Pre- or postoperative radiotherapy in rectal cancer--more to learn?

Concomitant boost radiotherapy and multidrug chemotherapy in the neoadjuvant treatment of locally advanced rectal cancer: results of a phase II study

BACKGROUND

An intensified multidrug chemotherapy regimen (raltitrexed plus oxaliplatin, Tom-Ox) plus concomitant boost radiotherapy, in the neoadjuvant treatment of locally advanced rectal cancer patients, was shown feasible in our previous study. The aim of this study was to evaluate the efficacy in terms of pathologic complete response to pre-operative therapy.

MATERIAL AND METHODS

A Phase II study was designed and clinical stage T3-T4 and/ or N ≥ 1 patients were treated with concomitant boost radiotherapy (55 Gy/5 weeks) plus concurrent chemotherapy (Tom-Ox). The primary endpoint was the assessment of efficacy in terms of clinical and pathologic response to pre-operative therapy. According to the Gehan's design study, 25 patients were enrolled. Toxicity was assessed according to the RTOG-EORTC and CTCAE v.3.0 criteria.

RESULTS

Twenty-five consecutive patients were treated. Twenty-two of the 25 (88%) patients had a partial clinical response at the time of pre-operative magnetic resonance imaging (MRI). Only one patient showed progressive systemic disease at pre-surgical revaluation and was subjected only to biopsy to evaluate pathological response. Twenty-four patients (96%) underwent surgery. Overall, pathologic complete response was observed in eight patients (32%; CI 0.95:12-55%) and only microscopic tumor foci (pTmic) in two patients (pT0-mic: 40%; CI 0.95:18-63%). Nineteen patients (76%) showed tumor down-staging. Proctitis and/or diarrhea were the most frequent acute side effects experienced. Eighteen patients had grade 1-2 toxicity (77%); whereas two patients experienced grade 3 toxicity (8%). Two-year Local control and actuarial Disease Free Survival were 100% and 91%, respectively. CONCLUSION. An intensified regimen of concomitant boost radiotherapy plus concurrent raltitrexed and oxaliplatin, can be safely administered in patients with locally advanced rectal cancer. This regimen produces high rates of pathological complete response. Based on available data, this type of treatment could be offered to patients with more advanced tumors (T4 or local recurrence).

Magnetic resonance imaging (MRI) in rectal cancer: a comprehensive review

Magnetic resonance imaging (MRI) has established itself as the primary method for local staging in patients with rectal cancer. This is due to several factors, most importantly because of the ability to assess the status of circumferential resection margin. There are several newer developments being introduced continuously, such as diffusion-weighted imaging and imaging with 3 T. Assessment of loco-regional lymph nodes has also been investigated extensively using different approaches, but more work needs to be done. Finally, evaluation of tumours during or after preoperative treatment is becoming an everyday reality. All these new aspects prompt a review of the most recent advances and opinions. In this review, a comprehensive overview of the current status of MRI in the loco-regional assessment and management of rectal cancer is presented. The findings on MRI and their accuracy are reviewed based on the most up-to-date evidence. Optimisation of MRI acquisition and relevant regional anatomy are also presented, based on published literature and our own experience.

Adjuvant and neoadjuvant chemoradiation or radiotherapy in rectal cancer--a review focusing on open questions

BACKGROUND

The therapy of rectal cancer has been a matter of debate since decades, especially with regard to the benefits of neoadjuvant or adjuvant therapies. Principles of additional therapies have been established nearly two decades ago and are questioned nowadays on the basis of more recently modified operative techniques. Benefits and sequelae of therapies have to be balanced against each other, and it seems somewhat likely that a more differentiated strategy than simply stating that every patient with stage II and III rectal cancer needs chemoradiation or radiotherapy will, in long term, be recommended.

CONCLUSION

It should be kept in mind that results of centers of excellence and of phase-III studies with their positively selected patient populations are not representative for all the patients with rectal cancer and physicians treating them.

Swedish Rectal Cancer Trial: long lasting benefits from radiotherapy on survival and local recurrence rate

PURPOSE

To evaluate the long-term effects on survival and recurrence rates of preoperative radiotherapy in the treatment of curatively operated rectal cancer patients.

PATIENTS AND METHODS

Of 1,168 randomly assigned patients in the Swedish Rectal Cancer Trial between 1987 and 1990, 908 had curative surgery; 454 of these patients had surgery alone, and 454 were administered preoperative radiotherapy (25 Gy in 5 days) followed by surgery within 1 week. Follow-up was performed by matching against three Swedish nationwide registries (the Swedish Cancer Register, the Hospital Discharge Register, and the Cause of Death Register).

RESULTS

Median follow-up time was 13 years (range, 3 to 15 years). The overall survival rate in the irradiated group was 38% v 30% in the nonirradiated group (P = .008). The cancer-specific survival rate in the irradiated group was 72% v 62% in the nonirradiated group (P = .03), and the local recurrence rate was 9% v 26% (P < .001), respectively. The reduction of local recurrence rates was observed at all tumor heights, although it was not statistically significant for tumors greater than 10 cm from the anal verge.

CONCLUSION

Preoperative radiotherapy with 25 Gy in 1 week before curative surgery for rectal cancer is beneficial for overall and cancer-specific survival and local recurrence rates after long-term follow-up.

Long-term anorectal dysfunction after postoperative radiotherapy for rectal cancer

PURPOSE

Adjuvant radiotherapy in the treatment of rectal cancer has been shown to increase long-term morbidity causing severe anorectal dysfunction with physiologic changes whose interaction remains poorly understood. This study examines long-term anorectal morbidity from adjuvant postoperative radiotherapy.

METHODS

In a prospective study, patients with Dukes B or C rectal carcinoma were randomized to postoperative radiotherapy or no adjuvant treatment after anterior resection. The long-term effect of radiotherapy on anorectal function in a subset of surviving patients was assessed from a questionnaire on subjective symptoms and from physiology laboratory evaluation and flexible sigmoidoscopy.

RESULTS

Twelve of 15 patients (80 percent) treated with radiotherapy had increased bowel frequency compared with 3 of the 13 patients (23 percent) who did not have radiation therapy (P = 0.003). The former group had loose or liquid stool more often (60 vs. 23 percent, P = 0.05), had fecal incontinence more often (60 vs. 8 percent, P = 0.004), and wore pad more often (47 vs. 0 percent, P = 0.004). They also experienced fecal urgency and were unable to differentiate stool from gas more often. Endoscopy revealed a pale and atrophied mucosa and telangiectasias in the irradiated patients. Anorectal physiology showed a reduced rectal capacity (146 vs. 215 ml, P = 0.03) and maximum squeeze pressure (59 vs. 93 cm H2O, P = 0.003) in the radiotherapy group. Impedance planimetry demonstrated a reduced rectal distensibility in these patients (P < 0.0001).

CONCLUSIONS

Adjuvant postoperative radiotherapy after anterior resection causes severe long-term anorectal dysfunction, which is mainly the result of a weakened, less sensitive anal sphincter and an undistensible rectum with reduced capacity.

Role of adjuvant chemoradiotherapy for abdominal malignancies

The rationale for combining surgery, radiotherapy and chemotherapy is discussed and the clinical results seen with surgery and adjuvant radiochemotherapy in three major abdominal malignancies are reviewed. A systematic approach to the literature was used. In rectal cancer, postoperative radiochemotherapy is an established treatment, although there is weak scientific support for the combined approach. The same clinical gains can also be reached much more easily with preoperative radiotherapy. In gastric cancer, a recent large randomised trial showed improved survival from postoperative radiotherapy. This was not seen in a comparably large trial in pancreatic cancer. The reasons for the different results according to primary tumour site are discussed. It is argued that adequate coverage of all adjacent regional lymph node stations is necessary for an effect on survival.

The role of preoperative and postoperative radiotherapy in rectal cancer

Radiotherapy has an important role to play when used in addition to surgery in primary and recurrent rectal cancer. In primary resectable rectal cancer, a large number of randomized trials have shown that preoperative radiotherapy can slightly improve survival and can decrease local recurrence rates by more than half. Postoperative radiotherapy may also decrease the risk of local failure although with less efficacy. A preoperative schedule of 5 Gy/day for 5 out of 7 days is a convenient and low-toxic treatment, provided it is not given with 2 beams to large volumes, and it appears to be at least as effective as postoperative radiochemotherapy, generally meaning 6 months of therapy with 5 weeks of radiation. The schedule of 5 Gy/day for 5 days also reduces local recurrences with total mesorectal excision. It is unlikely that preoperative radiochemotherapy will substantially increase the chances of a sphincter-preserving procedure in a low-lying rectal cancer and that the long-term function will be adequate even if this is believed by many. In primary nonresectable or locally recurrent rectal cancer, preoperative radiotherapy may downsize or downstage the tumor so that it can be resected. Scientific support that radiochemotherapy is more efficient than radiotherapy alone in this situation is weak.

Emerging standards of radiotherapy combined with radical rectal cancer surgery

For patients with resectable rectal cancer treated with total mesorectal excision, the routine use of radiotherapy should be omitted for stage I of the disease and for lesions located higher than 10 cm from the anal verge. Preoperative radiotherapy may be considered for all patients with a lesion with deep perirectal fat infiltration located in the lower two thirds of the rectum. The other option is to offer postoperative radiotherapy for patients with a positive surgical margin, N+ stage disease, mesorectal tumour implants, high tumour grade, perineural invasion, extramuscular blood and lymphatic vessel invasion and with inadvertent tumour perforation. The lower risk of small bowel damage and probable higher efficacy are arguments for the use of preoperative radiotherapy instead of postoperative radiotherapy. The impairment of anorectal function appears to be most frequent late postirradiation sequel. The analysis of acute complications (including toxic deaths) compliance, cost and convenience favours 5 x 5 Gy preoperative irradiation with immediate surgery for patients with resectable tumours in comparison to other commonly used schemes of radiotherapy. These advantages should be weighed against approximately 1.5% risk of late neurotoxicity. There is no clear answer to the question whether preoperative conventional radio(chemo)therapy offers an advantage in sphincter preservation. To answer this question, the results of two ongoing randomised trials are awaited. For patients with unresectable cancers, long-term preoperative radio(chemo)therapy with delayed surgery is a preferable scheme. The total mesorectal irradiation should be employed for mid- and low-lying lesions. Therefore, during radiotherapy planning, a contrast enema should be used to identify the anorectal ring, anatomically corresponding with the lowest edge of the mesorectum.

Radiotherapy in rectal cancer

Radiotherapy has an established role in the treatment of rectal cancer. In primary resectable cancer, numerous randomised trials have shown that particularly pre-operative, and to some extent also postoperative, radiotherapy substantially reduces the risk of local failure. This is seen also with total mesorectal excision. Secondary to the reduction in local failures, there is also a slight improvement in survival after pre-operative radiotherapy or postoperative radiochemotherapy. Using appropriate techniques, the morbidity of radiotherapy is low. In non-resectable cancer, radiotherapy may cause down-staging, allow surgery, and may cure some patients. Whether radiochemotherapy is more efficient has yet to be firmly established. The role of pre-operative radio(chemo)therapy to permit more sphincter-preserving procedures with adequate long-term function is not defined.