When should radiotherapy be given for rectal cancer?

Radical surgery and postoperative radiotherapy as combined treatment in rectal cancer. Final results of a phase III study of the European Organization for Research and Treatment of Cancer

BACKGROUND

There is controversy whether adjuvant radiotherapy should be given before or after surgery for locally advanced, resectable rectal cancer. Preoperative radiotherapy substantially reduces local recurrence rates but may increase postoperative complications. In addition, patients found to have early cancers are treated unnecessarily. This study is a randomized trial of postoperative radiotherapy in patients who had a potentially curative resection for locally advanced rectal carcinoma.

METHODS

Following complete excision of a Dukes B or C rectal cancer, 172 patients were randomized to adjuvant radiotherapy (46 Gy 5 days per week in 30-38 days) (84 patients) or controls (88 patients).

RESULTS

After a median follow-up of 85 months, no benefit from postoperative radiotherapy had been observed in disease-free survival (P = 0.81), overall survival (P = 0.52), local recurrence-free interval (P = 0.46) or in the number and sites of recurrence. Acute toxicity following radiotherapy included diarrhoea (20 per cent), cystitis (13 per cent), delayed wound healing (7 per cent), pneumonia (5 per cent) and seizures (1 per cent). Late complications included reoperation for small bowel obstruction (5 per cent), chronic diarrhoea (20 per cent), chronic cystitis (12 per cent) and persistent perineal sinus (9 per cent). In the group who had surgery alone, late morbidity was found in 11 per cent.

CONCLUSION

This trial failed to demonstrate any improvement in overall survival or local control when postoperative irradiation was given following resection of locally advanced rectal carcinoma.

Radiotherapy of presacral recurrence following radical surgery for rectal carcinoma

The records of 58 patients treated by radiotherapy for presacral recurrent rectal cancers between 1975 and 1982 were evaluated. Pain was one of the most distressing symptoms, occurring in 38 of 58 patients (66 percent) which, in 90 percent (34 of 38) of patients could be controlled by radiotherapy. Side effects were mild, and could be treated conservatively. The crude survival of the patients was 19.8 months (range, 3 to 71 months). Only 3 percent of those treated survived five years. The dose-survival study showed increased survival of patients treated with more than 44 Gy. Because of negative selection of patients irradiated with lower doses, certain conclusions cannot be made. Surgery, if performed radically, is the treatment of choice. But patients with inoperable disease treated with radiotherapy benefit symptomatically, and might have increased survivals with a small chance of cure.

Adenocarcinoma of the rectum. Results of radiotherapy and resection, endocavitary irradiation, local excision, and preoperative clinical staging

The management of rectal cancer in 102 patients at the Jewish Hospital of St. Louis is reviewed. Therapy combining external irradiation, endocavitary irradiation, local excision, and excisional operation has been used in the treatment of adenocarcinoma of the rectum. Pretreatment evaluation for tumor fixation, ulceration, palpable presacral lymph nodes, distance of tumor from dentate line, size of tumor, and histologic grades was used to assign patients to treatment groups. Local recurrence is less than 2 percent, and two-year tumor-free survival is approximately 87 percent in patients receiving 2000 R or 4500 R preoperatively. Pathologic downstaging of tumors was noted more frequently with 4500 R preoperative irradiation. Endocavitary irradiation appears adequate to treat only favorable lesions. Only tumor fixation and histologic grade of the tumor notably affected survival. A logical plan for choosing the appropriate method of treatment using combined modalities is proposed.

Survival following moderate-dose preoperative radiation therapy for carcinoma of the rectum

We performed a retrospective study of patients with carcinoma of the rectum or rectosigmoid undergoing surgical resection. Forty-two patients received adjuvant preoperative radiation therapy (4000-4500 rad). One hundred twenty patients underwent surgical resection alone. Survival of radiation patients was significantly improved over that of Surgery Only patients, even after adjusting for nontreatment factors using Cox regression. Crude 5-year survival was 63% for radiation patients (74% adjusted) compared to 46% for surgery-only patients (48% adjusted) (P less than 0.025). Radiation patients also had longer disease-free survival than surgery-only patients (P less than 0.05) and fewer recurrences (14% versus 37%; P less than 0.025). Fewer radiation patients had lymph nodes involved with tumor than surgery-only patients (20% versus 35%; P = 0.07). Although 71% of radiation patients experienced radiation reactions, these were primarily mild and transitory. We believe that preoperative radiation is an effective and safe adjunct to surgery in the treatment of rectal cancer and that its use can lead to improved survival rates.

An evaluation of pelvic lymphoscintigraphy in the staging of colorectal carcinoma

Lymphoscintigraphy was used to delineate the lymphatic drainage of the rectum and distal colon in 18 patients with carcinoma of the rectum or sigmoid colon, in four with inflammatory disease of the large bowel and in 20 controls without colorectal pathology. Abdominal imaging was performed after submucosal injection of either 4 mCi 99mTc-antimony sulphide colloid or 0.5 mCi 99mTc-dextran into the rectum through a proctoscope. In nine patients with colorectal carcinoma, abdominal imaging was performed immediately pre-operatively and the excised specimen of large bowel was also imaged in vitro immediately postoperatively. The presence or absence of nodal uptake of radionuclide on abdominal scanning did not discriminate between normal and diseased large bowel, and the extent of nodal uptake demonstrated either by abdominal scans or by in vitro scans of excised specimens bore no relationship to the presence or absence of nodal metastases demonstrated histologically in the cancer patients. Pelvic lymphoscintigraphy as performed in this study has no demonstrable value in the diagnosis or staging of colorectal cancer.

Defining the needs for adjuvant therapy of rectal and colonic cancer

Current trials concerned with the adjuvant therapy for large bowel cancer demonstrate for the first time that improvements in survival through the use of adjuvant therapy may be possible in rectal cancer. Similar results in well-designed studies are not evident for colonic cancer. These trials deserve confirmation. In addition, they demonstrate the biologic difference in the behavior of colonic and rectal cancer despite similar requirements in defining curative surgical resection. A comparison of trials unique to individual institutions suggests that the lenient criteria for patient selection and the use of historical control groups make the data from these studies impossible to interpret for extrapolation to wide clinical use. The variations in the survival rates of historical groups, both among different studies and within the same study, suggest that the design of adjuvant therapy programs without concurrent surgically treated control groups will predictably produce a study of limited value, but one that is guaranteed to generate continued controversy. Uniformity of language, staging, and method of reporting is invaluable if individual trials of adjuvant therapy are to become comparable. The development and widespread use of an agreed-upon staging method is an important step in the preparation for further adjuvant trials. The definition of additional prognostic factors (beyond mural penetration and nodal involvement) in rectal cancer and stratification for these additional factors in the design of studies concerning adjuvant therapy in rectal cancer seems to be a target of importance for future studies of adjuvant therapy. Focusing attention on which patients with rectal cancer actually derived a benefit from treatment may assist in the development of a pattern in which surgical goals and radiation goals can achieve better definition in clinical use.