Intensity modulated radiation therapy (IMRT) has achieved widespread use for prostate cancer; however, in relation to this use, outcomes studies are still relatively sparse. We report a single-institutional experience in outcomes analysis with the use of IMRT for the primary management of prostate cancer. One hundred thirty consecutive patients with adenocarcinoma of the prostate were treated at a single institution using IMRT with curative intent. Thirty-six (28%) patients were classified as low-risk, 69 (53%) as intermediate-risk, and 25 (19%) as high-risk. The median dose prescription was 76 Gy to the planning target volume. Sixty-five (50%) patients received androgen deprivation therapy (ADT) for a median 4 months, starting 2 months prior to IMRT. Biochemical failure was defined as PSA < post-treatment nadir+2. Gastrointestinal (GI) and Genitourinary (GU) toxicity were defined by RTOG criteria. Median follow-up was 53 months. By NCCN risk category, 4-year biochemical control was 97%, 94%, and 87% for low, intermediate, and high-risk patients, respectively. Among disease factors, multivariable analysis demonstrated the strongest association between biochemical control and Gleason score < or =6 (p=0.0371). Therapy was well tolerated with no Grade 4 toxicity and limited grade 3 GI or GU toxicity. Acute Grade 3+ GI and GU toxicity rates were 0% and 2%, and maximal late Grade 3+ GI and GU toxicity rates were 5% and 6%, respectively. Late rectal toxicity was associated with higher volumes of RT to the rectum. By last follow-up late Grade 3+ toxicity was 2% for both GI and GU systems. In conclusion, patients treated with IMRT for prostate cancer have excellent rates of biochemical control and low rates of severe toxicity of treatment.
To review outcomes of salvage radiation therapy (RT) after prostatectomy, comparing Intensity-Modulated RT (IMRT) with conformal/conventional (non-IMRT) techniques. Eighty-three patients with localized prostate cancer and a rising PSA after prostatectomy were treated at the University of Chicago between 1988 and 2005. Median pre-RT PSA was 0.64 ng/mL, 72% had pT3 disease, 12% had Gleason 8 disease or higher, and surgical margins were positive in 56%. Median RT dose was 66 Gy (range 46–76); 34 patients were treated with IMRT. 27 patients also had androgen deprivation therapy for a median 4 months. Biochemical failure was defined as any PSA >0.2 ng/mL with any consecutive rise thereafter. Median follow-up was 43 months, and was shorter for IMRT patients (median 29 months) than for non-IMRT patients (median 64 months, p < 0.0001). Toxicity was scored using RTOG criteria for gastrointestinal (GI) and genitourinary (GU) systems. At 4-years, freedom from biochemical failure (FFbF) was 53%. Margin status was the only variable associated with FFbF on univariate (p = 0.0157) and multivariate analysis (p = 0.0231) including pT3, Gleason score ≥4 + 3, hormone use, pre-RT PSA, and IMRT. Because whole pelvic treatment was associated with a higher rate of acute (p = 0.0555) or late Grade 2+ toxicity (56% vs 16%, p = 0.0124), 9 such patients were excluded for comparison between IMRT and non-IMRT (Table 1). Dose-volume histogram (DVH) data was available for 28 of 73 patients. No tested DVH parameters were associated with acute or late grade 2+ GI or GU toxicity. A comparison of DVH data for rectal tissue demonstrated that IMRT increased hot spots [V70 7% vs 0%, p = 0.0050, dose to hottest 10% of rectum 69 vs 67 Gy, p = 0.0117], reduced the volume of rectal tissue receiving medium doses of RT [V60, V40 lower for IMRT, p > 0.05], and increased the volume receiving lower doses [V20, V10 higher for IMRT, p > 0.05]. For bladder tissue, IMRT increased hot spots [V70 70% vs 67%, p = 0.0005, dose to hottest 10% of tissue 70 vs 65 Gy, p = 0.0004] but did not better spare bladder from medium or lower doses of RT [equal or higher V60, V40, V20, V10, p > 0.05]. Salvage RT is effective in select patients after prostatectomy. Even for limited prostate bed volumes, IMRT may reduce rectal tissue receiving 30–60 Gy and improve acute GI toxicity; however, this comes at the expense of increased hot spots to the rectum and bladder which may impact late toxicity. Further study is necessary to better assess the risk-benefit ratio of IMRT in this setting.Table 1Toxicity following salvage RT to the prostatic bedOverall (n = 73)IMRT (n = 31)Non-IMRT (n = 42)p-valueAcute ≥ Grade 2 GI20/72 (28%)13%38%0.0170 ≥ Grade 2 GU5/73 (7%)3%10%0.2719Late ≥ Grade 2 GI5/69 (7%)10%5%0.4828 ≥ Grade 2 GU11/69 (16%)26%8%0.0417 ≥ Grade 2 GI or GU15/69 (22%)32%13%0.0552 ≥ Grade 3 GI or GU3/69 (4%)10%0%0.0258 Open table in a new tab
The purpose of this study was to assess the efficacy and toxicity of intensity-modulated radiation therapy (IMRT) in the treatment of gastric cancer. Seven patients with gastric cancer were treated with IMRT. Six patients (all Stage III) received post-operative chemoradiotherapy with concurrent 5-fluorouracil and leucovorin. One received planned pre-operative radiation, though did not proceed to surgery. All patients were planned to receive 50.4 Gy in 1.8 Gy fractions. IMRT planning was compared with opposed anterior-posterior: posterior-anterior (AP/PA) and 3-field conventional three-dimensional plans. When compared with either AP/PA or 3-field plans, IMRT significantly reduced the volume exceeding the threshold dose of the liver and at least one kidney. Target coverage with IMRT was excellent, with 98+/-1% of the target receiving >or=100% of the dose. Compared with AP/PA and 3-field plans, IMRT plans had a greater percentage of target receiving the prescribed dose, but also a greater volume receiving >110% of the dose. IMRT was well tolerated; no patients developed acute gastrointestinal toxicity greater than grade 2. All seven experienced grade 2 nausea, three had grade 2 diarrhoea and two had grade 2 oesophagitis. Weight loss ranged from 0-12% (mean 6.1% and median 5.8%). IMRT in the treatment of gastric malignancies reduces the mean and above threshold doses to critical normal tissues. In an initial cohort of seven patients, 50.4 Gy delivered by IMRT is well tolerated and safe.
Radiation therapy plays an integral role in the treatment of gastric cancer in the postsurgery setting, the inoperable/palliative setting, and, as in the case of the current report, in the setting of neoadjuvant therapy prior to surgery. Typically, anterior-posterior/posterior-anterior (AP/PA) or 3-field techniques are used. In this report, we explore the use of intensity-modulated radiotherapy (IMRT) treatment in a patient whose care was transferred to our institution after 3-field radiotherapy (RT) was given to a dose of 30 Gy at an outside institution. If the 3-field plan were continued to 50 Gy, the volume of irradiated liver receiving greater than 30 Gy would have been unacceptably high. To deliver the final 20 Gy, an opposed parallel AP/PA plan and an IMRT plan were compared to the initial 3-field technique for coverage of the target volume as well as dose to the kidneys, liver, small bowel, and spinal cord. Comparison of the 3 treatment techniques to deliver the final 20 Gy revealed reduced median and maximum dose to the whole kidney with the IMRT plan. For this 20-Gy boost, the volume of irradiated liver was lower for both the IMRT plan and the AP/PA plan vs. the 3-field plan. Comparing the IMRT boost plan to the AP/PA boost-dose range (<10 Gy) in comparison to the AP/PA plan; however, the IMRT plan irradiated a smaller liver volume within the higher dose region (>10 Gy) in comparison to the AP/PA plan. The IMRT boost plan also irradiated a smaller volume of the small bowel compared to both the 3-field plan and the AP/PA plan, and also delivered lower dose to the spinal cord in comparison to the AP/PA plan. Comparison of the composite plans revealed reduced dose to the whole kidney using IMRT. The V20 for the whole kidney volume for the composite IMRT plan was 30% compared to approximately 60% for the composite AP/PA plan. Overall, the dose to the liver receiving greater than 30 Gy was lower for the composite IMRT plan and was well below acceptable limits. In conclusion, our study suggests a dosimetric benefit of IMRT over conventional planning, and suggests an important role for IMRT in the neoadjuvant treatment of gastric cancer.
The purpose of this report is to communicate the observed advantage of intensity-modulated radiotherapy (IMRT) in a patient with bilateral metallic hip prostheses. In this patient with early-stage low-risk disease, a dose of 74 Gy was planned in two phases--an initial 50 Gy to the prostate and seminal vesicles and an additional 24 Gy to the prostate alone. Each coplanar beam avoided the prosthesis in the beam's eye view. Using the same target expansions for each phase, IMRT and 3D-conformal radiotherapy (CRT) plans were compared for target coverage and inhomogeneity as well as dose to the bladder and rectum. The results of the analysis demonstrated that IMRT provided superior target coverage with reduced dose to normal tissues for both individual phases of the treatment plan as well as for the composite treatment plan. The dose to the rectum was significantly reduced with the IMRT technique, with a composite V 80 of 35% for the IMRT plan versus 70% for 3D-CRT plan. Similarly, the dose to the bladder was significantly reduced with a V 80 of 9% versus 20%. Overall, various dosimetric parameters revealed the corresponding 3D-CRT plan would not have been acceptable. The results indicate significant success with IMRT in a clinical scenario where there were no curative alternatives for local treatment other than external beam radiotherapy. Therefore, definitive external beam radiation of prostate cancer patients with bilateral prosthesis is made feasible with IMRT. The work described herein may also have applicability to other groups of patients, such as those with gynecological or other pelvic malignancies.
Purpose: To assess survival, local control, and toxicity of intensity modulated radiation therapy (IMRT) in squamous cell carcinoma of the anal canal.Methods and Materials: Seventeen patients were treated with nine-field IMRT plans. Thirteen received concurrent 5-fluorouracil and mitomycin C, whereas 1 patient received 5-fluorouracil alone. Seven patients were planned with three-dimensional anteroposterior/posterior-anterior (AP/PA) fields for dosimetric comparison to IMRT.Results: Compared with AP/PA, IMRT reduced the mean and threshold doses to small bowel, bladder, and genitalia. Treatment was well tolerated, with no Grade >= 3 acute nonhematologic toxicity. There were no treatment breaks attributable to gastrointestinal or skin toxicity. Of patients who received mitomycin C, 38% experienced Grade 4 hematologic toxicity. IMRT did not afford bone marrow sparing, possibly resulting from the clinical decision to prescribe 45 Gy to the whole pelvis in most patients, vs. the Radiation Therapy Oncology Group-recommended 30.6 Gy whole pelvic dose. Three of 17 patients, who did not achieve a complete response, proceeded to an abdominoperineal resection and colostomy. At a median follow-up of 20.3 months, there were no other local failures. Two-year overall survival, disease-free survival, and colostomy-free survival are: 91%, 65%, and 82% respectively.Conclusions: In this hypothesis-generating analysis, the acute toxicity and clinical outcome with IMRT in the treatment of anal cancer is encouraging. Compared with historical controls, local control is not compromised despite efforts to increase conformality and reduce normal structure dose. (c) 2005 Elsevier Inc.
Purpose: To assess the efficacy and toxicity of intensity-modulated radiotherapy (IMRT) in pancreatic and bile duct (cholangiocarcinoma) malignancies.Methods and Materials: Twenty-five patients with pancreatic and bile duct cancer were treated with IMRT. Twenty-three received concurrent 5-fluoruracil. One patient with a pancreatic primitive neuroectodermal tumor received concurrent etoposide and ifosfamide. Eight patients had resected tumors, and 17 had unresectable primary (n = 14) or recurrent (n = 3) tumors. Six patients underwent treatment planning with conventional three-dimensional four-field techniques for dosimetric comparison with IMRT.Results: Compared with conventional RT, IMRT reduced the mean dose to the liver, kidneys, stomach, and small bowel. IMRT was well tolerated, with 80% experiencing Grade 2 or less acute upper GI toxicity. At a median follow-up of 10.2 months, no resected patients had local failure, and only 1 of 10 assessable patients with unresectable cancer had local progression. The median survival and distant metastasis-free survival of the 24 patients with adenocarcinoma was 13.4 and 7.3 months, respectively. Grade 4 late liver toxicity occurred in 1 patient surviving >5 years. The remainder of the assessable patients experienced no (n = 9) or Grade 1 (n = 4) late toxicity.Conclusion: In this hypothesis-generating analysis, the acute and chronic toxicity profile with IMRT in the treatment of pancreatic and bile duct cancer was encouraging. Local control was not compromised, despite efforts to increase conformality and avoid doses to normal structures. Distant failure remains a major obstacle in pancreatic cancer. (C) 2004 Elsevier Inc.
Prostate cancer is among the most common solid malignancies. A number of treatment alternatives exist for localized prostate cancer, including observation, prostatectomy, brachytherapy, and externalbeam radiation therapy (EBRT). External-beam radiation therapy has changed dramatically during the past several years. Older techniques paved the way for 3-dimensional conformal radiation therapy (CRT), which in turn facilitated the introduction of intensity-modulated radiation therapy (IMRT). The prostate has served as a model disease site for the implementation of IMRT. As indicated by a growing body of experience, IMRT for prostate cancer represents a major technologic and clinical advance for radiation therapy. In this article, a review is provided of the evolution of EBRT leading to IMRT, the unique features making the prostate an ideal disease site for employing IMRT, the details of the clinical implementation of prostate IMRT and supporting technologic advancements, and the currently reported clinical outcomes of IMRT in prostate cancer. In addition, future directions of prostate IMRT, both technologic and clinical, are discussed.
A comparison of isocenter dose calculated by a commercial intensity modulated radiation therapy treatment planning system and independent monitor unit verification calculation (MUVC) software was made. The percent disparity between the treatment plan and MUVC doses were calculated for 507 treatments (head and neck, prostate, abdomen, female pelvis, rectum and anus, and miscellaneous) from 303 patients. The MUVC calculated dose was, on average, 1.4% higher than the treatment planning dose, with a 1.2% standard deviation. The distribution of the disparities appeared to be Gaussian in shape with some variation by treatment site. Based on our analysis, disparities outside the range of about the mean value should be checked and resolved prior to treatment delivery.PACS number(s): 87.53.–j, 87.66.–a
The incidence of cataracts in patients who have received total body irradiation (TBI) is about 20% and increases to 40% if the patient is treated for graft-versus-host disease. At our institution, all TBI patients are treated with two lateral opposed 24 MV photon fields. No attempt is usually made to shield the eyes during the TBI treatment because of the amount of lead required to adequately attenuate megavoltage photon beams, the difficulty in properly positioning an eye shield and the possibility of compromising the effectiveness of the treatment. However, we were asked to treat a TBI patient who is a professional pilot, and thus his livelihood is contingent upon maintaining perfect vision. A custom eye shield was constructed out of lead and ionization chamber and film measurements were performed under TBI conditions to determine the thickness and location of the eye block to optimize the competing effects of increased scatter and attenuation from the lead. Phantom data were also obtained for 6 MV irradiation for comparison with 24 MV. In-vivo patient and phantom measurements with thermoluminescent dosimeters showed that with visual positioning of the eye block the dose was reduced from 16 to 20% across the orbits of both eyes.