Response, toxicity, failure patterns, and survival in five Radiation Therapy Oncology Group (RTOG) trials of sequential and/or concurrent chemotherapy and radiotherapy for locally advanced non-small-cell carcinoma of the lung.

PURPOSE

The purpose of this study was to assess response, toxicity, failure patterns, and survival differences in three chemotherapy (ChT)/radiation therapy (RT) sequencing strategies for locally advanced non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

Five completed Radiation Therapy Oncology Group (RTOG) trials for Stage II-IIIA/B inoperable NSCLC patients employed one of the three following strategy groupings: 1) sequential ChT followed by standard RT (60 Gy in 6 weeks); 2) combined sequential and concurrent ChT and standard RT (60 Gy in 6 weeks); or 3) concurrent ChT and hyperfractionated RT (69.6 Gy in 6 weeks). All five trials required KPS > or = 70; two trials (314 patients) required <5% weight loss and three trials (147 patients) had no minimum weight loss requirement. In all five trials the ChT used cisplatin with either vinblastine or oral etoposide. Combining data for the five trials yielded an evaluable group of 461 patients. The three methods of sequencing ChT and RT were evaluated for differences in response, acute and late toxicity, patterns of failure, and survival. Acute toxicity was defined as that occurring within 90 days from the start of RT. Late toxicity was defined as that occurring after 90 days from the start of RT. Acute or late toxicity > or = grade 3 was defined as severe. Site of first failure was recorded by date. In-field failure excluded distant metastasis as a failure and included only tissue in the RT treatment field. Overall progression-free survival (PFS) was defined as survival without evidence of intra- or extrathoracic tumor or death from any cause.

RESULTS

Group 1 had a lower overall response rate (63%) compared to either Group 2 (77%) or Group 3 (79%), p = 0.03 and 0.003, respectively. Overall grade 4/5 acute toxicities were nearly equal between groups. The severe nonhematologic acute toxicities were significantly different by strategy group (p < 0.0001). Group 1 and 2 were not statistically different. Group 3 had significantly more patients with severe acute nonhematologic toxicity (55%) than either Group 1 (27%) or 2 (34%) with p < 0.0001 and p = 0.0005, respectively. This was due to a severe acute esophagitis rate of 34% for Group 3 versus 1.3% for Group 1 and 6% for Group 2 (p < 0.0001 for both comparisons). Overall grade 4/5 late toxicities did not differ by group. Severe late nonhematologic toxicities were different by group (p = 0.0098). Group 1 patients had significantly fewer severe late nonhematologic toxicities (14%) compared to patients in Groups 2 (26%) or 3 (28%) (p = 0.046 and 0.038, respectively). Severe late lung toxicity was 10% for Group 1 compared to 21% and 20% for Groups 2 and 3, respectively. Severe late lung toxicities differed by group (p = 0.033), but not severe late esophagitis (p = 0.077). There were no differences between the three strategy groups for patterns of first failure. The in-field failures were higher in Group 2 (71%) compared to Groups 1 (56%) and 3 (55%), p = 0.0478. Pairwise comparisons yielded p-values of 0.068 and 0.015 for Group 2 versus 1 and Group 2 versus 3, respectively. Three-year PFS was better in Group 2 (15%) and 3 (15%) compared to Group 1 (7%), but not statistically significant (p = 0.454). Similarly, in-field PFS was better in Group 2 (17%) and 3 (20%) than Group 1 (9%), but not significant (p = 0.167). There were improvements in 3-year survival for Group 2 (17%) and Group 3 (25%) compared to Group 1 (15%), but the differences were not statistically significant (p = 0.47). The same results were present for patients with less than 5% weight loss and patients with stage IIIA tumors.

CONCLUSION

Thus, concurrent ChT and hyperfractionated RT had a higher incidence of severe acute esophageal toxicity. Severe late lung toxicity with concurrent ChT/hyperfractionated RT, as well as with induction ChT followed by concurrent ChT/standard RT, may be greater compared to sequential ChT/RT. (ABSTRACT TRUNCATED)