Elena Nedea

Lung Dose-Volume Parameters and the Risk of Pneumonitis for Patients Treated With Accelerated Partial-Breast Irradiation Using Three-Dimensional Conformal Radiotherapy

PURPOSE There are no data on how complication rates after accelerated partial-breast irradiation delivered by three-dimensional conformal radiotherapy are affected by treatment technique. We therefore examined the risk of pneumonitis in relation to lung dose-volume parameters. PATIENTS AND METHODS Our prospective dose-escalation trial enrolled 198 treated patients from 2003 to 2007. Patients received 32 or 36 Gy in 4-Gy fractions, given twice daily: 29 (14%) were treated with pure photons; 149 (77%) with mixed photons and electrons; and 20 (10%) with protons. RESULTS There were four cases of pneumonitis at 4, 4, 7, and 9 months after treatment. All were in the 36-Gy cohort and were treated with pure photons. The risk of pneumonitis for the two cohorts combined was: 17% (four of 24) for an ipsilateral lung volume (ILV) receiving 20 Gy or higher (ILV, 20 Gy) of 3% or higher (P = .0002 for comparison to ILV 20 Gy < 3%, Fishers exact test); 20% (four of 20) for an ILV 10 Gy of 10% or higher (P = .0001); and 15% (four of 26) for an ILV 5 Gy of 20% or higher (P = .0002). CONCLUSION The risk of pneumonitis appeared related to the ILV treated. This volume can be reduced by using mixed photons and electron when possible. We recommend that the ILV 20 Gy should be lower than 3%, the ILV 10 Gy lower than 10%, and the ILV 5 Gy lower than 20% when purely coplanar techniques are used.

Organ Deformation and Dose Coverage in Robotic Respiratory-Tracking Radiotherapy

PURPOSE Respiratory motion presents a significant challenge in stereotactic body radiosurgery. Respiratory tracking that follows the translational movement of the internal fiducials minimizes the uncertainties in dose delivery. However, the effect of deformation, defined as any changes in the body and organs relative to the center of fiducials, remains unanswered. This study investigated this problem and a possible solution. METHODS AND MATERIALS Dose delivery using a robotic respiratory-tracking system was studied with clinical data. Each treatment plan was designed with the computed tomography scan in the end-expiration phase. The planned beams were applied to the computed tomography scan in end-inspiration following the shift of the fiducials. The dose coverage was compared with the initial plan, and the uncertainty due to the deformation was estimated. A necessary margin from the clinical target volume to the planning target volume was determined to account for this and other sources of uncertainty. RESULTS We studied 12 lung and 5 upper abdomen lesions. Our results demonstrated that for lung patients with properly implanted fiducials a 3-mm margin is required to compensate for the deformation and a 5-mm margin is required to compensate for all uncertainties. Our results for the upper abdomen tumors were still preliminary but indicated a similar result, although a larger margin might be required. CONCLUSION The effect of body deformation was studied. We found that adequate dose coverage for lung tumors can be ensured with proper fiducial placement and a 5-mm planning target volume margin. This approach is more practical and effective than a recent proposal to combine four-dimensional planning with respiratory tracking.

Stereotactic body radiotherapy (SBRT) reirradiation for pelvic recurrence from colorectal cancer

When surgery is not adequate or feasible, stereotactic body radiotherapy (SBRT) reirradiation has been used for recurrent cancers. We report the outcomes of a series of patients with pelvic recurrences from colorectal cancer reirradiated with SBRT.

Extraprostatic seed placement and its effect on seed loss

PURPOSEThe purpose of this study was to examine the relationship between extraprostatic seed placement and seed loss in a cohort of patients who had underwent both computed to-mographic (CT) and magnetic resonance (MR) scans at day 0 and day 30 following brachytherapy. MATERIALS AND METHODSTwenty-two patients with 1997 AJC clinical stage T1–T2 prostatic carcinoma were implanted with nonstranded I 125. Patients were selected solely by having a prostate volume between 15 and 60 cc and a willingness to return for 30-day follow-up CT and MR scans. The total number of I–125 sources implanted on day 0 ranged from 50 to 104 (median: 70). Preplan treatment planning methods have been previously described in detail: a modified peripheral loading pattern and treatment margins of 5–10 mm were used. Noncontrast postimplantation CT and MR scans were obtained 1–4 hours after implantation on day 0. The total seed count on days 0 and 30 was verified by plain radiograph. Pelvic MR (T1) images were registered with the CT images in the Varian planning system, using bony landmarks. The number of extracapsular seeds in each quadrant of the circumference was then totaled for each patient. A second set of plain radiographs (for seed counting), as well as CT and MR scans, were obtained 30 days after implantation (day 30) and were similarly analyzed. RESULTSThe number of extraprostatic seeds at day 0 ranged from 13 to 35, making up 17%–48% (median: 34%) of the total number implanted. Of the 22 patients, 10 lost one or more seeds between the implantation day and the 1-month follow-up. The mean number of seeds lost was 1.1 (± 1.7). There was no apparent relationship between the percent of extraprostatic seeds and the number of seeds lost. There was no apparent relationship between seed loss and number of seeds less than 3 mm or greater than 3 mm from the prostatic capsule. CONCLUSIONSWe have shown here that with CT and MR seed localization, extraprostatic seed placement does not appear to substantially increase the likelihood of seed loss after the procedure.

Patterns of Care for Non-Small-Cell Lung Cancer at an Academic Institution Affiliated With a National Cancer Institute-Designated Cancer Center

PURPOSE Evidence-based treatment guidelines for non-small-cell lung cancer (NSCLC) exist to improve the quality of care for patients with this disease. However, how often evidence-based decisions are used for care of NSCLC is poorly understood. PATIENTS AND METHODS We examined patterns of care and rate of adherence to evidence-based guidelines for 185 new NSCLC patients seen between 2007 and 2009. Evidence-based care status was determined for 150 patients. RESULTS Eighty-one percent of the patients were white, the mean age was 66 years, 49% were women, 11% were never smokers, 83% had Eastern Cooperative Oncology Group performance status 0 to 1, 49.7% of tumors were adenocarcinomas, 57.1% of never smokers had tumors genotyped (EGFR, ALK, KRAS), and 13.3% participated in clinical trials. The rate of evidence-based treatment adherence was 94.1% (16 of 17), 100% (21 of 21) and 100% (36 of 36) in patients with stages I, II, and III NSCLC, respectively. Stage IV disease, with adherence of 76.3% (58 of 76), was correlated with a higher rate of nonadherence when compared with stages I-III (odds ratio 16.33; 95% CI, 1.94 to 137.73). In patients with stage IV disease, the rate of evidence-based adherence was 95% (72 of 76) for first-line therapy, 95.2% (40 of 42) for second-line therapy, and only 33.3% (6 of 18) for third-line therapy (P < .001). There was no significant correlation between evidence-based adherence status and the patients age, sex, performance status, smoking history, ethnicity, or the treating physician. CONCLUSION These data point toward the need for improved evidence-based use of resources in the third-line setting of stage IV NSCLC.

Post operative stereotactic radiosurgery for positive or close margins after preoperative chemoradiation and surgery for rectal cancer

BACKGROUND The incidence of positive margins after neoadjuvant chemoradiation and adequate surgery is very low. However, when patients do present with positive or close margins, they are at a risk of local failure and local therapy options are limited. We evaluated the role of stereotactic body radiotherapy (SBRT) in patients with positive or close margins after induction chemoradiation and total mesorectal excision. METHODS This is a retrospective evaluation of patients treated with SBRT after induction chemoradiation and surgery for positive or close margins. Seven evaluable patients were included. Fiducial seeds were place at surgery. The Cyberknife(TM) system was used for planning and treatment. Patients were followed 1 month after treatment and 3-6 months thereafter. Descriptive statistics and Kaplan-Meir method was used to repot the findings. RESULTS Seven patients (3 men and 4 women) were included in the study with a median follow-up of 23.5 months. The median initial radiation dose was 5,040 cGy (in 28 fractions) and the median SBRT dose was 2,500 cGy (in 5 fractions). The local control at 2 years was 100%. The overall survival at 1 and 2 years was 100% and 71% respectively. There was no Grade III or IV toxicity. CONCLUSIONS SBRT reirradiation is an effective and safe method to address positive or close margins after neoadjuvant chemoradiation and surgery for rectal cancer.

Selection of Treatment for Patients with Early Stage Non-Small Cell Lung Cancer in a Multidisciplinary Thoracic Oncology Program

Lung cancer is the leading cause of cancer mortality in men and women. More than 170,000 Americans receive a diagnosis of lung cancer annually and the majority of them die of the disease [1]. There is considerable interest in improving treatment for lung cancer given its high impact on society. More than 80% of patients with lung cancer have non-small cell carcinoma (NSCLC). Surgery is the mainstay of treatment for patients with early stage NSCLC and results in cure of about 60–80% of patients with stage I (T1-2N0) disease [2]–[5].