Modeling tumor and treated lung volume influences in the irradiation of non-small-cell lung cancer patients.
OBJECTIVE
The proposal of a hypothetical model in patients treated by irradiation for non-small-cell lung cancer show the dependence of local tumor control and patient cure rates on the volume of tumor and irradiated lung tissue.


RESULTS
The local tumor control rates from conventional doses of irradiation decreases and the metastases rate increases with the tumor volume. Dose escalation will increase the potential cure rates (product of the local control and the freedom from metastases rates). Any potential gain will, however, be modified by the effect of irradiation on normal lung. Studies indicate that this is dependent on the volume of lung irradiated above a threshold dose.


CONCLUSIONS
A clinically significant and measurable increase in cure rates from dose escalation may be seen in smaller tumors. This is unlikely to occur in larger tumors, although dose escalation to a restricted volume combined with effective systemic chemotherapy is one of the options that may be explored. The relevance of modeling and future studies of tumor and normal tissue volume effects, will increase from the widespread usage of the dose-volume histogram.
Abratt
R P
RP
Radiation Oncology, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa., rpa@curie.uct.ac.za
D002289:Carcinoma, Non-Small-Cell Lung / Q000532:radiotherapy* / Q000556:secondary; D019583:Dose Fractionation, Radiation; D006801:Humans; D008168:Lung / Q000528:radiation effects*; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D009367:Neoplasm Staging; D011379:Prognosis; D011879:Radiotherapy Dosage; D016019:Survival Analysis