Five-year results of a prospective and randomized study: experience with combined radiotherapy and surgery of primary rectal carcinoma

Preoperative radiotherapy and curative surgery for the management of localised rectal carcinoma

BACKGROUND

This is an update of the original review published in 2007.Carcinoma of the rectum is a common malignancy, especially in high income countries. Local recurrence may occur after surgery alone. Preoperative radiotherapy (PRT) has the potential to reduce the risk of local recurrence and improve outcomes in rectal cancer.

OBJECTIVES

To determine the effect of preoperative radiotherapy for people with localised resectable rectal cancer compared to surgery alone.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library; Issue 5, 2018) (4 June 2018), MEDLINE (Ovid) (1950 to 4 June 2018), and Embase (Ovid) (1974 to 4 June 2018). We also searched ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) for relevant ongoing trials (4 June 2018).

SELECTION CRITERIA

We included randomised controlled trials comparing PRT and surgery with surgery alone for people with localised advanced rectal cancer planned for radical surgery. We excluded trials that did not use contemporary radiotherapy techniques (with more than two fields to the pelvis).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the 'Risk of bias' domains for each included trial, and extracted data. For time-to-event data, we calculated the Peto odds ratio (Peto OR) and variances, and for dichotomous data we calculated risk ratios (RR) using the random-effects method. Potential sources of heterogeneity hypothesised a priori included study quality, staging, and the use of total mesorectal excision (TME) surgery.

MAIN RESULTS

We included four trials with a total of 4663 participants. All four trials reported short PRT courses, with three trials using 25 Gy in five fractions, and one trial using 20 Gy in four fractions. Only one study specifically required TME surgery for inclusion, whereas in another study 90% of participants received TME surgery.Preoperative radiotherapy probably reduces overall mortality at 4 to 12 years' follow-up (4 trials, 4663 participants; Peto OR 0.90, 95% CI 0.83 to 0.98; moderate-quality evidence). For every 1000 people who undergo surgery alone, 454 would die compared with 45 fewer (the true effect may lie between 77 fewer to 9 fewer) in the PRT group. There was some evidence from subgroup analyses that in trials using TME no or little effect of PRT on survival (P = 0.03 for the difference between subgroups).Preoperative radiotherapy may have little or no effect in reducing cause-specific mortality for rectal cancer (2 trials, 2145 participants; Peto OR 0.89, 95% CI 0.77 to 1.03; low-quality evidence).We found moderate-quality evidence that PRT reduces local recurrence (4 trials, 4663 participants; Peto OR 0.48, 95% CI 0.40 to 0.57). In absolute terms, 161 out of 1000 patients receiving surgery alone would experience local recurrence compared with 83 fewer with PRT. The results were consistent in TME and non-TME studies.There may be little or no difference in curative resection (4 trials, 4673 participants; RR 1.00, 95% CI 0.97 to 1.02; low-quality evidence) or in the need for sphincter-sparing surgery (3 trials, 4379 participants; RR 0.99, 95% CI 0.94 to 1.04; I² = 0%; low-quality evidence) between PRT and surgery alone.Low-quality evidence suggests that PRT may increase the risk of sepsis from 13% to 16% (2 trials, 2698 participants; RR 1.25, 95% CI 1.04 to 1.52) and surgical complications from 25% to 30% (2 trials, 2698 participants; RR 1.20, 95% CI 1.01 to 1.42) compared to surgery alone.Two trials evaluated quality of life using different scales. Both studies concluded that sexual dysfunction occurred more in the PRT group. Mixed results were found for faecal incontinence, and irradiated participants tended to resume work later than non-irradiated participants between 6 and 12 months, but this effect had attenuated after 18 months (low-quality evidence).

AUTHORS' CONCLUSIONS

We found moderate-quality evidence that PRT reduces overall mortality. Subgroup analysis did not confirm this effect in people undergoing TME surgery. We found consistent evidence that PRT reduces local recurrence. Risk of sepsis and postsurgical complications may be higher with PRT.The main limitation of the findings of the present review concerns their applicability. The included trials only assessed short-course radiotherapy and did not use chemotherapy, which is widely used in the contemporary management of rectal cancer disease. The differences between the trials regarding the criteria used to define rectal cancer, staging, radiotherapy delivered, the time between radiotherapy and surgery, and the use of adjuvant or postoperative therapy did not appear to influence the size of effect across the studies.Future trials should focus on identifying participants that are most likely to benefit from PRT especially in terms of improving local control, sphincter preservation, and overall survival while reducing acute and late toxicities (especially rectal and sexual function), as well as determining the effect of radiotherapy when chemotherapy is used and the optimal timing of surgery following radiotherapy.

Evaluation of biologic effective dose and schedule of fractionation for preoperative radiotherapy for rectal cancer: meta-analyses and meta-regression

PURPOSE

To evaluate whether the risk of local recurrence depends on the biologic effective dose (BED) or fractionation dose in patients with resectable rectal cancer undergoing preoperative radiotherapy (RT) compared with surgery alone.

METHODS AND MATERIALS

A meta-analysis of randomized controlled trials (RCTs) was performed. The MEDLINE, Embase, CancerLit, and Cochrane Library databases were systematically searched for evidence. To evaluate the dose-response relationship, we conducted a meta-regression analysis. Four subgroups were created: Group 1, RCTs with a BED >30 Gy(10) and a short RT schedule; Group 2, RCTs with BED >30 Gy(10) and a long RT schedule; Group 3, RCTs with BED ≤ 30 Gy(10) and a short RT schedule; and Group 4, RCTs with BED ≤ 30 Gy(10) and a long RT schedule.

RESULTS

Our review identified 21 RCTs, yielding 9,097 patients. The pooled results from these 21 randomized trials of preoperative RT showed a significant reduction in mortality for groups 1 (p = .004) and 2 (p = .03). For local recurrence, the results were also significant in groups 1 (p = .00001) and 2 (p = .00001).The only subgroup that showed a greater sphincter preservation (SP) rate than surgery was group 2 (p = .03). The dose-response curve was linear (p = .006), and RT decreased the risk of local recurrence by about 1.7% for each Gy(10) of BED.

CONCLUSION

Our data have shown that RT with a BED of >30 Gy(10) is more efficient in reducing local recurrence and mortality rates than a BED of ≤ 30 Gy(10), independent of the schedule of fractionation used. A long RT schedule with a BED of >30 Gy(10) should be recommended for sphincter preservation.

Pre-operative radiotherapy and curative surgery for the management of localized rectal carcinoma

BACKGROUND

Preoperative radiotherapy (PRT) has become part of standard practice offered to improve treatment outcomes in patients with rectal cancer.

OBJECTIVES

To determine if PRT improves outcome for patients with localized resectable rectal cancer and how it compared with other adjuvant or neoadjuvant strategies.

SEARCH STRATEGY

A computerized search was performed December 2006 on MEDLINE (from 1966 to December 2006) and the Cochrane Central Register of Controlled Trials (CENTRAL), conference proceedings, using MeSH and textwords where appropriate to identify randomized trials in PRT and rectal cancer. In addition, MetaRegister of Clinical Trials was searched for ongoing trials.

SELECTION CRITERIA

Randomized trials with a PRT arm versus surgery alone, or other neoadjuvant or adjuvant (NA/A) strategies, targeted patients with localized rectal cancer planned for radical surgery were included.

DATA COLLECTION AND ANALYSIS

Trials were selected, data extracted and quality assessed by 2 authors. Quality was assessed using a 14 point checklist. Summary statistics included Hazard ratios and variances (for the outcomes: overall (OA) mortality, cause specific (CS) mortality, any recurrence and local recurrences (LR)) and Odds Ratio (OR) for other outcomes. Potential sources of heterogeneity hypothesized a priori included study quality, biological effective dose (BED), radiotherapy RT technique, and total mesorectal excision (TME) surgery.

MAIN RESULTS

Nineteen trials compared PRT versus surgery alone. Overall (OA) mortality was marginally improved HR 0.93 [95% CI -0.87-1](absolute difference is 2% if the expected survival rate is 60%). Local recurrence (LR) was improved but the magnitude of benefit was heterogeneous across trials. Sensitivity analyses suggested greater benefits in patients treated with BED>30Gy(10) and multiple field RT techniques. There was significantly more pelvic or perineal wound infection, late rectal and sexual dysfunction. Nine trials compared PRT vs. other NA/A. Available evidence did not support an OA mortality or sphincter preserving benefit with the use of combined chemoradiotherapy (CRT) or selective postoperative RT. CRT provides incremental benefit for local control compared with PRT, which was independent of the timing of the CT. There was no significant difference in outcome for different intervals between RT and surgery (2 vs. 8 wk). Dose escalation with endocavitary boost showed significant effect on sphincter preservation.

AUTHORS' CONCLUSIONS

Optimal PRT improves LR, OA mortality, but no increase in sphincter sparing procedure. CRT further increases local control. If the objective is to increase the incidence of sphincter sparing surgery, endocavitary boost showed the most promise. Strategies with the potential to improve outcomes, especially OAS and sphincter sparing while reducing acute and late toxicities (rectal and sexual function) are needed to guide future strategy designs.

The use of preoperative radiotherapy in the management of patients with clinically resectable rectal cancer: a practice guideline

BACKGROUND

This systematic review with meta-analysis was designed to evaluate the literature and to develop recommendations regarding the use of preoperative radiotherapy in the management of patients with resectable rectal cancer.

METHODS

The MEDLINE, CANCERLIT and Cochrane Library databases, and abstracts published in the annual proceedings of the American Society of Clinical Oncology and the American Society for Therapeutic Radiology and Oncology were systematically searched for evidence. Relevant reports were reviewed by four members of the Gastrointestinal Cancer Disease Site Group and the references from these reports were searched for additional trials. External review by Ontario practitioners was obtained through a mailed survey. Final approval of the practice guideline report was obtained from the Practice Guidelines Coordinating Committee.

RESULTS

Two meta-analyses of preoperative radiotherapy versus surgery alone, nineteen trials that compared preoperative radiotherapy plus surgery to surgery alone, and five trials that compared preoperative radiotherapy to alternative treatments were obtained. Randomized trials demonstrate that preoperative radiotherapy followed by surgery is significantly more effective than surgery alone in preventing local recurrence in patients with resectable rectal cancer and it may also improve survival. A single trial, using surgery with total mesorectal excision, has shown similar benefits in local recurrence.

CONCLUSION

For adult patients with clinically resectable rectal cancer we conclude that: Preoperative radiotherapy is an acceptable alternative to the previous practice of postoperative radiotherapy for patients with stage II and III resectable rectal cancer. Both preoperative and postoperative radiotherapy decrease local recurrence but neither improves survival as much as postoperative radiotherapy combined with chemotherapy. Therefore, if preoperative radiotherapy is used, chemotherapy should be added postoperatively to at least patients with stage III disease.

Adjuvant radiotherapy for rectal cancer: a systematic overview of 8,507 patients from 22 randomised trials

BACKGROUND

At least 28 randomised, controlled trials have compared outcomes of surgery for rectal cancer combined with preoperative or postoperative radiotherapy with those of surgery alone. We have done a collaborative meta-analysis of these results to give a more balanced view of the total evidence and to increase statistical precision.

METHODS

We centrally checked and analysed individual patient data from 22 randomised comparisons between preoperative (6,350 patients in 14 trials) or postoperative (2157 in eight trials) radiotherapy and no radiotherapy for rectal cancer.

FINDINGS

Overall survival was only marginally better in patients who were allocated to radiotherapy than in those allocated to surgery alone (62% vs 63% died; p=0.06). Rates of apparently curative resection were not improved by preoperative radiotherapy (85% radiotherapy vs 86% control). Yearly risk of local recurrence was 46% (SE 6) lower in those who had preoperative radiotherapy than in those who had surgery alone (p=0.00001), and 37% (10) lower in those who had postoperative treatment than those who had surgery alone (p=0.002). Fewer patients who had preoperative radiotherapy died from rectal cancer than did those who had surgery alone (45% vs 50%, respectively, p=0.0003), but early (</=1 year after treatment) deaths from other causes increased (8% vs 4% died, p<0.0001).

INTERPRETATION

Preoperative radiotherapy (at biologically effective doses >/=30 Gy) reduces risk of local recurrence and death from rectal cancer. If safety can be improved without compromising effectiveness, then overall survival would be moderately improved by use of preoperative radiotherapy, especially for young, high risk patients. Postoperative radiotherapy also reduces local recurrence, but short preoperative radiation schedules seem to be at least as effective as longer schedules.

Analysis of local recurrence rates after surgery alone for rectal cancer

Local recurrence (LR) continues to be a major problem following surgical treatment for rectal cancer, and proposed ways of reducing this remain controversial. The aim of this study was to review results from published surgical series in which adjuvant therapies were not used. A Medline search identified series published between January 1982 and December 1992 with follow-up on at least 50 patients with rectal cancer treated surgically for cure, without adjuvant therapy. Fifty one papers reported follow-up on 10,465 patients with a median LR rate of 18.5%. LR was 8.5%, 16.3% and 28.6% in Dukes' A, B and C patients respectively, 16.2% following anterior resection and 19.3% following abdominoperineal resection. Nine papers (1,176 patients) reported LR rates of 10% or less. LR was 7.1% in 1,033 patients having total mesorectal excision and 12.4% in 476 patients having extended pelvic lymphadenectomy. Routine cytocidal stump washout in 1,364 patients was associated with 12.2% LR, however a higher proportion (41%) also underwent total mesorectal excision. In 52% of cases, LR was reported to have occurred with no evidence of disseminated disease. Surgical technique is an important determinant of LR risk. LR rates of 10% or less can be achieved with surgery alone in expert hands.

Low-dose preoperative radiation postpones recurrences in operable rectal cancer. Results of a randomized multicenter trial in western Norway

A randomized, multicenter clinical trial was conducted in Western Norway to study the effectiveness of preoperative radiation therapy in operable rectal cancer, given at a dosage of 3150 cGy in 18 fractions, 2 to 3 weeks before radical surgery. Three hundred nine patients were entered into the trial between May 1976 and December 1985. After radiation no tumor was seen in 4.5% of the patients. There was no increased morbidity or mortality at surgery. The 5-year survival for evaluable patients was 57.5% in the control group and 56.7% in the radiotherapy group. For patients operated on for cure the 5-year survival was 60.9% and 64.2% in the control group and radiotherapy group, respectively. Radiation significantly delayed both local and distant recurrences in patients in the radiation group who had curative resection from 13.3 months in controls to 27.1 months. The local recurrence rate in the corresponding groups was 21.1% and 13.7%, respectively. We conclude that higher preoperative radiation doses should be used in new trials as a higher dosage may transform the observed positive effects into a survival benefit.