation rate. However, despite the progress of these combined modality treatment strategies for LARC, the radiotherapy details in clinical trials have not changed significantly. To guide future radiotherapy for LARC with clinical and radiobiological evidence, this study reviewed recent neoadjuvant clinical trials evaluating TNT and immunotherapy from a radiation oncologist’s perspective.

Deep learning empowered volume delineation of whole-body organs-at-risk for accelerated radiotherapy

In radiotherapy for cancer patients, an indispensable process is to delineate organs-at-risk (OARs) and tumors. However, it is the most time-consuming step as manual delineation is always required from radiation oncologists. Herein, we propose a lightweight deep learning framework for radiotherapy treatment planning (RTP), named RTP-Net, to promote an automatic, rapid, and precise initialization of whole-body OARs and tumors. Briefly, the framework implements a cascade coarse-to-fine segmentation, with adaptive module for both small and large organs, and attention mechanisms for organs and boundaries. Our experiments show three merits: 1) Extensively evaluates on 67 delineation tasks on a large-scale dataset of 28,581 cases; 2) Demonstrates comparable or superior accuracy with an average Dice of 0.95; 3) Achieves near real-time delineation in most tasks with <2 s. This framework could be utilized to accelerate the contouring process in the All-in-One radiotherapy scheme, and thus greatly shorten the turnaround time of patients.

Anal squamous cell carcinoma: Impact of radiochemotherapy evolution over years and an explorative analysis of MRI prediction of tumor response in a mono-institutional series of 131 patients

Introduction

Radiochemotherapy (RCHT) for the treatment of anal squamous cell carcinoma (ASCC) has evolved dramatically, also thanks to intensity-modulated RT (IMRT) and 3D image guidance (3D IGRT). Despite most patients presenting fair outcomes, unmet needs still exist. Predictors of poor tumor response are lacking; acute toxicity remains challenging; and local relapse remains the main pattern of failure.

Patients and methods

Between 2010 and 2020, ASCC stages I–III treated with 3D conformal radiotherapy or IMRT and CDDP-5FU or Mytomicine-5FU CHT were identified. Image guidance accepted included 2D IGRT or 3D IGRT. The study endpoints included freedom from locoregional recurrence (FFLR), colostomy free survival (CFS), freedom from distant metastasis (FFDM), overall survival (OS), and acute and late toxicity as measured by common terminology criteria for adverse events (CTCAE) version 5.0. An exploratory analysis was performed to identify possible radiomic predictors of tumor response. Feature extraction and data analysis were performed in Python™, while other statistics were performed using SPSS^® v.26.0 software (IBM^®).

Results

A total of 131 patients were identified. After a median FU of 52 months, 83 patients (63.4%) were alive. A total of 35 patients (26.7%) experienced locoregional failure, while 31 patients (23.7%) relapsed with distant metastasis. Five year FFLR, CFS, DMFS and PS resulted 72.3%, 80.1%, 74.5% and 64.6%. In multivariate analysis, 2D IGRT was associated with poorer FFLR, OS, and CFS (HR 4.5, 4.1, and 5.6, respectively); 3DcRT was associated with poorer OS and CFS (HR 3.1 and 6.6, respectively). IMRT reduced severe acute gastro-intestinal (GI) and severe skin acute toxicity in comparison with 3DcRT. In the exploratory analysis, the risk of relapse depended on a combination of three parameters: Total Energy, Gray Level Size Zone Matrix’s Large Area High Gray Level Emphasis (GLSZM’s LAHGLE), and GTV volume.

Conclusions

Advances in radiotherapy have independently improved the prognosis of ASCC patients over years while decreasing acute GI and skin toxicity. IMRT and daily 3D image guidance may be considered standard of care in the management of ASCC. A combination of three pre-treatment MRI parameters such as low signal intensity (SI), high GLSZM’s LAHGLE, and GTV volume could be integrated in risk stratification to identify candidates for RT dose-escalation to be enrolled in clinical trials.

Histopathological and Haemogram Features Correlate with Prognosis in Rectal Cancer Patients Receiving Neoadjuvant Chemoradiation without Pathological Complete Response

Background: Neoadjuvant chemoradiation therapy (NCRT) followed by surgery is the standard treatment for locally advanced rectal cancer (LARC); approximately 80% of patients do not achieve complete response. Identifying prognostic factors predictive of survival in these patients to guide further management is needed. The intratumoural lymphocytic response (ILR), peritumoural lymphocytic reaction (PLR), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PtLR) are correlated with the tumour microenvironment and cancer-related systemic inflammation. This study aimed to explore the ability of the ILR, PLR, NLR, and PtLR to predict survival in LARC patients without a complete response to NCRT. Methods: Sixty-nine patients who underwent NCRT and surgery were retrospectively reviewed. The ILR and PLR were assessed in surgical specimens, and the NLR and PtLR were calculated using pre- and post-NCRT blood count data. The Kaplan–Meier method and Cox regression analyses were performed for survival analysis. Results: A high PLR and high post-NCRT NLR and PtLR were significantly associated with better prognosis. Lymphovascular invasion (LVI), post-NCRT neutrophil count, and lymphocyte count were significant predictors of overall survival. LVI and the PLR were independent predictors of disease-free survival. Conclusions: NCRT-induced local and systemic immune responses are favourable prognostic predictors in LARC patients without complete response to NCRT.

The Kinetics of FMS-Related Tyrosine Kinase 3 Ligand (Flt-3L) during Chemoradiotherapy Suggests a Potential Gain from the Earlier Initiation of Immunotherapy

The optimal sequence of chemoradiotherapy with immunotherapy is still not established. The patient’s immune status may play a role in determining this order. We aim to determine the kinetics of a multi-potential haemopoietic factor FMS-related tyrosine kinase 3 ligand (Flt-3L) during chemoradiotherapy. Our pilot, a single arm prospective study, enrolled patients with rectal cancer who qualified for neoadjuvant chemoradiotherapy. Blood samples for Flt-3L were collected before and every second week of chemoradiotherapy for a complete blood count every week. The kinetics of Flt-3L were assessed using Friedman’s ANOVA. A multiple factor analysis (MFA) was performed to find relevant factors affecting levels of serum Flt-3L during chemoradiotherapy. FactoMineR and factoextra R packages were used for analysis. In the 33 patients enrolled, the level of Flt-3L increased from the second week and remained elevated until the end of treatment (p < 0.01). All patients experienced Grade ≥2 lymphopenia with a nadir detected mostly in the 5/6th week. MFA revealed the spatial partitioning of patients among the first and second dimensions (explained by 38.49% and 23.14% variance). The distribution along these dimensions represents the magnitude of early changes of Flt-3L. Patients with the lowest values of Flt-3L change showed the highest lymphocyte nadirs and lowest dose/volume parameters of active bone marrow. Our hypothesis-generating study supports the concept of early initiation of immuno-therapy when the concentration of Flt-3L is high and no lymphopenia has yet occurred.

CT-Only Radiotherapy: An Exploratory Study for Automatic Dose Prediction on Rectal Cancer Patients Via Deep Adversarial Network

Purpose

Current deep learning methods for dose prediction require manual delineations of planning target volume (PTV) and organs at risk (OARs) besides the original CT images. Perceiving the time cost of manual contour delineation, we expect to explore the feasibility of accelerating the radiotherapy planning by leveraging only the CT images to produce high-quality dose distribution maps while generating the contour information automatically.

Materials and Methods

We developed a generative adversarial network (GAN) with multi-task learning (MTL) strategy to produce accurate dose distribution maps without manually delineated contours. To balance the relative importance of each task (i.e., the primary dose prediction task and the auxiliary tumor segmentation task), a multi-task loss function was employed. Our model was trained, validated and evaluated on a cohort of 130 rectal cancer patients.

Results

Experimental results manifest the feasibility and improvements of our contour-free method. Compared to other mainstream methods (i.e., U-net, DeepLabV3+, DoseNet, and GAN), the proposed method produces the leading performance with statistically significant improvements by achieving the highest HI of 1.023 (3.27E-5) and the lowest prediction error with ΔD95 of 0.125 (0.035) and ΔDmean of 0.023 (4.19E-4), respectively. The DVH differences between the predicted dose and the ideal dose are subtle and the errors in the difference maps are minimal. In addition, we conducted the ablation study to validate the effectiveness of each module. Furthermore, the results of attention maps also prove that our CT-only prediction model is capable of paying attention to both the target tumor (i.e., high dose distribution area) and the surrounding healthy tissues (i.e., low dose distribution areas).

Conclusion

The proposed CT-only dose prediction framework is capable of producing acceptable dose maps and reducing the time and labor for manual delineation, thus having great clinical potential in providing accurate and accelerated radiotherapy. Code is available at https://github.com/joegit-code/DoseWithCT

Early results from implementation of a 'watch and wait' protocol for complete clinical response following chemoradiotherapy for rectal cancer

BACKGROUND

Neoadjuvant long course chemoradiotherapy (NLCRT) for rectal cancer can result in complete pathological response (pCR). In 2017, we started offering patients who had a complete clinical response (cCR), a choice between total mesorectal excision (TME) and an intensive surveillance or 'watch and wait' (W&W) program. We report the early outcomes of this prospective study.

METHODS

All patients undergoing NLCRT from 2017 to 2019 were included. All patients were restaged at 8 weeks, and those who had a cCR were offered TME or W&W.

RESULTS

Of 59 patients who underwent NLCRT, 55 had restaging. Eleven of these patients had a cCR (20%). Three chose to have TME and all had a pCR. Eight were enrolled in W&W. Two patients were diagnosed with local regrowth and underwent TME at 7 and 17 months after NLCRT. A further nine patients, who were surgically unfit or refused TME, and had an excellent response to NLCRT, but one that did not reach criteria for a cCR, were also managed with W&W. Of these, two patients developed regrowth with distant metastases. From 2017 to 2019, of the 17 patients who were managed with a W&W approach, 13 patients have remained regrowth free after a median of 28 (13-58) months of W&W.

CONCLUSION

Preliminary findings suggest management with W&W, following cCR, may be a safe alternative to TME. There have so far been no instances of distant failure, and those with cCR that had regrowth, were identified early and successfully managed with salvage TME.

ECOG-ACRIN Guideline for Contouring and Treatment of Early Stage Anal Cancer Using IMRT/IGRT

PURPOSE

Previous anal cancer guidelines delineate target volumes similarly for all patients with squamous cell carcinoma of the anal canal and/or perianal skin (SCCA), regardless of disease stage. The purpose of this guideline is to provide customized radiation treatment recommendations for early stage (T1-2 N0 M0) anal cancer treated with intensity modulated and image guided radiation therapy (RT).

METHODS AND MATERIALS

A contouring atlas and radiation treatment recommendations for the ongoing, randomized phase II trial of deintensified chemoradiation for early stage SCCA (EA2182) was created by an expert panel of radiation oncologists. A literature search was conducted to update and expand these recommendations into a guideline for routine clinical use.

RESULTS

For the majority of cases, we recommend treatment in the supine, frog leg position with the use of a customized immobilization device and daily image guided RT to ensure optimal bone and soft tissue alignment. Vaginal dilators can be used daily during RT to maximize genitalia sparing. We recommend use of a 10-mm margin on the gross tumor plus including the anal complex to create the primary clinical target volume. To define the elective lymph node clinical target volume, we recommend starting with a 7-mm expansion on blood vessels, but then further refining these volumes based on the anatomic location. A 5- to 10-mm planning target volume (PTV) margin is suggested based on institutional setup and patient-specific factors. When using a simultaneous integrated boost technique, a dose of 50.4 Gy to primary PTV and 42 Gy to lymph node PTV, both delivered over 28 fractions, with chemotherapy is appropriate for early stage anal cancer.

CONCLUSIONS

This guideline provides anatomic, clinical, and technical instructions to guide radiation oncologists in the planning and delivery of intensity modulated and image guided RT for early stage SCCA.

Correcting rotational error in rectal cancer radiation therapy: Can planning target volume margins be safely reduced?

INTRODUCTION

The magnitude and impact of rotational error is unclear in rectal cancer radiation therapy. This study evaluates rotational errors in rectal cancer patients, and investigates the feasibility of planning target volume (PTV) margin reduction to decrease organs at risk (OAR) irradiation.

METHODS

In this study, 10 patients with rectal cancer were retrospectively selected. Rotational errors were assessed through image registration of daily cone beam computed tomography (CBCT) and planning CT scans. Two reference treatment plans (TP_R ) with PTV margins of 5 mm and 10 mm were generated for each patient. Pre-determined rotational errors (±1°, ±3°, ±5°) were simulated to produce six manipulated treatment plans (TP_M ) from each TP_R . Differences in evaluated dose-volume metrics between TP_R and TP_M of each rotation were compared using Wilcoxon Signed-Rank Test. Clinical compliance was investigated for statistically significant dose-volume metrics.

RESULTS

Mean rotational errors in pitch, roll and yaw were -0.72 ± 1.81°, -0.04 ± 1.36° and 0.38 ± 0.96° respectively. Pitch resulted in the largest potential circumferential displacement of clinical target volume (CTV) at 1.42 ± 1.06 mm. Pre-determined rotational errors resulted in statistically significant differences in CTV, small bowel, femoral heads and iliac crests (P < 0.05). Only small bowel and iliac crests failed clinical compliance, with majority in the PTV 10 mm margin group.

CONCLUSION

Rotational errors affected clinical compliance for OAR dose but exerted minimal impact on CTV coverage even with reduced PTV margins. Both PTV margin reduction and rotational correction decreased irradiated volume of OAR. PTV margin reduction to 5 mm is feasible, and rotational corrections are recommended in rectal patients to further minimise OAR irradiation.

Overview of Radiation Treatment Volume Variations in Anal Cancer Contouring Guidelines

Recently, the XXX guideline was published to describe recommended treatment volumes in patients with diagnosis of early-stage anal cancer. There are notable differences in descriptions for the both the primary target and elective nodal volumes when comparing this guideline with established guidelines from the United Kingdom National Cancer Research Institute, Australasian Gastrointestinal Trials Group and Radiation Therapy Oncology Group. Support for these volume differences is based on retrospective data, but ultimately, prospective data from ongoing clinical trials are needed to validate these approaches.

Necessity of external iliac lymph nodes and inguinal nodes radiation in rectal cancer with anal canal involvement

Background and purpose

We aimed to explore the necessity of the external iliac lymph nodes (EIN) along with inguinal nodes (IN) region in clinical target volume (CTV) for rectal carcinomas covering the anal canal region.

Materials and methods

This research premise enrolled 399 patients who had primary low rectal cancer detected below the peritoneal reflection via magnetic resonance imaging (MRI) and were treated with neoadjuvant radiotherapy (NRT), without elective EIN along with IN irradiation. We stratified the patients into two groups based on whether the lower edge of the rectal tumor extended to the anal canal (P group, n = 109) or not (Rb group, n = 290). Comparison of overall survival (OS), locoregional recurrence-free survival (LRFS), disease-free survival (DFS), as well as distant metastasis-free survival (DMFS) were performed via inverse probability of treatment weighting (IPTW) along with multivariable analyses. We compared the EIN and IN failure rates between the two groups via the Fisher and Gray’s test.

Results

P group showed a similar adjusted proportion along with five-year cumulative rate of EIN failure compared with the Rb group. The adjusted proportion and five-year cumulative rate of IN failure in the P group was higher in comparison to the Rb group. There were no remarkable differences in the adjusted five-year OS, DFS, DMFS or LRFS between the two groups. Anal canal involvement (ACI) exhibited no effect on OS, LRFS, DFS, or DMFS.

Conclusions

During NRT for rectal cancer with ACI, it may be possible to exclude the EIN and IN from the CTV.

Anal Cancer: Emerging Standards in a Rare Rare Disease

The social stigma surrounding an anal cancer diagnosis has traditionally prevented open discussions about this disease. However, as recent treatment options and an increasing rate of diagnoses are made worldwide, awareness is growing. In the United States alone, 9,090 individuals were expected to be diagnosed with anal cancer in 2021. The US annual incidence of squamous cell carcinoma of the anus continues to increase by 2.7% yearly, whereas the mortality rate increases by 3.1%. The main risk factor for anal cancer is a human papillomavirus infection; those with chronic immunosuppression are also at risk. Patients with HIV are 19 times more likely to develop anal cancer compared with the general population. In this review, we have provided an overview of the carcinoma of the anal canal, the role of screening, advancements in radiation therapy, and current trials investigating acute and chronic treatment-related toxicities. This article is a comprehensive approach to presenting the existing data in an effort to encourage continuous international interest in anal cancer.

Multicenter, Randomized, Phase III Trial of Short-Term Radiotherapy Plus Chemotherapy Versus Long-Term Chemoradiotherapy in Locally Advanced Rectal Cancer (STELLAR)

PURPOSE

To ascertain if preoperative short-term radiotherapy followed by chemotherapy is not inferior to a standard schedule of long-term chemoradiotherapy in patients with locally advanced rectal cancer.

MATERIALS AND METHODS

Patients with distal or middle-third, clinical primary tumor stage 3-4 and/or regional lymph node-positive rectal cancer were randomly assigned (1:1) to short-term radiotherapy (25 Gy in five fractions over 1 week) followed by four cycles of chemotherapy (total neoadjuvant therapy [TNT]) or chemoradiotherapy (50 Gy in 25 fractions over 5 weeks, concurrently with capecitabine [chemoradiotherapy; CRT]). Total mesorectal excision was undertaken 6-8 weeks after preoperative treatment, with two additional cycles of CAPOX (intravenous oxaliplatin [130 mg/m², once a day] on day 1 and capecitabine [1,000 mg/m², twice a day] from days 1 to 14) in the TNT group and six cycles of CAPOX in the CRT group. The primary end point was 3-year disease-free survival (DFS).

RESULTS

Between August 2015 and August 2018, a total of 599 patients were randomly assigned to receive TNT (n = 302) or CRT (n = 297). At a median follow-up of 35.0 months, 3-year DFS was 64.5% and 62.3% in TNT and CRT groups, respectively (hazard ratio, 0.883; one-sided 95% CI, not applicable to 1.11; P < .001 for noninferiority). There was no significant difference in metastasis-free survival or locoregional recurrence, but the TNT group had better 3-year overall survival than the CRT group (86.5% v 75.1%; P = .033). Treatment effects on DFS and overall survival were similar regardless of prognostic factors. The prevalence of acute grade III-V toxicities during preoperative treatment was 26.5% in the TNT group versus 12.6% in the CRT group (P < .001).

CONCLUSION

Short-term radiotherapy with preoperative chemotherapy followed by surgery was efficacious with acceptable toxicity and could be used as an alternative to CRT for locally advanced rectal cancer.

Improving the accuracy and consistency of clinical target volume delineation for rectal cancer by an education program

BACKGROUND

Accurate target volume delineation is the premise for the implementation of precise radiotherapy. Inadequate target volume delineation may diminish tumor control or increase toxicity. Although several clinical target volume (CTV) delineation guidelines for rectal cancer have been published in recent years, significant interobserver variation (IOV) in CTV delineation still exists among radiation oncologists. However, proper education may serve as a bridge that connects complex guidelines with clinical practice.

AIM

To examine whether an education program could improve the accuracy and consistency of preoperative radiotherapy CTV delineation for rectal cancer.

METHODS

The study consisted of a baseline target volume delineation, a 150-min education intervention, and a follow-up evaluation. A 42-year-old man diagnosed with stage IIIC (T3N2bM0) rectal adenocarcinoma was selected for target volume delineation. CTVs obtained before and after the program were compared. Dice similarity coefficient (DSC), inclusiveness index (IncI), conformal index (CI), and relative volume difference [ΔV (%)] were analyzed to quantitatively evaluate the disparities between the participants’ delineation and the standard CTV. Maximum volume ratio (MVR) and coefficient of variation (CV) were calculated to assess the IOV. Qualitative analysis included four common controversies in CTV delineation concerning the upper boundary of the target volume, external iliac area, groin area, and ischiorectal fossa.

RESULTS

Of the 18 radiation oncologists from 10 provinces in China, 13 completed two sets of CTVs. In quantitative analysis, the average CTV volume decreased from 809.82 cm³ to 705.21 cm³ (P = 0.001) after the education program. Regarding the indices for geometric comparison, the mean DSC, IncI, and CI increased significantly, while ΔV (%) decreased remarkably, indicating improved agreement between participants’ delineation and the standard CTV. Moreover, an 11.80% reduction in MVR and 18.19% reduction in CV were noted, demonstrating a smaller IOV in delineation after the education program. Regarding qualitative analysis, the greatest variations in baseline were observed at the external iliac area and ischiorectal fossa; 61.54% (8/13) and 53.85% (7/13) of the participants unnecessarily delineated the external iliac area and the ischiorectal fossa, respectively. However, the education program reduced these variations.

CONCLUSION

Wide variations in CTV delineation for rectal cancer are present among radiation oncologists in mainland China. A well-structured education program could improve delineation accuracy and reduce IOVs.

Protective ileostomy increased the incidence of rectal stenosis after anterior resection for rectal cancer

BACKGROUND

In most of the views, rectal stenosis after anterior resection for rectal cancer results from pelvic radiotherapy. However, patients without receiving radiotherapy also suffer stenosis. In this study, we evaluated the factors associated with rectal stenosis after anterior rectal resection (ARR).

METHODS

We conducted a retrospective study with ARR patients who underwent neoadjuvant chemoradiotherapy and the patients without radiotherapy. Patients who received watch and wait strategy with a clinical complete response after chemoradiotherapy were also included. Patients with colonoscopy follow-up were included for further analyses; 439 patients who underwent neoadjuvant chemoradiotherapy; 545 patients who received ARR without radiotherapy and 33 patients who received watch and wait strategy. Stenosis was diagnosed when a 12-mm diameter colonoscopy could not be passed through the rectum. Univariate and multivariate logistic regression analyses were performed to identify variables associated with rectal stenosis.

RESULTS

According to the multivariate analysis in patients receiving ARR, both protective stoma and preoperative radiotherapy affected the occurrence of stenosis, with the odds ratios (ORs) of 3.375 and 2.251, respectively. According to the multivariate analysis, a preventive ileostomy was the only factor associated with stenosis both in patients receiving preoperative radiotherapy and without radiotherapy. Non-reversal ileostomy and long time between ileostomy and restoration increased the possibility of stenosis. In 33 patients who received watch and wait strategy, only one patient (3%) experienced stenosis.

CONCLUSION

Both surgery and radiotherapy are risk factors for rectal stenosis in rectal cancer patients. Compared to preoperative radiotherapy, a protective ileostomy is a more critical factor associated with rectal stenosis.

Analysis of Clinicopathological Factors Associated with Radiation-Induced Cystitis in Patients with Cervical Cancer

Objective

To analyze the clinicopathological characteristics associated with radiation-induced cystitis (RIC) in patients with cervical cancer treated with chemoradiotherapy (CRT) alone or postoperational (post-op) CRT.

Methods

107 patients with cervical cancer were retrospectively recruited into the study. The surgical status, FIGO staging, total and fractionated doses of radiotherapy (RT), and multiparameters including the dose, volume irradiated to the total bladder, and bladder wall were evaluated for RIC. The criteria on RIC were referred to CTCAE v5.0.

Results

Surgical operation and post-op CRT were delivered in 65 patients and CRT or RT alone in 42 patients. Among those with post-op CRT, 33/34 (97.06%), 22/43 (51.16%), and 10/30 (33.33%) patients were classified as FIGO stage I, II, and III/IV, respectively. The incidence of RIC was 30.84% for the whole group with 87.87% occurred in stage I and II patients. The incidence of CTCAE grade 2 and beyond was significantly higher in patients treated with post-op CRT than those with CRT alone (13.85% vs 2.38%, p = 0.043). Further analyses showed that the CTCAE level of RIC in the post-op CRT group was related to the relatively smaller average bladder volume (p = 0.029), whereas the difference in volume of bladder and bladder wall irradiated to 35.0 Gy or 40.0 Gy was not statistically significant between patients with or without RIC. Conclusion. The combination of surgery and post-op CRT may increase the incidence and severity of radiation-induced cystitis when compared to CRT alone, suggesting that bladder dysfunction associated with surgical procedure might increase the frequency and severity radiation related bladder toxicity. Further study is merited.

Characteristics of anal canal cancer in Japan

Anal canal cancer (ACC) has been reported to be an uncommon cancer in Japan, as in the USA, Europe, and Australia. This retrospective multi‐institutional study was conducted to clarify the characteristics of ACC in Japan. First, the histological ACC type cases treated between 1991 and 2015 were collected. A detailed analysis of the characteristics of anal canal squamous cell carcinoma (SCC) cases was then conducted. The results of the histological types revealed that of the 1781 ACC cases, 435 cases (24.4%) including seven cases of adenosquamous cell carcinomas were SCC and 1260 cases (70.7%) were adenocarcinoma. However, the most common histological type reported in the USA, Europe, and Australia is SCC. Most ACC cases are adenocarcinomas and there is a low incidence of SCC in Japan which is different from the above‐mentioned countries. Moreover, we reclassified T4 into the following two groups based on tumor size: T4a (tumor diameter of 5 cm or less) and T4b (tumor diameter of more than 5 cm). The results of the TNM classification of SCC revealed that the hazard ratio (HR) to T1 of T2, T3, T4a, and T4b was 2.45, 2.28, 2.89, and 4.97, respectively. As T4b cases had a worse prognosis than T4a cases, we propose that T4 for anal canal SCC in Japan be subclassified into T4a and T4b.

Current treatment and future directions in the management of anal cancer

Although rare, the rate of squamous cell carcinoma of the anus (SCCA) is rising globally. Most patients present with nonmetastatic disease and are curable with appropriate treatment, which has evolved significantly over the last several decades. Before the 1970s, SCCA was managed with radical surgery, resulting in a permanent colostomy. Researchers found that preoperative treatment with chemotherapy and concurrent radiation could achieve a pathologic complete response. After this observation, definitive therapy shifted from radical surgery to sphincter-preserving chemoradiation. Investigations into the necessity of chemotherapy and the optimal regimen found that chemotherapy with mitomycin-C and 5-fluorouracil is required for cure. Further studies evaluating the addition of induction or maintenance chemotherapy, monoclonal antibody therapy, or higher radiation doses have demonstrated no significant benefit to disease control. Advanced radiation delivery with intensity-modulated radiotherapy techniques is now considered the standard of care because of its prospectively determined, favorable acute toxicity profile compared with 3-dimensional conformal radiation. It is important to note that chemoradiation treatment response may be slow (up to 26 weeks) and should be assessed through serial clinical examinations. Today, surgical management of SCCA is reserved only for the lowest risk, early stage tumors or for recurrent/persistent disease. Current studies are evaluating radiation dose de-escalation in early stage disease and radiation dose escalation and the addition of immune checkpoint inhibitors in locally advanced cancers. In reviewing how and why modern-day treatment of SCCA was established, the objective of this report is to reenforce adherence to current treatment paradigms to assure the best possible outcomes for patients.