International journal of radiation oncology, biology, physics
-
Int. J. Radiat. Oncol. Biol. Phys. · Oct 1996
Conformal irradiation of the prostate: estimating long-term rectal bleeding risk using dose-volume histograms.
Dose-volume histograms (DVHs) may be very useful tools for estimating probability of normal tissue complications (NTCP), but there is not yet an agreed upon method for their analysis. This study introduces a statistical method of aggregating and analyzing primary data from DVHs and associated outcomes. It explores the dose-volume relationship for NTCP of the rectum, using long-term data on rectal wall bleeding following prostatic irradiation. ⋯ There is a dose-volume relationship for rectal mucosal bleeding in the region between 60 and 75 CGE; therefore, efforts to spare rectal wall volume using improved treatment planning and delivery techniques are important. Stratifying dose-volume histograms (DVHs) into risk groups, as done in this study, represents a useful means of analyzing empirical data as a function of hetereogeneous dose distributions. Modeling efforts may extend these results to more heterogeneous treatment techniques. Such analysis of DVH data may allow practicing clinicians to better assess the risk of various treatments, fields, or doses, when caring for an individual patient.
-
Int. J. Radiat. Oncol. Biol. Phys. · Oct 1996
Nonrandomized evaluation of pelvic lymph node irradiation in localized carcinoma of the prostate.
A great deal of controversy exists regarding the potential benefit of pelvic lymph node irradiation compared with treatment to the prostate only in patients with localized prostate cancer. Despite numerous reports, including a randomized study, this issue has not been completely elucidated. ⋯ In this retrospective analysis, pelvic lymph node irradiation did not influence local/pelvic tumor control, incidence of distant metastases, or disease-free survival in patients with clinical Stage A2 (T1b,c) or B (T2) localized carcinoma of the prostate. In patients with Stage C (T3) disease, irradiation of the pelvic lymph nodes with doses of 50 to 55 Gy resulted in a lower incidence of pelvic recurrences and improved disease-free survival. Morbidity of therapy was acceptable, although patients with Stage C disease had a somewhat higher incidence of Grade 2 rectosigmoid morbidity. Pelvic lymph node irradiation is being elucidated in properly designed prospective, randomized protocols.
-
Int. J. Radiat. Oncol. Biol. Phys. · Oct 1996
Assessing the variability of outcome for patients treated with localized prostate irradiation using different definitions of biochemical control.
Biochemical control using serial posttreatment serum prostate specific antigen (PSA) levels is being increasingly used to assess treatment efficacy for localized prostate cancer. However, no standardized definition of biochemical control has been established. We reviewed our experience treating patients with localized prostate cancer and applied three different commonly used definitions of biochemical control to determine if differences in therapeutic outcome would be observed. ⋯ When different definitions of biochemical control are used in assessing treatment outcome, significantly different rates of success are noted. Until a standardized definition of biochemical control is adopted, differences in treatment outcome cannot be meaningfully compared.