Results of a pilot study with extended fractionation in the treatment of lung cancer

Non-uniform dose/time fractionated radiation therapy and chemotherapy for non-small cell lung cancer

PURPOSE

A Non-uniform Fractionation schedule of large priming doses combined with concurrent chemotherapy and protracted RT was undertaken for the treatment of NSCLC. With several 5-year survivors, this study is reviewed with regard to local control, toxicity, and survival of patients.

METHODS AND MATERIALS

Forty-two patients with unresectable NSCLC were treated prospectively with initial priming doses followed by large field irradiation to the tumor and regional nodes to 3500 cGy. Patients were given a 1-week break and the treatment was repeated. A total dose of 7000 cGy was delivered over 9 weeks. Thirteen patients (Group A) were treated with RT alone. Twenty-nine patients (Group B) received concurrent chemotherapy; Cisplatin, 100 mg/m2, and 5-FU, 1 g/m2 for 24 h times 5 days. Sixteen patients also received Vinblastine, 3 mg/m2 on a weekly schedule. All patients have been followed more than 5 years.

RESULTS

Overall complete response rate was 36% and partial response rate was 57%. Absolute survival at 2 years was 26% and at 5 years was 14%. Local failure occurred in 28/42 (67%) patients. Late complications included pulmonary fibrosis (3), and osteochondritis (2).

CONCLUSION

This approach of high-dose Non-uniform fractionated radiation therapy has yielded an absolute 5-year survival of 14%, which appears better than the long-term results often seen in treatment of NSCL cancer.

Fractionation in radiation therapy: theoretical basis, experimental, and clinical studies

In summary, there is a growing body of clinical evidence along with laboratory studies that in rapidly growing tumors, small doses per fraction given over a short time interval, as in hyperfractionation or accelerated fractionation, may increase the therapeutic ratio. For slowly growing tumors, small doses per fraction may still have an advantage, but they need not be compressed into a short time interval. Finally, for certain "radioresistant" tumors, with a large shoulder to the survival curve, there may be a clinical advantage to larger doses per fraction, but this will have to be weighed against the potential long-term chronic toxicity which increases rapidly with large doses per fraction.

The effect of resection on local failure in irradiated non-oat cell carcinoma of the lung

From January 1969 through December 1979, 171 patients completed a course of high dose definitive radiotherapy alone for non-oat cell carcinoma of the lung. During the same period, 53 patients completed a course of definitive postoperative radiotherapy after undergoing resection of the primary tumor. The two groups were otherwise very similar with regard to patient related and tumor related variables. A detailed analysis of the incidence of clinically documented local (in-field) failure on the basis of clinical T and N stages was performed. A comparison of the incidence of local failure as the first site of failure for patients with T1-2 tumors demonstrated a statistically significant decrease in local failure in patients whose primary tumors were resected. This was true for all patients with T1-2 tumors whose failure status was known (p less than .001), for all patients known to have failed (p less than .001), and for patients whose clinical node status was other than gross mediastinal (N2) lymphadenopathy (p less than .05). Local failure was decreased in patients with clinical T3 tumors who underwent resection, but the difference was not significant (p greater than .1). Histology (epidermoid vs. non-epidermoid) had no apparent effect on the frequency of local failure, either with or without resection. A review of past experience indicates that local failure is common after definitive irradiation alone, and is due to a low rate of sterilization of the primary tumor, even with tolerance doses of irradiation. Data are presented to support a reappraisal of the role of combined resection and irradiation in future clinical trials, to reduce the present unacceptably high rate of local failure in potentially curable patients treated by irradiation alone.