The potential use of intensity modulated radiotherapy (IMRT) in women with pectus excavatum desiring breast-conserving therapy

The purpose of this study was to determine if intensity modulated radiation therapy (IMRT) offers a better treatment plan compared to conventional radiotherapy for patients with pectus excavatum desiring breast-conserving therapy and to assess the feasibility of simultaneous modulated accelerated radiation therapy (SMART) boost. A patient with pectus excavatum desired breast-conserving therapy for her early stage breast cancer. She underwent lumpectomy and axillary lymph node dissection followed by chemotherapy. She was then referred for radiotherapy. A breast board (Med-Tec) with aquaplast body cast was used to limit the movement of the patient, chest wall, and breasts before planning a computed tomography (CT) scan. IMRT including dose-volume histogram (DVH) was compared to that of the conventional plan using parallel opposed tangential beams with a 15-degree wedge pair. Forty-five gray was prescribed to the whole breast to each plan, while 50 Gy was prescribed to the tumor bed using IMRT with SMART boost in 25 fractions over 5 weeks. The coverage of the whole breast was adequate for both plans. IMRT allowed a more homogeneous dose distribution within the breast at the desired dose range. With IMRT there is less volume of ipsilateral lung receiving the radiation dose that is above the tolerance threshold of 15 Gy when compared to that of the conventional plan. However, there is more volume of surrounding normal tissues (the heart, spinal cord, and contralateral breast and lung) receiving low-dose irradiation when IMRT was employed. SMART boost was feasible, allowing a mean dose of 57 Gy to be delivered to the tumor bed simultaneously along with the rest of the breast in 5 weeks. IMRT is feasible in treating early breast cancer patients with pectus excavatum by decreasing the ipsilateral lung volume receiving high-dose radiation when compared to the conventional method. SMART boost shortens the overall treatment time that may have potential radiobiological benefit.

Malignant meningioma: an indication for initial aggressive surgery and adjuvant radiotherapy

Malignant meningiomas constitute a rare subset of meningiomas and display a marked propensity for postsurgical recurrence. This retrospective study evaluates the various parameters which alter the recurrence rate. The records of all malignant meningioma patients treated from 1984 through 1992 were reviewed, and the time to recurrence or current patient status was determined, and the influence of various patient and disease parameters were analyzed. Thirty-eight patients were treated with 48 malignant meningioma resections performed (28 total and 20 subtotal), 25 at initial presentation and 23 for recurrent disease; 19 patients received postoperative radiotherapy. Subtypes included 32 anaplastic meningioma, 11 hemangiopericytoma, 2 meningiosarcoma, and 3 papillary meningioma. Followup ranged from 3 to 144 months, with five patients excluded from analysis. Actuarial disease free/progression free survival (DFS) at 5 years was 39% following total resection versus 0% after subtotal resection (p=0.001). For all totally excised lesions, the 5-yr DFS was improved from 28% for surgery alone to 57% with adjuvant radiotherapy (p=NS). Adjuvant irradiation following initial resection increased the 5-yr DFS rates from 15% to 80% (p=0.002). When administered for recurrent lesions, adjuvant radiotherapy improved the 2-yr DFS from 50% to 89% (p=0.015), but had no impact on 5-yr DFS. Multivariate analysis indicates extent of resection, adjuvant radiotherapy, and recurrence status are independent prognostic factors. Malignant meningiomas display a tendency for post surgical recurrence, with recurrence significantly increased for multicentric and recurrent disease. Complete surgical resection and the administration of adjuvant irradiation following initial resection are crucial to long-term control.

The Baylor College of Medicine experience with gold seed implantation

Advances in imaging technology and implant technique have led to the resurgent interest and practice of brachytherapy for the treatment of prostate cancer. Brachytherapy is a form of radiation treatment in which radioactive sources are placed directly into the tumor; it offers the advantage of maximizing the radiation dose delivered to the tumor while sparing the adjacent normal tissue. Permanent implants have become an important component of radiation delivery. Interstitial gold radioisotope (Au-198) implants for prostate cancer were introduced at Baylor College of Medicine in 1965. The rationale for using Au-198, instead of the two most commonly used radioisotopes, Palladium-103 (Pd-103) and Iodine-125 (I-125), is discussed, and the Baylor implant technique is compared to that used in other centers. Retrospective review divides the patient population into pre-ultrasound versus post-ultrasound eras. Dosimetric calculation and disease control with the Au-198 seed implant for prostatic cancer are reviewed for the two different eras; toxicity is evaluated in the post-ultrasound era only. In the pre-ultrasound era, 510 patients were treated with pelvic lymph node sampling and gold seed insertion of the prostate followed by external beam radiation. In the post-ultrasound era, 54 patients were treated definitively with ultrasound-guided transperineal Au-198 implant followed by external beam irradiation. A small group of 30 patients in the post-ultrasound era were evaluated for the efficacy of Au-198 re-implantation for locally recurrent disease.

Treatment of secretory pituitary adenoma with radiation therapy

A retrospective review of 44 patients with secretory pituitary adenoma treated with radiation therapy (median total dose of 4,500 cGy with a median fraction size of 225 cGy) was performed to analyze response rates and possible variables associated with failure to respond and with complications. The treatment technique used for 75% of the patients was a combination field; an opposed-lateral fields technique was used for the remainder. Median follow-up was 78.5 months, with 59% followed up for more than 60 months and 34% for more than 120 months. Overall survival was 90%, and disease-free survival was 62%. Response rates were 86% for the group with prolactinoma, 67% for the group with acromegaly, and 50% for the group with Cushing disease; the overall response rate was 71%. Findings of suprasellar extension and those from treatment with opposed-lateral fields correlated significantly with failure to respond. A higher percentage of patients with invasive macroadenomas also failed to respond. More complications were found in patients treated with opposed-lateral fields, but the numbers were too small to reach significance. Radiation therapy remains an important adjunct for the treatment of many patients with secretory pituitary adenoma.

Interstitial radiogold implantation for the treatment of recurrent high-grade gliomas

Thirty-three patients were treated at the Methodist Hospital, Baylor College of Medicine (Houston) between 1983 and 1987, for high-grade gliomas which had recurred after conventional external-beam radiation therapy. The mean dose to the tumor volume from the external-beam therapy was 5800 cGy. Thirteen patients had recurrent astrocytoma Grade 4 (glioblastoma), whereas 20 had recurrent astrocytoma Grade 3 (anaplastic astrocytoma). All patients were treated for their recurrence by the combination of reexcision of as much of the tumor mass as was technically feasible and intraoperative radiogold (198Au) seed implantation of the residual tumor and/or tumor bed. The mean dose to the tumor volume from the implant was 4000 cGy. For the 13 patients treated for recurrent glioblastoma the 1-year, 2-year, and 3-year survival rates were 46%, 15%, and 8%, respectively. For the 20 patients treated for recurrent anaplastic astrocytoma the 1-year, 2-year, and 3-year survival rates were 75%, 50%, and 15%, respectively. Survival was measured from the time of implant. The median survival for patients with glioblastoma was 9 months. The median survival for patients with anaplastic astrocytoma was 17 months. One patient died in the immediate postoperative period from a gastrointestinal bleed. No patient required reoperation for radiation necrosis. The authors believe that this technique is an effective treatment for patients with high-grade gliomas recurring after external-beam radiation therapy, and are now including interstitial irradiation in the initial management of selected patients with high-grade gliomas.