Results of radiotherapy for inoperable locally advanced esophageal cancer

Biology of esophageal cancer and the role of combined modality therapy

1. The biology of esophageal cancer involves multifactorial environmental and genetic events. 2. The understanding of the clinical significance of molecular markers is rapidly evolving. 3. Combined-modality approaches should still include surgery in good performance status (ECOG scale < or = 2) patients. 4. Neoadjuvant chemoradiation is probably better than surgical resection alone for patients with potentially curable disease, but only validation of this approach by CALGB-9781 can justify this as a new "proven" standard-of-care in the United States. 5. A pathologic complete response to neoadjuvant therapy is the strongest predictor of long-term survival. 6. 5-FU, by either short course or protracted continuous infusion, comprises the backbone of combination chemotherapy in combined-modality design. 7. Radiation therapy should be given at standard 1.8 to 2 Gy/fraction without a scheduled break. 8. Only by enrolling sufficient numbers of patients in prospective clinical trials will clinicians be able to further define the optimal sequencing and actual necessity of each individual component of combined-modality therapy.

[Radiotherapy in the multimodal treatment of esophageal carcinoma. A review]

BACKGROUND

The curative potential of exclusively applied surgery or radiotherapy on esophageal carcinoma is exhausted. The 5-year survival rate of surgically treated esophageal carcinoma is stagnant at 20 to 30%, that for radiotherapeutically treated esophageal carcinoma at < or = 10%. The unchanged bad prognoses motivate the search for multimodal therapeutical concepts in order to improve the results of basic therapies.

METHOD, RESULTS AND CONCLUSIONS

While neither perioperative radiotherapy nor perioperative chemotherapy were able to improve the treatment results significantly, a progress in the field of primary and preoperative radiochemotherapy emerges. On locally restricted tumors the latest findings show that a simultaneous radiochemotherapy with Cisplatin is more effective than radiotherapy alone. 20 to 30% histologically verified complete remissions can be reached through preoperative radiochemotherapy. These results will influence future treatment concepts. Brachytherapy can be taken into consideration in highly palliative situations as exclusive method of treatment or for support of laser treatment or bouginage for removal of stenosis. As the number of clinically controlled studies is not sufficient the importance of the brachytherapy boost for potentially curative intentions is not yet clear. Up to now the intraluminal hyperthermia is a underestimated method for improving the results of radiotherapy. Our overview summarizes all presently published randomized studies and relevant phase I/II-studies.

Sequential chemotherapy and radiotherapy for squamous cell esophageal carcinoma

A Phase II study of sequential chemotherapy with 5-fluorouracil and cisplatin followed by radiotherapy was initiated to see whether the use of two therapies sequentially could have an effect on response rate. Thirteen patients with advanced squamous cell carcinoma of the esophagus were treated with 1,000 mg/m2/day 5-fluorouracil days 1-5 continuously and 100 mg/m2 cisplatin on day 1. An average of four cycles (range, one to nine) were given every 28 days; 11 patients received more than three cycles. The radiation consisted of 60 Gy over 6-8 weeks. There was only one (8%) complete response (CR) and 11 (85%) partial responses (PRs). Restaging after radiation revealed no conversion of PR to CR. Median survival was 39 weeks (range, 6-208+). Chemotherapy alone or its use sequentially with radiotherapy is inadequate, and newer approaches are needed to to improve survival.

Radiation therapy alone or combined with chemotherapy in the treatment of esophageal cancer

Radiation therapy has been used in the adjuvant setting or as a primary treatment modality for esophageal cancer. Although there are design flaws in all of the trials of adjuvant radiation therapy for esophageal cancer, there is no clear survival advantage when radiation therapy is delivered in the adjuvant setting (preoperatively or postoperatively). Phase II results of preoperative, combined modality therapy are encouraging; however, the approach remains investigational. When radiation therapy is used as a primary modality, the most favorable results are seen when it is combined with adequate doses of systemic chemotherapy. Phase III intergroup trials are in progress which are examining the effectiveness of higher doses of radiation therapy when combined with chemotherapy.

Effect of overall treatment time on local control in radical radiotherapy for squamous cell carcinoma of esophagus

PURPOSE

To analyze the effect of overall treatment time on local control in radical radiotherapy for squamous cell carcinoma of esophagus.

METHODS AND MATERIALS

Three hundred and fifty-three patients with inoperable esophageal cancer (tumor length < or = 10 cm in all cases) treated during 1963-1988 by radical radiotherapy alone either as continuous or split-course therapy. The overall treatment time varied from 35 to 55 days and the total dosage from 50 to 71 Gy in the continuous therapy group (n = 138), and in the split-course group (n = 215) with a planned 3-week rest interval in the middle of the treatment from 56 to 70 days and from 55 to 70 Gy, respectively. The logit method of the linear-quadratic formula for local control at 1 year was used to examine the effect of treatment time on local control. All patients were pooled to obtain a wide range of overall treatment times.

RESULTS

The 1-, 2-, and 5-year actuarial survival rates according to the T-stage in the continuous therapy group from the first day of the radiotherapy were: 57%, 32%, and 10% for the T1 tumors and 23%, 8%, and 5% for the T2 tumors. The corresponding figures for the split-course group were: 50%, 19%, and 4% for the T1 tumors and 17%, 6%, and 3% for the T2 tumors. The 1-year local control rate was 56% for the T1 tumors and 15% for the T2 tumors in the continuous therapy group and 48% for the T1 tumors and 10% for the T2 tumors in the split-course group. The results of the logit method did not fit well with the T1 tumors. For the T2 tumors, they showed Dprolif to be about 0.24 Gy/day for local control at 1 year. As a consequence, protraction of overall time by 1 week should be compensated by increasing the total dose by 1.8 Gy for 1 year local control.

CONCLUSIONS

More attention should be focused on repopulation. Shortening of overall treatment time might be beneficial for the treatment of squamous cell carcinoma of esophagus.

High dose external beam radiation therapy with or without concomitant chemotherapy for esophageal carcinoma

Esophageal cancer patients treated with radiotherapy (RTx) are most often those with malignancies too extensive for surgery or those who deemed medically unsuitable for an aggressive surgical approach. Summarizing RTx series, the 2-year survival rate is in the range of 10% and at 5 years about 5%. Although not randomly compared, these results are not significantly worse than those achieved with surgery in more advanced tumors. In stage I/II tumors, more recent trials reported of 5-year survival rates varying between 12% and 20%. These data indicate that irradiation may be administered with curative intention but usually only for patients who are also candidates for primary surgery. On the other hand, modern RTx (doses > 60 Gy) +/- endoluminal after-loading may provide good palliation (relief of dysphagia) for patients with good prognostic factors such as weight loss of less than 10% body weight, good performance status, younger age, and location of the tumor. In the perioperative setting, RTx reduced the frequency of the local recurrences but did not increase the overall resection and R0 resection rates and did not improve survival due to more patients relapsing at distant sites. Combined chemoradiotherapy has shown to be superior to RTx alone with respect to local control, disease free survival and overall survival and in a marked reduction of distant failures. These data support the use of chemoradiotherapy as standard treatment of locally advanced and nonresectable esophageal cancer. They also provide a basis for randomized trials comparing chemoradiotherapy alone versus preoperative treatment modalities.

Current status and future directions in the treatment of localized esophageal cancer

Due to insufficient local tumor control in the majority of esophageal carcinoma (EC) patients and due to distant recurrences, the dismal prognosis of patients with EC has not essentially changed during the past two decades. This holds true despite extended surgical procedures and improved radiation techniques. The 2-year survival rates in stage IIB/III which represent two-thirds of the patients with localized EC is still less than 20%. Therefore, clinical efforts in the management of EC focus on combined modality treatment (CTM), usually preoperative chemotherapy (CTx)/chemoradiotherapy (CTx/RTx) or CTx/RTx alone. Up to now, results of CTM in potentially resectable EC have not shown that preoperative CTx or CTx/RTx is superior to surgery alone with respect to resectability, local tumor control and overall survival. However, CTx responders who subsequently underwent a complete tumor resection had a markedly improved long term survival indicating that the inclusion of CTx in the treatment of EC may improve the prognosis. The benefit of CTx could also be demonstrated in a randomized trial comparing RTx alone versus CTx/RTx with a reduction of local and distant failures and significantly improved survival in the CTM arm. Similar observations were made with CTM in locally advanced disease. To date, there is sufficient evidence that preoperative treatment of EC may improve prognosis at least of subgroups of patients with this tumor. However, this has to be confirmed in well designed (proper staging including endoscopic ultrasound, etc.) randomized trials.(ABSTRACT TRUNCATED AT 250 WORDS)

Low-dose rate telecobalt therapy as a boost against esophageal carcinomas

The results of treating 54 esophageal carcinomas with low-dose rate telecobalt therapy (LDRT) as a boost were compared with those of treating 97 esophageal carcinomas with conventionally fractionated irradiation alone (CFI). The LDRT (100 cGy/hr, 500 to 700 cGy/day, a total dose of 1400 to 2000 cGy) was boosted at 10 days after 6000 cGy of the CFI dose. Although the LDRT group included more advanced cases than the CFI group, local effects and survival rates in the former group were slightly better than in the latter group. Late complications were more severe in the LDRT group. However, they were acceptable when the total dose administered to this group was less than 8000 cGy. Using LDRT as a boost against esophageal carcinomas was found to be satisfactory therapeutically.

Prognostic factors in radiation-treated esophageal carcinoma

Prognostic factors in esophageal carcinoma treated with irradiation were examined. The prognosis of 111 patients without metastasis who had received more than 60 Gy was analyzed. Significant associations were found between survival rates and tumor length, stage, radioresponse of the primary tumor and the s.c. X-P classification based on barium contrast radiography; superficial type (tumor limited to the surface of the esophageal wall), tumorous type (solid mass without ulceration), Ul-A type (tumor with shallow ulceration with regular margin), Ul-B type (tumor with deep ulceration or irregular ulcer margin), and funneled type (tumor invading the esophageal wall in a scirrhous pattern). In multiple regression analysis, the X-P classification had the strongest correlation with survival and the survival rates of patients with the superficial type, the tumorous type and the s.c. Ul-A type were significantly higher than those of patients with the other tumor types (p < 0.001).

Intracavitary brachytherapy combined with external-beam irradiation for squamous cell carcinoma of the thoracic esophagus

During the 15 year period from 1974 to 1988, 277 patients with previously untreated, histologically confirmed, squamous cell carcinoma of the thoracic esophagus were treated with the Time Dose and Fractionation (TDF) factor of more than 99. Of these, 161 patients were treated with external beam irradiation combined with intracavitary brachytherapy. Intracavitary brachytherapy was done for all patients for whom insertion of an outer applicator 1 cm in diameter was possible and for whom a relatively good performance status was seen at completion of external beam irradiation. Except for mild radiation-induced esophagitis, no acute radiation injuries were noted. The early clinical effect of radiation upon the esophageal lesion was determined by esophagography and esophagoscopy, approximately 1 month after the combined radiotherapy; a complete response was observed in 86 (53.4%) of the 161 patients. Furthermore, after a 5 year follow-up, local control of esophageal cancer was found to have been successful in 51 (31.7%) of the 161 patients. The highest rate of local control was associated with the following criteria: Stage I, T1, tumor length less than 5 cm, and superficial or tumorous type of tumor. The 5-year actuarial survival rates were 43.3% for Stage I, 21.1% for Stage II, and 0% for both Stages III and IV. Benign radiation-induced esophageal ulcerations or strictures did develop in five of the long-term survivors, suggesting that the dosage is close to the maximal tolerance of the esophagus. We recommend that 1500-2000 cGy in two or three fractions is the optimal dosage for intracavitary radiation of the esophageal mucosa after external irradiation of 5500 cGy in 22 fractions for 5.5 weeks or 6000 cGy in 30 fractions for 6 weeks. We believe that intracavitary treatment of esophageal carcinoma is a highly effective and a safe therapeutic modality, not only as a palliative therapy, but also as a radical treatment for patients in Stages I and II.