Later Outcomes and Alpha/Beta Estimate From Hypofractionated Conformal Three-Dimensional Radiotherapy Versus Standard Fractionation for Localized Prostate Cancer

What do we know about the α/β for prostate cancer?

“…Leborgne et al 28 reported a low a/b derived from the outcome of patients treated with hypofractionated EBRT delivered in 3.0-3.15 Gy fractions and patients treated with standard fractionation. The parameter value which better matched the actuarial bNED at 5 years was 1.86 Gy (95% CI 0.7, 5.1).…”

“…37 However, several reports were published ever since with new estimations for the prostate cancer a/b. 22,23,[25][26][27][28]44 Similarly, several studies comparing the biochemical outcome and late toxicity in patients treated with hypofractionation and conventional regimens are now available, showing the feasibility of hypofractionation used to treat prostate cancer by radiation. 22,24,25,28,[48][49][50][51][52] Although the first estimations from randomized trials have drawn the idea of a low a/b value for prostate cancer, 20,21 the associated large width of the 95% confidence intervals indicated a considerable uncertainty related with such evaluations.…”

“…8 Several recent studies have reported low a/b values for prostate cancer. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] If this a/b is proven to be lower than values estimated for late complications, then hypofractionated regimens are expected to improve the therapeutic ratio, 8,[29][30][31][32][33][34][35][36] beyond the advantages on cost saving and patient convenience.…”

“…129 A relative increase of 6% in biochemical failures was found when the treatment time was elapsed for 1 week (total of 7 weeks) in low-and intermediate risk patients. 130 Leborgne et al, 28 regarding these last results, 130 considered a T K of 52 days and a proliferation rate of 0.25 Gy/d which yielded a slight increment in the a/b from 1.86 Gy (assuming no proliferation) up to 2.1 Gy. More studies are needed to understand the role of repopulation on prostate cancer treatment by radiation and what is its real impact on the a/b value.…”

Treatment outcomes with hypofractionated high-dose radiation therapy for prostate cancer

“…[1][2][3] Evidence from experimental and clinical studies suggest that prostate cancer has a lower ˛/ˇ ratio than the surrounding organs. 4,5 This relationship between the ˛/ˇ has raised the idea that a hypofractionated schedule might be more advantageous in terms of patient convenience, cost, and resource utilization than conventional schedules. 6 The clinical results of randomized clinical trials have also supported the practice of hypofractionated schedule in patients with localized prostate cancer.…”