Simultaneous integrated boost with stereotactic radiotherapy for dominant intraprostatic lesion of localized prostate cancer: a dosimetric planning study

Abstract

Dominant intraprostatic lesion (DIL) has been known as the most common local recurrence site of prostate cancer. We evaluated the feasibility of simultaneous integrated boost (SIB) to DIL with CyberKnife stereotactic body radiotherapy (CK-SBRT). We selected 15 patients with prostate cancer and visible DIL and compared 3 plans for each patient: 1) No boost plan of 35 Gy to prostate, 2) DIL_40 plan of SIB 40 Gy to DIL and 35 Gy to prostate, and 3) DIL_45 plan with 45 Gy to DIL and 35 Gy to the prostate in 5 fractions. All targets satisfied with the prescription coverage per protocol. However, some patients failed to meet the Dmax of the rectum in DIL_40 plans (n = 4), and DIL_45 plans (n = 6). Violations of bladder constraints occurred in four DIL_45 plans. Consequently, the DIL boost with SBRT was possible in 73% of patients with DIL_40 plans, and 60% of patients with DIL_45 plans without any violation of normal organ constraints. All patients who experienced constraint violations had DILs in posterior segments. DIL boost using CK-SBRT could be an option for localized prostate cancer patients. For patients who had DIL in posterior segments, a moderate dose escalation of 40 Gy seemed appropriate.

Focal Boost in Prostate Cancer Radiotherapy: A Review of Planning Studies and Clinical Trials

“…The longest reported follow-up time was 124 months [49]. In the planning studies, as shown in Table 2, the majority of studies utilized mpMRI for GTV delineation [10,18,45,[57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75]. Five studies utilized PET-CT [12,[76][77][78][79][80], and four studies used "other methods" such as histopathology data or hypothetical IPLs [81][82][83][84].…”

Technological Advancements in External Beam Radiation Therapy (EBRT): An Indispensable Tool for Cancer Treatment

“…SBRT has also been researched as a way of focally escalating the dose delivered to the dominant intra-prostatic lesion. 28 Furthermore, the technique has been shown to be effective in the treatment of early non-small cell lung cancer for patients that were unfit for surgery. 29 However, several disadvantages of SBRT in NSLC patients are radiation pneumonitis, skin toxicity, odynophagia, rib fracture pain, and nerve injury.…”

Dosimetric Uncertainties in Dominant Intraprostatic Lesion Simultaneous Boost Using Intensity Modulated Proton Therapy

“…(5,6) Such dose escalation has been shown to be feasible with brachytherapy (3,(7)(8)(9)(10)(11)(12) and photon X-ray beams using volumetric modulated arc therapy (VMAT), (4,8,(13)(14)(15) Tomotherapy, (16) particle therapy, (9,17) and Cyberknife. (18) Proton therapy provides superior dose distributions and dosimetric advantages over photon X-ray beams in many sites. Though the data supporting protons over intensity-modulated RT (IMRT) for prostate cancer has been conflicting, (19,20) these studies predominantly included men treated with first-generation passive scattering proton therapy.…”

“… 5 , 6 Such dose escalation has been shown to be feasible with brachytherapy 3 , 7 , 8 , 9 , 10 , 11 , 12 and external beams using volumetric modulated arc therapy, 4 , 8 , 13 , 14 , 15 tomotherapy, 16 particle therapy, 9 , 17 and Cyberknife. 18 …”