Definitive radical external beam radiotherapy for rectal cancer: evaluation of local effectiveness and risk of late small bowel damage

Definitive radiotherapy or chemoradiotherapy for distal rectal cancer with early stage of cT1-2N0

Objectives: Patients with early-stage distal rectal cancer, if treated with radical surgery, usually suffer a poor quality of life. Definitive radiotherapy or chemoradiotherapy may be another treatment option for them. The aim of this study was to evaluate the role of definitive external beam radiotherapy or chemoradiotherapy in treating distal rectal cancer with stage cT1-2N0.

Methods: We performed a retrospective study of 231 distal rectal cancer patients who were staged as cT1-2N0 from March 2002 to March 2015. All patients were treated by definitive radiotherapy or chemoradiotherapy. Overall survival (OS), progression-free survival (PFS), and short-term efficacy were analyzed. Multivariate analysis was performed to explore clinical factors significantly associated with PFS, local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) for the whole group.

Results: For the whole group, 135 patients (58.4%) achieved clinical complete response (cCR). The 5-year OS, PFS, and LRFS were 86.19%, 83.30%, and 92.50%, respectively. Patients with cCR acquired better survival than those with non-cCR. In multivariable analysis, it revealed that clinical stage, carcinoembryonic antigen (CEA level) and concurrent chemotherapy were independent predictors of PFS.

Conclusion: Definitive radiotherapy or chemoradiotherapy may be feasible in some early-stage distal rectal cancer regarding its favorable efficacy.

Optimal management of localized rectal cancer in older patients

In advising the optimal management for older patients, health care professionals try to balance the risks from frailty, vulnerability, and comorbidity against the patient's ultimate prognosis, potential functional outcomes and quality of life (QOL). At the same time it is important to involve the patient and incorporate their preferences. But how can we present and balance the potential downside of radical radiotherapy and risks of unsalvageable recurrence against the potential risks of postoperative morbidity and mortality associated with radical surgery? There are currently no nationally approved and evidence-based guidelines available to ensure consistency in discussions with older adults or frail and vulnerable patients. In this overview we hope to provide an insightful discussion of the relevant issues and options currently available.

Late small bowel toxicity after aggressive abdominopelvic intensity modulated radiation therapy

Purpose

We retrospectively analyzed late small bowel toxicity in patients who received abdominal or pelvic intensity modulated radiation therapy (IMRT) to the small bowel with a maximum dose greater than the generally accepted maximal tolerable dose of 45 Gy.

Methods and materials

All patients (N = 94) who received IMRT with a point dose of at least 45 Gy to tightly contoured small bowel between 2005 and 2014 at our institution were included. The median prescribed treatment dose was 70.2 Gy. The median follow-up was 20.1 months. Late small bowel toxicity was assessed using the Common Terminology Criteria for Adverse Events Version 3.0. Dosimetric variables and clinical factors were assessed for their relationship to small bowel toxicity.

Results

The median maximal small bowel point dose (D_max) was 6546.5 cGy. The estimated 5-year rates of freedom from at least grade 1, at least grade 2, and at least grade 3 late small bowel toxicity were 72.4% (95% confidence interval [CI], 60.7%-86.5%), 91.9% (95% CI, 84.1%-100%), and 93.6% (95% CI, 86.2%-100%), respectively. One patient (1.1%) developed grade 3 late toxicity, and 2 patients (2.1%) developed grade 4 late toxicity. Use of capecitabine/5-fluorouracil treatment was a significant predictor (P < 0.001) of at least grade 1 and at least grade 2 small bowel toxicity. No other clinical factors were associated with toxicity. None of the dose-volume parameters were significant predictors of small bowel toxicity.

Conclusion

It may be possible with IMRT to deliver high doses to small volumes of small bowel with low rates of significant long-term complications. Further studies should explore tolerable dose-volume relationships in cases in which aggressive abdominal or pelvic treatment may be warranted to treat the underlying malignancy.

Optimal Time Intervals between Pre-Operative Radiotherapy or Chemoradiotherapy and Surgery in Rectal Cancer?

BACKGROUND

In rectal cancer therapy, radiotherapy or chemoradiotherapy (RT/CRT) is extensively used pre-operatively to (i) decrease local recurrence risks, (ii) allow radical surgery in non-resectable tumors, and (iii) increase the chances of sphincter-saving surgery or (iv) organ-preservation. There is a growing interest among clinicians and scientists to prolong the interval from the RT/CRT to surgery to achieve maximal tumor regression and to diminish complications during surgery.

METHODS

The pros and cons of delaying surgery depending upon the aim of the pre-operative RT/CRT are critically evaluated.

RESULTS

Depending upon the clinical situation, the need for a time interval prior to surgery to allow tumor regression varies. In the first and most common situation (i), no regression is needed and any delay beyond what is needed for the acute radiation reaction in surrounding tissues to wash out can potentially only be deleterious. After short-course RT (5Gyx5) with immediate surgery, the ideal time between the last radiation fraction is 2-5 days, since a slightly longer interval appears to increase surgical complications. A delay beyond 4 weeks appears safe; it results in tumor regression including pathologic complete responses, but is not yet fully evaluated concerning oncologic outcome. Surgical complications do not appear to be influenced by the CRT-surgery interval within reasonable limits (about 4-12 weeks), but this has not been sufficiently explored. Maximum tumor regression may not be seen in rectal adenocarcinomas until after several months; thus, a longer than usual delay may be of benefit in well responding tumors if limited or no surgery is planned, as in (iii) or (iv), otherwise not.

CONCLUSION

A longer time interval after CRT is undoubtedly of benefit in some clinical situations but may be counterproductive in most situations. After short-course RT, long-term results from the clinical trials are not yet available to routinely recommend an interval longer than 2-5 days, unless the tumor is non-resectable at diagnosis.