Evaluation of the ESMO-Magnitude of Clinical Benefit Scale version 1.1 (ESMO-MCBS v1.1) for adjuvant radiotherapy in breast cancer.

BACKGROUND: The European Society of Medical Oncology (ESMO) has suggested using the ESMO-Magnitude of Clinical Benefit Scale (MCBS) to grade the magnitude of clinical benefit of cancer therapies. This approach has not been applied to radiation therapy (RT) yet. We applied the ESMO-MCBS to experiences describing the use of RT to assess (1) the 'scoreability' of the data, (2) evaluate the reasonableness of the grades for clinical benefit and (3) identify potential shortcomings in the current version of the ESMO-MCBS in its applicability to RT. MATERIALS AND METHODS: We applied the ESMO-MCBS v1.1 to a selection of studies in radiotherapy that had been identified as references in the development of American Society for Radiation Oncology (ASTRO) evidence-based guidelines on whole breast radiation. Of the 112 cited references, we identified a subset of 16 studies that are amenable to grading using the ESMO-MCBS. RESULTS: Of the 16 studies reviewed, 3/16 were scoreable with the ESMO tool. Six of 16 studies could not be scored because of shortcomings in the ESMO-MCBS v1.1: (1) in 'non-inferiority studies', there is no credit for improved patient convenience, reduced patient burden or improved cosmesis; (2) in 'superiority studies' evaluating local control as a primary endpoint, there is no credit for the clinical benefit such as reduced need for further interventions. In 7/16 studies, methodological deficiencies in the conduct and reporting were identified. CONCLUSIONS: This study represents a first step in determining the utility of the ESMO-MCBS in the evaluation of clinical benefit in radiotherapy. Important shortcomings were identified that would need to be addressed in developing a version of the ESMO-MCBS that can be robustly applied to radiotherapy treatments. Optimization of the ESMO-MCBS instrument will proceed to enable assessment of value in radiotherapy.

Prophylactic irradiation to the contralateral breast for BRCA mutation carriers with early-stage breast cancer.

BACKGROUND: Women who carry germ-line mutations in BRCA1/2 are at very high risk of developing breast and ovarian cancer. Breast conserving therapy is associated with a similar risk of ipsilateral cancer recurrence in BRCA carriers compared with non-carriers. However, the risk of subsequent contralateral breast cancer in carriers is markedly increased. Therefore, mastectomy of the diseased breast along with risk reducing mastectomy of the contralateral breast is often advocated for BRCA carriers who are treated for early breast cancer. Yet, many BRCA carriers forgo this option for fear of harmful effects and choose breast conserving treatment and observation instead. In Israel, BRCA-associated breast cancer is relatively common. Accordingly, a national protocol was devised for this enriched population. PATIENTS AND METHODS: In this Institutional Review Board-approved phase II trial, the option of prophylactic irradiation to the contralateral breast, in addition to standard loco-regional treatment, was offered to BRCA carrier patients treated for early breast cancer who declined contralateral mastectomy. The primary end point was contralateral breast cancer. RESULTS: Between May 2007 and October 2017, 162 patients were enrolled. Eighty-one patients opted for standard loco-regional treatment including surgery and radiation to the involved side (control arm) and 81 patients chose additional contralateral breast irradiation (intervention arm). At a median follow-up of 58 months, 10 patients developed contralateral breast cancer in the control arm at a median of 32 months, as compared with 2 patients in the intervention arm who developed contralateral breast cancer 80 and 105 months after bilateral breast irradiation (log-rank P = 0.011). CONCLUSIONS: Among BRCA carrier patients treated for early breast cancer, the addition of contralateral breast irradiation was associated with a significant reduction of subsequent contralateral breast cancers and a delay in their onset. CLINICAL TRIAL: Phase II, comparative two-arm trial (NCT00496288).

Hypofractionated adjuvant radiation therapy of soft-tissue sarcoma achieves excellent results in elderly patients.

OBJECTIVE: Adjuvant radiation therapy (RT) is an essential part of combined limb-sparing treatment of soft-tissue sarcoma (STS). Elderly or medically unfit patients often have difficulty in completing 6-7 weeks of standard fractionated daily treatment. Our aim was to evaluate the efficacy of a hypofractionated adjuvant approach with RT for STS in elderly and debilitated patients. METHODS: 21 elderly patients were treated with a short course of adjuvant RT (39-48 Gy, 3 Gy per fraction) for STS. The medical records of the patients were retrospectively reviewed for local or distant recurrence and side effects of RT. RESULTS: At a mean 26 months of follow-up, three local recurrences (14%) were detected. Eight patients (38%) had lung metastases during the observed period. Three of them died from metastatic disease. The hypofractionated radiation was well tolerated with minimum long-term side effects. CONCLUSION: Hypofractionated adjuvant radiation appears to be an effective treatment in terms of local control in elderly and debilitated patients. ADVANCES IN KNOWLEDGE: The results of this study might provide an alternative to commonly used standard fractionation of radiotherapy in sarcoma patients.

Patterns of missing mini mental status exam (MMSE) in radiation therapy oncology group (RTOG) brain cancer trials.

The Mini Mental Status Exam (MMSE) instrument has been commonly used in the Radiation Therapy Oncology Group (RTOG) to assess mental status in brain cancer patients. Evaluating patient factors in relation to patterns of incomplete MMSE assessments can provide insight into predictors of missingness and optimal MMSE collection schedules in brain cancer clinical trials. This study examined eight RTOG brain cancer trials with ten treatment arms and 1,957 eligible patients. Patient data compliance patterns were categorized as: (1) evaluated at all time points (Complete), (2) not evaluated from a given time point or any subsequent time points but evaluated at all the previous time points (Monotone drop-out), (3) not evaluated at any time point (All missing), and (4) all other patterns (Mixed). Patient characteristics and reasons for missingness were summarized and compared among the missing pattern groups. Baseline MMSE scores and change scores after radiation therapy (RT) were compared between these groups, adjusting for differences in other characteristics. There were significant differences in frequency of missing patterns by age, treatment type, education, and Zubrod performance status (ZPS; P < 0.001). Ninety-two percent of patients were evaluated at least once: seven percent of patients were complete pattern, 49% were Monotone pattern, and 36% were mixed pattern. Patients who received RT only regimens were evaluated at a higher rate than patients who received RT + other treatments (49-64% vs. 27-45%). Institutional error and request to not be contacted were the most frequent known reasons for missing data, but most often, reasons for missing MMSE was unspecified. Differences in baseline mean MMSE scores by missing pattern (Complete, Monotone dropout, Mixed) were statistically significant (P < 0.001) but differences were small (<1.5 points) and significance did not persist after adjustment for age, ZPS, and other factors related to missingness. Post-RT change scores did not differ significantly by missing pattern. While baseline and change scores did not differ widely by missing pattern for available measurements, incomplete data was common and of unknown reason, and has potential to substantially bias conclusions. Higher compliance rates may be achievable by addressing institutional compliance with assessment schedules and patient refusal issues, and further exploration of how educational and health status barriers influence compliance with MMSE and other tools used in modern neurocognitive batteries.

Memory performance used to detect radiation effects on cognitive functioning.

Although radiotherapy remains a necessary and frequently used treatmentfor brain tumors, uncertainty remains about the nature and severity of neurocognitive morbidity. We show that verbal-semantic memory (free recall of word list) is sensitive to damaging radiation effects in 20 patients with low-grade, supratentorial, primary brain tumors who received moderate doses of partial-brain irradiation. We previously reported that verbal-semantic memory is dissociated from visual memory (acquisition and recall) during the same phase ofradiation effects, indicating that memory is differentially affected by radiation. In this study, we provide evidence of the nature of the iatrogenic radiation effect on memory by testing collateral cognitive functions that might explain the specific memory impairment. We found that the verbal-semantic recall impairment was not associated with impairments in auditory attention, auditory processing speed, auditory-verbal working memory, or in the temporal coding or subjective organization of word-list recall. These findings focus damaging radiation effects on primary retrievalprocesses, rather than on earlier cognitive processes or executive processes affecting recall. Knowledge of the specific patterns of change in cognition would guide the differential diagnosis and rehabilitation of survivors of brain tumors whose conditions are complicated by tumors with multiple treatments.

Stereotactic radiosurgery and fractionated stereotactic radiotherapy for the treatment of acoustic schwannomas: comparative observations of 125 patients treated at one institution.

BACKGROUND: Stereotactic radiosurgery (SRS) and, more recently, fractionated stereotactic radiotherapy (SRT) have been recognized as noninvasive alternatives to surgery for the treatment of acoustic schwannomas. We review our experience of acoustic tumor treatments at one institution using a gamma knife for SRS and the first commercial world installation of a dedicated linac for SRT. METHODS: Patients were treated with SRS on the gamma knife or SRT on the linac from October 1994 through August 2000. Gamma knife technique involved a fixed-frame multiple shot/high conformality single treatment, whereas linac technique involved daily conventional fraction treatments involving a relocatable frame, fewer isocenters, and high conformality established by noncoplanar arc beam shaping and differential beam weighting. RESULTS: Sixty-nine patients were treated on the gamma knife, and 56 patients were treated on the linac, with 1 NF-2 patient common to both units. Three patients were lost to follow-up, and in the remaining 122 patients, mean follow-up was 119 +/- 67 weeks for SRS patients and 115 +/- 96 weeks for SRT patients. Tumor control rates were high (> or =97%) for sporadic tumors in both groups but lower for NF-2 tumors in the SRT group. Cranial nerve morbidities were comparably low in both groups, with the exception of functional hearing preservation, which was 2.5-fold higher in patients who received conventional fraction SRT. CONCLUSION: SRS and SRT represent comparable noninvasive treatments for acoustic schwannomas in both sporadic and NF-2 patient groups. At 1-year follow-up, a significantly higher rate of serviceable hearing preservation was achieved in SRT sporadic tumor patients and may therefore be preferable to alternatives including surgery, SRS, or possibly observation in patients with serviceable hearing.

Strong correlation between imaging response and survival among patients with primary central nervous system lymphoma: a secondary analysis of RTOG studies 83-15 and 88-06.

PURPOSE: Primary central nervous system lymphoma (PCNSL) is the brain tumor with the most rapidly increasing incidence, yet little is known about its radiographic response to cranial irradiation. If traditionally used doses of radiotherapy ( approximately 60 Gy) are associated with low rates of complete response and poor survival, then an argument can be made to consider dose escalation of radiotherapy. Alternatively, if poor survival rates are associated with high rates of complete response, there would be no reason to subject patients to higher radiation doses with increased risks of treatment-related morbidity. The purpose of this analysis is to provide a detailed review of response following cranial irradiation. Based on these findings, recommendations are offered for future protocol design. METHODS AND MATERIALS: Patients were treated on either RTOG 83-15 (whole brain irradiation to 40 Gy followed by a 20 Gy boost to the tumor plus 2-cm margin) or RTOG 88-06 (induction cyclophosphamide, doxorubicin, vincristine, dexamethasone [CHOD] followed by whole brain irradiation to 41.4 Gy and an 18 Gy tumor boost). Imaging surveillance (CT, MR) was required following surgery, prior to the initiation of RT and following completion of RT. Complete response referred to the absence of enhancement on follow-up scans in comparison to the pretherapy study. A tumor size reduction of at least 50% in the product of the largest cross-sectional diameter and its largest perpendicular diameter was scored as a partial response. RESULTS: Seventy-nine patients had scans available for central review. Complete response was achieved in 83% and 85% of patients treated on RTOG 83-15 and 88-06, respectively. The rates of partial response (14%, 11%) and radiographic progression (3%, 4%) also were comparable between the studies. For survival analyses, data were aggregated from the two studies. The 4-year survival rates were 24% for complete responders versus 11% for other patients (p = 0.0006). In multivariate analysis, only complete radiographic response (p < 0.0007), and high Karnofsky performance status (KPS >/= 70) (p < 0.005) were independently associated with increased rates of 4-year survival. CONCLUSION: A high rate of complete radiographic response was observed following moderate doses of cranial irradiation (alone or in combination with CHOD chemotherapy). Although complete responders had a statistically significant survival advantage at 4 years when compared with partial responders and nonresponders, the majority of patients who achieved complete response were dead of disease by 4 years following treatment. Based on this analysis of the RTOG database, there is no rationale for radiation dose escalation as a therapeutic strategy to combat PCNSL. Consequently, the radiotherapy component of the current RTOG Phase II trial (RTOG 93-10) now includes relatively low total doses of hyperfractionated irradiation for patients without residual disease (36 Gy/1.2 Gy, twice a day) as well as a more aggressive chemotherapy regimen.

Radiotherapeutic effects on brain function: double dissociation of memory systems.

OBJECTIVE: The neurocognitive sequelae of therapeutic cranial irradiation are not well characterized in adults with primary brain tumors. To address this problem, we prospectively examined neuropsychological findings during two phases of radiation effects. BACKGROUND: Investigations of radiation effects have revealed variable outcomes that range from no radiation-associated morbidity to severe cognitive impairment, but have relied on case reports or retrospective studies of late-delayed changes in white matter or in cognition. No reliable radiographic or neurocognitive tools exist to describe the multiple phases of radiation effects. METHOD: Twenty adult patients (median age, 39 years) from a university hospital were treated with radiotherapy (RT) for low-grade primary brain tumors. Prospective longitudinal neuropsychological studies were compared at baseline (after surgery and before irradiation) and at 3, 6, and 12 months after RT to examine early-delayed effects, including verbal memory changes in 20 patients and visual memory changes in 11 patients. We also examined cognitive changes during the late-delayed phase for up to 3 years after RT and determined whether early-delayed memory deficit predicted late-delayed memory deficit in a small subset of patients. A comprehensive neuropsychological battery was used, including verbal and visual memory tests designed to compare learning, storage, and retrieval. RESULTS: Patients demonstrated normal verbal memory at baseline, decrement, and then rebound in verbal retrieval. Deficit at baseline and recovery up to 1 year after RT defined visual memory. Together, these observations constitute a double dissociation of memory functions. No changes over time were observed in other neurocognitive tests or in fatigue or mood measures. Time-dependent patterns of each long-term memory test were examined in relation to lesion site in individual patients. CONCLUSIONS: The double dissociation of memory functions after RT may provide markers for the damaging and facilitative early-delayed effects of RT. Late-delayed effects were not predicted based on early-delayed changes in a small sample.

Evaluation of the spatial accuracy of magnetic resonance imaging-based stereotactic target localization for gamma knife radiosurgery of functional disorders.

PURPOSE: This study was undertaken to determine the impact of geometric distortions on the spatial accuracy of magnetic resonance imaging (MRI)-guided stereotactic localization for gamma knife functional radiosurgery. METHOD: The spatial accuracy of MRI was evaluated by comparing stereotactic coordinates of intracranial targets, external fiducials, and anatomic structures defined by computed tomographic and MRI studies of the Radionics skull phantom (Radionics, Inc., Burlington, MA), the Rando head phantom, and 11 patients who underwent gamma knife functional radiosurgery. The distortion in MRI was assessed from computed tomographic and MRI fusion studies for these patients, as well as from MRI studies acquired by swapping the direction of the magnetic field gradients for five patients who underwent gamma knife radiosurgery and three patients who underwent MRI-guided frameless surgery. A follow-up program to compare the location of the created lesion with the intended target complemented the analysis. RESULTS: The average difference between computed tomographic and MRI stereotactic coordinates of external fiducials, intracranial targets, and anatomic landmarks was of the order of 1 pixel size (0.9 x 0.9 x 1 mm3) along the x, y, and z axes. The average linear scaling along these axes as determined by fusion studies was approximately 0.8% and consistent with a single pixel. The follow-up studies, available for seven patients, revealed good agreement between the location of the created lesion and the intended target. CONCLUSION: The spatial accuracy of an MRI-based localization system can be comparable to computed tomography-based localization with the added benefit of MRI resolution. Both machine- and object-related MRI distortions can be reduced to an acceptable level with contemporary scanners, optimized scanning sequences, and distortion-resistant stereotactic instruments.

Apoptosis as a predictor of paclitaxel-induced radiosensitization in human tumor cell lines.

Paclitaxel is a deterpene with antitumor activity against a variety of human neoplasms. Paclitaxel cytotoxicity is thought to derive mainly from a stabilization of microtubules as a result of enhanced tubulin polymerization that leads to an accumulation of cells in the mitotic (M) phase of the cell cycle. Because cells in this phase of the cell cycle are known to be radiosensitive, it was thought that paclitaxel, in addition to its direct toxicity, may also sensitize tumor cell populations to radiation. Studies evaluating the radiosensitizing potential of paclitaxel in cultured cells have been equivocal, with only approximately 50% of the tested cell lines showing radiosensitization. To explain this variability, we advanced the hypothesis that the ability of paclitaxel to radiosensitize cells may be inversely correlated to the efficiency with which it induces apoptosis. To test this hypothesis, we studied paclitaxel-induced apoptosis and radiosensitization in seven human tumor cell lines. Approximately one-half of these cell lines showed radiosensitization that was associated with a low apoptotic index (<20% after a 48-h treatment with 10 or 20 nM paclitaxel). The results suggest that the level of apoptosis, after paclitaxel treatment, may predict for paclitaxel-induced radiosensitization, and that it could be introduced as a parameter for the optimization of combined treatment protocols.

Does androgen suppression enhance the efficacy of postoperative irradiation? A secondary analysis of RTOG 85-31. Radiation Therapy Oncology Group.

OBJECTIVES: To evaluate the effect of immediate androgen suppression in conjunction with standard external beam irradiation (RT) versus RT alone on a group of men after prostatectomy who had indications for adjuvant treatment. METHODS: A national prospective randomized trial (Radiation Therapy Oncology Group [RTOG] 85-31) comparing standard external beam RT plus immediate androgen suppression versus external beam RT alone with delayed hormonal treatment at relapse was initiated for patients with locally advanced adenocarcinoma of the prostate. One hundred thirty-nine of the patients in this trial had indications for adjuvant treatment after prostatectomy (eg, capsular penetration, seminal vesicle involvement). Seventy-one of the patients received RT with immediate androgen suppression (luteinizing hormone-releasing hormone [LHRH] agonist); 68 patients received RT alone with hormonal manipulation instituted only at the time of relapse. RESULTS: With a median follow-up of 5 years, the estimated progression-free survival rate (failure defined as prostate-specific antigen [PSA] greater than 0.5 ng/mL) was 65% for the men who received combination therapy and 42% for those treated by RT alone with hormones reserved for relapse (P = 0.002). Differences in the rates of freedom from biochemical relapse were observed when failure was defined as PSA of 1.0 to 3.9 ng/mL (71% versus 46%; P = 0.008) and PSA greater than 4.0 ng/mL (76% versus 55%; P = 0.05), respectively. No differences were observed between the groups with respect to the end points of local control, distant failure, and overall survival. The use of immediate androgen suppression (ie, LHRH agonists) and the absence of pathologic nodal involvement were independently associated with prolongation of freedom from biochemical relapse by multivariate analysis. CONCLUSIONS: Patients with prostate cancer and indications for postoperative RT should be considered for combined RT and hormonal manipulation. Because statistically significant advantages for this experimental approach could not be defined for all end points studied (in particular, overall survival), efforts should be made to enroll these patients in the recently activated RTOG trial (96-01) comparing RT plus placebo to the combination of RT plus Casodex in the postoperative setting.

Variation of clinical target volume definition in three-dimensional conformal radiation therapy for prostate cancer.

PURPOSE: Currently, three-dimensional conformal radiation therapy (3D-CRT) planning relies on the interpretation of computed tomography (CT) axial images for defining the clinical target volume (CTV). This study investigates the variation among multiple observers to define the CTV used in 3D-CRT for prostate cancer. METHODS AND MATERIALS: Seven observers independently delineated the CTVs (prostate +/- seminal vesicles [SV]) from the CT simulation data of 10 prostate cancer patients undergoing 3D-CRT. Six patients underwent CT simulation without the use of contrast material and serve as a control group. The other 4 had urethral and bladder opacification with contrast medium. To determine interobserver variation, we evaluated the derived volume, the maximum dimensions, and the isocenter for each examination of CTV. We assessed the reliability in the CTVs among the observers by correlating the variation for each class of measurements. This was estimated by intraclass correlation coefficient (ICC), with 1.00 defining absolute correlation. RESULTS: For the prostate volumes, the ICC was 0.80 (95% confidence interval [CI]: 0.56-0.96). This changed to 0.92 (95% CI: 0.75-0.99) with the use of contrast material. Similarly, the maximal prostatic dimensions were reliable and improved. There was poor agreement in defining the SV. For this structure, the ICC never exceeded 0.28. The reliability of the isocenter was excellent, with the ICC exceeding 0.83 and 0.90 for the prostate +/- SV, respectively. CONCLUSIONS: In 3D-CRT for prostate cancer, there was excellent agreement among multiple observers to define the prostate target volume but poor agreement to define the SV. The use of urethral and bladder contrast improved the reliability of localizing the prostate. For all CTVs, the isocenter was very reliable and should be used to compare the variation in 3D dosimetry among multiple observers.

Palliative treatment of epidemic Kaposi sarcoma of the feet.

Limited information is available in the medical literature on epidemic Kaposi sarcoma (EKS) of the foot. Patients with EKS of the foot can experience severe discomfort that makes it difficult to ambulate and even wear shoes. Between 1985 and 1996, 36 patients with EKS of the foot were treated with palliative intent. Most patients were referred for radiation therapy because of foot discomfort or marked difficulty with ambulation. From the pool of 36 patients, data were available at completion of treatment for 46 sites, and at 1 month for 44 sites. Morbidity was assessed for 35 sites. The median follow-up time for the 44 sites with at least 1 month follow-up was 8 months. The most frequently used regimen was a novel fractionation schedule of three fractions a week at 3.5 Gy/fx to a total dose of 21.0 Gy. The overall response rate and complete response rate for the 44 sites with at least 1 month follow-up were 91% and 80%, respectively. The 46 treated sites evaluated at the completion of treatment had a complete response rate of only 13% and an overall response rate of 63%. Of the 35 sites assessed for acute toxicity, 63% experienced discomfort related to the radiation therapy. This discomfort usually resolved without intervention within 2 weeks of completion of radiation therapy. For patients with and without a history of opportunistic infections, complete responses were observed in 8 of 12 sites (67%) and 25 of 27 sites (93%), respectively (p = 0.06). Radiation therapy for EKS of the foot yields excellent response rates, comparable with responses seen in other cutaneous sites with EKS. Appropriate patient education and support are needed because initial responses to radiation therapy are often disappointing and pedal discomfort can be exacerbated transiently. However, the discomfort resolves and complete response occurs in most patients. The 3.5-Gy triweekly fractionation schedule is a convenient and effective regimen and minimizes treatment visits for patients with ambulatory discomfort. A history of opportunistic infections appears to be a poor prognosticator of response to radiation treatments.

Stereotactic Irradiation: potential new treatment method for brain metastases resulting from ovarian cancer.

Stereotactic irradiation (radiosurgery) is a method of precisely focusing well-defined beams of radiation at small intracranial targets. The technique has been applied to the treatment of brain lesions that are benign (e.g., arteriovenous malformations, meningiomas, pituitary adenomas) and malignant (e.g., gliomas, metastases). This paper introduces preliminary data suggesting the possible value of radiosurgery in the management of ovarian cancer metastatic to the brain. Among 32 women with ovarian cancer metastatic to the brain treated with whole brain irradiation, nine (29%) experienced a complete radiographic response, compared with two of the five patients (40%) treated with radiosurgery. The 2-year survival rate was 60% among those treated with radiosurgery and 15% among those who received whole brain irradiation without radiosurgical boost. Stereotactic irradiation may be of clinical benefit to select patients with brain metastases resulting from ovarian cancer. A prospective randomized trial has been implemented by the Radiation Therapy Oncology Group (RTOG 95-08) to determine whether such observations are reproducible on a national scale.

A phase I dose escalation study of hypofractionated stereotactic radiotherapy as salvage therapy for persistent or recurrent malignant glioma.

PURPOSE: A phase I dose escalation of hypofractionated stereotactic radiotherapy (H-SRT) in recurrent or persistent malignant gliomas as a means of increasing the biologically effective dose and decreasing the high rate of reoperation due to toxicity associated with single-fraction stereotactic radiosurgery (SRS) and brachytherapy. MATERIALS AND METHODS: From November 1994 to September 1996, 25 lesions in 20 patients with clinical and/or imaging evidence of malignant glioma persistence or recurrence received salvage H-SRT. Nineteen patients at the time of initial diagnosis had glioblastoma multiforme (GBM) and one patient had an anaplastic astrocytoma. All of these patients with tumor persistence or recurrence had received initial fractionated radiation therapy (RT) with a mean and median dose of 60 Gy (44.0-72.0 Gy). The median time from completion of initial RT to H-SRT was 3.1 months (0.7-45.5 months). Salvage H-SRT was delivered using daily 3.0-3.5 Gy fractions (fxs). Three different total dose levels were sequentially evaluated: 24.0 Gy/3.0 Gy fxs (five lesions), 30.0 Gy/3.0 Gy fxs (10 lesions), and 35.0 Gy/3.5 Gy fxs (nine lesions). Median treated tumor volume measured 12.66 cc (0.89-47.5 cc). The median ratio of prescription volume to tumor volume was 2.8 (1.4-5.0). Toxicity was judged by RTOG criteria. Response was determined by clinical neurologic improvement, a decrease in steroid dose without clinical deterioration, and/or radiologic imaging. RESULTS: No grade 3 toxicities were observed and no reoperation due to toxicity was required. At the time of analysis, 13 of 20 patients had died. The median survival time from the completion of H-SRT is 10.5 months with a 1-year survival rate of 20%. Neurological improvement was found in 45% of patients. Decreased steroid requirements occurred in 60% of patients. Minor imaging response was noted in 22% of patients. Using Fisher's exact test, response of any kind correlated strongly to total dose (p = 0.0056). None of six lesions treated with 21 Gy or 24 Gy responded, whereas there was a 79% response rate among the 19 lesions treated with 30 or 35 Gy. Tumor volumes < or =20 cc were associated with a higher likelihood of response (p = 0.053). CONCLUSIONS: H-SRT used in this cohort of previously irradiated patients with malignant glioma was not associated with the need for reoperation due to toxicity or grade 3 toxicity. This low toxicity profile and encouraging H-SRT dose-related response outcome justifies further evaluation and dose escalation.

Immediate side effects of stereotactic radiotherapy and radiosurgery.

PURPOSE: Despite increased utilization of fractionated stereotactic radiation therapy (SRT) or stereotactic radiosurgery (SRS), the incidence and nature of immediate side effects (ISE) associated with these treatment techniques are not well defined. We report immediate side effects from a series of 78 patients. MATERIALS AND METHODS: Intracranial lesions in 78 adult patients were treated with SRT or SRS, using a dedicated linear accelerator. Those lesions included 13 gliomas, 2 ependymomas, 19 metastatic tumors, 15 meningiomas, 12 acoustic neuromas, 4 pituitary adenomas, 1 optic neuroma, 1 chondrosarcoma, and 11 arteriovenous malformations (AVM). SRT was used in 51 and SRS in 27 patients. Mean target volume was 9.0 cc. Eleven patients received prior external-beam radiation therapy within 2 months before SRT/SRS. Any side effects occurring during and up to 2 weeks after the course of radiation were defined as ISE and were graded as mild, moderate, or severe. The incidence of ISE and the significance of their association with several treatment and pretreatment variables were analyzed. RESULTS: Overall, 28 (35%) of 78 patients experienced one or more ISE. Most of the ISE (87%) were mild, and consisted of nausea (in 5), dizziness/vertigo (in 5), seizures (in 6), and new persistent headaches (in 17). Two episodes of worsening neurological deficit and 2 of orbital pain were graded as moderate. Two patients experienced severe ISE, requiring hospitalization (1 seizure and 1 worsening neurological deficit). ISE in 6 cases prompted computerized tomography of the brain, which revealed increased perilesional edema in 3 cases. The incidence of ISE by diagnosis was as follows: 46% (6 of 13) for gliomas, 50% (6 of 12) for acoustic neuromas, 36% (4 of 11) for AVM, 33% (5 of 15) for meningiomas, and 21% (4 of 19) for metastases. A higher incidence of dizziness/vertigo (4 of 12 = 33%) was seen among acoustic neuroma patients than among other patients (p< 0.01). There was no significant association of dizziness/vertigo with either a higher average and maximum brainstem dose (p = 0.74 and 0.09, respectively) or with 2-Gy equivalents of the average and maximum brainstem doses (p = 0.28 and 0.09, respectively). Higher RT dose to the margin and higher maximum RT dose were associated with a higher incidence of ISE (p = 0.05 and 0.01, respectively). However, when RT dose to the margin was converted to a 2-Gy dose-equivalent, it lost its significance as predictor of ISE (p = 0.51). Recent conventional external-beam radiation therapy, target volume, number of isocenters, collimator size, dose inhomogeneity, prescription isodose, pretreatment edema, dose of prior radiation, fraction size (2.0-7.0 Gy with SRT and 13.0-21.0 Gy with SRS), fractionation schedule, and dose to brainstem were not significantly associated with ISE. ISE occurred in 26% (8) of 31 patients taking corticosteroids prior to SRT/SRS and in 20 (42%) of 47 patients not taking them (p = 0.15). CONCLUSION: ISE occur in one third of patients treated with SRT and SRS and are usually mild or moderate and self-limited. Dizziness/vertigo are common and unique for patients with acoustic neuromas and are not associated with higher brainstem doses. We are unable to detect a relationship between ISE and higher margin or maximum RT doses. No specific conclusion can be drawn with regard to the effect of corticosteroids, used prior to SRS/SRT, on the occurrence of ISE.

A dynamic model for the estimation of optimum timing of computed tomography scan for dose evaluation of 125I or 103Pd seed implant of prostate.

PURPOSE/OBJECTIVE: The dosimetric evaluation of permanent 125I or 103Pd prostate implant is based on the assumption that both prostate and seeds are static throughout the entire treatment time which lasts months. However, the prostate is often edematous after the surgical implantation of seeds. Therefore, both the volume of the prostate and the seed locations change dynamically as the edema resolves. This effect has impact on the validity of postimplant analysis based upon a CT scan. If a CT scan is taken too early after implantation while there is edema in the prostate, the dose delivered by the implant may be underestimated. If the imaging is delayed too long, the dose may be overestimated. The magnitude of this effect depends on both of the half-life of the isotope used and the half-life and magnitude of the edema. This study describes a dynamic biomathematical model which takes edema into account in calculating the dose delivered by the implant and is used to investigate the optimum time to obtain the postimplant CT scan. MATERIALS AND METHODS: The dynamic biomathematical model is a numerical integration of the accumulated dose in which the prostate dimensions, the seed locations, and the source strength are all functions of time. The function which describes the change in prostate dimensions and seed locations as a function of time was determined in a separate study by analysis of serial postimplant CT scans. Dose-volume histograms (DVH) of the prostate for the total dose generated by the dynamic model are compared to DVHs generated by CT scans simulated for postimplant intervals ranging from 0 to 300 days after the implantation for 30 different combinations of the magnitude and duration of edema. RESULTS: DVHs of the prostate calculated by taking edema into account show that the time of obtaining a CT scan for postimplant analysis is critical to the accuracy of dose evaluations. The comparison of the DVHs generated by the dynamic model to those generated by the CT scans simulated for a range of postimplant intervals show that obtaining the CT scan too early tends to underestimate the total dose while obtaining the CT scan after the edema is resolved tends to overestimate it. The results show that the optimum timing of the CT scan depends upon the duration of the edema and the half-life of the radioisotope used. It is almost independent of the magnitude of the edema. Thus, a unique optimum time window for the imaging study cannot be defined for either 125I or 103Pd implants. However, an optimum time window can be identified for which the calculated dose, on the average, will generally differ from the actual dose by less than 5%, with a maximum error not exceeding 15%. Such a window is 4 to 10 weeks after the implantation for an 125I implant, and 2 to 4 weeks for a 103Pd implant. CONCLUSIONS: A dynamic biomathematical model to correct for the effects of edema in calculating the total dose delivered by an 125I or 103Pd seed implant has been developed. The model has been used to investigate the optimum time window during which the postimplant CT scans for analysis should be obtained.

Durable efficacy of early postoperative radiation therapy for high-risk pT3N0 prostate cancer: the importance of radiation dose.

OBJECTIVES: To determine the durable efficacy of early postoperative radiation therapy (RT) in patients with pT3N0 prostate cancer who were at an increased risk of biochemical failure. We also evaluated the long-term benefit derived from using higher RT doses. METHODS: Seventy-nine patients with pathologic Stage T3N0 prostate cancer and high-risk postoperative features underwent RT within 6 months after surgery. No patient received prior hormonal therapy. Fifty-nine patients had positive surgical margin, 29 had pathologic seminal vesicle invasion, and 27 had persistently elevated postoperative prostate-specific antigen (PSA) levels. Freedom from biochemical relapse (bNED) was defined as an undetectable (less than 0.2 ng/mL) PSA level. Median follow-up time was 39 months, and the median radiation dose was 64.8 Gy. All patients were followed for at least 2 years to be considered biochemically controlled. RESULTS: Patients receiving adjuvant RT for an undetectable pre-RT PSA level had a 3-year bNED rate of 90%, compared with 44% for those receiving salvage RT for a detectable level (P < 0.0001). In the group of adjuvant patients, RT doses more than 61.2 Gy resulted in a 3-year bNED rate of 90% compared with 64% for those receiving a lower dose (P=0.015). The salvage patients irradiated with a dose of 64.8 Gy or greater had a 3-year bNED rate of 52% compared with 18% for those irradiated with lower doses (P=0.048). Severe late RT-related complications were infrequent and did not correlate with dose. CONCLUSIONS: In patients with high-risk pT3N0 prostate cancer, an RT dose response may exist. Although some studies suggest limited durable efficacy for early postoperative RT, our data suggest that RT doses of 64.8 Gy or more appear superior to prevent future biochemical failures. A prospective randomized study evaluating a postoperative RT dose response is warranted.

Effect of higher radiation dose on biochemical control after radical prostatectomy for PT3N0 prostate cancer.

PURPOSE: The appropriate radiation dose has not been determined for postoperative radiation therapy (RT) of prostate cancer. Postoperative PSA level is a useful marker of local residual disease, and may allow evaluation of RT dose-response after radical prostatectomy. METHODS AND MATERIALS: Between 1989 and 1996, 86 consecutive patients with pT3N0 prostate cancer who did not receive prior hormonal therapy or chemotherapy were irradiated postoperatively. All patients received 55.8 to 70.2 Gy (median = 64.8 Gy) to the prostatic/seminal vesicle bed. Patients were judged to be free of biochemical failure (bNED) if their PSA remained undetectable or decreased to undetectable level (< 0.2 ng/ml). The median follow-up time was 32 months from time of irradiation. RESULTS: Univariate and multivariate analyses of variables showed that the preRT PSA level was the most significant predictor of improved bNED survival (p < 0.001). Actuarial analyses of radiation dose grouped with preRT PSA levels found higher radiation dose to be significant (p < 0.05). For the 52 patients with an undetectable preRT PSA level, the 3-year bNED rate was 91% for patients irradiated to 61.5 Gy or more and 57% for those irradiated to lower doses (p = 0.01). For the 21 patients with preRT PSA level > 0.2 and < or = 2.0 ng/ml, the 3-year bNED rate was 79% for patients irradiated to 64.8 Gy or more and 33% for those irradiated to a lower dose (p = 0.02). No other preRT PSA interval or radiation dose level was associated with a dose-response function. CONCLUSION: In patients with pT3N0 prostate cancer after radical prostatectomy, a radiation dose-response function may be present and depends on the preRT PSA value. Patients with high postoperative PSA levels (> 2.0 ng/ml) may be less likely to benefit from higher doses of RT, and should be considered a group for which systemic therapy should be tested.