Local control with pre-operative radiotherapy alone versus "sandwich" radiotherapy for rectal carcinoma

[Indications for neoadjuvant therapy in rectal carcinoma]

Pre- and postoperative adjuvant treatments for locally advanced, operable (R0 resection) rectum carcinoma have led to improved results. In principle, according to the interdisciplinary consensus of the German Cancer Society, the recommended treatment for rectum carcinoma (T3/4; N0; M0; any T stage; N+; M0) is still postoperative adjuvant radiochemotherapy. In the meantime, however, based on the good results obtained from various clinical trials preoperative adjuvant treatment is favored internationally. Not only does this treatment scheme show a comparably better compliance of the patients but it also seems to be better tolerated. One treatment option for resectable T3 tumors immediately followed by surgery is the sole hypofractionated preoperative 3-4 field external beam radiotherapy. An additional benefit can be expected from protracted preoperative radiochemotherapy (single dose 2 Gy, total dose >40 Gy, chemotherapy based on 5-FU) followed by operation several weeks later. For T4 tumors with expected R1 or R2 resection, preoperative treatment is urgently recommended. A further aim in compliance with the surgical approach (R0 resection!) and multimodal treatment may be for individual cases the preservation of continence.

Late complications after a combined pre and postoperative (sandwich) radiotherapy for rectal cancer

BACKGROUND AND PURPOSE

The purpose of this study was to analyse the treatment related side effects, the outcome and the prognostic significance of clinical parameters in two groups of patients with rectal cancer receiving either preoperative or pre and postoperative radiotherapy after radical resection. The authors of this study were not involved in the radiation treatments.

PATIENTS AND METHODS

From 1986 to 1990, 63 patients received a combined pre and postoperative (sandwich) radiotherapy. Preoperative irradiation was given in four fractions of 5 Gy each applied within 2 or 3 days. Postoperative irradiation consisted mostly of 15 x 2 Gy (31 patients) but the range was 20-40 Gy. The results were compared with those on 73 patients who only received preoperative radiotherapy in the same time period. The distribution of prognostic factors was not very different between treatment groups. Out of 63 patients in the sandwich group, 22 received concurrent chemotherapy and 18 also received radiotherapy to the liver. Radical surgery usually followed on the day after the last preoperative radiotherapy session. Median follow-up of survivors was 6 years.

RESULTS

Local tumour control was 88% after 5 years and 84% after 8 years in the sandwich group, and 90 and 85%, respectively, in the preoperative radiotherapy group. Thus, tumour control was similar for the two radiotherapy regimens applied. However, the percentage of patients suffering from one or more complications after 5 years was 84% in the sandwich and 17% in the preoperative radiotherapy group. The incidence of severe late complications (grade > or = 3) was recorded as a function of time after start of treatment. In the sandwich group the actuarial rates of late complications at 5 years (and the median time to diagnosis) were 53% (27 months) for anorectum, 43% (37 months) for bladder, 28% (51 months) for bone, 19% (36 months) for dermis, 47% (48 months) for ileum, 41% (32 months) for lymphatic and soft tissue, and 44% (53 months) for ureters.

CONCLUSIONS

Severe late reactions did not occur within a certain period of time, but continued to appear for at least 10 years after radiotherapy. Sandwich therapy, as given in this series, did not appear to give a greater tumour control than preoperative radiotherapy alone, whereas the rate of complications was drastically enhanced. Thus, the rationale of a sandwich therapy with a long time interval between surgery and postoperative irradiation appears questionable.

Rapid growth of microscopic rectal cancer as a determinant of response to preoperative radiation therapy

PURPOSE

To quantify the dose-time fractionation factors in preoperative radiation therapy for microscopic pelvic deposits of rectal cancer. This provides a biologic basis for understanding and improving the results of adjuvant therapies for this disease.

METHODS

The reduction in incidence of pelvic relapses as a function of radiation dose and overall treatment time was determined from the literature. The displacement of dose-response curves to higher doses reflects the growth during radiation treatment of subclinical pelvic deposits which are beyond the future surgical margins.

RESULTS

Dose-response curves are steep if the effect of overall duration of radiation therapy is accounted for. The time-related displacement of these steep dose-response curves is consistent with a median doubling time for malignant clonogenic cells of about 4 or 5 days, much faster than the growth rate of the average primary tumor at diagnosis. This rapid growth is evident within the first few days of irradiation, implying that the natural growth rate of these microscopic deposits if fast, and/or that an acceleration of growth follows initiation of radiation injury with a very short lag time.

CONCLUSION

Subclinical pelvic deposits of rectal cancer grow rapidly during preoperative radiation therapy with an adverse influence on the rate of pelvic tumor control from protracting the duration of adjuvant treatment. Low doses only offer clinically relevant reduction in risk of pelvic relapses if the overall radiation treatment time is short. For a given overall treatment duration there is a relatively steep dose-response curve, predicting that significant improvements in tumor control are possible.

Adjuvant postoperative radiotherapy in rectal cancer: 148 cases treated at Florence University with 8 years median follow-up

BACKGROUND AND PURPOSE

To analyse the outcome, the treatment related side effects, the prognostic significance of clinical parameters in a group of patients with rectal cancer receiving postoperative radiotherapy after radical resection.

MATERIALS AND METHODS

From 1980 to 1990 148 consecutive patients with rectal carcinoma stage B2-B3 or C1-C2-C3 were treated with postoperative radiotherapy after radical surgery. All patients received 50 Gy in 25 sessions in 5 weeks. In 42 a "flash' dose of 5 Gy was also given within 24 h before surgery. Median follow up was 8.1 years.

RESULTS

At 5 years the overall survival was 54%, the determined (cancer specific) survival 61%, the local recurrence-free survival 88%. The influence of stage, histotype, distance from anal margin, type of surgery, number of involved nodes and flash dose were analysed. Overall and determined survival and distant metastasis rate were significantly influenced (P < 0.005) by the pathological stage. Patients with more than 3 involved nodes presented a significantly lower determined survival (P < 0.001) and a higher distant relapse rate (P < 0.005) than those with 3 or less involved nodes. A higher determined survival (P < 0.01) was also found in patients receiving the preoperative "flash'; this group was however unbalanced in respect to the relative number of cases with 3 or less involved nodes. The incidence of major side effects requiring surgery or hospitalization for medical treatment was 35% before 1985 and 12% thereafter. The systematic use of small bowel visualization during simulation and the discontinuation of the flash dose were the main modifications introduced in the second period. As a consequence of the small bowel visualization the size of lateral fields was slightly reduced and some patients were excluded from the treatment.

CONCLUSIONS

Value of postoperative radiotherapy to decrease the incidence of local recurrence was confirmed in this retrospective study; the incidence of side effects was however considerable and did not support the addition of chemotherapy as advised by the NIH consensus meeting. Our policy was therefore moved to preoperative irradiation whose combination with chemotherapy was recently reported to be better tolerated and highly effective.

The rationale to switch from postoperative hyperfractionated accelerated radiotherapy to preoperative hyperfractionated accelerated radiotherapy in rectal cancer

PURPOSE

To demonstrate the feasibility of preoperative Hyperfractionated Accelerated RadioTherapy (preop-HART) in rectal cancer and to explain the rationales to switch from postoperative HART to preoperative HART.

METHODS AND MATERIALS

Fifty-two consecutive patients were introduced in successive Phase I trials since 1989. In trial 89-01, postoperative HART (48 Gy in 3 weeks) was applied in 20 patients. In nine patients with locally advanced rectal cancer, considered unresectable by the surgeon, 32 Gy in 2 weeks was applied prior to surgery (trial 89-02). Since 1991, 41.6 Gy in 2.5 weeks has been applied preoperatively to 23 patients with T3-T4 any N rectal cancer immediately followed by surgery (trial 91-01). All patients were irradiated at the department of radiation-oncology with a four-field box technique (1.6 Gy twice a day and with at least a 6-h interval between fractions). The minimal accelerating potential was 6 MV. Acute toxicity was scored according to the World Health Organization (WHO for skin and small bowel) and the Radiation Therapy Oncology Group criteria (RTOG for bladder). This was done weekly during treatment and every 3 months thereafter. Small bowel volume was estimated by a modified "Gallagher's" method.

RESULTS

Acute toxicity was acceptable both in postoperative and preoperative setup. The mean acute toxicity was significantly lower in trial 91-01 compared to 89-01. This difference was due to the smaller amount of small bowel in irradiation field and lower total dose in trial 91-01. Moreover, there was a significantly reduced delay between surgery and radiotherapy favoring trial 91-01 (median delay 4 days compared to 46 days in trial 89-01). Nearly all patients in trial 89-02 and 91-01 underwent surgery (31 out of 32; 97%). Resection margins were negative in 29 out of 32. Hospitalization duration in trial 91-01 was not significantly different from trial 89-01 (19 vs. 21 days, respectively).

CONCLUSIONS

Hyperfractionated accelerated radiotherapy immediately followed by surgery is feasible as far as acute toxicity is concerned. Preoperative HART is favored by a significantly lower acute toxicity related, in part, to a smaller amount of irradiated small bowel, and a shorter duration of the delay between radiotherapy and surgery. Moreover, the hospital stay after preoperative HART is not significantly increased.

Evaluation of preoperative radiation therapy in operable colorectal cancer

MATERIALS AND METHODS

Patients with operable colorectal cancer in the ascending colon, descending colon, and rectum were randomized to 500 cGy before definitive surgery. Patients with stage A and B1 lesions received no further treatment. All patients with stage B2, B3, C1, C2, and C3 received a minimum of 4500 cGy postoperatively.

RESULTS

Three hundred fifty-three patients were registered for the study. Three hundred one patients were available for analyses. Follow-up was a minimum of 5 years on all study patients. The majority of patients had rectal cancer. Complications of treatment were acceptable. Two hundred thirty-one patients had stage B2, B3, C1, C2, or C3 tumors. Estimated 5-year rates for no preoperative therapy versus preoperative therapy were as follows: local recurrence 29% versus 26%; metastasis 41% versus 43%; and survival 54% versus 54%. No statistical benefit was observed for preoperative treatment.

CONCLUSIONS

In a prospective randomized trial designed to test the value of low-dose preoperative irradiation followed by surgery and postoperative irradiation, the authors were unable to observe any benefit to low-dose preoperative therapy in patients with unfavorable stages.

Treatment of rectal cancer by low anterior resection with coloanal anastomosis

OBJECTIVE

Our institution's experience with low anterior resection in combination with coloanal anastomosis (LAR/CAA) for primary rectal cancer was reviewed (1) to determine cancer treatment results, 2) to identify risk factors for pelvic recurrence, and 3) to assess the long-term success of sphincter preservation.

SUMMARY BACKGROUND DATA

Use of sphincter-preserving resection for mid-rectal and selected distal-rectal cancers continues to increase. As surgical techniques and adjuvant therapy evolve, treatment results must be carefully assessed.

METHODS

One hundred thirty-four patients treated for primary rectal cancer by LAR/CAA between 1977 and 1990 were studied retrospectively. All pathologic slides were reviewed. Median follow-up was 4 years.

RESULTS

Actuarial 5-year survival for all patients was 73%. Among 36 patients who relapsed, distant metastatic disease had developed at the time of first clinical relapse in most (86%). Pelvic recurrence was detected in 13 patients, an actuarial rate of 11% at 5 years. Mesenteric implants, positive microscopic resection margin, T3 tumor, perineural invasion, blood vessel invasion, and high tumor grade were associated with increased risk for pelvic recurrence. Eleven patients ultimately required permanent colostomy, and in eight instances the cause was pelvic recurrence.

CONCLUSIONS

Low anterior resection combined with coloanal anastomosis provides good treatment for mid-rectal cancers and for some distal rectal cancers. Pelvic recurrence is not associated with short distal resection margins but is correlated with the presence of histopathologic markers of aggressive disease in the primary tumor. Long-term preservation of anal sphincter function depends primarily on control of pelvic tumor and can be achieved in more than 90% of patients.

The importance of patient selection for adjunctive postoperative radiation therapy for cancer of the rectum. Patient selection in adjunctive therapy

BACKGROUND

Clinical stage of disease is an important selection criterion for choice of primary treatment and strategies for adjunctive therapy for most cancers. For adenocarcinoma of the rectum, strategies for adjuvant treatment are based primarily on pathologic stage alone, without consideration of presenting clinical factors. This analysis was undertaken to assess the effect of patient selection on results of adjunctive therapy.

METHODS

Three groups of patients with Astler-Coller Stage B2 and C rectal cancer were compared to assess the effect of patient selection factors on outcome of treatment after adjuvant postoperative radiation. Thirty-two patients in Group 1 received only 5 Gy preoperatively; 54 patients in Group 2 received low-dose (5 Gy) preoperative and high-dose (45 Gy) postoperative radiation; and 53 patients in Group 3 received high-dose (45 Gy) postoperative radiation. All patients have a minimum follow-up of 5 years. Whereas Group 1 and Group 2 patients were similar in distribution by clinical tumor characteristics, Group 3 had more patients with poor clinical features: higher median age, more men, and a higher proportion of tumors in the distal rectum. Group 3 also had a slightly higher percentage of C2 tumors compared with the other two groups.

RESULTS

Treatment was well tolerated with minimal side effects. Patients in Group 1 had no long-term complications. Four percent of patients (2 of 54) in Group 2 and 6% of patients (3 of 53) in Group 3 experienced major small bowel complications. The incidence of local recurrence was 34% (11 of 32) in Group 1, 9% (5 of 54) in Group 2, and 21% (11 of 53) in Group 3. The incidence of distant metastasis was 28% (9 of 32), 22% (12 of 54), and 38% (20 of 53), respectively. Absolute 5-year survival rates were 54%, 72%, and 41% in these three groups, respectively.

CONCLUSIONS

Low-dose preoperative adjunctive radiation alone (Group 1) resulted in a high incidence of local recurrence and poor survival compared with patients treated more appropriately with low-dose preoperative plus adjunctive postoperative irradiation (Group 2). In spite of postoperative radiation, patients with clinically unfavorable rectal cancer (Group 3) did worse than carefully selected patients, although both were nominally Stage B2 and C. Careful patient selection before surgery, histopathologic stage of disease postsurgery, and adequate adjunctive therapy are all important factors in obtaining the best results from adjunctive therapy.

Improved local control and survival with the "sandwich" technique of pelvic radiotherapy for resectable rectal cancer. A retrospective, multivariate analysis

PURPOSE

The following study was done to evaluate the therapeutic value of radiotherapy as an adjunct to surgery for rectal cancer patients.

METHODS

One-hundred twenty-four patients underwent curative resection by one surgeon (RC) from 1982 to 1991. Forty patients received combined preoperative and postoperative (sandwich) radiotherapy, 30 patients received postoperative radiotherapy, and 54 patients were treated by surgery alone. During the study period sandwich radiotherapy was primarily offered as a free treatment option for patients with tumors which were believed to be transmurally invasive, whereas postoperative radiotherapy was an alternative therapeutic option offered to patients with tumor classified as Dukes B and C at histopathologic examination.

RESULTS

Operative mortality was 2 percent in the sandwich radiotherapy group vs. 7 percent in the surgery alone group. After a median follow-up of 60 months, the actuarial locoregional recurrence rate at five years was 3 percent for the sandwich radiotherapy group compared with 18 and 30 percent for the postoperative radiotherapy and surgery alone groups, respectively (P = 0.019). A multivariate analysis using the Cox model confirmed the favorable independent influence of sandwich radiotherapy on local tumor control, especially in distal tumors. The therapeutic benefit of sandwich radiotherapy translated into increased survival in the low-rectum Dukes B subgroup of patients. The actuarial five-year survival rates were 86 percent, 50 percent, and 28 percent in the sandwich radiotherapy, postoperative radiotherapy and surgery alone groups, respectively (P = 0.05).

CONCLUSIONS

Preoperative radiotherapy has a significant effect on the prognosis of rectal cancer patients.

Long-term functional results of coloanal anastomosis for rectal cancer

In a survey of patients treated with coloanal anastomosis for rectal cancer, 81 of 90 eligible patients responded to a questionnaire evaluating current anorectal function. Time from operation to assessment ranged from 1.3 to 12.3 years (median: 4.3 years). The median stool frequency was two per day; 22% of patients reported four or more stools per day. In the patients surveyed, fecal continence was complete in 51%, incontinence to gas only in 21%, minor leak in 23%, and significant leak in 5%. Complete evacuation of the neorectum was problematic in 32%. Overall function was excellent in 28%, good in 28%, fair in 32%, and poor in 12%. The impact of treatment variables on functional outcome was assessed by univariate and multivariate analyses. No surgical technique correlated with improved or impaired outcome. Time since surgery (reduced stool frequency) and use of postoperative adjuvant radiotherapy (increased stool frequency, increased difficulty with evacuation) did appear to influence functional outcome. We conclude that the functional results of coloanal anastomosis are good but not optimal. Continued investigation of the effects of surgical technique and adjuvant therapy is warranted.

Pre-operative and post-operative radiotherapy and rectal cancer

The appropriate role for additional radiotherapy in patients with resectable rectal cancer is not yet settled. Irradiation has been considered by surgeons and radiotherapists as superfluous since no effect on survival has been shown. However, numerous trials have demonstrated that peri-operative radiotherapy decreases an often high local recurrence rate while others believe it has a definite place in routine management. Several surgeons have, on the contrary, claimed that a skilled surgeon compared to a less skilled surgeon, will get the same acceptably low local recurrence rates. Since we will probably never have a randomized trial comparing "good" and "bad" surgeons, this argument cannot be settled. A further obstacle arises in the difficulty of persuading surgeons to organize their routine work so that it is performed in an optimal way by those specializing in this field. The question also arises whether radiotherapy should be delivered pre-operatively, postoperatively or as a "sandwich" technique, i.e., both pre-operatively and postoperatively. According to radio-biological considerations and results from reported trials, the best effect on local tumor control has been achieved using pre-operative radiotherapy.

Pre-operative radiotherapy as adjuvant treatment in rectal cancer

From January, 1975 to December, 1987, 241 patients with rectal cancer underwent pre-operative irradiation and surgical resection. The radiation was delivered with 25 MeV photons, 5 days per week by 2.4 grays fractions up to a total dose of 36 grays. Surgery was curative in 195 patients; 57% had abdomino-perineal resection. Irradiation had to be discontinued in 3 patients and 4 patients subsequently developed severe acute ileitis. Postoperative mortality rate was 2.9%. The most frequent postoperative complications were delayed healing of abdominal wounds (18%) and perineal wounds (14%). Severe late complications occurred in 27 (13%) patients. The incidence of intestinal obstruction was 5%. Follow-up survivors ranged from 18 months to 13 years. Local failure occurred in 24 (12%) of the 195 patients. Local failure rates were 10% for Dukes' A tumors, 11.6% for Dukes' B, and 22.7% for Dukes' C tumors. Five and 10 year actuarial survival rates after curative surgery were 70% and 52%. The Dukes' classification was the only factor that influenced survival.

A prospective study of the accuracy of preoperative computed tomographic staging of patients with biopsy-proven rectal carcinoma

From June 1983 to January 1986, 91 patients with biopsy-proven adenocarcinoma of the rectum had computed tomographic scans of the pelvis performed before treatment as part of a "sandwich" radiotherapy-surgery regimen. Two experienced diagnostic radiologists performed locoregional staging of all scans according to the University of California at San Francisco criteria; one of these radiologists repeated this staging at a later time to test the reproducibility of a single observer. Staging was performed without the use of any other radiographic studies or of any clinical information except the patients' age, sex, and the diagnosis of rectal carcinoma, to test the value of computed tomographic scans alone for staging. Agreement between the two stagings performed by the first observer was 51 percent, and interobserver agreement was only 37 percent. Agreement with Dukes' staging was only 33 percent. Therefore, preoperative pelvic computed tomographic scanning of primary rectal adenocarcinoma should not be relied upon for staging or for the selection of patients for treatment options.

Adjuvant external beam and intraoperative radiation therapy in rectal cancer

The use of radical surgery has maximized local control, sphincter preservation, and overall survival in patients with rectal cancer. Despite the advances in surgical techniques, local recurrence still remains a problem. Following potentially curative surgery, the incidence of local recurrence in patients with stages B2, C disease varies from 15% to 65%. There are four major approaches in which radiation therapy (RT) has been used in the adjuvant treatment of rectal cancer. These include postoperative RT +/- chemotherapy, preoperative RT +/- chemotherapy, both pre- and postoperative RT (sandwich technique), and intraoperative RT in conjunction with preoperative external beam RT. In patients with resectable rectal cancer, adjuvant RT has been shown to decrease the incidence of local recurrence and, in some series, may influence survival rates. In patients with locally advanced, unresectable, or recurrent rectal cancer, the use of preoperative radiation therapy, attempted surgical resection, and intraoperative RT further enhances local control.