A multi-centre analysis of adjuvant contact X-ray brachytherapy (CXB) in rectal cancer patients treated with local excision - Preliminary results of the CONTEM1 study

Contact X-ray Brachytherapy as a sole treatment in selected patients with early rectal cancer - Multi-centre study

Background and purpose

Radical surgery is the standard of care for early rectal cancer. However, alternative organ-preserving approaches are attractive, especially in frail or elderly patients as these avoid surgical complications. We have assessed the efficacy of sole Contact X-ray Brachytherapy (CXB) treatment in stage-1 rectal cancer patients who were unsuitable for or declined surgery.

Materials and methods

This retrospective multi-centre study (2009-2021) evaluated 76 patients with T1/2-N0-M0 rectal adenocarcinomas who were treated with CXB alone. Outcomes were assessed for the entire cohort and sub-groups based on the T-stage and the criteria for receiving CXB alone; Group A: patients who were fit enough for surgery but declined, Group B: patients who were high-risk for surgery and Group C: patients who had received prior pelvic radiation for a different cancer.

Results

With a median follow-up of 26(IQR:12-49) months, initial clinical Complete Response (cCR) was 82(70-93)% with rates of local regrowth 18(8-29)%, 3-year actuarial local control (LC) 84(75-95)%, distant relapse 3 %, and no nodal relapse. 5-year disease-free survival (DFS) and overall survival (OS) were 66(48-78)% and 58(44-75)%. Lower OS was observed in Groups B [HR:2.54(95 %CI:1.17, 5.59), p = 0.02] and C [HR:2.75(95 %CI:1.15, 6.58), p = 0.03]. Previous pelvic radiation predicted lower cCR and OS. The main toxicity was G1-2 rectal bleeding (26 %) and symptoms of impaired anal sphincter function were not reported in any patients.

Conclusion

CXB treatment alone achieved a high cCR rate with satisfactory LC and DFS. Inferior oncological outcomes were observed in patients who had received prior pelvic radiotherapy. CXB alone, with its favourable toxicity profile and avoidance of general anaesthesia and surgery risks, therefore, can be considered for patients who are unsuitable for or refuse surgery.

Sequence of Contact X-ray Brachytherapy (CXB) and External Beam Radiation (EBRT) in organ-preserving treatment for small rectal cancer

BACKGROUND AND PURPOSE

External Beam Radiotherapy (EBRT) followed by Contact X-ray Brachytherapy (CXB) and vice versa are viable alternatives to surgery for selected rectal cancer patients who have small tumours (≤3 cm). However, the optimal sequence of treatment needs to be established. We compared two approaches using Propensity Score (PS) matching and inverse probability treatment weighting (IPTW) analyses to investigate whether the sequence of treatment affected patient outcomes.

MATERIALS AND METHODS

This retrospective analysis (2008-2019) included patients with rectal adenocarcinoma (cT1-3,N0-1,M0, grade 1-2, size ≤ 3 cm) who received both EBRT and CXB, irrespective of treatment sequence. PS matching and IPTW were conducted to balance covariate standardised mean differences between groups. Oncological outcomes and rate of post-treatment rectal bleeding were assessed.

RESULTS

Following PS matching and IPTW analyses from 251 eligible patients; 103 starting with EBRT (median follow-up: 37 [IQR:18-56] months) and 148 with CXB (median follow-up: 32 [IQR:16-54] months, a significant improvement in 3-year overall survival (77% vs 85%, p = 0.02, [HR:0.58 (95% CI:0.37-0.91)]) and a higher risk of post-treatment rectal bleeding (grade 1 (26%) and grade 2 (6%)) were found in patients who started with CXB (p = 0.08). No significant differences were observed in local regrowth (18% vs 12%, p = 0.47), distant relapse (10% vs 6%, p = 0.53), 3-year organ preservation rates (70% vs 75%, p = 0.20, [HR:0.66 (95% CI: 0.35-1.26)]), or disease-free survival (78% vs 82%, p = 0.17, [HR: 0.47 (95% CI: 0.16-1.38)]) CONCLUSION: In patients with rectal cancer (≤3 cm), commencing with CXB rather than EBRT, was associated with improved overall survival, but had a higher risk of G1/2 rectal bleeding. No statistically significant differences were observed in other oncological outcomes.

High Rates of Organ Preservation in Rectal Cancer with Papillon Contact X-ray Radiotherapy: Results from a Swiss Cohort

Rectal cancer typically necessitates a combination of radiotherapy (RT), chemotherapy, and surgery. The associated functional disorders and reduction in quality of life have led to an increasing interest in organ preservation strategies. Response strongly correlates with RT dose, but dose escalation with external beam remains limited even with modern external beam RT techniques because of toxicity of the surrounding tissues. This study reports on the use of Papillon, an endocavitary Radiotherapy device, in the treatment of rectal cancer. The device delivers low energy X-rays, allowing for safe dose escalation and better complete response rate. Between January 2015 and February 2024, 24 rectal cancer patients were treated with the addition of a boost delivered by Papillon to standard RT, with or without chemotherapy, in an upfront organ preservation strategy. After a median follow-up (FU) of 43 months, the organ preservation rate was 96% (23/24), and the local relapse rate was 8% (2/24). None of our patients developed grade 3 or more toxicities. Our results demonstrate that the addition of Papillon contact RT provides a high rate of local remission with sustained long-term organ preservation, offering a promising alternative to traditional surgical approaches in patients with rectal cancer.

Management after local excision of small rectal cancers. Indications for completion total mesorectal excision and possible alternatives

The treatment of superficial rectal cancers (local excision, or proctectomy with total mesorectal excision (TME) remains controversial. Endoscopy and endorectal ultrasonography are essential for the precise initial definition of these small cancers. During endoscopy, the depth of the lesion can be estimated using virtual chromoendoscopy with magnification, thereby aiding the assessment of the possibilities of local excision. Current international recommendations indicate completion proctectomy after wide local excision for cases where the pathologic examination reveals poorly-differentiated lesions, lymphovascular invasion, grade 2 or 3 tumor budding, and incomplete resection. But debate persists regarding whether the depth of submucosal invasion can accurately predict the risk of lymph node spread. Recent data from the literature suggest that the depth of submucosal invasion should no longer, by itself, be an indication for additional oncological surgery. Adjuvant radio-chemotherapy could be an alternative to completion proctectomy in patients with pT1 rectal cancer and unfavorable histopathological criteria. A Dutch randomized controlled trial is underway to validate this strategy.

Treatment Options for Distal Rectal Cancer in the Era of Organ Preservation

OPINION STATEMENT

The introduction of total mesorectal excision into the radical surgery of rectal cancer has significantly improved the oncological outcome with longer survival and lower local recurrence. Traditional treatment modalities of distal rectal cancer, relying on radical surgery, while effective, take their own set of risks, including surgical complications, potential damage to the anus, and surrounding structure owing to the pursuit of thorough resection. The progress of operating methods as well as the integration of systemic therapies and radiotherapy into the peri-operative period, particularly the exciting clinical complete response of patients after neoadjuvant treatment, have paved the way for organ preservation strategy. The non-inferiority oncological outcome of "watch and wait" compared with radical surgery underscores the potential of organ preservation not only to control local recurrence but also to reduce the need for treatments followed by structure destruction, hopefully improving the long-term quality of life. Radical radiotherapy provides another treatment option for patients unwilling or unable to undergo surgery. Organ preservation points out the direction of treatment for distal rectal cancer, while additional researches are needed to answer remaining questions about its optimal use.

Brachytherapy for rectal and anal cancer: Where are we and current perspectives?

Anal and rectal cancers were some of the first disease sites treated with brachytherapy due to the anatomic ease of implantation. As external beam radiotherapy grew in popularity the use of ano-rectal brachytherapy declined. However, the past few years have seen a steady resurgence in the use of brachytherapy in the ano-rectum supported by the use of large clinical series and randomized trials. The increasing acceptance by the surgical community of organ preservation as a valid treatment strategy for rectal cancer has encouraged the use of nonsurgical approaches and brachytherapy has shown itself to be a valuable tool for this. The current role of anal and rectal brachytherapy is presented with perspectives on its future use.

Prognostic impact of tumor budding in rectal cancer after neoadjuvant therapy: a systematic review and meta-analysis

BACKGROUND

Tumor budding (TB) is a negative prognostic factor in colorectal cancer; however, its prognostic impact following neoadjuvant therapy for patients with rectal cancer remains unclear. This study aims to assess the prognostic impact of TB and the correlation between TB and other pathological features in patients with rectal cancer after neoadjuvant therapy.

METHODS

A comprehensive search of PubMed, Embase, Cochrane, Scopus, CNKI, Wanfang, and ClinicalKey databases was conducted for studies on the prognosis of TB in rectal cancer after neoadjuvant therapy from the inception of the databases to January 2023, and the final literature included was determined using predefined criteria. Quality assessment of the studies included, extraction of general and prognostic information from them, and meta-analyses were carried out progressively.

RESULTS

A total of 11 studies were included, and the results of the meta-analysis showed that high-grade tumor budding (TB-1) increased the risk of poor 5-year disease-free survival (HR = 1.75, 95% CI 1.38-2.22, P < 0.00001), 5-year overall survival (HR = 1.77, 95% CI 1.21-2.59, P = 0.003), local recurrence (OR = 4.15, 95% CI 1.47-11.75, P = 0.007), and distant metastasis (OR = 5.36, 95% CI 2.51-11.44, P < 0.0001) in patients with rectal cancer after neoadjuvant therapy. TB-1 was significantly associated with poor differentiation and lymphatic, perineural, and venous invasion.

CONCLUSION

Tumor budding is significantly correlated with unfavorable prognosis and poor pathological characteristics following neoadjuvant therapy for rectal cancer. We anticipate more high-quality, prospective studies in the future to confirm our findings.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022377564.

Organ and Function Preservation in Gastrointestinal Malignancies

Radiation plays an important role in organ preservation for gastrointestinal malignancies, with a watch and wait strategy enabling surgery to be avoided in patients who are not suitable or who are refusing surgery. Brachytherapy boost allows the radiation dose to be escalated, which plays a pivotal role in the successful outcome of achieving organ preservation. Here we describe the role of brachytherapy in two common gastrointestinal malignancies (oesophagus and rectum). Their indications and how the brachytherapy procedures are carried out, together with the dose and fractionation commonly used are discussed. The use of brachytherapy needs to be included in the training curriculum at all academic centres so that its use is developed by the newer generation of radiation oncologists. Its current non-use due to bias, lack of training and availability is no longer justified, given the overwhelming published evidence for the role of brachytherapy to improve organ preservation for both radical treatment and palliation in gastrointestinal malignancies.

Local Excision for Early Rectal Cancer

Local excision is an established treatment for significant benign rectal tumours and early-stage cancers. It provides cure for most patients with pT1 disease, with minimum impact on quality of life. It is particularly suitable for elderly or comorbid patients. Local excision is associated with a risk of local recurrence, and this may vary from 5 to 30%, as determined by pathological risk factors. Recurrent cancer may be challenging to manage, but this may be mitigated by early detection with intensive surveillance and the use of adjuvant radiotherapy. This approach offers a realistic option for organ preservation in carefully selected early-stage disease compared with primary treatment with radiotherapy or total neoadjuvant treatment.

Planned organ preservation for elderly patients with rectal cancer using short course radiotherapy and a contact brachytherapy boost-an International multi-institution analysis

Background and purpose

The use of external beam radiotherapy (EBRT) and contact X-Ray brachytherapy (CXB) is emerging as an effective alternative in patients with early stage rectal cancer with the intent of organ preservation (OP). Short course radiotherapy (SCRT) is an alternative EBRT schedule for patients not fit for chemotherapy or for longer courses of EBRT. There are no multicentre studies that have reported on the outcomes of SCRT with a CXB boost, therefore we present these from patients from centres from the UK and Sweden.

Materials and methods

From the Guildford Colorectal Database or local databases, 258 patients who underwent SCRT and CXB with the intent of OP from five centres treated between 2007 and 2019 were identified. Response and survival data was analysed and presented.

Results

With a median age of 81, 226 patients were treated with radiotherapy alone (RTA) and 32 immediately after local excision (ILE). Median follow-up was 24 months. 70% and 97% of patients in the RTA and ILE groups respectively had a complete clinical response (cCR) after SCRT with CXB. Of those, local relapse was seen in 16% of the RTA and 3% of the ILE group. Median survival was 40 months after CXB in the RTA and 52 months in the ILE group. 94% of patients remained stoma-free to the point of latest follow-up.

Conclusion

This data suggests that CXB when combined with SCRT, in a mainly elderly and comorbid population, provides good palliation with stoma-avoidance. Oncological outcomes compare with previously published work. A greater focus is required on quality of life outcomes after OP.

Image-guided high-dose-rate brachytherapy for rectal cancer: technical note and first clinical experience on an organ-preserving approach

PURPOSE

As the population ages, the incidence of rectal cancer among elderly patients is rising. Due to the risk of perioperative morbidity and mortality, alternative nonoperative treatment options have been explored in elderly and frail patients who are clinically inoperable or refuse surgery.

METHODS

Here we present technical considerations and first clinical experience after treating a cohort of six rectal cancer patients (T1‑3, N0‑1, M0; UICC stage I-IIIB) with definitive external-beam radiation therapy (EBRT) followed by image-guided, endorectal high-dose-rate brachytherapy (HDR-BT). Patients were treated with 10-13 × 3 Gy EBRT followed by HDR-BT delivering 12-18 Gy in two or three fractions. Tumor response was evaluated using endoscopy and magnetic resonance imaging of the pelvis.

RESULTS

Median age was 84 years. All patients completed EBRT and HDR-BT without any high-grade toxicity (> grade 2). One patient experienced rectal bleeding (grade 2) after 10 weeks. Four patients (67%) demonstrated clinical complete response (cCR) or near cCR, there was one partial response, and one residual tumor and hepatic metastasis 8 weeks after HDR-BT. The median follow-up time for all six patients is 42 weeks (range 8-60 weeks). Sustained cCR without evidence of local regrowth has been achieved in all four patients with initial (n)cCR to date.

CONCLUSION

Primary EBRT combined with HDR-BT is feasible and well tolerated with promising response rates in elderly and frail rectal cancer patients. The concept could be an integral part of a highly individualized and selective nonoperative treatment offered to patients who are not suitable for or refuse surgery.

Targeted Radiotherapy Using Contact X-ray Brachytherapy 50 kV

Rectal adenocarcinoma is a quite radioresistant tumor. In order to achieve non-operative management (NOM) radiotherapy plays a major role. Targeted radiotherapy aiming at high precision 3D radiotherapy uses stereotactic image-guided external beam radiotherapy machines. To further safely increase the tumor dose, endocavitary brachytherapy (ECB) is an original approach. There are two different ways to perform such an ECB: contact X-ray brachytherapy (CXB) using a 50 kV X-ray generator with an X-ray tube positioned under eye guidance into the rectal cavity and high-dose-rate brachytherapy (HDRB) using iridium-192 sources positioned into the rectal cavity under image guidance. This study focused on CXB. CXB uses a small mobile generator that produces 50 kV X-rays with limited penetration. This technique is well adapted to accessible tumors of limited size and especially needs a high dose rate (≥15 Gy/minutes) for rectal tumors. It is performed on an ambulatory basis. A total dose between 80−110 Gy is delivered in 3−4 fractions over 3 to 6 weeks into a small volume (5 cm3). CXB was pioneered in the 1970s by Papillon using the Philips RT 50TM. Since 2009, the Papillon P50TM has been used in 11 institutions in Europe. The OPERA Phase III trial tested the hypothesis that a CXB boost (90 Gy/3 fr) compared to an EBRT boost (9 Gy/5 fr) for T2−T3 ab < 5 cm and N0−N1 < 8 mm will increase the 3-year organ preservation (OP) rate when combined with 45 Gy/5 weeks with concomitant capecitabine. Out of more than 300 patients with tumors < 3 cm (1962−1992), Papillon reported a long-term local control close to 85%. Similar results were published in Europe and USA at that time. The Lyon R96-2 Phase III trial (2004) demonstrated that, when combined with preoperative EBRT, a CXB boost (90 Gy/3 fr) significantly increased the rate of clinical complete response (cCR) and sphincter preservation, with some patients having OP at 10 years. With more than 2000 patients treated in Europe (2010−2020) using the Papillon 50TM, organ preservation appears possible in close to 80% of cases in selected early T2−T3. The OPERA trial closed after 141 inclusions (2015−2020) after an independent data monitoring committee recommendation because of promising results. At the 2-year follow-up (blinded data), the rate of cCR and OP were 77% and 72%, respectively, for the 141 tumors, and for T < 3 cm (61 pts), they were 86% and 85%, respectively, with good bowel function. The final results should be available in 2022. Organ preservation using NOM appears to be a promising approach for rectal cancer. A CXB boost with chemoradiotherapy in selected early T2−T3 could become an attractive option to achieve a planned OP. This approach should be proposed to well-informed patients after discussion in an MDT.

GEC ESTRO ACROP consensus recommendations for contact brachytherapy for rectal cancer

•

CXB appears to be an efficacious technique for rectal cancer treatment and may allow rectal preservation in selected patients.

•

These GEC ESTRO ACROP recommendations recommend dose schemes in for rectal CXB.

•

These recommendations advise reporting of tumour depth to enable future refinement of dose prescription and target definition.

•

The routine collection and publication of outcome data including patient reported outcomes (PROs) is recommended.

Purpose

To issue consensus recommendations for contact X-Ray brachytherapy (CXB) for rectal cancer covering pre-treatment evaluation, treatment, dosimetric issues and follow-up. These recommendations cover CXB in the definitive and palliative setting.

Methods

Members of GEC ESTRO with expertise in rectal CXB issued consensus-based recommendations for CXB based on literature review and clinical experience. Levels of evidence according to the Oxford Centre for Evidence based medicine guidance are presented where possible.

Results

The GEC ESTRO ACROP consensus recommendations support the use of CXB to increase the chances of clinical complete remission and cure for patients who are elderly with high surgical risk, surgically unfit or refusing surgery. For palliative treatment, the use of CXB is recommended for symptomatic relief and disease control. The use of CXB in an organ-preservation setting in surgically fit patients is recommended within the setting of a clinical trial or registry.

Conclusions

The GEC ESTRO ACROP recommendations for CXB are provided. Recommendations towards standardisation of reporting and prescription are given. Practitioners are encouraged to follow these recommendations and to develop further clinical trials to examine this treatment modality and increase the evidence base for its use. The routine collection of outcomes both clinical and patient-reported is also encouraged.