Ms. Anscher et al., Using plasma transforming growth factor beta-1 during radiotherapy to select patients for dose escalation, J CL ONCOL, 19(17), 2001, pp. 3758-3765
Purpose : The ability to prescribe treatment based on relative risks for no
rmal tissue injury has important implications for oncologists. In non-small
-cell lung cancer, increasing the dose of radiation may improve local contr
ol and survival. Changes in plasma transforming growth factor beta (TGF bet
a) levels during radiotherapy (RT) may identify patients at low risk for co
mplications in whom higher doses of radiation could be safely delivered.
Patient and Methods: Patients with locally advanced or medically inoperable
non-small-cell lung cancer received three-dimensional conformal RT to the
primary tumor and radiographically involved nodes to a dose of 73.6 Gy (1.6
Gy twice daily). If the plasma TGF beta level was normal after 73.6 Gy, ad
ditional twice daily RT was delivered to successively higher total doses. T
he maximum-tolerated dose was defined as the highest radiation dose at whic
h less than or equal to one grade 4 (life-threatening) late toxicity and le
ss than or equal to two grade 3 to 4 (severe life-threatening) late toxicit
ies occurred.
Results: Thirty-eight patients were enrolled. Median follow-up was 16 month
s. Twenty-four patients were not eligible for radiation dose escalation bey
ond 73.6 Gy because of persistently abnormal TGF beta levels. Fourteen pati
ents whose TGF beta levels were normal after 73.6 Gy were escalated to 80 G
y (n = 8) and 86.4 Gy (n = 6). In the 86.4-Gy group, dose-limiting toxicity
was reached because there were two (33%) grade 3 late toxicities.
Conclusion: It is feasible to use plasma TGF beta levels to select patients
for RT dose escalation for non-small-cell lung cancer. The maximum-tolerat
ed dose using this approach is 86.4 Gy.