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.

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.

Contact X-ray brachytherapy for rectal cancer: Past, present, and future

The Papillon experience and the Lyon R96-02 trial have shown that contact X-ray brachytherapy of 50kV is efficient and safe to achieve long term local control and organ preservation for cT1 and early cT2-3 rectal cancers. The OPERA trial, using the Papillon 50™ machine, brings further support to this preservation strategy for selected T2T3ab lesions. Future trials using a contact X-ray boost will try to consolidate and enlarge its place in organ preservation for rectal cancers.

Clinical response assessment after contact X-Ray brachytherapy and chemoradiotherapy for organ preservation in rectal cancer T2-T3 M0: The time/dose factor influence

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Treatment initiation of T2-T3 rectal cancers with Contact (CXB) provides a fast clinical complete response.

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In T2N0< 3 cm tumors, CXB first with chemoradiotherapy can achieve local control in more than 85%.

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The Phase III OPERA trial should bring robust data in favor of CXB as initial treatment of T2N0< 3 cm.

Introduction

A neoadjuvant treatment aimed at rectal preservation should achieve a clinical complete response. This study comparing neoadjuvant treatment initiated with Contact X-ray (CXB) or External Beam radiotherapy (EBRT) is evaluating the influence of the time/dose parameter on clinical response during the first six months.

Materials and methods

This retrospective consecutive series included T2-3 rectal adenocarcinoma staged using digital examination (DRE), endoscopy, magnetic radiation imaging and/or endorectal ultrasound. All patients were treated with organ preservation intent. Treatment protocol combined CXB (80–110 Gy/3–4 fractions) and EBRT ± concurrent capecitabine. In tumor exceeding 3.5 cm treatment was often initiated using EBRT. Clinical response was assessed (DRE, proctoscopy ± imaging) at very close interval between 2 weeks and 6 months after treatment initiation.

Results

Between 2002 and 2017, 61 patients (T2: 31; T3: 30) M0 (median age: 76 years) were treated. Treatment was initiated in 40 patients (T2: 28, T3: 12) with contact X-ray and in 21 (T2: 4, T3: 17) with EBRT. Using contact X-ray or EBRT first treatment, clinical complete (or near complete) response at week 14(±1) was respectively 88% [95CI:74–96] and 33% [95CI:15–57]. In multivariate analysis the treatment chronology was the most significant factor influencing cCR (OR: 7.53). At 6 months, with contact X-ray first all patients were in clinical complete response and five with EBRT remained in partial response. With 61 months median follow-up time, the local recurrence rate was 10% [95% CI: 6–16] at 5 years. T3 and fungating tumors were at higher risk of local recurrence. Organ preservation with good function was achieved in 95% of cases.

Conclusion

This non randomized study tends to show that in early T2-3 tumors, a strategy using upfront contact therapy, which is reducing the overall treatment time, is an option allowing a more favorable outcome than EBRT first.

Planned organ preservation for early T2-3 rectal adenocarcinoma: A French, multicentre study

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRT) and watch-and-wait policy as reported by Habr-Gama are references for organ preservation in rectal cancer. To increase the clinical complete response (cCR) and reduce the local recurrence rates, we report a retrospective analysis of a prospective cohort of selected T2-3 tumours treated in three French institutions using contact X-ray brachytherapy (CXB) with nCRT.

METHODS

Tumour selection was based on digital rectal examination (DRE), rigid rectoscopy, magnetic resonance imaging (MRI) and/or endorectal ultrasound. Adenocarcinoma T2-3 < 5 cm largest diameter, M0 were treated, all with organ preservation intent. CXB delivering 90 Gy/3 fractions/4 weeks was combined with CRT (capecitabine 50). Strict evaluation of tumour response using DRE and rectoscopy ± MRI was performed at regular interval with prolonged surveillance.

FINDINGS

Between 2002 and 2016, 74 consecutive patients were treated (median age: 74 years. T2: 45 and T3: 29). A cCR or near-cCR (mainly rectal wall ulceration) was noted at week 14 in 71 patients (95%). A local excision was performed in 13 patients. Of three partial responses (PRs), one salvage anterior resection was performed. With a median follow-up of 3 years, local recurrence (mainly in the rectal wall) was seen in seven patients. The 3-year local recurrence rate was 10%, and the cancer-specific survival, 88%. Two patients underwent radical proctectomy for PR or local recurrence and 96% preserved their rectum. Grade III acute toxicity was recorded in five patients. Rectal bleeding was the main late toxicity (grade III in 12%). Bowel function was scored as good or excellent in 85% of patients.

INTERPRETATION

Combining CXB and nCRT in selected early T2-T3 rectal cancers may safely provide a high rate of cCR, organ preservation, and good bowel function with a risk of local recurrence below 15%. Such an approach could be offered to operable patients as a planned option for organ preservation.

The role of contact X-ray brachytherapy in a monocentric series of 112 patients

BACKGROUND

Contact X-ray brachytherapy (CXB) has been used at Centre Antoine Lacassagne since 2002 to increase the chance of conservative treatment (organ or sphincter preservation) in rectal cancer. A consecutive series of 112 patients (pts) is reported.

METHODS

Three protocols were used in selected rectal adenocarcinomas. Group 1: T1 N0 treated with local excision (LE) followed by adjuvant CXB. Group 2: T2 or 'early' T3 N0 treated with CXB combined with chemoradiotherapy (CRT) followed by surveillance or LE. Group 3: distal 'locally advanced' T3 N0-2 treated with CXB and CRT before total proctectomy.

RESULTS

Group 1: 27 pt (pTis: 3; pT1: 21; pT2: 3). After LE with CXB alone (20 pt) or CXB + CRT (7 pt) one local recurrence occurred. Organ preservation was achieved in 26 pt (96%). Group 2: 45 pt (T1: 2; T2: 23; T3: 20) treated with CXB alone (4 pt) or CXB + CRT or external beam radiotherapy (EBRT) (41 pt). A clinical complete response (cCR) was observed in 43/45 (96%) and 3 pt developed a local recurrence (11% at 5 years). The specific survival was 76% at 5 years and the rate of organ preservation was 89% (40/45 pt) with good bowel function in 36 pt. Group 3: 40 pt, anterior resection (with sphincter preservation) was possible in 35 pt (86%) with a 3-year local recurrence of 6%.

CONCLUSION

CXB usually combined as a boost with CRT or EBRT may safely increase the chance of a conservative treatment (organ or sphincter preservation) for selected rectal cancers.