Patterns of locoregional recurrence after surgery and radiotherapy or chemoradiation for rectal cancer

Lateral Lymph Node Dissection for Locally Advanced Rectal Carcinoma: A Step-by-Step Description of Surgical Anatomical Planes During Cadaveric Dissection and Minimally Invasive Surgery

PURPOSE

Total mesorectal excision (TME) is accepted as gold standard method in rectal cancer globally. But there is no standard for lateral lymph nodes. Combination of neoadjuvant treatment plus lateral lymph node dissection (LLND) in select patients might be a promising method. Our purpose is to describe the anatomic landmarks of LLND on cadavers and minimally invasive surgery.

MATERIALS AND METHODS

Local advanced rectal cancer and lateral lymph node (LLN) metastasis are accepted as an indication of neoadjuvant treatment. LLND was performed according to preoperative imaging after radiochemotherapy.

RESULTS

Twenty-eight (10.5%) of 267 patients with rectal cancer who had suspected lateral lymph node metastasis (LLNM) with magnetic resonance imaging (MRI) underwent LLND in addition to TME after neoadjuvant chemoradiotherapy. Eight of them had LLNM. Three patients had bilateral LLND and only 1 had LLNM. The median number of harvested lymph nodes was 6. The rates of LLNM increased with the presence of poor prognosis markers. One regional and 1 distant recurrence were detected in patients who had no LLN metastasis compared with2 regional and 4 distant recurrences in the LLN-positive group.

CONCLUSIONS

Local advanced rectal cancer cases may benefit from LLND, but it does not appear to have an effect on overall survival. There is no consensus whether size and/or morphologic criteria in MRI are the ideal guide for LLND.

Modern Techniques in Re-Irradiation for Locally Recurrent Rectal Cancer: A Systematic Review

BACKGROUND

Radiotherapy (RT) plays an important role in the treatment of patients with previously irradiated locally recurrent rectal cancer (LRRC). Over the years, numerous technologies and different types of RT have emerged. The aim of our systematic literature review was to determine whether the new techniques have led to improvements in both outcomes and toxicities.

METHODS

A computerized search was performed by MEDLINE and the Cochrane database. The studies reported data from patients treated with carbon ion radiotherapy (CIRT), intensity-modulated photon radiotherapy (IMRT), and stereotactic radiotherapy (SBRT).

RESULTS

Seven publications of the 126 titles/abstracts that emerged from our search met the inclusion criteria and presented outcomes of 230 patients. OS was reported with rates of 90.0% and 73.0% at 1 and 2 years, respectively; LC was 89.0% and 71.6% at 1 and 2 years after re-RT, respectively. Toxicity data vary widely, with emphasis on acute and chronic gastrointestinal and urogenital toxicity, even with modern techniques.

CONCLUSION

data on toxicity and outcomes of re-RT for LRRC with new technologies are promising compared with 3D techniques. Comparative studies are needed to define the best technique, also in relation to the site of recurrence.

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.

Protocol: The role of defunctioning stoma prior to neoadjuvant therapy for locally advanced colonic and rectal cancer-A systematic review

Defunctioning stomas (ileostomy and colostomy) may be used prior to commencement of neoadjuvant therapy in patients with locally advanced colon or rectal cancer, in order to prevent clinical large bowel obstruction caused by radiotherapy associated oedema or progression of disease in patients who are not obstructed. However, the exact rate of clinical obstruction in patients undergoing neoadjuvant therapy who do not receive a defunctioning stoma is not known. Furthermore, it is not clear which factors predispose patients to developing clinical large bowel obstruction. Given that defunctioning stomas are associated with post operative and intra-operative risks, it is not currently possible to tailor defunctioning stomas to patients who have the greatest risk of developing obstruction. This systematic review which is in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement (PRISMA), aims to define the role of defunctioning stomas in prevention of obstruction patients with locally advanced colon or rectal cancer while undergoing neoadjuvant therapy. Two researchers will perform the literature search which will include all published and “in process” articles published in the English language between 2002–2022 in the following databases: EMBASE (OVID), MEDLINE (EBSCO), CINHAL complete, Web of Science, Cochrane Central Registry of Controlled Trials, Clinical Trials Registry. The full text of the selected articles will be independently screened by two researchers against the inclusion criteria. Data will be extracted from each article regarding: study design, participants, type of intervention and outcomes. The effect size will be expressed in incidence rates and when appropriate in relative risk with 95% confidence intervals. If possible, we will perform a meta-analysis. Heterogeneity will be assessed using I² statistics. We will pool the data extracted from the randomised controlled trials to perform a meta-analysis using the Review Manager 5 software (RevMan 5). The Grades of Recommendation, Assessment, Development and Evaluation (GRADE) system will be used to assess the certainty of the evidence.

Locally Recurrent Rectal Cancer According to a Standardized MRI Classification System: A Systematic Review of the Literature

(1) Background: The classification of locally recurrent rectal cancer (LRRC) is not currently standardized. The aim of this review was to evaluate pelvic LRRC according to the Beyond TME (BTME) classification system and to consider commonly associated primary tumour characteristics. (2) Methods: A systematic review of the literature prior to April 2020 was performed through electronic searches of the Science Citation Index Expanded, EMBASE, MEDLINE, and CENTRAL databases. The primary outcome was to assess the location and frequency of previously classified pelvic LRRC and translate this information into the BTME system. Secondary outcomes were assessing primary tumour characteristics. (3) Results: A total of 58 eligible studies classified 4558 sites of LRRC, most commonly found in the central compartment (18%), following anterior resection (44%), in patients with an 'advanced' primary tumour (63%) and following neoadjuvant radiotherapy (29%). Most patients also classified had a low rectal primary tumour. The lymph node status of the primary tumour leading to LRRC was comparable, with 52% node positive versus 48% node negative tumours. (4) Conclusions: This review evaluates the largest number of LRRCs to date using a single classification system. It has also highlighted the need for standardized reporting in order to optimise perioperative treatment planning.

Role of diffusion-weighted MRI in recurrent rectal cancer treated with carbon ion radiotherapy

Aim: To evaluate the association between pretreatment diffusion-weighted MRI (DW-MRI) and 12-month radiological response in locally recurrent rectal cancer treated with carbon ion radiotherapy. Methods: Histogram analysis was performed on pretreatment DW-MRI for patients re-irradiated with carbon ion radiotherapy for local recurrence of rectal cancer. Results: A total of 17 patients were enrolled in the study. Pretreatment DW-MRI b-value of 1000 s/mm² (b1000) and apparent diffusion coefficient (ADC) lesion median values for 1-year nonresponders (six patients) and responders (11 patients) demonstrated a median (interquartile of median values) of 62.5 (23.9) and 34.0 (13.0) and 953.0 (277.0) and 942.5 (339.0) μm²/s, respectively. All b1000 histogram features (h-features) and ADC h-kurtosis showed statistically significant differences, whereas only b1000 h-median, b1000 h-interquartile range and ADC h-kurtosis demonstrated remarkable diagnostic accuracy. Conclusion: DW-MRI showed promising results in predicting carbon ion radiotherapy outcome in local recurrence of rectal cancer, particularly with regard to b1000 h-median, b1000 h-interquartile range and ADC h-kurtosis.

Comparison of clinical outcomes between carbon ion radiotherapy and X-ray radiotherapy for reirradiation in locoregional recurrence of rectal cancer

Carbon ion radiotherapy (CIRT) has garnered interest for the treatment of locoregional rectal cancer recurrence. No study has compared CIRT and X-ray radiotherapy (XRT) for reirradiation (reRT) in such cases. We analyzed and compared the clinical outcomes such as local control, overall survival, and late toxicity rate between CIRT and XRT, for treating locoregional rectal cancer recurrence. Patients with rectal cancer who received reRT to the pelvis by CIRT or XRT from March 2005 to July 2019 were included. The CIRT treatment schedule was 70.4 Gy (relative biological effectiveness) in 16 fractions. For the XRT group, the median reRT dose was 50 Gy (range 25-62.5 Gy) with a median of 25 fractions (range 3-33). Thirty-five and 31 patients received CIRT and XRT, respectively. Tumour and treatment characteristics such as recurrence location and chemotherapy treatment differed between the two groups. CIRT showed better control of local recurrence (adjusted hazard ratio [HR] 0.17; p = 0.002), better overall survival (HR 0.30; p = 0.004), and lower severe late toxicity rate (HR 0.15; p = 0.015) than XRT. CIRT was effective for treating locoregional rectal cancer recurrence, with high rates of local control and survival, and a low late severe toxicity rate.

Radiotherapy resistance: identifying universal biomarkers for various human cancers

Radiotherapy (RT) is considered as a standard in the treatment of most solid cancers, including glioblastoma, lung, breast, rectal, prostate, colorectal, cervical, esophageal, and head and neck cancers. The main challenge in RT is tumor cell radioresistance associated with a high risk of locoregional relapse and distant metastasis. Despite significant progress in understanding mechanisms of radioresistance, its prediction and overcoming remain unresolved. This review presents the state-of-the-art for the potential universal biomarkers correlated to the radioresistance and poor outcome in different cancers. We describe radioresistance biomarkers functionally attributed to DNA repair, signal transduction, hypoxia, and angiogenesis. We also focus on high throughput genetic and proteomic studies, which revealed a set of molecular biomarkers related to radioresistance. In conclusion, we discuss biomarkers which are overlapped in most several cancers.

Dose summation and image registration strategies for radiobiologically and anatomically corrected dose accumulation in pelvic re-irradiation

BACKGROUND

Re-irradiation (reRT) is a promising technique for patients with localized recurrence in a previously irradiated area but presents major challenges. These include how to deal with anatomical change between two courses of radiotherapy and integration of radiobiology when summating original and re-irradiation doses. The Support Tool for Re-Irradiation Decisions guided by Radiobiology (STRIDeR) project aims to develop a software tool for use in a commercial treatment planning system to facilitate more informed reRT by accounting for anatomical changes and incorporating radiobiology. We evaluated three approaches to dose summation, incorporating anatomical change and radiobiology to differing extents.

METHODS

In a cohort of 21 patients who previously received pelvic re-irradiation the following dose summation strategies were compared: (1) Rigid registration (RIR) and physical dose summation, to reflect the current clinical approach, (2) RIR and radiobiological dose summation in equivalent dose in 2 Gy fractions (EQD2), and (3) Patient-specific deformable image registration (DIR) with EQD2 dose summation.

RESULTS

RIR and physical dose summation (Strategy 1) resulted in high cumulative organ at risk (OAR) doses being 'missed' in 14% of cases, which were highlighted by EQD2 dose summation (Strategy 2). DIR (with EQD2 dose summation; Strategy 3) resulted in improved OAR overlap and distance to agreement metrics compared to RIR (with EQD2 dose summation; Strategy 2) and was consistently preferred in terms of clinical utility. DIR was considered to have a clinically important impact on dose summation in 38% of cases.

CONCLUSION

Re-irradiation cases require individualized assessment when considering dose summation with the previous treatment plan. Fractionation correction is necessary to meaningfully assess cumulative doses and reduce the risk of unintentional OAR overdose. DIR can add clinically relevant information in selected cases, especially for significant anatomical change. Robust solutions for cumulative dose assessment offer the potential for future improved understanding of cumulative OAR tolerances.

Carbon Ion Radiotherapy for Locally Recurrent Rectal Cancer of Patients with Prior Pelvic Irradiation

BACKGROUND

This study aimed to assess the safety and efficacy of carbon-ion radiotherapy (CIRT) for salvage of previously X-ray-irradiated (XRT) locally recurrent rectal cancer (LRRC).

METHODS

Between September 2005 and December 2017, 77 patients with LRRC were treated with CIRT re-irradiation. All the patients had received prior XRT with a median dose of 50.0 Gy (range 20-74 Gy), principally for neoadjuvant or adjuvant recurrence prophylaxis in 34 patients and for recurrence in 43 patients. The total CIRT dose of 70.4 Gy (RBE) (gray relative biologic effectiveness) was administered in 16 fixed fractions during 4 weeks (4.4 Gy [RBE] per fraction).

RESULTS

All the patients completed the scheduled treatment course. None of the patients received resection after CIRT. Acute grade 3 toxicities occurred for eight patients (10 %), including five grade 3 pelvic infections (2 involving pain and 1 involving neuropathy). Late grade 3 toxicities occurred for 16 patients (21 %): 13 with late grade 3 pelvic infections, 9 with gastrointestinal toxicity, 1 with skin toxicity, 2 with pain, and 4 with neuropathy. No grade 4+ toxicity was noted. The overall local control rates (infield + out-of-field recurrence) were 69 % at 3 years and 62 % at 5 years. In the planning target volume (PTV), the infield recurrence rates were 90 % and 87 % respectively. The control rates for regional recurrence were 85 % at 3 years and 81 % at 5 years. The median overall survival time was 47 months. The survival rates were 61 % at 3 years and 38 % at 5 years.

CONCLUSION

Carbon-ion re-irradiation of previously X-ray-irradiated locally recurrent rectal cancer appears to be safe and effective, providing good local control and survival advantage without unacceptable morbidity.

Locoregional relapses in the ACCORD 12/0405-PRODIGE 02 study: Dosimetric study and risk factors

PURPOSE

The aim of this study is to correlate locoregional relapse with radiation therapy volumes in patients with rectal cancer treated with neoadjuvant chemoradiation in the ACCORD 12/0405-PRODIGE 02 trial.

PATIENTS AND METHODS

We identified patients who had a locoregional relapse included in ACCORD 12's database. We studied their clinical, radiological, and dosimetric data to analyze the dose received by the area of relapse.

RESULTS

39 patients (6.5%) presented 54 locoregional relapses. Most of the relapses were in-field (n = 21, 39%) or marginal (n = 13, 24%) with only six out-of-field (11%), 14 could not be evaluated. Most of them happened in the anastomosis, the perirectal space, and the usual lymphatic drainage areas (presacral and posterior lateral lymph nodes). Only patients treated for a lower rectum adenocarcinoma had a relapse outside of the treated volume. 2 patients with T4 tumors extending into anterior pelvic organs had relapses in anterior lateral and external iliac lymph nodes.

CONCLUSIONS

Lowering the upper limit of the treatment field for low rectal tumors increased the risk of out of the field recurrence. For very low tumors, including the inguinal lymph nodes in the treated volume should be considered. Recording locoregional involvement, treated volumes, and relapse areas in future prospective trials would be of paramount interest to refine delineation guidelines.

Systematic review of classification systems for locally recurrent rectal cancer

Background

Classification of pelvic local recurrence (LR) after surgery for primary rectal cancer is not currently standardized and optimal imaging is required to categorize anatomical site and plan treatment in patients with LR. The aim of this review was to evaluate the systems used to classify locally recurrent rectal cancer (LRRC) and the relevant published outcomes.

Methods

A systematic review of the literature prior to April 2020 was performed through electronic searches of the Science Citation Index Expanded, EMBASE, MEDLINE and CENTRAL databases. The primary outcome was to review the classifications currently in use; the secondary outcome was the extraction of relevant information provided by these classification systems including prognosis, anatomy and prediction of R0 after surgery.

Results

A total of 21 out of 58 eligible studies, classifying LR in 2086 patients, were reviewed. Studies used at least one of the following eight classification systems proposed by institutions or institutional groups (Mayo Clinic, Memorial Sloan-Kettering – original and modified, Royal Marsden and Leeds) or authors (Yamada, Hruby and Kusters). Negative survival outcomes were associated with increased pelvic fixity, associated symptoms of LR, lateral compared with central LR and involvement of three or more pelvic compartments. A total of seven studies used MRI with specifically defined anatomical compartments to classify LR.

Conclusion

This review highlights the various imaging systems in use to classify LRRC and some of the prognostic indicators for survival and oncological clearance based on these systems. Implementation of an agreed classification system to document pelvic LR consistently should provide more detailed information on anatomical site of recurrence, burden of disease and standards for comparative outcome assessment.

Re-irradiation With Carbon Ion Radiotherapy for Pelvic Rectal Cancer Recurrences in Patients Previously Irradiated to the Pelvis

BACKGROUND/AIM

Re-irradiation of locally recurrent rectal cancer poses challenges due to the proximity of critical organs, such as the bowel. This study aimed at evaluating the safety and efficacy of re-irradiation with Carbon Ion Radiotherapy (CIRT) in rectal cancer patients with local recurrence.

PATIENTS AND METHODS

Between 2014 and 2018, 14 patients were treated at the National Center of Oncological Hadrontherapy (CNAO Foundation) with CIRT for locally recurrent rectal cancer.

RESULTS

All patients concluded the treatment. No G≥3 acute/late reaction nor pelvic infections were observed. The 1-year and 2-year local control rates were, 78% and 52%, respectively, and relapse occurred close to the bowel in 6 patients. The 1-year and 2-year overall survival rates were 100% and 76.2% each; while the 1-year and 2-year metastasis free survival rates were 64.3% and 43%.

CONCLUSION

CIRT as re-irradiation for locally recurrent rectal cancer emerges as a safe and valid treatment with an acceptable rate of morbidity of surrounding healthy tissue.

Updating Perspectives on Meta-Analyses in the Field of Radiation Oncology

Meta-analyses have been conventionally performed to extract the firmest conclusions from randomized controlled trials while minimizing the risk of bias. However, the field of oncology does not always allow for collecting the best evidence. Radiation oncology is a discipline where intractable or rare diseases are commonly encountered; hence, more practical data suitable for detailed clinical evaluations are needed. This review discusses new viewpoints regarding meta-analyses by pointing out heterogeneities among clinical studies and issues related to analyzing observational studies, thus clarifying the practical utility of meta-analyses in radiation oncology. Limitations of previous systematic reviews or meta-analyses are also assessed to suggest future directions.

Long-Term Outcomes and Prognostic Analysis of Computed Tomography-Guided Radioactive 125I Seed Implantation for Locally Recurrent Rectal Cancer After External Beam Radiotherapy or Surgery

Background

Management of locally recurrent rectal cancer (LRRC) after surgery or external beam radiotherapy (EBRT) remains a clinical challenge, given the limited treatment options and unsatisfactory outcomes. This study aimed to assess long-term outcomes of computed tomography (CT)-guided radioactive ¹²⁵I seed implantation in patients with LRRC and associated prognostic factors.

Methods

A total of 101 patients with LRRC treated with CT-guided ¹²⁵I seed implantation from October 2003 to April 2019 were retrospectively studied. Treatment procedures involved preoperative planning design, ¹²⁵I seed implantation, and postoperative dose evaluation. We evaluated the therapeutic efficacy, adverse effects, local control (LC) time, and overall survival (OS) time.

Results

All the patients had previously undergone surgery or EBRT. The median age of patients was 59 (range, 31–81) years old. The median follow-up time was 20.5 (range, 0.89–125.8) months. The median LC and OS time were 10 (95% confidence interval (CI): 8.5–11.5) and 20.8 (95% CI: 18.7–22.9) months, respectively. The 1-, 2-, and 5-year LC rates were 44.2%, 20.7%, and 18.4%, respectively. The 1-, 2-, and 5-year OS rates were 73%, 31.4%, and 5%, respectively. Univariate analysis of LC suggested that when short-time tumor response achieved partial response (PR) or complete response (CR), or D₉₀>129 Gy, or GTV ≤ 50 cm³, the LC significantly prolonged (P=0.044, 0.041, and <0.001, respectively). The multivariate analysis of LC indicated that the short-time tumor response was an independent factor influencing LC time (P<0.001). Besides, 8.9% (9/101) of the patients had adverse effects (≥grade 3): radiation-induced skin reaction (4/101), radiation-induced urinary reaction (1/101), fistula (2/101), and intestinal obstruction (2/101). The cumulative irradiation dose and the activity of a single seed were significantly correlated with adverse effects ≥grade 3 (P=0.047 and 0.035, respectively).

Conclusion

CT-guided ¹²⁵I seed implantation is a safe and effective salvage treatment for LRRC patients who previously underwent EBRT or surgery. D₉₀ and GTV significantly influenced prognosis of such patients.

ESTRO/ACROP IORT recommendations for intraoperative radiation therapy in primary locally advanced rectal cancer

Carcinoma of the rectum is a heterogeneous disease. The clinical spectrum identifies a subset of patients with locally advanced tumours that are close to or involve adjoining structures, such as the sacrum, pelvic sidewalls, prostate or bladder. Within this group of patients categorized as "locally advanced", there is also variability in the extent of disease with no uniform definition of resectability. A practice-oriented definition of a locally advanced tumour is a tumour that cannot be resected without leaving microscopic or gross residual disease at the resection site. Since these patients do poorly with surgery alone, irradiation and chemotherapy have been added to improve the outcome. Intraoperative irradiation (IORT) is a component of local treatment intensification with favourable results in this subgroup of patients. International guidelines (National Comprehensive Cancer Network (NCCN) guidelines) currently recommend the use of IORT for rectal cancer resectable with very close or positive margins, especially for T4 and recurrent cancers. We report the ESTRO-ACROP (European Society for Radiotherapy and Oncology - Advisory Committee on Radiation Oncology Practice) recommendations for performing IORT in primary locally advanced rectal cancer.

Stereotactic Body Radiation Therapy Reirradiation for Locally Recurrent Rectal Cancer: Outcomes and Toxicity

Purpose

Stereotactic body radiation therapy (SBRT) has emerged as a potential therapeutic option for locally recurrent rectal cancer (LRRC) but contemporaneous clinical data are limited. We aimed to evaluate the local control, toxicity, and survival outcomes in a cohort of patients previously treated with neoadjuvant pelvic radiation therapy for nonmetastatic locally recurrent rectal cancer, now treated with SBRT.

Methods and Materials

Inoperable rectal cancer patients with ≤3 sites of pelvic recurrence and >6 months since prior pelvic radiation therapy were identified from a prospective registry over 4 years. SBRT dose was 30 Gy in 5 fractions, daily or alternate days, using cumulative organ at risk dose constraints. Primary outcome was local control (LC). Secondary outcomes were progression free survival, overall survival, toxicity, and patient reported quality of life scores using the EQ visual analog scale (EQ-VAS) tool.

Results

Thirty patients (35 targets) were included. Median gross tumor volume size was 14.3 cm³. In addition, 27 of 30 (90%) previously received 45 to 50.4 Gy in 25 of 28 fractions, with 10% receiving an alternative prescription. All patients received the planned reirradiation SBRT dose. The median follow-up was 24.5 months (interquartile range, 17.8-28.8). The 1-year LC was 84.9% (95% confidence interval [CI], 70.6-99) and a 2-year LC was 69% (95% CI, 51.8-91.9). The median progression free survival was 12.1 months (95% CI, 8.6-17.66), and median overall survival was 28.3 months (95% CI, 17.88-39.5 months). No patient experienced >G2 acute toxicity and only 1 patient experienced late G3 toxicity. Patient-reported QoL outcomes were improved at 3 months after SBRT (Δ EQ-VAS, +10 points, Wilcoxon signed-rank, P = .009).

Conclusions

Our study demonstrates that, for small volume pelvic disease relapses from rectal cancer, reirradiation with 30 Gy in 5 fractions is well tolerated and achieves an excellent balance between high local control rates with limited toxicity.

ESTRO/ACROP IORT recommendations for intraoperative radiation therapy in locally recurrent rectal cancer

Multimodal strategies have been implemented for locally recurrent rectal cancer scheduled for complete surgical resection. Irradiation and systemic therapy have been added to improve the oncological outcome, as surgery alone was associated with a poor prognosis. Intraoperative irradiation (IORT) is a component of irradiation intensification. Long-term cancer control and a higher survival rate were consistently reported in patients who had IORT as a component of their multidisciplinary treatment. The experience reported by expert IORT groups is reviewed and recommendations to guide clinical practice are explained in detail.

To Radiate or Not to Radiate-The Challenges of Pelvic Reirradiation

Patients who receive pelvic radiation are at risk for both local recurrences of their primary malignancy or for the development of a new malignancy in the irradiated pelvic structures. The management of postirradiation pelvic tumor is complicated and can be associated with both poor prognosis and significant morbidity. Historically, reirradiation within the pelvis was never entertained as part of treatment management due to concern for severe toxicity and exceeding of normal-tissue tolerances. However, it may play a role with modern techniques and careful patient selection. The following case and accompanying expert opinions demonstrate some of the key considerations for pelvic reirradiation as a treatment option.

Treatment Outcomes of Re-irradiation in Locoregionally Recurrent Rectal Cancer and Clinical Significance of Proper Patient Selection

Background and Purpose: Majority of patients with locoregionally recurrent rectal cancer will require re-irradation (reRT). This study aimed to analyze the treatment outcomes, particularly infield progression, and severe late toxicity rates after reRT for recurrent rectal cancer and further identify a subgroup of patients who may optimally benefit from reRT.

Materials and Methods: Patients with rectal cancer who underwent reRT to the pelvis between January 2000 and December 2017 were included for analysis.

Results: The records of 41 patients were retrospectively reviewed. The median follow-up period after reRT was 53.7 months (range 3.5–130.3 months). The 2-year infield progression-free rate (IPFR) was 49.4%. The 2-year overall survival (OS) and progression-free survival (PFS) rates were 55.3 and 28.5%, respectively. Severe late toxicity events occurred in 17 patients, and the median time from reRT to severe late toxicity event was 10.5 months (range 2.3–33.3 months). The 2-year severe late toxicity free-rate (SLTFR) was 55.5%, and the median SLTFR was 33.3 months. Patients who did not experience severe late toxicity events showed a significantly higher number of recurred tumors at the posterior or lateral location compared to axial or anterior location. The selected subgroup with recurrent tumor size <3.3 cm and treated with total reRT dose of >50 Gy_ab10 (n = 13) showed superior IPFR, OS, and PFS to the other patients.

Conclusion: ReRT was a reasonable treatment option for patients with locoregionally recurrent rectal cancer. However, severe late toxicity rates were substantially high. Thus, patients indicated for ReRT with curative dose should be selected properly according to tumor size and location.

Targeting Enox1 in tumor stroma increases the efficacy of fractionated radiotherapy

The goal of this investigation was to clarify the question of whether targeting Enox1 in tumor stroma would synergistically enhance the survival of tumor-bearing mice treated with fractionated radiotherapy. Enox1, a NADH oxidase, is expressed in tumor vasculature and stroma. However, it is not expressed in many tumor types, including HT-29 colorectal carcinoma cells. Pharmacological inhibition of Enox1 in endothelial cells inhibited repair of DNA double strand breaks, as measured by γH2AX and 53BP1 foci formation, as well as neutral comet assays. For 4 consecutive days athymic mice bearing HT-29 hindlimb xenografts were injected with a small molecule inhibitor of Enox1 or solvent control. Tumors were then administered 2 Gy of x-rays. On day 5 tumors were administered a single ‘top-up’ fraction of 30 Gy, the purpose of which was to amplify intrinsic differences in the radiation fractionation regimen produced by Enox1 targeting. Pharmacological targeting of Enox1 resulted in 80% of the tumor-bearing mice surviving at 90 days compared to only 40% of tumor-bearing mice treated with solvent control. The increase in survival was not a consequence of reoxygenation, as measured by pimonidazole immunostaining. These results are interpreted to indicate that targeting of Enox1 in tumor stroma significantly enhances the effectiveness of 2 Gy fractionated radiotherapy and identifies Enox1 as a potential therapeutic target.

Comparison of MRI and colonoscopy in determining tumor height in rectal cancer

Background and aim

Endoscopy and magnetic resonance imaging (MRI) are used routinely in the diagnostic and preoperative work-up of rectal cancer. We aimed to compare colonoscopy and MRI in determining rectal tumor height.

Methods

Between 2002 and 2012, all patients with rectal cancer with available MRIs and endoscopy reports were included. All MRIs were reassessed for tumor height by two abdominal radiologists. To obtain insight in techniques used for endoscopic determination of tumor height, a survey among regional endoscopists was conducted.

Results

A total of 211 patients with rectal cancer were included. Tumor height was significantly lower when assessed by MRI than by endoscopy with a mean difference of 2.5 cm (95% CI: 2.1-2.8). Although the agreement between tumor height as measured by MRI and endoscopy was good (intraclass correlation coefficient (ICC) 0.7 (95% CI: 0.7-0.8)), the 95% limits of agreement varied from -3.0 cm to 8.0 cm. In 45 patients (21.3%), tumors were regarded as low by MRI and middle-high by endoscopy. MRI inter- and intraobserver agreements were excellent with an ICC of 0.8 (95% CI: 0.7-0.9) and 0.9 (95% CI: 0.9-1.0), respectively. The survey showed no consensus among endoscopists as to how to technically measure tumor height.

Conclusion

This study showed large variability in rectal tumor height as measured by colonoscopy and MRI. Since MRI measurements showed excellent inter- and intraobserver agreement, we suggest using tumor height measurement by MRI for diagnostic purposes and treatment allocation.

[The possibilities of treatment of recurrent colorectal cancer with sacral invasion]

AIM

To describe current methods of surgical treatment of rare form of recurrent rectal cancer with sacral invasion.

MATERIAL AND METHODS

The article presents the methodology for the treatment of patients with recurrent colorectal cancer and sacral invasion using preoperative chemoradiotherapy followed by high-tech surgery of recurrent tumor removal with sacral resection at various levels (including high intersection at S1 level).

CONCLUSION

It was concluded that chemoradiotherapy is indicated in patients with recurrent colorectal cancer if it was not made at the first stage of treatment. Additional radiotherapy up to optimum overall focal dose prior to surgery is advisable in those patients who previously underwent radiotherapy with partial dose. This type of operations has high risk of complications and requires a personalized approach to the selection of patients. However, R0-resection is associated with favorable long-term prognosis, significantly increased survival and overall quality of life. Combined surgery for recurrent tumors with sacral invasion should be performed by multidisciplinary surgical team in specialized centers using current possibilities of anesthesiology and intensive care.

Local recurrence after curative resection for rectal carcinoma: The role of surgical resection

Local recurrence of rectal cancer is difficult to treat, may cause severe and disabling symptoms, and usually has a fatal outcome. The aim of this study was to document the clinical nature of locally recurrent rectal cancer and to determine the effect of surgical resection on long-term survival.A retrospective review was conducted of the prospectively collected medical records of 2485 patients with primary rectal adenocarcinoma who underwent radical resection between September 1994 and December 2008.In total, 147 (5.9%) patients exhibited local recurrence. The most common type of local recurrence was lateral recurrence, whereas anastomotic recurrence was the most common type in patients without preoperative concurrent chemoradiotherapy (CCRT). Tumor location with respect to the anal verge significantly affected the local recurrence rate (P < 0.001), whereas preoperative CCRT did not affect the local recurrence rate (P = 0.433). Predictive factors for surgical resection of recurrent rectal cancer included less advanced tumor stage (P = 0.017, RR = 3.840, 95% CI = 1.271-11.597), axial recurrence (P < 0.001, RR = 5.772, 95% CI = 2.281-14.609), and isolated local recurrence (P = 0.006, RR = 8.679, 95% CI = 1.846-40.815). Overall survival after diagnosis of local recurrence was negatively influenced by advanced pathologic tumor stage (P = 0.040, RR = 1.867, 95% CI = 1.028-3.389), positive CRM (P = 0.001, RR = 12.939, 95% CI = 2.906-57.604), combined distant metastases (P = 0.001, RR = 2.086, 95% CI = 1.352-3.218), and nonsurgical resection of recurrent tumor (P < 0.001, RR = 4.865, 95% CI = 2.586-9.153).In conclusion, the clinical outcomes of local recurrence after curative resection of rectal cancer are diverse. Surgical resection of locally recurrent rectal cancer should be considered as an initial treatment, especially in patients with less advanced tumors and axial recurrence.

Rectal Radiotherapy--Intensity-modulated Radiotherapy Delivery, Delineation and Doses

The use of intensity-modulated radiotherapy in rectal cancer is attractive in that it may reduce acute and late toxicities and potentially facilitate dose escalation. Intensity-modulated radiotherapy probably has a role in selected patients, but further investigation is required to identify the parameters for selection. Delineation of specific nodal groups allows maximal sparing of bladder and small bowel. In locally advanced tumours a simultaneous integrated boost allows dose escalation incorporating hypofractionation and a shorter overall treatment time. However, due to a sparsity of data on late toxicity in doses ≥ 60 Gy, doses at this level should be used with caution, ideally within prospective trials. Future studies investigating dose escalation must ascertain late toxicity as well as local control, as both can significantly affect quality of life and without both, the risk-benefit ratio cannot be calculated.

Reirradiation Using Carbon Ions in Patients with Locally Recurrent Rectal Cancer at HIT: First Results

BACKGROUND

Locally recurrent rectal cancer remains a dreaded event because curative resection is unlikely to be performed in a large number of cases. Carbon ion radiotherapy offers physical and biologic advantages. A high precise local dose deposition and sparing of normal tissue is possible. This work summarizes our experience on feasibility and early toxicity of carbon ion radiotherapy in previously irradiated and operated patients.

METHODS

Between 2010 and 2013, a total of 19 patients with a median age of 62 years (range 14-76 years) received carbon ion irradiation to treat locally recurrent rectal cancer at the Heidelberg Ion Beam Therapy Center (HIT). All patients had a history of surgery and pelvic radiotherapy of at least 50.4 Gy. Median dose was 36 Gy [relative biologic efficacy (RBE)] [range 36-51 Gy(RBE)], and median planning target volume was 456 ml (range 75-1,597 ml). Some patients were treated in the recruiting phase I/II of the PANDORA study (NCT01528683).

RESULTS

Median follow-up was 7.8 months. Four patients were diagnosed with local relapse after carbon ion radiotherapy, and three patients developed distant metastases. Estimated mean local progression-free survival was 20.6 months by the Kaplan-Meier estimator. Two patients had preexisting rectovaginal fistula, and another patient had a preexisting presacral localized abscess formation in which the local relapse took place. No grade III or higher toxicities were observed.

CONCLUSIONS

Our first experiences in a pretreated patient group with a dismal prognosis are encouraging, and therapy-related side effects are mild. Longer follow-up is required to determine possible late effects and long-term disease control.

Post-chemoradiation intraoperative electron-beam radiation therapy boost in resected locally advanced rectal cancer: long-term results focused on topographic pattern of locoregional relapse

BACKGROUND

Patients with locally advanced rectal cancer (LARC) have a dismal prognosis. We investigated outcomes and risk factors for locoregional recurrence (LRR) in patients treated with preoperative chemoradiotherapy (CRT), surgery and IOERT.

METHODS

A total of 335 patients with LARC [⩾cT3 93% and/or cN+ 69%) were studied. In multivariate analyses, risk factors for LRR, IFLR and OFLR were assessed.

RESULTS

Median follow-up was 72.6 months (range, 4-205). In multivariate analysis distal margin distance ⩽10 mm [HR 2.46, p = 0.03], R1 resection [HR 5.06, p = 0.02], tumor regression grade 1-2 [HR 2.63, p = 0.05] and tumor grade 3 [HR 7.79, p < 0.001] were associated with an increased risk of LRR. A risk model was generated to determine a prognostic index for individual patients with LARC.

CONCLUSIONS

Overall results after multimodality treatment of LARC are promising. Classification of risk factors for LRR has contributed to propose a prognostic index that could allow us to guide risk-adapted tailored treatment.

Post-chemoradiation anastomotic recurrence in locally advanced rectal cancer: no increased risk associated with distal margin

BACKGROUND AND PURPOSE

Anastomotic recurrence after radical sphincter-preserving surgery preceded by neoadjuvant therapy in locally advanced rectal cancer is an uncommon event that merits further assessment. The aim of this study is to analyze the effect of preoperative chemoradiation on the risk of anastomotic recurrence. Based on the initial extension of the tumor, we analyzed whether the distal surgical section was calculated through the virtual initial extension of the rectal tumor.

PATIENTS AND METHODS

Eligible patients with locally advanced rectal cancer were offered preoperative chemoradiation, sphincter sparing surgery and intraoperative radiation therapy boost.

RESULTS

180 patients were treated with anterior resection (40 %), low anterior resection (45.6 %) and ultra-low anterior resection (14.4 %). With a median follow-up of 41.1 months (0.36-143 months), anastomotic recurrence was diagnosed in 9 patients (5 %). There was no statistical correlation with downstaging (T or N), downsizing effects, or with distance from the lower limit of the residual lesion to the distal margin. Virtual intratumoral surgical section was speculated in 44 patients (3 developed anastomotic recurrence; 6.8 vs 4.8 %, p = 0.482).

CONCLUSION

Anastomotic recurrence in patients with rectal cancer treated with neoadjuvant chemoradiation is an infrequent event. Virtual intratumoral surgical sections followed by anastomosis do not contribute to an excessive risk of recurrence. Our findings encourage the development of policies for preservation of the ano-rectal complex in rectal cancer patients.

[Preoperative radiotherapy for rectal cancer: target volumes]

Preoperative radiochemotherapy followed by total mesorectal excision is the standard of care for T3-T4-N0 or TxN1 rectal cancer. Defining target volumes relies on the patterns of nodal and locoregional failures. The lower limit of the clinical target volume depends also on the type of surgery. Conformational radiotherapy with or without intensity-modulated radiotherapy implies an accurate definition of volumes and inherent margins in the context of mobile organs such as the upper rectum. Tumoral staging recently improved with newer imaging techniques such as MRI with or without USPIO and FDG-PET-CT. The role of PET-CT remains unclear despite encouraging results and MRI is a helpful tool for a reliable delineation of the gross tumour volume. Co-registration of such modalities with the planning CT may particularly guide radiation oncologists through the gross tumour volume delineation. Acute digestive toxicity can be reduced with intensity modulation radiation therapy. Different guidelines and CT-based atlas regarding the target volumes in rectal cancer give the radiation oncologist a lot of ground for reproducible contours.

Risk factors for local recurrence following neoadjuvant chemoradiotherapy for rectal cancers

Local recurrence (LR) has an adverse impact on rectal cancer treatment. Neoadjuvant chemoradiotherapy (nCRT) is increasingly administered to patients with progressive cancers to improve the prognosis. However, LR still remains a problem and its pattern can alter. Correspondingly, new risk factors have emerged in the context of nCRT in addition to the traditional risk factors in patients receiving non-neoadjuvant therapies. These risk factors are decisive when reviewing treatment options. This review aims to elucidate the distinctive risk factors related to LR of rectal cancers in patients receiving nCRT and to clarify their clinical significance. A search was conducted on PubMed to identify original studies investigating patients with rectal cancer receiving nCRT. Outcomes of interest, especially potential risk factors for LR in patients with nCRT, were then analyzed. The clinical importance of these risk factors is discussed. Remnant cancer cells, lymph-nodes and tumor response were found to be major risk factors. Remnant cancer cells decide the status of resection margins. Local excision following nCRT is promising in ypT0-1N0M0 cases. Dissection of lateral lymph nodes should be considered in advanced low-lying cancers. Although better tumor response resulted in a relatively lower recurrence rate, the evidence available is insufficient to justify a non-operative approach in clinical complete responders to nCRT. LR cannot be totally avoided by current multidisciplinary approaches. The related risk factors resulting from nCRT should be considered when making decisions regarding treatment selection.

Is Two-Dimensional Field Definition Sufficient for Pelvic Node Coverage in Rectal Cancer Compared to Technical Three-Dimensional Definition?

Background and aim

To assess the effectiveness of the potential advantages with 3-dimensional-based treatment planning versus 2-dimensional pelvic bone-based treatment planning in patients with rectal cancer, controlled for clinical stage.

Methods and materials

Areas at risk from computed tomography in 30 patients were delineated: mesorectum, presacral, internal iliac, obturator and external iliac nodes. Two planning target volumes per patient were created: PTV_T3 (M + PSN + ON + IIN) and PTV_T4 (M + PSN + ON + IIN + EIN). Two- and 3–dimensional treatment plans for each planning target volume were calculated. Three analyses were performed: 1) mean volume receiving doses >95% and >105%; according to the percentage of prescribed dose to cover at least 95% of the planning target volume, the treatment plan was defined as optimal dose >95%, acceptable dose between 95% and 90%, inferior dose <90%; 2) comparison of the percentage of volume covered by the dose for 2- vs 3-dimensional; 3) determination of the doses at which the lack of volume coverage started to decrease significantly.

Results

For PTV_T3, the following was seen: 1) 2D vs 3D comparison showed optimal PTV_T3 coverage in 76.7% and 96.7%, respectively; 2) 2D vs 3D TP coverage difference was significant between 29%-95% of the total dose; 3) the lack of volume coverage started at 30% for 2D and 89% for 3D. For PTV_T4, the following was seen: 1) 2D vs 3D comparison showed an optimal PTV_T4 coverage in 33.3% and 86.7%, respectively; 2) 2D vs 3D TP coverage difference was significant between 7%-97% of the total dose; 3) the lack of volume coverage started at 7% for 2D and 87% for 3D.

Conclusions

The 3D treatment planning was superior to 2D treatment planning in covering areas at risk for pelvic recurrence in patients treated for rectal cancer. The areas with suboptimal coverage may lead to an increased risk of recurrence and should be correlated with the patterns of recurrence.

Patterns of local recurrence in rectal cancer after a multidisciplinary approach

Improvements in surgery and the application of combined approaches to fight rectal cancer have succeeded in reducing the local recurrence (LR) rate and when there is LR it tends to appear later and less often in isolation. Moreover, a subtle change in the distribution of LRs with respect to the pelvis has been observed. In general terms, prior to total mesorectal excision the most common LRs were central types (perianastomotic and anterior) while lateral and posterior forms (presacral) have become more common since the growth in the use of combined treatments. No differences have been reported in the current pattern of LRs as a function of the type of approach used, that is, neo-adjuvant therapies (short-term or long-course radiotherapy, or chemoradiotherapy versus extended lymphadenectomy, though there is a trend towards posterior or presacral LR in patients in the Western world and lateral LR in Asia. Nevertheless, both may arise from the same mechanism. Moreover, as well as the mode of treatment, the type of LR is related to the height of the initial tumor. Nowadays most LRs are related to the advanced nature of the disease. Involvement of the circumferential radial margin and spillage of residual tumor cells from lymphatic leakage in the pelvic side wall are two plausible mechanisms for the genesis of LR. The patterns of pelvic recurrence itself (pelvic subsites) also have important implications for prognosis and are related to the potential success of salvage curative approach. The re-operability for cure and prognosis are generally better for anastomotic and anterior types than for presacral and lateral recurrences. Overall survival after LR diagnosis is lower with radio or chemoradiotherapy plus optimal surgery approaches, compared to optimal surgery alone.

Accelerated hyperfractionation field-involved re-irradiation combined with concurrent capecitabine chemotherapy for locally recurrent and irresectable rectal cancer

OBJECTIVES

To evaluate the efficacy and treatment-related toxicity of accelerated hyperfractionation field-involved re-irradiation combined with concurrent capecitabine chemotherapy for locally recurrent and irresectable rectal cancer (LRIRC).

METHODS

72 patients with LRIRC who underwent the treatment were studied. Three-dimensional conformal accelerated hyperfractionation radiotherapy (3D-CAHRT) was performed and the dose was delivered with a schedule of 1.2 Gy twice daily, with an interval of at least 6 h between fractions, 5 days a week. Concurrent capecitabine chemotherapy was administered twice daily. After 36 Gy in 30 fractions over 3 weeks, patients were evaluated to define the resectability of the disease. If resection was not feasible irradiation was resumed until the total dose administered to the tumour reached 51.6-56.4 Gy.

RESULTS

Two patients temporarily interrupted concurrent chemoradiation because of Grade IV diarrhoea. The remaining 70 patients completed the planned concurrent chemoradiation. In all patients, the complete response rate was 8.3% and the partial response rate was 51.4%. The overall response rate was 59.7% and clinical benefit rate was 93.1%. Symptomatic responses proved to be obvious and tumour resection was performed in 18 patients. The overall median survival time and median progression-free survival time were 32 and 17 months, respectively. 3 year overall survival and progression-free survival were 45.12% and 31.19%, respectively. Severely acute toxicities included Grade III-IV diarrhoea and granulocytopenia with 9.7% and 8.3% incidence respectively. Small bowel obstruction was severely late toxicity, and the incidence was 1.4%.

CONCLUSION

Three-dimensional conformal accelerated hyperfractionation field-involved re-irradiation combined with concurrent capecitabine chemotherapy might be an effective and well-tolerated regimen for patients with LRIRC.

Radiosensitization of cancer cells by hydroxychalcones

Radiation sensitization is significantly increased by proteotoxic stress, such as a heat shock. We undertook an investigation, seeking to identify natural products that induced proteotoxic stress and then determined if a compound exhibited radiosensitizing properties. The hydroxychalcones, 2',5'-dihydroxychalcone (D-601) and 2,2'-dihydroxychalcone (D-501), were found to activate heat shock factor 1 (Hsf1) and exhibited radiation sensitization properties in colon and pancreatic cancer cells. The radiosensitization ability of D-601 was blocked by pretreatment with α-napthoflavone (ANF), a specific inhibitor of cytochrome P450 1A2 (CYP1A2), suggesting that the metabolite of D-601 is essential for radiosensitization. The study demonstrated the ability of hydroxychalcones to radiosensitize cancer cells and provides new leads for developing novel radiation sensitizers.

Hyperfractionated accelerated radiotherapy for rectal cancer in patients with prior pelvic irradiation

PURPOSE

To retrospectively determine rates of toxicity, freedom from local progression, and survival in rectal cancer patients treated with reirradiation.

METHODS AND MATERIALS

Between February 2001 and February 2005, 50 patients with a history of pelvic radiotherapy were treated with hyperfractionated accelerated radiotherapy for primary (n = 2 patients) or recurrent (n = 48 patients) rectal adenocarcinoma. Patients were treated with 150-cGy fractions twice daily, with a total dose of 39 Gy (n = 47 patients) if the retreatment interval was >or=1 year or 30 Gy (n = 3) if the retreatment interval was <1 year. Concurrent chemotherapy was administered to 48 (96%) patients. Eighteen (36%) patients underwent surgical resection following radiotherapy.

RESULTS

Two patients had grade 3 acute toxicity and 13 patients had grade 3 to 4 late toxicity. The 3-year rate of grade 3 to 4 late toxicity was 35%. The 3-year rate of freedom from local progression was 33%. The 3-year freedom from local progression rate was 47% in patients undergoing surgery and 21% in those not undergoing surgery (p = 0.057). The 3-year overall survival rate was 39%. The 3-year overall survival rate was 66% in patients undergoing surgery and 27% in those not undergoing surgery (p = 0.003). The 3-year overall survival rate was 53% in patients with a retreatment interval of >2 years and 21% in those with a retreatment interval of <or=2 years (p = 0.001).

CONCLUSIONS

Hyperfractionated, accelerated reirradiation was well tolerated, with low rates of acute toxicity and moderate rates of late toxicity. Reirradiation may help improve pelvic control in rectal cancer patients with a history of pelvic radiotherapy.

Future directions in neoadjuvant therapy of rectal cancer: maximizing pathological complete response rates

Neoadjuvant therapy is widely accepted as the current standard of care for localized rectal cancer. Downstaging of disease has been significantly improved and pathological complete response rates (pCR) which were historically below 10% with preoperative radiation alone, now range from 15% to 30% with preoperative chemo-radiation. While the availability of new chemotherapeutic drugs (Irinotecan, Oxaliplatin, etc.) and molecular targeted agents (Bevacizamab, Cetuximab, etc.) hold a great deal of promise, results of recent studies indicate that the pCR rate with neoadjuvant therapy appears to have plateaued at 20-30%. The use of more intensive multidrug combinations has, however, significantly increased the toxicity of treatment. New paradigms in neoadjuvant therapy are therefore needed to further improve results of treatment. This review presents strategies for neoadjuvant therapy, with the potential to improve pCR rates and also survival of patients.