Radioactive bone cement for the treatment of spinal metastases: a dosimetric analysis of simulated clinical scenarios.

Vertebral metastases are a common manifestation of many cancers, potentially leading to vertebral collapse and neurological complications. Conventional treatment often involves percutaneous vertebroplasty/kyphoplasty followed by external beam radiation therapy. As a more convenient alternative, we have introduced radioactive bone cement, i.e. bone cement incorporating a radionuclide. In this study, we used a previously developed Monte Carlo radiation transport modeling method to evaluate dose distributions from phosphorus-32 radioactive cement in simulated clinical scenarios. Isodose curves were generally concentric about the surface of bone cement injected into cadaveric vertebrae, indicating that dose distributions are relatively predictable, thus facilitating treatment planning (cement formulation and dosimetry method are patent pending). Model results indicated that a therapeutic dose could be delivered to tumor/bone within ∼4 mm of the cement surface while maintaining a safe dose to radiosensitive tissue beyond this distance. This therapeutic range should be sufficient to treat target volumes within the vertebral body when tumor ablation or other techniques are used to create a cavity into which the radioactive cement can be injected. With further development, treating spinal metastases with radioactive bone cement may become a clinically useful and convenient alternative to the conventional two-step approach of percutaneous strength restoration followed by radiotherapy.

Brachytherapy for primary and recurrent nasopharyngeal carcinoma: 20 years' experience at Long Beach Memorial.

PURPOSE: We evaluated treatment outcomes of patients with mostly locally advanced primary and recurrent cancer of the nasopharynx managed with interstitial and intraluminal brachytherapy. METHODS AND MATERIALS: This is a retrospective analysis of 56 patients with cancer arising from the nasopharynx treated with interstitial and intracavitary afterloading brachytherapy from 1978 to 1997. Patients were divided into three treatment groups: 15 patients with primary cancer (Group 1), 34 patients with recurrent or persistent disease (Group 2), and 7 patients with cancer in the nasopharynx who had history of previous definitive radiation therapy to the nasopharynx for head and neck cancer (Group 3). Fifty-three percent of patients in Group 1 had 1992 AJCC Stage IV disease, and 49% of patients in Groups 2 and 3 had extensive disease (defined as T3, T4, or parapharyngeal extension). Group 1 received megavoltage radiation to 50-60 Gy followed by a boost to the primary site and neck (in cases of persistent neck disease) with a combination of interstitial and intracavitary brachytherapy (mean dose 33-37 Gy). Five patients received chemotherapy, and 6 patients received hyperthermia. Groups 2 and 3 patients were treated with brachytherapy implants (mean dose 50-58 Gy) without external beam radiation. Twenty-five patients received chemotherapy either before or during radiation, and 21 patients received hyperthermia. RESULTS: The overall survival at 2, 5, and 10 years for patients in Group 1 was 79%, 61%, and 61%, respectively, and for patients in Groups 2 and 3 combined was 48%, 30%, and 20%, respectively. Cause-specific survival at 2, 5, and 10 years was 87%, 74%, and 74%, respectively, for patients in Group 1; and 82%, 60%, and 60%, respectively, for patients in Groups 2 and 3. Local control at 2, 5, and 10 years was 93%, 93%, and 77%, respectively, for patients in Group 1; and 81%, 59%, and 49%, respectively, for patients in Groups 2 and 3. Control in the neck at 2, 5, and 10 years was achieved in 93%, 93%, and 93% of patients, respectively, in Group 1; and 88%, 81%, and 81%, respectively, for patients in Groups 2 and 3. Disease-free survival was 87%, 74%, and 62%, respectively, for patients in Group 1, and 56%, 41%, and 34%, respectively, for patients in Groups 2 and 3. There were 4 peri-operative deaths. One death (2%) was attributable to the development of late complications. Forty-five percent of patients experienced some form of late complications. CONCLUSION: Interstitial afterloading brachytherapy can provide effective treatment for nasopharyngeal cancers, especially for locally persistent/recurrent and locally extensive lesions.

Radiation-induced CA 125 production by mesothelial cells.

CA 125 levels are often falsely elevated in disease-free endometrial cancer patients who have undergone abdominal radiation therapy. Because peritoneal irritation or mediators of inflammation can induce CA 125 production in mesothelium, the possibility that irradiated cultured mesothelial cells secrete CA 125 was investigated. Seven mesothelial cell isolates, an ovarian cell line which does not secrete CA 125, normal mammary epithelium, and normal fibroblasts were exposed to 500 cGy of 6-MV photon irradiation. Irradiated mesothelial cells showed little or no growth, while untreated cells increased in number. Twenty-four-hour CA 125 production was measured in the tissue culture medium on Day 4, and daily for one mesothelial cell isolate. Radiation stimulated CA 125 secretion in mesothelial cells up to 32 times over nonirradiated controls. The time course study showed that CA 125 levels increased rapidly in irradiated cells by Day 3 and remained elevated for the next 3 days. Increased immunoreactivity for p53 in irradiated mesothelial cells confirmed that a protein known to be radiation-inducible could be produced by the same conditions. Normal fibroblasts, mammary epithelium, and the ovarian cell line did not produce CA 125 in either the presence or absence of radiation. Thus, irradiated mesothelial cells are a potential source of serum CA 125 in patients who have received abdominal irradiation.

Extent of disease as an indication for pelvic radiation following radical hysterectomy and bilateral pelvic lymph node dissection in the treatment of stage IB and IIA cervical carcinoma.

The role of adjuvant pelvic radiation following radical hysterectomy and pelvic lymph node dissection in the treatment of stage IB and IIA cervical cancer is controversial. Patients most likely to benefit from postoperative radiation include those with lesions that invade deeply into the cervical stroma, extend into the parametria, or have metastasized to regional lymph nodes. Between 1977 and 1987, 95 patients were treated with this combined regimen at the University of California Irvine Medical Center and Long Beach Memorial Medical Center, including 30 patients with deep cervical stromal invasion alone, 9 patients with parametrial extension alone, 37 patients with lymph node metastasis alone, and 19 patients with both positive nodes and parametrial extension. The estimated 5-year survival for this high-risk population was 67%. Pelvic recurrences alone occurred in 12 (13%) patients, and 14 additional patients (15%) recurred outside of the radiation field. In the node-positive group, the 5-year survival was 78% when the parametrium was not involved but decreased to 39% when parametrial extension was documented (P < 0.05). Patients with grossly involved nodes or multiple nodal metastases were also more likely to recur. Finally, the estimated 5-year survival for patients with deep cervical stromal invasion as the sole indication for radiotherapy was 73%. A retrospective analysis identified tumor grade and cell type also to be of prognostic importance. Severe complications attributable to radiation combined with radical surgery included two small bowel obstructions and one urinary tract fistula. These data suggest that radical hysterectomy, pelvic lymphadenectomy, and adjuvant radiotherapy produce favorable survival results with limited morbidity in patients with high-risk cervical cancer independent of node status except in that subset of patients with both occult parametrial spread and nodal metastasis.

Open interstitial brachytherapy for the treatment of local-regional recurrences of uterine corpus and cervix cancer after primary surgery.

Patients who develop locally recurrent uterine corpus or uterine cervix cancer after primary surgery are usually treated with radiotherapy. The optimal radiotherapeutic approach, however, has not been defined. We report the use of exploratory laparotomy, omental pedicle grafting, and intraoperative transperineal interstitial brachytherapy in the treatment of 28 such patients (10 with recurrent corpus and 18 with recurrent cervix cancer). In addition, 22 patients also received perioperative whole pelvic teletherapy while 21 also received a second closed interstitial application. Local control was achieved in 20 patients (71%), but only 10 (36%) continue to be alive without disease after a median of 44 months. Eighteen patients have died (17 of disease) a median of 13 months after open implant. Patients treated with a single implant (n = 7), with side wall involvement (n = 5), with tumors greater than 6 cm in size (n = 4), with a history of previous pelvic irradiation (n = 8), or with persistent disease after open interstitial therapy (n = 8), were not salvaged. Ten patients suffered acute morbidity which included deep venous thrombosis (n = 1), wound separation (n = 1), urinary infection (n = 2), wound infection (n = 2), pneumonia (n = 1), and fever (n = 3). Two other patients experienced chronic non-tumor-related comorbidities. These included a vesicovaginal fistula with a rectovaginal fistula in 1 patient and a small bowel obstruction with a ureteral stricture in another. A single individual suffered from both acute and chronic complications (fever, ureterointestinal fistula).(ABSTRACT TRUNCATED AT 250 WORDS)