The impact of induction chemotherapy and the associated tumor response on subsequent radiation-related changes in lung function and tumor response.
OBJECTIVE
To assess the impact of induction chemotherapy, and associated tumor shrinkage, on the subsequent radiation-related changes in pulmonary function and tumor response.


METHODS
As part of a prospective institutional review board-approved study, 91 evaluable patients treated definitively with thoracic radiation therapy (RT) for unresectable lung cancer were analyzed. The rates of RT-associated pulmonary toxicity and tumor response were compared in the patients with and without pre-RT chemotherapy. In the patients receiving induction chemotherapy, the rates of RT-associated pulmonary toxicity and tumor response were compared in the patients with and without a response (modified Response Evaluation Criteria in Solid Tumor criteria) to the pre-RT chemotherapy. Comparisons of the rates of improvements in pulmonary function tests (PFTs) post-RT, dyspnea requiring steroids, and percent declines in PFTs post-RT were compared in patient subgroups using Fisher's exact test, analysis of variance, and linear or logistic regression.


RESULTS
The use of pre-RT chemotherapy appears to increase the rate of radiation-induced pneumonitis (p = 0.009-0.07), but has no consistent impact on changes in PFTs. The degree of induction chemotherapy-associated tumor shrinkage is not associated with the rate of subsequent RT-associated pulmonary toxicity. The degree of tumor response to chemotherapy is not related to the degree of tumor response to RT.


CONCLUSIONS
Additional study is needed to better clarify the impact of chemotherapy on radiation-associated disfunction.
Mao
Jingfang
J
Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
Kocak
Zafer
Z
Zhou
Sumin
S
Garst
Jennifer
J
Evans
Elizabeth S
ES
Zhang
Junan
J
Larrier
Nicole A
NA
Hollis
Donna R
DR
Folz
Rodney J
RJ
Marks
Lawrence B
LB
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004417:Dyspnea / Q000188:drug therapy / Q000209:etiology; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D008168:Lung / Q000187:drug effects* / Q000503:physiopathology / Q000528:radiation effects*; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000503:physiopathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D017564:Radiation Pneumonitis / Q000209:etiology* / Q000503:physiopathology; D012074:Remission Induction; D014797:Vital Capacity / Q000187:drug effects / Q000528:radiation effects