High-dose-rate intraluminal brachytherapy during preoperative chemoradiation for locally advanced rectal cancers

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.

Neoadjuvant Radiotherapy Dose Escalation in Locally Advanced Rectal Cancer: a Systematic Review and Meta-analysis of Modern Treatment Approaches and Outcomes

AIMS

Improving pathological complete response (pCR) rates after neoadjuvant chemoradiotherapy for locally advanced rectal cancer may facilitate surgery-sparing treatment paradigms. Radiotherapy boost has been linked to higher rates of pCR; however, outcomes in moderately escalated inverse-planning studies have not been systematically evaluated. We therefore carried out a systematic review and meta-analysis of radiation dose-escalation studies in the context of neoadjuvant therapy for locally advanced rectal cancer.

MATERIALS AND METHODS

A systematic search of Pubmed, EMBASE and Cochrane databases for synonyms of 'rectal cancer', 'radiotherapy' and 'boost' was carried out. Studies were screened for radiotherapy prescription >54 Gy. Prespecified quality assessment was carried out for meta-analysis inclusion suitability. Pooled estimates of pCR, acute toxicity (grade ≥3) and R0 resection rates were determined with random-effects restricted maximum-likelihood estimation. Heterogeneity was assessed with Higgins I² and Cochran Q statistic. Subset analysis examined outcomes in modern inverse-planning studies. Meta-regression with permutation correction was carried out for each outcome against radiation dose, radiotherapy technique, boost technique, chemotherapy intensification and other patient- and treatment-related cofactors.

RESULTS

Forty-nine primary and three follow-up publications were included in the systematic review. Pooled estimates of pCR, toxicity and R0 resection across 37 eligible publications (n = 1817 patients) were 24.1% (95% confidence interval 21.2-27.4%), 11.2% (95% confidence interval 7.2-17.0%) and 90.7% (95% confidence interval 87.9-93.8%). Within inverse-planning studies (17 publications, n = 959 patients), these rates were 25.7% (95% confidence interval 21.0-31.1%), 9.8% (95% confidence interval 4.6-19.7%) and 95.3% (95% confidence interval 91.6-97.4%). Regression analysis did not identify any significant predictor of pCR (P > 0.05).

CONCLUSIONS

Radiotherapy dose escalation above 54 Gy is associated with high rates of pCR and does not seem to increase the risk of acute grade ≥3 toxicity events. pCR rates approaching 25% may be achievable utilising moderate escalation (54-60 Gy) with modern inverse-planning techniques; however, a clear dose-response relationship was not identified in regression analysis and additional evidence is awaited given the prevalence of heterogenous single-arm studies to date.

Dosimetric Evaluation of a Flexible Dual Balloon-Constructed Applicator in Treating Anorectal Cancer

Background and Purpose:

Materials and Methods:

Results:

Conclusion:

Aims of combined modality therapy in rectal cancer (M0)

OPTIMIZING THE COST/BENEFIT RATIO OF TREATMENT: Evidence Based The aim of a cancer treatment is always to achieve the maximum of cure rate with a minimum of toxicity and best quality of life at an acceptable cost for the society. It is always a multifactorial challenge depending on the patient, the tumor, the doctor, and the society cultural and financial backgrounds. The goal is to find the best cost/benefit ratio between all possible strategies in agreement with a well-informed patient. In rectal cancer (M0) surgery is the cornerstone of treatment. Combined modality therapies aim at optimizing the cost/benefit ratio of possible strategies and only randomized trials can bring strong evidence regarding their results and recommendations. LESSONS FROM RANDOMIZED TRIALS: quite modest During the past decades many phase III trials have shown that: (1) neoadjuvant treatment even with "TME" surgery was better than adjuvant, (2) chemoradiotherapy (CRT) was better than RT alone, (3) long course CRT was probably more efficient (in terms of ypCR) than short course (25/5), and (4) capecitabine was as efficient as 5 FU but oxaliplatin was not adding benefit. Overall, the gains of nCRT remain modest and it is mainly a reduction in local relapse not exceeding 5 %, but no benefit in survival and neither in sphincter saving surgery has been proven. The way forwards organ preservation in case of CCR. Local control: can probably be improved for T4 tumors by RT dose escalation. Survival: can be increased by innovative medical treatment either before or after surgery.

TOXICITY

may be reduced by a less aggressive treatment in elderly. Conservative treatment: A new field of clinical research is to achieve "organ preservation" (and not only sphincter saving). To modify the surgical approach and preserve the whole rectum, neoadjuvant treatment must achieve safely a clinical complete response. As rectal adenocarcinoma is a relatively radioresistant tumor endocavitary irradiation (contact X-Ray) is a promising safe approach and this hypothesis will be addressed by the OPERA randomized trial.