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ABSTRACT: To compare dose-volume histograms of target volumes and organs at risk in 57 patients with nasopharyngeal carcinoma (NPC) with inverse- (IP) or forward-planned (FP) intensity-modulated radiation treatment (IMRT).
The DVHs of 57 patients with NPC with IMRT with or without chemotherapy were reviewed. Thirty-one patients underwent IP IMRT, and 26 patients underwent FP IMRT. Treatment goals were to prescribe a minimum dose of 66-70 Gy for gross tumor volume and 59.4 Gy for planning target volume to greater than 95% of the volume. Multiple selected end points were used to compare dose-volume histograms of the targets, including minimum, mean, and maximum doses; percentage of target volume receiving less than 90% (1-V90%), less than 95% (1-V95%), and greater than 105% (1-V105%). Dose-volume histograms of organs at risk were evaluated with characteristic end points.
Both planning methods provided excellent target coverage with no statistically significant differences found, although a trend was suggested in favor of improved target coverage with IP IMRT in patients with T3/T4 NPC (p = 0.10). Overall, IP IMRT statistically decreased the dose to the parotid gland, temporomandibular joint, brain stem, and spinal cord overall, whereas IP led to a dose decrease to the middle/inner ear in only the T1/T2 subgroup.
Use of IP and FP IMRT can lead to good target coverage while maintaining critical structures within tolerance. The IP IMRT selectively spared these critical organs to a greater degree and should be considered the standard of treatment in patients with NPC, particularly those with T3/T4. The FP IMRT is an effective second option in centers with limited IP IMRT capacity. As a modification of conformal techniques, the human/departmental resources to incorporate FP-IMRT should be nominal.
International Journal of Radiation OncologyBiologyPhysics 01/2008; 69(5):1625-33. · 4.11 Impact Factor
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Allen M Chen,
Megan E Daly,
M Kara Bucci,
Ping Xia, Clayton Akazawa,
Jeanne M Quivey,
Vivian Weinberg,
Joaquin Garcia,
Nancy Y Lee,
Michael J Kaplan,
Ivan El-Sayed,
David W Eisele,
Karen K Fu,
Theodore L Phillips
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ABSTRACT: To compare clinical outcomes of patients with carcinomas of the paranasal sinuses and nasal cavity according to decade of radiation treatment.
Between 1960 and 2005, 127 patients with sinonasal carcinoma underwent radiotherapy with planning and delivery techniques available at the time of treatment. Fifty-nine patients were treated by conventional radiotherapy; 45 patients by three-dimensional conformal radiotherapy; and 23 patients by intensity-modulated radiotherapy. Eighty-two patients (65%) were treated with radiotherapy after gross total tumor resection. Nineteen patients (15%) received chemotherapy. The most common histology was squamous cell carcinoma (83 patients).
The 5-year estimates of overall survival, local control, and disease-free survival for the entire patient population were 52%, 62%, and 54%, respectively. There were no significant differences in any of these endpoints with respect to decade of treatment or radiotherapy technique (p > 0.05, for all). The 5-year overall survival rate for patients treated in the 1960s, 1970s, 1980s, 1990s, and 2000s was 46%, 56%, 51%, 53%, and 49%, respectively (p = 0.23). The observed incidence of severe (Grade 3 or 4) late toxicity was 53%, 45%, 39%, 28%, and 16% among patients treated in the 1960s, 1970s, 1980s, 1990s, and 2000s, respectively (p = 0.01).
Although we did not detect improvements in disease control or overall survival for patients treated over time, the incidence of complications has significantly declined, thereby resulting in an improved therapeutic ratio for patients with carcinomas of the paranasal sinuses and nasal cavity.
International Journal of Radiation OncologyBiologyPhysics 09/2007; 69(1):141-7. · 4.11 Impact Factor
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ABSTRACT: The first aim of the present study was to investigate the feasibility of using fewer beam angles to improve delivery efficiency for the treatment of oropharyngeal cancer (OPC) with inverse-planned intensity-modulated radiation therapy (IP-IMRT). A secondary aim was to evaluate whether the simplified IP-IMRT plans could reduce the indirect radiation dose. The treatment plans for 5 consecutive OPC patients previously treated with a forward-planned IMRT (FP-IMRT) technique were selected as benchmarks for this study. The initial treatment goal for these patients was to deliver 70 Gy to > or = 95% of the planning gross tumor volume (PTV-70) and 59.4 Gy to > or = 95% of the planning clinical tumor volume (PTV-59.4) simultaneously. Each case was re-planned using IP-IMRT with multiple beam-angle arrangements, including four complex IP-IMRT plans using 7 or more beam angles, and one simple IMRT plan using 5 beam angles. The complex IP-IMRT plans and simple IP-IMRT plans were compared to each other and to the FPIMRT plans by analyzing the dose coverage of the target volumes, the plan homogeneity, the dose-volume histograms of critical structures, and the treatment delivery parameters including delivery time and the total number of monitor units (MUs). When comparing the plans, we found no significant difference between the complex IP-IMRT, simple IP-IMRT, and FP-IMRT plans for tumor target coverage (PTV-70: p = 0.56; PTV-59.4: p = 0.20). The plan homogeneity, measured by the mean percentage isodose, did not significantly differ between the IP-IMRT and FP-IMRT plans (p = 0.08), although we observed a trend toward greater inhomogeneity of dose in the simple IP-IMRT plans. All IP-IMRT plans either met or exceeded the quality of the FP-IMRT plans in terms of dose to adjacent critical structures, including the parotids, spinal cord, and brainstem. As compared with the complex IP-IMRT plans, the simple IP-IMRT plans significantly reduced the mean treatment time (maximum probability for four pairwise comparisons: p = 0.0003). In conclusion, our study demonstrates that, as compared with complex IP-IMRT, simple IP-IMRT can significantly improve treatment delivery efficiency while maintaining similar target coverage and sparing of critical structures. However, the improved efficiency does not significantly reduce the total number of MUs nor the indirect radiation dose.
Journal of Applied Clinical Medical Physics 01/2007; 8(2):26-36. · 1.29 Impact Factor
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ABSTRACT: The aim of this study was to quantify gains in lymph node coverage and critical structure dose reduction for whole-pelvis (WP) and extended-field (EF) radiotherapy in prostate cancer using intensity-modulated radiotherapy (IMRT) compared with three-dimensional conformal radiotherapy (3DCRT) for the first treatment phase of 45 Gy in the concurrent treatment of lymph nodes and prostate.
From January to August 2005, 35 patients with localized prostate cancer were treated with pelvic IMRT; 7 had nodes defined up to L5-S1 (Group 1), and 28 had nodes defined above L5-S1 (Group 2). Each patient had 2 plans retrospectively generated: 1 WP 3DCRT plan using bony landmarks, and 1 EF 3DCRT plan to cover the vascular defined volumes. Dose-volume histograms for the lymph nodes, rectum, bladder, small bowel, and penile bulb were compared by group.
For Group 1, WP 3DCRT missed 25% of pelvic nodes with the prescribed dose 45 Gy and missed 18% with the 95% prescribed dose 42.75 Gy, whereas WP IMRT achieved V(45 Gy) = 98% and V(42.75 Gy) = 100%. Compared with WP 3DCRT, IMRT reduced bladder V(45 Gy) by 78%, rectum V(45 Gy) by 48%, and small bowel V(45 Gy) by 232 cm3. EF 3DCRT achieved 95% coverage of nodes for all patients at high cost to critical structures. For Group 2, IMRT decreased bladder V(45 Gy) by 90%, rectum V(45 Gy) by 54% and small bowel V(45 Gy) by 455 cm3 compared with EF 3DCRT.
In this study WP 3DCRT missed a significant percentage of pelvic nodes. Although EF 3DCRT achieved 95% pelvic nodal coverage, it increased critical structure doses. IMRT improved pelvic nodal coverage while decreasing dose to bladder, rectum, small bowel, and penile bulb. For patients with extended node involvement, IMRT especially decreases small bowel dose.
International Journal of Radiation OncologyBiologyPhysics 12/2006; 66(3):654-62. · 4.11 Impact Factor
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ABSTRACT: To describe in detail a forward-planned multisegment technique (FPMS) as an alternative treatment method for patients who are not suitable for inverse-planned intensity-modulated radiation therapy (IP-IMRT), or for situations where IP-IMRT is not available in a medical clinic.
Between April 1995 and February 2002, 38 primary head-and-neck patients were treated using the FPMS technique, which has evolved over the past 7 years at our medical center. In the most recent version of the FPMS technique, which includes 5 patients examined in this analysis, the primary tumor and the upper neck nodes were treated with 7 gantry angles, including an anterior, 2 lateral, 2 anterior oblique, and 2 posterior oblique beams with a total of 13 beam shapes formed by multileaf collimators (MLC), called MLC segments. The shape of each MLC segment was carefully designed, and the associated weights were optimized through manual iterations. The lower neck nodes and the supraclavicular nodes were treated with a split-beam anterior field, matched to the inferior border of the FPMS plan at the isocenter. With an autosequencing delivery system, all fields, including dynamic wedges, can be automatically treated. The dosimetric accuracy of this technique was verified with a phantom plan and measured with an ionization chamber, as well as film dosimetry. A sample FPMS plan is described in detail, and the average results for the 5 patients treated with FPMS are retrospectively compared to results for similar patients treated with IP-IMRT.
The gross tumor volume was prescribed to 70 Gy (2.12 Gy/fraction) at the 88% isodose line, whereas the clinical target volume received a dose of 59.4 Gy (1.8 Gy/fraction) at the 75% isodose line. The maximum dose to the brainstem and spinal cord was below 54 and 45 Gy, respectively, comparable to IP-IMRT. The mean dose to the parotid glands was 32 Gy with FPMS vs. 26 Gy with IP-IMRT. Average delivery time was shorter for FPMS (15 min) than IP-IMRT (30 min), whereas the planning time depended on the expertise of the planner. Dosimetric accuracy for FPMS and IP-IMRT plans using phantom measurements was similar, within 1% of the phantom plan. With a median follow-up of 31 months, there was no local-regional recurrence, and the incidence of xerostomia is reduced compared to conventional techniques.
FPMS achieved plans comparable to those for IP-IMRT and is an ideal alternative treatment technique for a center without the capabilities of IP-IMRT or for a patient who is not a suitable candidate, because of prolonged treatment time. The treatment outcomes from our clinical experience indicate that FPMS can achieve excellent local freedom from progression rates without causing excessive toxicity. Lastly, IP-IMRT plans should be comparable to, if not better than, FPMS plans in the treatment of head-and-neck cancer.
International Journal of Radiation OncologyBiologyPhysics 07/2004; 59(2):584-94. · 4.11 Impact Factor
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ABSTRACT: To review the University of California-San Francisco (UCSF) experience of using intensity-modulated radiation therapy (IMRT) to treat head-and-neck cancer focusing on the importance of target volume delineation and adequate target volume coverage.
Between April 1995 and January 2002, 150 histologically confirmed patients underwent IMRT for their head-and-neck cancer at our institution. Sites included were nasopharynx 86, oropharynx 22, paranasal sinus 22, thyroid 6, oral tongue 3, nasal cavity 2, salivary 2, larynx 2, hypopharynx 1, lacrimal gland 1, skin 1, temporal bone 1, and trachea 1. One hundred seven patients were treated definitively with IMRT +/- concurrent platinum chemotherapy (92/107), whereas 43 patients underwent gross surgical resection followed by postoperative IMRT +/- concurrent platinum chemotherapy (15/43). IMRT was delivered using three different techniques: 1) manually cut partial transmission blocks, 2) computer-controlled auto-sequencing segmental multileaf collimator, and 3) sequential tomotherapy using dynamic multivane intensity-modulating collimator. Forty-two patients were treated with a forward plan, 102 patients with an inverse plan, and 6 patients with both forward and inverse plans. The gross target volume (GTV) was defined as tumor detected on physical examination or imaging studies. In postoperative cases, the GTV was defined as the preoperative gross tumor volume. The clinical target volume (CTV) included all potential areas at risk for microscopic tumor involvement by either direct extension or nodal spread including a margin for patient motion and setup errors. The average prescription doses to the GTV were 70 Gy and 66 Gy for the primary and the postoperative cases, respectively. The site of recurrence was determined by the diagnostic neuroradiologist to be either within the GTV or the CTV volume by comparison of the treatment planning computed tomography with posttreatment imaging studies.
For the primary definitive cases with a median follow-up of 25 months (range 6 to 78 months), 4 patients failed in the GTV. The 2- and 3-year local freedom from progression (LFFP) rates were 97% and 95%. With a median follow-up of 17 months (range 8 to 56 months), 7 patients failed in the postoperative setting. The 2-year LFFP rate was 83%. For the primary group, the average maximum, mean, and minimum doses delivered were 80 Gy, 74 Gy, 56 Gy to the GTV, and 80 Gy, 69 Gy, 33 Gy to the CTV. An average of only 3% of the GTV and 3% of the CTV received less than 95% of the prescribed dose. For the postoperative group, the average maximum, mean, and minimum doses delivered were 79 Gy, 71 Gy, 37 Gy to the GTV and 79 Gy, 66 Gy, 21 Gy to the CTV. An average of only 6% of the GTV and 6% of the CTV received less than 95% of the prescribed dose.
Accurate target volume delineation in IMRT treatment for head-and-neck cancer is essential. Our multidisciplinary approach in target volume definition resulted in few recurrences with excellent LFFP rates and no marginal failures. Higher treatment failure rates were noted in the postoperative setting in which lower doses were prescribed. Potential dose escalation studies may further improve the local control rates in the postoperative setting.
International Journal of Radiation OncologyBiologyPhysics 10/2003; 57(1):49-60. · 4.11 Impact Factor
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ABSTRACT: To compare intensity-modulated radiotherapy (IMRT) treatment planning with three-dimensional conformal radiotherapy (3D-CRT) planning for paranasal sinus carcinoma.
Treatment plans using traditional 3-field technique, 3D-CRT planning, and inverse planning IMRT were developed for a case of paranasal sinus cancer requiring adjuvant radiotherapy. Plans were compared with respect to dose conformality, dose-volume histograms, doses to critical normal tissues, and ease of treatment delivery.
The inverse-planned IMRT technique was more conformal around the tumor target volume than conventional techniques. The dose-volume histograms demonstrated significantly better critical normal-tissue sparing with the IMRT plans, while able to deliver a minimum dose of 60 Gy to the clinical tumor volume and 70 Gy to the gross tumor volume. Acute toxicities in our analysis were minimal.
IMRT planning provided improved tumor target coverage when compared to 3D-CRT treatment planning. There was significant sparing of optic structures and other normal tissues, including the brainstem. Inverse planning IMRT provided the best treatment for all paranasal sinus carcinomas, but required stringent immobilization criteria. Further studies are needed to establish the true clinical advantage of this modality.
International Journal of Radiation OncologyBiologyPhysics 06/2003; 56(1):158-68. · 4.11 Impact Factor
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ABSTRACT: To update our experience with intensity-modulated radiotherapy (IMRT) in the treatment of nasopharyngeal carcinoma (NPC).
Between April 1995 and October 2000, 67 patients underwent IMRT for NPC at the University of California-San Francisco (UCSF). There were 20 females and 47 males, with a mean age of 49 (range 17-82). The disease was Stage I in 8 (12%), Stage II in 12 (18%), Stage III in 22 (33%), and Stage IV in 25 (37%). IMRT was delivered using three different techniques: 1) manually cut partial transmission blocks, 2) computer-controlled auto-sequencing segmental multileaf collimator (SMLC), and 3) sequential tomotherapy using a dynamic multivane intensity modulating collimator (MIMiC). Fifty patients received concomitant cisplatinum and adjuvant cisplatinum and 5-FU chemotherapy according to the Intergroup 0099 trial. Twenty-six patients had fractionated high-dose-rate intracavitary brachytherapy boost and 1 patient had gamma knife radiosurgery boost after external beam radiotherapy. The prescribed dose was 65-70 Gy to the gross tumor volume (GTV) and positive neck nodes, 60 Gy to the clinical target volume (CTV), 50-60 Gy to the clinically negative neck, and 5-7 Gy in 2 fractions for the intracavitary brachytherapy boost. Acute and late normal tissue effects were graded according to the Radiation Therapy Oncology Group (RTOG) radiation morbidity scoring criteria. The local progression-free, local-regional progression-free, distant metastasis-free rates, and the overall survival were calculated using the Kaplan-Meier method.
With a median follow-up of 31 months (range 7 to 72 months), there has been one local recurrence at the primary site. One patient failed in the neck. Seventeen patients developed distant metastases; 5 of these patients have died. The 4-year estimates of local progression-free, local-regional progression-free, and distant metastases-free rates were 97%, 98%, and 66% respectively. The 4-year estimate of overall survival was 88%. The worst acute toxicity documented was as follows: Grade 1 or 2 in 51 patients, Grade 3 in 15 patients, and Grade 4 in 1 patient. The worst late toxicity was Grade 1 in 20 patients, Grade 2 in 15 patients, Grade 3 in 7 patients, and Grade 4 in 1 patient. At 3 months after IMRT, 64% of the patients had Grade 2, 28% had Grade 1, and 8% had Grade 0 xerostomia. Xerostomia decreased with time. At 24 months, only one of the 41 evaluable patients had Grade 2, 32% had Grade 1, and 66% had Grade 0 or no xerostomia. Analysis of the dose-volume histograms (DVHs) showed that the average maximum, mean, and minimum dose delivered were 79.3 Gy, 74.5 Gy, and 49.4 Gy to the GTV, and 78.9 Gy, 68.7 Gy, and 36.8 Gy to the CTV. An average of only 3% of the GTV and 3% of the CTV received less than 95% of the prescribed dose.
Excellent local-regional control for NPC was achieved with IMRT. IMRT provided excellent tumor target coverage and allowed the delivery of a high dose to the target with significant sparing of the salivary glands and other nearby critical normal tissues.
International Journal of Radiation OncologyBiologyPhysics 06/2002; 53(1):12-22. · 4.11 Impact Factor
