H. Hsu

Feasibility of MR Imaging/MR Spectroscopy-Planned Focal Partial Salvage Permanent Prostate Implant (PPI) for Localized Recurrence After Initial PPI for Prostate Cancer

PURPOSE To assess the feasibility of magnetic resonance imaging (MRI)-planned partial salvage permanent prostate implant (psPPI) among patients with biopsy-proven local recurrence after initial PPI without evidence of distant disease. METHODS AND MATERIALS From 2003-2009, 15 patients underwent MRI/magnetic resonance spectroscopy (MRS) planning for salvage brachytherapy (psPPI, I-125 [n=14; 144 Gy]; Pd-103 [n=1; 125 Gy]) without hormone therapy. Full dose was prescribed to areas of recurrence and underdosage, without entire prostate implantation. Limiting urethral and rectal toxicity was prioritized. Follow-up was from salvage date to prostate-specific antigen (PSA) concentration failure (Phoenix criteria = nadir + 2.0; ASTRO = 3 consecutive rises), recurrence, distant metastases, or last follow-up PSA level. Progression-free survival (PFS) was defined as no PSA failure or biopsy-proven recurrence without all-cause mortality. Toxicity was scored using Common Terminology Criteria for Adverse Events version 4.0. RESULTS At salvage, median age was 68 years, and PSA concentration was 3.5 ng/mL (range, 0.9-5.6 ng/mL). Abnormal MRI/MRS findings were evident in 40% of patients. Biopsy-proven recurrences consisted of a single focus (80%) or 2 foci (20%). At recurrence, Gleason score was 6 (67%) or ≥7 (27%). Median interval between initial and salvage implantation was 69 months (range, 28-132 months). psPPI planning characteristics limited doses to the rectum (mean V100 = 0.5% [0.07 cc]) and urethra (V100 = 12% [0.3 cc]). At median follow-up (23.3 months; range, 8-88 months), treatment failure (n=2) resulted only in localized recurrence; both patients underwent second psPPI with follow-up PSA tests at 12 and 26 months, resulting in 0.6 and 0.7 ng/mL, respectively. American Society for Radiation Oncology PFS rates at 1, 2, and 3 years were 86.7%, 78.4%, and 62.7%, respectively, with 5 patients for whom treatment failed (n=3 with negative transrectal ultrasound-guided biopsy results). Phoenix PFS rates at 1, 2, and 3 years were 100%, 100%, and 71.4%. 73%, respectively; achieved PSA nadir of <0.5 ng/mL; and 47% of patients had a nadir of <0.1 ng/mL. Treatment-related toxicity was minimal, with no operative interventions, fistulas, or other grade ≥3 gastrointestinal (GI)/genitourinary (GU) toxicity. Thirteen percent had grade 1 GI and 33% had grade 2 GU toxicities. Postsalvage, 20% of patients had no erectile dysfunction, 67% of patients had medication-responsive erectile dysfunction, and 13% of patients had erectile dysfunction refractory to medication. CONCLUSIONS Focal psPPI with MR-planning in highly selected patients is feasible with short-term control comparable to conventional salvage, with less toxicity. Longer follow-up is needed to confirm its impact on quality of life and treatment.

PRONE ACCELERATED PARTIAL BREAST IRRADIATION AFTER BREAST-CONSERVING SURGERY: FIVE YEAR RESULTS OF 100 PATIENTS

PURPOSE To report the 5-year results of a prospective trial of three-dimensional conformal external beam radiotherapy (3D-CRT) to deliver accelerated partial breast irradiation in the prone position. METHODS AND MATERIALS Postmenopausal patients with Stage I breast cancer with nonpalpable tumors <2 cm, negative margins and negative nodes, positive hormone receptors, and no extensive intraductal component were eligible. The trial was offered only after eligible patients had refused to undergo standard whole-breast radiotherapy. Patients were simulated and treated on a dedicated table for prone setup. 3D-CRT was delivered at a dose of 30 Gy in five 6-Gy/day fractions over 10 days with port film verification at each treatment. Rates of ipsilateral breast failure, ipsilateral nodal failure, contralateral breast failure, and distant failure were estimated using the cumulative incidence method. Rates of disease-free, overall, and cancer-specific survival were recorded. RESULTS One hundred patients were enrolled in this institutional review board-approved prospective trial, one with bilateral breast cancer. One patient withdrew consent after simulation, and another patient elected to interrupt radiotherapy after receiving two treatments. Ninety-eight patients were evaluable for toxicity, and, in 1 case, both breasts were treated with partial breast irradiation. Median patient age was 68 years (range, 53-88 years); in 55% of patients the tumor size was <1 cm. All patients had hormone receptor-positive cancers: 87% of patients underwent adjuvant antihormone therapy. At a median follow-up of 64 months (range, 2-125 months), there was one local recurrence (1% ipsilateral breast failure) and one contralateral breast cancer (1% contralateral breast failure). There were no deaths due to breast cancer by 5 years. Grade 3 late toxicities occurred in 2 patients (one breast edema, one transient breast pain). Cosmesis was rated good/excellent in 89% of patients with at least 36 months follow-up. CONCLUSIONS Five-year efficacy and toxicity of 3D-CRT delivered in prone partial breast irradiation are comparable to other experiences with similar follow-up.

Prone Accelerated Partial Breast Irradiation After Breast-Conserving Surgery: Compliance to the Dosimetry Requirements of RTOG-0413

PURPOSE The dosimetric results from our institutions trials of prone accelerated partial breast irradiation are compared with the dosimetric requirements of RTOG-0413. METHODS AND MATERIALS Trial 1 and Trial 2 are 2 consecutive trials of prone-accelerated partial breast irradiation. Eligible for both trials were stage I breast cancer patients with negative margins after breast-conserving surgery. The planning target tumor volume (PTV) was created by extending the surgical cavity 2.0 cm for Trial 1 and 1.5 cm for Trial 2, respectively. Contralateral breast, heart, lungs, and thyroid were contoured. Thirty Gray was delivered in five daily fractions of 6 Gy by a three-dimensional conformal radiation therapy technique in Trial 1 and were by image-guided radiation therapy/intensity-modulated radiation therapy in Trial 2. Dosimetric results from the trials are reported and compared with RTOG 0413 requirements. RESULTS One hundred forty-six consecutive plans were analyzed: 67 left and 79 right breast cancers. The plans from the trials complied with the required>90% of prescribed dose covering 90% of PTV_EVAL (=generated from the PTV by cropping 0.5 cm from the skin edge and excluding the chest wall): V90% was 98.1±3.0% (with V100% and V95%, 89.4±12.8%, 96.4±5.1%, respectively). No significant difference between laterality was found (Students t test). The dose constraints criteria of the RTOG-0413 protocol for ipsilateral and contralateral lung (V30<15% and Dmax<3%), heart (V5<40%), and thyroid (Dmax<3%) were satisfied because the plans showed an average V5% of 0.6% (range, 0-13.4) for heart, an average V30% of 0.6% (range, 0-9.1%) for ipsilateral lung, and <2% maximum dose to the thyroid. However, our partial breast irradiation plans demonstrated a higher dose to contralateral breast than that defined by RTOG constraints, with a median value of maximum doses of 4.1% (1.2 Gy), possibly as a result of contouring differences. CONCLUSIONS Our technique for prone accelerated partial breast irradiation generally satisfied RTOG-0413 requirements.

Surveillance Epidemiology and End Results Analysis Demonstrates Improvement in Overall Survival for Cervical Cancer Patients Treated in the Era of Concurrent Chemoradiotherapy

Background In February 1999, the National Cancer Institute (NCI) issued a clinical alert based on five randomized trials that reported better overall survival (OS) with concurrent chemoradiotherapy (CCRT) than with surgery or radiation alone for locoregional cervical cancer. This study analyzes data from the surveillance epidemiology and end results (SEER) program to evaluate the improvement in survival in the era of CCRT. Methods The SEER database was queried for FIGO stages IB2–IVA cervical cancer patients treated with radiotherapy between 1995 and 2002. Patients diagnosed between 1999 and 2002 (CCRT era) were assumed to have received CCRT more frequently than patients diagnosed between 1995 and 1998 (RT era). Cases were stratified by period of diagnosis, age, and SEER region. OS and cause specific survival (CSS) were compared between the two time periods with chi-square log-rank tests. Multivariable Cox models were also used to compare OS and CSS between the two time periods, with adjustment for stratification variables and other covariates. Results The study included 3517 patients. Unadjusted OS and CSS were significantly improved in 1999–2002 compared with 1995–1998 (OS: p < 0.001, hazard ratio (HR): 0.81; CSS: p < 0.001, HR: 0.79). Significant improvements in OS and CSS were retained after adjustment for multiple variables (multivariable OS HR 0.78; CSS HR 0.76). Conclusion Cervical cancer patients treated with radiotherapy after 1999 had improved OS and CSS compared with patients treated before 1999, likely reflecting increased usage of CCRT. This study adds to the population-level evidence supporting the adoption of CCRT as the standard of care for locoregional cervical cancer.

Radiation therapy improves survival in rectal small cell cancer - Analysis of Surveillance Epidemiology and End Results (SEER) data

BackgroundSmall cell carcinoma of the rectum is a rare neoplasm with scant literature to guide treatment. We used the Surveillance Epidemiology and End Results (SEER) database to investigate the role of radiation therapy in the treatment of this cancer.MethodsThe SEER database (National Cancer Institute) was queried for locoregional cases of small cell rectal cancer. Years of diagnosis were limited to 1988–2010 (most recent available) to reduce variability in staging criteria or longitudinal changes in surgery and radiation techniques. Two month conditional survival was applied to minimize bias by excluding patients who did not survive long enough to receive cancer-directed therapy. Patient demographics between the RT and No_RT groups were compared using Pearson Chi-Square tests. Overall survival was compared between patients who received radiotherapy (RT, n = 43) and those who did not (No_RT, n = 28) using the Kaplan-Meier method. Multivariate Cox proportional hazards model was used to evaluate important covariates.ResultsMedian survival was significantly longer for patients who received radiation compared to those who were not treated with radiation; 26 mo vs. 8 mo, respectively (log-rank P = 0.009). We also noted a higher 1-year overall survival rate for those who received radiation (71.1% vs. 37.8%). Unadjusted hazard ratio for death (HR) was 0.495 with the use of radiation (95% CI 0.286-0.858). Among surgery, radiotherapy, sex and age at diagnosis, radiation therapy was the only significant factor for overall survival with a multivariate HR for death of 0.393 (95% CI 0.206-0.750, P = 0.005).ConclusionsUsing SEER data, we have identified a significant survival advantage with the use of radiation therapy in the setting of rectal small cell carcinoma. Limitations of the SEER data apply to this study, particularly the lack of information on chemotherapy usage. Our findings strongly support the use of radiation therapy for patients with locoregional small cell rectal cancer.

Preplanning prediction of the left anterior descending artery maximum dose based on patient, dosimetric, and treatment planning parameters

Purpose Maximum dose to the left anterior descending artery (LADmax) is an important physical constraint to reduce the risk of cardiovascular toxicity. We generated a simple algorithm to guide the positioning of the tangent fields to reliably maintain LADmax <10 Gy. Methods and materials Dosimetric plans from 146 consecutive women treated prone to the left breast enrolled in prospective protocols of accelerated whole breast radiation therapy, with a concomitant daily boost to the tumor bed (40.5 Gy/15 fraction to the whole breast and 48 Gy to the tumor bed), provided the training set for algorithm development. Scatter plots and correlation coefficients were used to describe the bivariate relationships between LADmax and several parameters: distance from the tumor cavity to the tangent field edge, cavity size, breast separation, field size, and distance from the tangent field. A logistic sigmoid curve was used to model the relationship of LADmax and the distance from the tangent field. Furthermore, we tested this prediction model on a validation data set of 53 consecutive similar patients. Results A lack of linear relationships between LADmax and distance from cavity to LAD (−0.47), cavity size (−0.18), breast separation (−0.02), or field size (−0.28) was observed. In contrast, distance from the tangent field was highly negatively correlated to LADmax (-0.84) and was used in the models to predict LADmax. From a logistic sigmoid model we selected a cut-point of 2.46 mm (95% confidence interval, 2.19-2.74 mm) greater than which LADmax is <10 Gy (95% confidence interval, 9.30-10.72 Gy) and LADmean is <3.3 Gy. Conclusions Placing the edge of the tangents at least 2.5 mm from the closest point of the contoured LAD is likely to assure LADmax is <10 Gy and LADmean is <3.3 Gy in patients treated with prone accelerated breast radiation therapy.

Local Control of Low-Volume Brain Metastasis Using Stereotactic Radiosurgery

Stereotactic radiosurgery (SRS) is a non-invasive means of treating brain metastases with high dose radiation therapy in a single fraction. It is a useful alternative to surgical resection in selected patients with good performance status and low-volume brain metastases. It can complement or replace whole brain radiation therapy (WBRT), which has historically been the mainstay of palliative brain radiation therapy. Randomized clinical trials have demonstrated the survival benefit of adding SRS to WBRT in the case of a single brain metastasis in a patient with good performance status. Conversely, there appears to be no survival detriment to using SRS alone in patients with up to 4 and possibly even more brain metastases. While there is an increase in recurrent lesions either locally or in distant areas of the brain with the use of SRS alone, these are amenable to salvage therapy if found early with stringent follow-up imaging. Such a strategy has been used successfully in our institution and others to delay or forego WBRT in most patients with low-volume brain metastases. This helps to avoid the morbidities that have been documented with WBRT including neurocognitive impairment, alopecia, fatigue and associated psychological stress. In addition, SRS alone avoids the delay in systemic therapy that is common with the use of WBRT. In this chapter, we focus on the randomized clinical trials that have examined SRS as a primary treatment modality for low-volume brain metastases.