A phase II trial of preoperative concurrent chemotherapy and dose escalated intensity modulated radiotherapy (IMRT) for locally advanced rectal cancer

Prospective evaluation of dose-escalated preoperative concurrent chemo-radiation with image guided-IMRT in locally advanced rectal cancers

Purpose

To analyse the safety and efficacy of neoadjuvant chemoradiation (NACRT) with dose-escalated image-guided intensity modulated radiation therapy (IG-IMRT) in locally advanced (T3/4; T1-4N1-2) rectal cancers (LARCs).

Materials and methods

Twenty patients with the diagnosis of LARC were recruited in this prospective interventional single-arm study treated by IG-IMRT with 45 Gray (Gy) in 25 fractions to elective nodal volumes and 55 Gy in 25 fractions to the gross primary and nodal disease with concurrent capecitabine 825 mg/m2 twice daily on radiotherapy days. Patients underwent total mesorectal excision 6-8 weeks post completion of NACRT followed by adjuvant chemotherapy (Capecitabine and oxaliplatin every 3 weekly for 6-8 cycles). Primary end point was acute toxicity assessment and secondary end points were pathological complete response (pCR) and loco-regional control (LRC).

Results

Clinical T stage was T3:T4 in 19:1 and clinical N0:N1: N2 in 2:7:11 patients, respectively. With a median follow up of 21.2 months (13.8-25.6 months), 18 of 20 (90%) patients received the full course of treatment. Tumour and nodal downstaging was achieved in 78% and 84% of patients, respectively. pCR and overall complete response (defined as pCR and near CR) was achieved in 22.2% and 44.4% of patients, respectively. 2 (10%) patients completed NACRT, and achieved complete clinical response but refused surgery. Adjuvant chemotherapy course was completed by 17/18 (94.5%) patients. Grade 3 toxicities were observed in 2 (10%) patients during NACRT. All patients were disease-free at the time of the last follow up.

Conclusion

Dose-escalation of NACRT therapy with IG-IMRT in LARC patients offers decent rates of pCR and overall response with excellent LRC and acceptable toxicities.

[Impact of IMRT for neoadjuvant rectal cancer?]

The standard management of locally advanced rectal tumors as cT3-T4 and/or N0/N1 is based on preoperative treatment combining radiotherapy of 45 to 50Gy and chemotherapy based on 5-fluorouracil. Intensity-modulated radiotherapy has already shown its interest compared to conformal radiotherapy in other locations, like in pelvic cancer. The role of intensity-modulated radiotherapy in the pre/postoperative treatment of rectal cancers is not a standard of care. Published studies showed its feasibility with the objective of less toxicity with equivalent efficacy.

Simultaneous Integrated Boost Volumetric Modulated Arc Therapy for Rectal Cancer: Long-Term Results after Protocol-Based Treatment

Background

Volumetric modulated arc therapy (VMAT) with simultaneous integrated boost (SIB) is an advanced form of radiotherapy (RT) technology. The purpose of this study was to report long-term treatment outcomes in patients with locally advanced rectal cancer undergoing VMAT-SIB based concurrent chemoradiotherapy (CRT).

Methods

Between January 2016 and January 2018, a total of 22 patients with operable stage II-III rectal adenocarcinoma were recruited for the pre-designed VMAT-SIB RT protocol. All patients underwent standard diagnostic and staging work-up. The RT target volumes included the following areas: PTV1 = mesorectum that contained gross tumors and enlarged lymph node regions and PTV2 = mesorectum and regional lymphatics from L4-5/S1 to 3-4 cm below the tumor or levator ani muscle, excluding PTV1. The VMAT-SIB dose prescription was as follows: PTV1 = 52.5 Gy/daily 2.1 Gy/25 fractions, PTV2 = 45 Gy/daily 1.8 Gy/25 fractions.

Results

The mean age of the study population was 64 (range, 18-84) years, and 15 (68.2%) patients were male. Radical operation (total mesorectal excision) was performed by either low anterior resection, ultralow anterior resection, or abdominal perineal resection. All five (22.7%) of the patients with confirmed increasing serum carcinoembryonic antigen (CEA) level at diagnosis showed normalization of serum CEA level after the planned treatment. Among 20 patients who underwent preoperative CRT and surgery, tumor down staging in T- and N-stages was achieved in 10 patients (50%) and 13 patients (65%), respectively, with 20% of ypT0/Tis. With a median follow-up of 54.2 (range, 22.6-61.1) months, the 5-year disease-free survival, overall survival, and local control rates were 64.6%, 81.8%, and 84.4%, respectively. Five patients developed distant metastasis and one developed local recurrence as a first event. Two cases with anastomosis site leakage, three with adhesive ileus, and two with abscess formation were observed during postoperative periods.

Conclusions

The current VMAT-SIB-based CRT protocol provided acceptable treatment and toxicity outcomes.

Preoperative intensity-modulated chemoradiotherapy with simultaneous integrated boost in rectal cancer: five-year follow-up results of a phase II study

Background

We conducted a phase II study to investigate the feasibility and safety of preoperative radiochemo-therapy experimental fractionation, using intensity-modulated radiation therapy with simultaneous integrated boost (IMRT SIB) to shorten the overall treatment time without dose escalation in intermediate/locally advanced rectal cancer with the aim to improving treatment outcome.

Patients and methods

A total of 51 patients with operable stage II–III rectal carcinoma were included between January 2014 and January 2015. Fifty patients completed preoperative IMRT treatment with an elective dose of 41.8 Gy and simultaneously delivered 46.2 Gy to T2/T3 and 48.4 Gy to T4 tumour in 22 fractions, with concomitant capecitabine (825 mg/m2/12 h, including at weekends). Median follow-up was 70 months (range 11–80 m).

Results

Forty-seven patients completed treatment per protocol. Acute toxicity occurred in 2 (4%) patients. R0 resection was achieved in all but 1 and pathologic complete response (pCR) in 12 (25.5%) patients who had 5-year overall survival (OS), disease-free survival (DFS) and local control (LC) of 91.7%, 100% and 100%, respectively. The intention-to-treat analysis showed that the type of surgery significantly moderated OS and DFS, while total downstaging and pN were predictive for DFS only. For treatment per protocol 5-year OS, DFS and LC were 80.9% (95% confidence interval [CI] 69.7–92.1), 77.1% (95% CI 65.1–89.1) and 95.2% (95% CI 88.7–100), respectively. The proportion of patients with severe late (CTCAE G ≥ 3) gastrointestinal, urinary and sexual toxicity was 15%, 2% and 8% respectively, with one reported secondary carcinoma.

Conclusions

Preoperative IMRT-SIB without dose escalation was well tolerated, with a low acute toxicity profile, we achieved a high rate of pCR and showed encouraging 5-year OS, DFS and LC.

Neoadjuvant radiotherapy dose escalation for locally advanced rectal cancers in the new era of radiotherapy: A review of literature

BACKGROUND

The standard treatment of locally advanced rectal cancers (LARC) consists on neoadjuvant chemoradiotherapy followed by total mesorectal excision. Different data in literature showed a benefit on tumor downstaging and pathological complete response (pCR) rate using radiotherapy dose escalation, however there is shortage of studies regarding dose escalation using the innovative techniques for LARC (T3-4 or N1-2).

AIM

To analyze the role of neoadjuvant radiotherapy dose escalation for LARC using innovative radiotherapy techniques.

METHODS

In December 2020, we conducted a comprehensive literature search of the following electronic databases: PubMed, Web of Science, Scopus and Cochrane library. The limit period of research included articles published from January 2009 to December 2020. Screening by title and abstract was carried out to identify only studies using radiation doses equivalent dose 2 Gy fraction (EQD2) ≥ 54 Gy and Volumetric Modulated Arc Therapy (VMAT), intensity-modulated radiotherapy or image-guided radiotherapy (IGRT) techniques. The authors’ searches generated a total of 2287 results and, according to PRISMA Group (2009) screening process, 21 publications fulfil selection criteria and were included for the review.

RESULTS

The main radiotherapy technique used consisted in VMAT and IGRT modality. The mainly dose prescription was 55 Gy to high risk volume and 45 Gy as prophylactic volume in 25 fractions given with simultaneous integrated boosts technique (42.85%). The mean pCR was 28.2% with no correlation between dose prescribed and response rates (P value ≥ 0.5). The R0 margins and sphincter preservation rates were 98.88% and 76.03%, respectively. After a mean follow-up of 35 months local control was 92.29%. G3 or higher toxicity was 11.06% with no correlation between dose prescription and toxicities. Patients receiving EQD2 dose > 58.9 Gy and BED > 70.7 Gy had higher surgical complications rates compared to other group (P value = 0.047).

CONCLUSION

Dose escalation neoadjuvant radiotherapy using innovative techniques is safe for LARC achieving higher rates of pCR. EQD2 doses > 58.9 Gy is associated with higher rate of surgical complications.

Intensity-modulated Radiotherapy for Rectal Cancer in the UK in 2020

AIMS

Preoperative (chemo)radiotherapy followed by total mesorectal excision is the current standard of care for patients with locally advanced rectal cancer. The use of intensity-modulated radiotherapy (IMRT) for rectal cancer is increasing in the UK. However, the extent of IMRT implementation and current practice was not previously known. A national survey was commissioned to investigate the landscape of IMRT use for rectal cancer and to inform the development of national rectal cancer IMRT guidance.

MATERIALS AND METHODS

A web-based survey was developed by the National Rectal Cancer IMRT Guidance working group in collaboration with the Royal College of Radiologists and disseminated to all UK radiotherapy centres. The survey enquired about the implementation of IMRT with a focus on the following aspects of the workflow: dose fractionation schedules and use of a boost; pre-treatment preparation and simulation; target volume/organ at risk definition; treatment planning and treatment verification. A descriptive statistical analysis was carried out.

RESULTS

In total, 44 of 63 centres (70%) responded to the survey; 30/44 (68%) and 36/44 (82%) centres currently use IMRT to treat all patients and selected patients with rectal cancer, respectively. There was general agreement concerning several aspects of the IMRT workflow, including patient positioning, use of intravenous contrast and bladder protocols. Greater variation in practice was identified regarding rectal protocols; use of a boost to primary/nodal disease; target volume delineation; organ at risk delineation and dose constraints and treatment verification. Delineation of individual small bowel loops and daily volumetric treatment verification were considered potentially feasible by most centres.

CONCLUSION

This survey identified that IMRT is already used to treat rectal cancer in many UK radiotherapy centres, but there is heterogeneity between centres in its implementation and practice. These results have been a valuable aid in framing the recommendations within the new National Rectal Cancer IMRT Guidance.

Recent advances in (chemo-)radiation therapy for rectal cancer: a comprehensive review

The role of radiation therapy in the treatment of (colo)-rectal cancer has changed dramatically over the past decades. Introduced with the aim of reducing the high rates of local recurrences after conventional surgery, major developments in imaging, surgical technique, systemic therapy and radiation delivery have now created a much more complex environment leading to a more personalized approach. Functional aspects including reduction of acute or late treatment-related side effects, sphincter or even organ-preservation and the unsolved problem of still high distant failure rates have become more important while local recurrence rates can be kept low in the vast majority of patients. This review summarizes the actual role of radiation therapy in different subgroups of patients with rectal cancer, including the current standard approach in different subgroups as well as recent developments focusing on neoadjuvant treatment intensification and/or non-operative treatment approaches aiming at organ-preservation.

[Preoperative intensity-modulated radiotherapy of rectal cancers: Relevance and modalities]

Preoperative radiotherapy boosted by chemotherapy is a recommended treatment in locally advanced rectal cancers. This treatment is delivered by three dimensional conformal irradiation, which is usually well tolerated but can induce potential toxicity such as rectitis, cystitis and hematologic adverse effects. Intensity-modulated radiotherapy, widely available nowadays, allows optimization of volume covering and sparing of organs at risk such as bladder and bone marrow. This review presents relevant clinical situations and requirements for a beneficial and safe preoperative irradiation of rectal cancers by intensity-modulated technique. This technique is compared to three-dimensional conformal radiotherapy.

The challenges in colorectal cancer management during COVID-19 epidemic

It has been over 2 months since the start of the Coronavirus disease 2019 (COVID-19) outbreak. The epidemic stage of COVID-19 has brought great challenges to the diagnosis and management of colorectal cancer (CRC) patients. Symptoms, such as fever and cough caused by cancer, and the therapeutic process (including chemotherapy and surgery) should be differentiated from some COVID-19 related characteristics. Besides, clinical workers should not only consider the therapeutic strategy for cancer, but also emphasize COVID-19's prevention. Moreover, the detailed therapeutic regimens of CRC patients may be different from the usual. Also, treatment principles may various for CRC patients with or without severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, as well as patients with or without an emergency presentation. In this paper, we want to discuss the above-mentioned problems based on previous guidelines, the current working status and our experiences, to provide a reference for medical personnel.

Dose-time fractionation schedules of preoperative radiotherapy and timing to surgery for rectal cancer

Chemoradiotherapy (CRT) is extensively used prior to surgery for rectal cancer to provide significantly better local control, but the radiotherapy (RT), as the other component of CRT, has been subject to less interest than the drug component in recent years. With considerable developments in RT, the use of advanced techniques, such as intensity-modulated radiotherapy (IMRT) in rectal cancer, is garnering more attention nowadays. The radiation dose can be better conformed to the target volumes with possibilities for synchronous integrated boost without increased complications in normal tissue. Hopefully, both local recurrence and toxicities can be further reduced. Although those seem to be of interest, many issues remain unresolved. There is no international consensus regarding the radiation schedule for preoperative RT for rectal cancer. Moreover, an enormous disparity exists regarding the RT delivery. With the advent of IMRT, variations will likely increase. Moreover, time to surgery is also quite variable, as it depends upon the indication for RT/CRT in the clinical practices. In this review, we discuss the options and problems related to both the dose-time fractionation schedule and time to surgery; furthermore, it addresses the research questions that need answering in the future.

Radiation therapy for rectal cancer

Radiotherapy (RT) has remained an important pillar in the multi-modality management of rectal cancer. Adjuvant RT with concurrent chemotherapy (chemo-RT) was once the standard of care for locally advanced rectal cancer, but with time, that has now changed and neoadjuvant chemo-RT followed by total mesorectal excision (TME) surgery is the new standard. Alternatively, neoadjuvant RT alone remains an option and clinicians are tasked to choose between the two. In an era of personalised oncological management, it is unsurprising that the treatment for rectal cancer is following suit and upcoming trials are studying ways to improve outcomes and minimise toxicity for patients while tailoring treatments specific to each patient's tumour. We review the evolution of the role of RT in rectal cancer and look forward to what the future holds.

Concomitant dose escalation with image-guided Tomotherapy in locally advanced mid-low rectal cancer: a single-center study

Purpose

The purpose of this study was to evaluate the efficacy and toxicity of concomitant dose-escalated Tomotherapy in locally advanced mid–low rectal cancer.

Patients and methods

Patients with locally advanced (T3/T4 or N+), low–mid (≤10 cm from anal verge) rectal carcinoma treated with neoadjuvant chemoradiotherapy followed by surgery between May 2012 and October 2017 in Peking Union Medical College Hospital were included in this study. A dose of 45/50 Gy in 25 fractions was delivered to the pelvis with Tomotherapy, and 55 Gy was prescribed for the primary tumor with a simultaneous, integrated boost. Megavolt computed tomography was performed before every delivery. The concurrent chemotherapy regimen included capecitabine alone and XELOX.

Results

A total of 141 patients were enrolled; 129 patients (91.5%) had stage cT3 or cT4, and 121 patients (85.8%) had positive lymph nodes. The location of the tumors was in the lower rectum in 88 patients (62.4%). After neoadjuvant chemoradiotherapy, 113 patients (80.1%) underwent sphincter-preserving resection. Downstaging was observed in 121 patients (85.8%), including 80 patients (56.7%) with T downstaging and 101 patients (83.5%) with N downstaging. Thirty-two patients (22.7%) obtained pathological complete response (pCR). The median follow-up was 38.5 months (range, 9.3–73.6 months). Only 36 patients (25.5%) experienced treatment failure, including distant metastasis in 29 patients (20.6%) and pelvic recurrent in 7 patients (5.0%). The estimated 5-year overall survival (OS), disease-free survival (DFS), and local control (LC) rates of patients were 75.1%, 70.9%, and 95.5%, respectively. pCR was an independent prognostic factor for DFS (HR 0.13, 95% CI: 0.02–0.93, P = 0.043), but it did not improve OS or LC. Grade 3 or greater acute leukopenia and diarrhea rates were 5.7% and 7.8%, respectively, and 15 patients (10.6%) developed postoperative complications.

Conclusion

This study indicates that neoadjuvant, image-guided Tomotherapy with 55 Gy boosted to the primary tumor was well tolerated and resulted in high rates of sphincter-preserving surgery, pCR, LC, and DFS for locally advanced rectal cancer.

[Image-guided radiotherapy contribution and patient setup for anorectal cancer treatment]

Intensity-modulated radiation therapy is recommended in anal squamous cell carcinoma treatment and is increasingly used in rectal cancer. It adapts the dose to target volumes, with a high doses gradient. Intensity-modulated radiation therapy allows to reduce toxicity to critical normal structures and to consider dose-escalation studies or systemic treatment intensification. Image-guided radiation therapy is a warrant of quality for intensity-modulated radiation therapy, especially for successful delivery of the dose as planned. There is no recommended international or national anorectal cancer image-guided radiation therapy protocol currently available. Dose-escalation trials or expert opinions about intensity-modulated/image-guided radiation therapy good practice guidelines recommend daily volumetric imaging throughout the treatment or during the five first fractions and weekly thereafter as a minimum. Image-guided radiation therapy allows to reduce margins related to patient setup errors. Internal margin, related to the internal organ motion, needs to be adapted according to short- or long-course radiotherapy, gender, rectal location; it can be higher than current recommended planning target volume margins, particularly in the upper and anterior part of mesorectum, which has the most significant movement. Image-guided radiation therapy based on volumetric imaging allows to take target volume shrinkage into account and to develop adaptive strategies, in particular for mesorectum shrinkage during rectal cancer treatment. Lastly, the emergence of new image-guided radiation therapy technologies including MRI (which plays a major role in pelvic tumours assessment and diagnosis) opens up interesting perspectives for adaptive radiotherapy, taking into account both organs' movements and tumour shrinkage.