Re-Irradiation in Patients with Recurrent Rectal Cancer is Safe and Feasible

Analysis of re-recurrent rectal cancer after curative treatment of locally recurrent rectal cancer

PURPOSE

Substantiating data guiding clinical decision making in locally recurrent rectal cancer (LRRC) is lacking, specifically in target volume (TV) definition for chemoradiotherapy (CRT). A case-by-case review of local re-recurrences (re-LRRC) after multimodal treatment for LRRC was performed, to determine location of re-LRRC and assess whether treatment could have been improved.

METHODS

All patients treated with curative intent for LRRC at the Catharina Hospital Eindhoven from October 2016 onwards, in whom complete imaging of (re-)LRRC and radiotherapy was available, were retrieved. Patients were discussed in plenary meetings with expert colorectal surgeons, radiation oncologists and radiologists. Each case was classified based on re-LRRC location, whether it was in accordance with the (current) radiotherapy protocol, and whether multimodal management would have been different in retrospect.

RESULTS

Thirty-three cases were discussed. LRRC treatment was deemed suboptimal in 17/33 patients, due to different target volumes (13/17) and/or different surgery (9/17). 15/33 (46 %) of re-LRRC developed in-field of the prior radiotherapy TV, possibly showing RT-resistant disease. Other re-LRRCs developed out-field (n = 5, 15 %), marginally (n = 6, 18 %), or in a combined fashion (n = 7, 21 %). In retrospect, 48 % of cases were irradiated in line with current TV recommendations. TVs of 13/33 cases would have been altered if irradiated today.

CONCLUSION

This study highlights room for improvement within current standard-ofcare treatment for LRRC. Different surgical management or TVs may have improved outcome in up to half of discussed cases. Further delineation guideline development, incorporating the results from this study, may improve oncological outcome, specifically local control, for LRRC patients.

The Role of Intraoperative Radiotherapy Treatment of Locally Advanced Rectal Cancer

Intraoperative radiation therapy (IORT) has been used in the treatment of locally advanced and recurrent rectal cancers for the last several decades. Given the heterogeneity of patients treated and different indications for use and dosing at different institutions, it has been difficult to discern if IORT adds any appreciable benefit to standard of care therapies. Herein, the rationale for IORT in rectal cancer is discussed along with the most modern and best available data in 2023. IORT is likely indicated in patients with locally advanced and locally recurrent rectal cancer with threatened margins (R0 or R1 resection) to help improve local control. High-quality imaging and multidisciplinary discussion are necessary to ensure optimal patient selection. Appropriate counseling of the patient and excellent team communication are of the utmost importance given the challenging nature of these cases and the prognostic implications of R1 and R2 resections in this patient population.

Treatment of Locally Recurrent Rectal Cancer: A Review

ABSTRACT

Up to 10% of patients with locally advanced rectal cancer will experience locoregional recurrence. In the setting of prior surgery and often radiation and chemotherapy, these represent uniquely challenging cases. When feasible, surgical resection offers the best chance for oncologic control yet risks significant morbidity. Studies have consistently indicated that a negative surgical resection margin is the strongest predictor of oncologic outcomes. Chemoradiation is often recommended to increase the chance of an R0 resection, and in cases of close/positive margins, intraoperative radiation/brachytherapy can be utilized. In patients who are not surgical candidates, radiation can provide symptomatic relief. Ongoing phase III trials are aiming to address questions regarding the role of reirradiation and induction multiagent chemotherapy regimens in this population.

Dutch national guidelines for locally recurrent rectal cancer

Due to improvements in treatment for primary rectal cancer, the incidence of LRRC has decreased. However, 6-12% of patients will still develop a local recurrence. Treatment of patients with LRRC can be challenging, because of complex and heterogeneous disease presentation and scarce - often low-grade - data steering clinical decisions. Previous consensus guidelines have provided some direction regarding diagnosis and treatment, but no comprehensive guidelines encompassing all aspects of the clinical management of patients with LRRC are available to date. The treatment of LRRC requires a multidisciplinary approach and overarching expertise in all domains. This broad expertise is often limited to specific expert centres, with dedicated multidisciplinary teams treating LRRC. A comprehensive, narrative literature review was performed and used to develop the Dutch National Guideline for management of LRRC, in an attempt to guide decision making for clinicians, regarding the complete clinical pathway from diagnosis to surgery.

Contemporary results from the PelvEx collaborative: improvements in surgical outcomes for locally advanced and recurrent rectal cancer

AIM

The PelvEx Collaborative collates global data on outcomes following exenterative surgery for locally advanced and locally recurrent rectal cancer (LARC and LRRC, respectively). The aim of this study is to report contemporary data from within the collaborative and benchmark it against previous PelvEx publications.

METHOD

Anonymized data from 45 units that performed pelvic exenteration for LARC or LRRC between 2017 and 2021 were reviewed. The primary endpoints were surgical outcomes, including resection margin status, radicality of surgery, rates of reconstruction and associated morbidity and/or mortality.

RESULTS

Of 2186 patients who underwent an exenteration for either LARC or LRRC, 1386 (63.4%) had LARC and 800 (36.6%) had LRRC. The proportion of males to females was 1232:954. Median age was 62 years (interquartile range 52-71 years) compared with a median age of 63 in both historical LARC and LRRC cohorts. Compared with the original reported PelvEx data (2004-2014), there has been an increase in negative margin (R0) rates from 79.8% to 84.8% and from 55.4% to 71.7% in the LARC and LRRC cohorts, respectively. Bone resection and flap reconstruction rates have increased accordingly in both cohorts (8.2%-19.6% and 22.6%-32% for LARC and 20.3%-41.9% and 17.4%-32.1% in LRRC, respectively). Despite this, major morbidity has not increased.

CONCLUSION

In the modern era, patients undergoing pelvic exenteration for advanced rectal cancer are undergoing more radical surgery and are more likely to achieve a negative resection margin (R0) with no increase in major morbidity.

Magnetic Resonance Imaging of Macrophage Response to Radiation Therapy

BACKGROUND

Magnetic resonance imaging (MRI) is a non-invasive imaging modality which, in conjunction with biopsies, provide a qualitative assessment of tumor response to treatment. Intravenous injection of contrast agents such as fluorine (19F) nanoemulsions labels systemic macrophages, which can, then, be tracked in real time with MRI. This method can provide quantifiable insights into the behavior of tumor-associated macrophages (TAMs) in the tumor microenvironment and macrophage recruitment during therapy.

METHODS

Female mice received mammary fat pad injections of murine breast or colon cancer cell lines. The mice then received an intravenous 19F nanoemulsion injection, followed by a baseline 19F MRI. For each cancer model, half of the mice then received 8 Gy of localized radiation therapy (RT), while others remained untreated. The mice were monitored for two weeks for tumor growth and 9F signal using MRI.

RESULTS

Across both cohorts, the RT-treated groups presented significant tumor growth reduction or arrest, contrary to the untreated groups. Similarly, the fluorine signal in treated groups increased significantly as early as four days post therapy. The fluorine signal change correlated to tumor volumes irrespective of time.

CONCLUSION

These results demonstrate the potential of 19F MRI to non-invasively track macrophages during radiation therapy and its prognostic value with regard to tumor growth.

High-dose rate endorectal brachytherapy for rectal cancer: A state-of-the-art review

Rectal cancer is a common malignancy that requires multidisciplinary treatment. By utilizing the dose-response relationship in rectal cancer radiotherapy, increasing the radiotherapy dose can improve clinical complete remission rates. High-dose rate endorectal brachytherapy (HDREBT) is a novel technique that delivers high doses of radiotherapy directly to the tumor via an endorectal applicator, sparing the adjacent normal tissues from excessive radiation exposure. HDREBT includes contact X-ray brachytherapy and high-dose-rate intracavitary brachytherapy. We introduce the latest developments in applicators and imaging techniques for HDREBT in rectal cancer and summarize the current evidence on the efficacy, safety, and feasibility of HDREBT as a neoadjuvant, definitive, or palliative treatment option for all stages of rectal cancer patients. We also discuss the potential advantages and challenges of HDREBT in achieving organ preservation and improving the quality of life of rectal cancer patients. HDREBT has shown promising results in achieving high complete response rates, enabling nonoperative management, improving organ preservation rates, and providing effective palliation in rectal cancer patients. More studies are needed to optimize its dose and fractionation schemes in different clinical scenarios.

Oncological outcomes of multimodality treatment for patients undergoing surgery for locally recurrent rectal cancer: A systematic review

BACKGROUND

There are several strategies in the management of locally recurrent rectal cancer (LRRC) with the optimum treatment yet to be established. This systematic review aims to compare oncological outcomes in patients undergoing surgery for LRRC who underwent neoadjuvant radiotherapy or chemoradiotherapy (CRT), adjuvant CRT, surgery only or surgery and intraoperative radiotherapy (IORT).

METHODS

A literature search of MEDLINE, EMBASE and CINAHL was performed for studies that reported data on oncological outcomes for the different treatment modalities in patients with LRRC from January 1990 to January 2022. Weighted means were calculated for the following outcomes: postoperative resection status, local control, and overall survival at 3 and 5 years.

RESULTS

Fifteen studies of 974 patients were included and they received the following treatment: 346 neoadjuvant radiotherapy, 279 neoadjuvant CRT, 136 adjuvant CRT, 189 surgery only, and 24 surgery and IORT. The highest proportion of R0 resection was found in the neoadjuvant CRT group followed by neoadjuvant radiotherapy and adjuvant CRT groups (64.07% vs 52.46% vs 47.0% respectively). The neoadjuvant CRT group had the highest mean 5-year local control rate (49.50%) followed by neoadjuvant radiotherapy (22.0%). Regarding the 5-year overall survival rate, the neoadjuvant CRT group had the highest mean of 34.92%, followed by surgery only (29.74%), neoadjuvant radiotherapy (28.94%) and adjuvant CRT (20.67%).

CONCLUSIONS

The findings of this systematic review suggest that neoadjuvant CRT followed by surgery can lead to improved resection status, long-term disease control and survival in the management of LRRC. However, treatment strategies in LRRC are complex and further comparisons, particularly taking into account previous treatments for the primary rectal cancer, are required.