Sphincter Preservation in Four Consecutive Phase II Studies of Preoperative Chemoradiation: Analysis of 247 T3 Rectal Cancer Patients

Colorectal Cancer in the Elderly Patient: The Role of Neo-adjuvant Therapy

Background

Neoadjuvant chemoradiotherapy has a significant role in downstaging cancer. It improves the local control of the disease and can make conservative resection of rectal cancer possible.

Methods

We enrolled 114 patients with subperitoneal rectal cancer who underwent neoadjuvant chemoradio-therapy and radical excision with total mesorectal excision (TME). The primary endpoint was oncological outcomes and the secondary endpoint was surgical outcomes.We evaluate the experience of a multidisciplinary team and the role of neoadjuvant chemoradiotherapy in integrated treatment of cancer of the subperitoneal rectum.

Results

Surgical procedures performed were abdominal perineal resection in 4 cases (3.5%), anterior resection in 89 cases (78%), Hartmann’s procedure in 5 cases (4.4%), and ultralow resection with coloanal anastomosis and diverting stoma in 16 patients (14%).

Local recurrence occurred in 6 patients (5.2%), the overall survival was 71.9% at 5 years and disease-free survival was about 60%.

Conclusions

The effect of pathological downstaging amounted to 58.8%, including cPR. The pathologic complete remission occurred in 8.8% of cases.

The outcomes of neoadjuvant therapy can be achieved when this treatment is associated with correct surgical technique with TME and the prognosis is defined by an anatomopathological examination performed according to Quirke’s protocol.

Phase 2 Neoadjuvant Treatment Intensification Trials in Rectal Cancer: A Systematic Review

PURPOSE

Multiple phase 2 trials of neoadjuvant treatment intensification in locally advanced rectal cancer have reported promising efficacy signals, but these have not translated into improved cancer outcomes in phase 3 trials. Improvements in phase 2 trial design are needed to reduce these false-positive signals. This systematic review evaluated the design of phase 2 trials of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification in locally advanced rectal cancer.

METHODS AND MATERIALS

The PubMed, EMBASE, MEDLINE, and Cochrane Library databases were searched for published phase 2 trials of neoadjuvant treatment intensification from 2004 to 2016. Trial clinical design and outcomes were assessed, with statistical design and compliance rated using a previously published system. Multivariable meta-regression analysis of pathologic complete response (pCR) was conducted.

RESULTS

We identified 92 eligible trials. Patients with American Joint Committee on Cancer stage II and III equivalent disease were eligible in 87 trials (94.6%). In 43 trials (46.7%), local staging on magnetic resonance imaging was mandated. Only 12 trials (13.0%) were randomized, with 8 having a standard-treatment control arm. Just 51 trials (55.4%) described their statistical design, with 21 trials (22.8%) failing to report their sample size derivation. Most trials (n=84, 91.3%) defined a primary endpoint, but 15 different primary endpoints were used. All trials reported pCR rates. Only 38 trials (41.3%) adequately reported trial statistical design and compliance. Meta-analysis revealed a pooled pCR rate of 17.5% (95% confidence interval, 15.7%-19.4%) across treatment arms of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification and substantial heterogeneity among the reported effect sizes (I² = 55.3%, P<.001). Multivariable meta-regression analysis suggested increased pCR rates with higher radiation therapy doses (adjusted P=.025).

CONCLUSIONS

Improvement in the design of future phase 2 rectal cancer trials is urgently required. A significant increase in randomized trials is essential to overcome selection bias and determine novel schedules suitable for phase 3 testing. This systematic review provides key recommendations to guide future treatment intensification trial design in rectal cancer.

Preoperative intensified radiochemotherapy for rectal cancer: experience of a single institution

PURPOSE

The aim of our study was to evaluate the feasibility and the effectiveness of an intensified neoadjuvant protocol with the addition of weekly oxaliplatin in the preoperative strategy of rectal cancer treatment.

PATIENTS AND METHODS

Patients with locally advanced rectal cancer received continous infusion 5-Fluorouracil (5-FU) 200 mg/m(2)/day in combination with weekly oxaliplatin at a dose of 50 mg/m(2). Doses of radiotherapy were 45 Gy to the whole pelvis plus 5.4-9 Gy to the tumour mass. The primary end-points of the study were evaluation of toxicity, compliance with radiotherapy and chemotherapy, downstaging, pathological complete response (pCR) and the rate of sphincter preservation for distal cancers. Secondary end-points were relapse-free and overall survival.

RESULTS

From November 2006 to June 2009, 51 patients were enrolled into the study. Compliance with chemotherapy was 80%. The incidence of G3 diarrhoea and proctitis were 17.6% and 21.5%, respectively. Surgery was performed in 48 patients with 100% R0 resection. 76.4% of low-lying tumours underwent conservative treatment. Seventy-nine percent of patients were downstaged: T and N downstaging were observed in 71% and 75% of patients, respectively. A pCR was obtained in 11 (22.9%) patients.

CONCLUSIONS

Intensification of neoadjuvant treatment for rectal cancer with the addition of weekly oxaliplatin is feasible, with remarkable rates of downstaging and pathological complete response. Data on sphincter preservation for distal cancers were excellent. Phase III trials with a longer follow-up will establish whether this good outcome in terms of surrogate end-points will translate into better rates of disease-free and overall survival.

Management of rectal cancer: short- vs. long-course preoperative radiation

There is considerable debate on the optimum approach to neoadjuvant therapy in rectal cancer. This review of major published studies of short-course preoperative radiation and the more conventional approach of long-course neoadjuvant chemoradiation was undertaken in an effort to understand the potential advantages and disadvantages of each of these approaches. Studies were evaluated with regard to patient selection, clinical outcomes, and toxicities. Short-course preoperative radiation has shown a clear advantage over surgery alone in reducing local recurrence rates and improving survival of patients with rectal cancer. However, studies using short-course preoperative treatment have included a significant number of early (30%; Stage I/II) and more proximal cancers yet appear to have higher positive margin rates, higher abdominoperineal resection rates, and lower aggregate survival than patients treated with long-course neoadjuvant chemoradiation. Although long-course preoperative chemoradiation is associated with higher rates of reversible acute toxicity, there appears to be more significant and a higher rate of late gastrointestinal toxicity observed in short-course preoperative radiation studies. Patient convenience and lower cost of treatment, however, can be a significant advantage in using a short-course treatment schedule. Selective utilization of either of these approaches should be based on extent of disease and goals of treatment. Patients with distal cancers or more advanced disease (T3/T4) appear to have better outcomes with neoadjuvant chemoradiation, especially where downstaging of disease is critical for more complete surgical resection and sphincter preservation.

Randomized, multicenter, phase IIb study of preoperative chemoradiotherapy in T3 mid-distal rectal cancer: raltitrexed + oxaliplatin + radiotherapy versus cisplatin + 5-fluorouracil + radiotherapy

PURPOSE

To prospectively compare the rates of pathologic response, acute toxicity, and sphincter preservation with two different schedules of preoperative chemoradiotherapy in patients with cT3 mid-distal rectal cancer.

METHODS AND MATERIALS

Patients with cT3 and/or N+ resectable rectal carcinoma were randomized to receive one of the two following chemoradiotherapy regimens: cisplatin, 5-fluorouracil, and radiotherapy (PLAFUR) or raltitrexed, oxaliplatin, and radiotherapy (TOMOX-RT). For PLAFUR, cisplatin (60 mg/m(2)) was given on Days 1 and 29, with a prolonged infusion of 5-fluorouracil (1,000 mg/m(2)) on Days 1-4 and 29-32, plus concurrent radiotherapy (50.4 Gy in 1.8-Gy fractions daily). For TOMOX-RT, raltitrexed (3 mg/m(2)) and oxaliplatin (130 mg/m(2)) was given on Days 1, 19, and 38 with the same radiotherapy regimen as used for PLAFUR. Surgery was performed 6-8 weeks after completion of chemoradiotherapy. All pathologic specimens were reviewed by a designated expert pathologist. The primary endpoint of this study was pathologic tumor downstaging (defined as tumor regression grade 1-2). Secondary endpoints included the incidence of ypT0, clinical tumor downstaging, sphincter-saving surgery, and acute treatment-related toxicity.

RESULTS

Between 2002 and 2005, 164 patients were accrued in 10 Italian centers, 83 patients in the PLAFUR arm and 81 in the TOMOX-RT arm. Overall, tumor regression grade 1-2 was observed in 76 patients (46.4%) and ypT0 in 49 (29.9%). The tumor regression grade 1-2 rate was 41.0% vs. 51.9% (p = 0.162) and the ypT0 rate was 24.1% vs. 35.8% (p = 0.102) for the PLAFUR vs. TOMOX-RT arm, respectively. The overall rate of tumor regression grade 1 and ypN+ was 4.6%. The occurrence of ypT downstaging was significantly greater in the TOMOX-RT arm (p = 0.035). Grade 3-4 acute toxicity occurred in 19 patients (11.6%): 7.1% in the PLAFUR arm vs. 16.4% in the TOMOX-RT arm. Sphincter-saving surgery was performed in 143 patients (87.2%) overall: 87.9% in the PLAFUR arm and 86.4% in the TOMOX-RT arm.

CONCLUSIONS

Compared with the PLAFUR regimen, TOMOX-RT achieved a greater incidence of downstaging but was associated with a correspondingly greater rate of acute Grade 3+ toxicity. With longer follow-up, the local control and survival rates might offer additional guidance as to the choice of regimen.