Primary, Adjuvant, and Palliative Radiation Therapy (7)
Five-year survivals in these groups were 16% and 26%, respectively. These studies suggest that there clearly is a subset of patients with lung cancer who can be cured with radiation therapy alone; thus, a watchful waiting policy is not the appropriate approach. Two recent reports of similar series of patients substantiated these findings.
Unresectable Lung Cancer
Similar to the group of patients with resectable but inoperable lung cancer, there is a subset of patients with unresectable nonmetastatic lung cancer who are cured by radiation therapy (60 Gy in 6 weeks). Published series of patients consistently report around a 6% 5-year survival rate. Higher doses (to 74 Gy) of conventionally fractionated radiation therapy may improve on these results. A recendy reported cooperative group study of hyperfractionated radiation therapy in patients with N2 lung cancer suggests that this technique with doses of 69.6 Gy in 6 weeks produces superior early (up to 3 years) results compared to conventional radiation therapy. This is now being tested in a phase III trial.
Correlates of improved local/regional control and survival are smaller tumor size and higher radiation doses. Thus, early treatment and careful radiotherapeutic technique (to minimize the risk of complications) are important to improve the probability of success of radiation therapy. Patients not cured are benefited by relief or prevention of symptoms related to local regional disease. Carefully planned and precisely administered radiation therapy has low associated morbidity, and on balance the quality of life of these patients is improved.
Because of the low cure rate of radiation therapy in these patients and the frequent failure of treatment due to dissemination, concurrent or sequential chemotherapy has been advocated. However, with one recent exception, randomized trials comparing radiation therapy alone to radiation therapy plus chemotherapy consistendy show no benefit from the combined modality approach (Table 9). Induction chemotherapy prior to radiotherapy may improve median survival in this group of patients and is being tested in national phase III protocols.
Table 9—Effects of Radiation Therapy and Chemotherapy for Non-Small CeU Lung Cancer in Randomized Trials
|Study||Treatment*||No. of Patients||Radiation Dose, Gy||Median Survival, mo||Chest Failure, %|
|Minet et al||Chemotherapy (CAPV) and radiation therapy||40||48||8|
|Radiation therapy alone||41||48||8|
|Soresi et al||Chemotherapy (P) and radiation therapy||45||50||16||27|
|Mattson et al||Chemotherapy (CAP) and radiation therapy||119||55||10||31|
|Radiation therapy alone||119||55||10||35|
|Dillman et al||Chemotherapy (CVb) and radiation therapy||78||60||14||NA|
|Radiation therapy alone||77||60||10||NA|