A current perspective on stereotactic body radiation therapy for pancreatic cancer

Pancreatic cancer is a formidable malignancy with poor outcomes. The majority of patients are unable to undergo resection, which remains the only potentially curative treatment option. The management of locally advanced (unresectable) pancreatic cancer is controversial; however, treatment with either chemotherapy or chemoradiation is associated with high rates of local tumor progression and metastases development, resulting in low survival rates. An emerging local modality is stereotactic body radiation therapy (SBRT), which uses image-guided, conformal, high-dose radiation. SBRT has demonstrated promising local control rates and resultant quality of life with acceptable rates of toxicity. Over the past decade, increasing clinical experience and data have supported SBRT as a local treatment modality. Nevertheless, additional research is required to further evaluate the role of SBRT and improve upon the persistently poor outcomes associated with pancreatic cancer. This review discusses the existing clinical experience and technical implementation of SBRT for pancreatic cancer and highlights the directions for ongoing and future studies.

Radiation Therapy for Soft Tissue Sarcoma: Indications and Controversies for Neoadjuvant Therapy, Adjuvant Therapy, Intraoperative Radiation Therapy, and Brachytherapy

Soft tissue sarcomas are rare mesenchymal cancers that pose a treatment challenge. Although small superficial soft tissue sarcomas can be managed by surgery alone, adjuvant radiotherapy in addition to limb-sparing surgery substantially increases local control of extremity sarcomas. Compared with postoperative radiotherapy, preoperative radiotherapy doubles the risk of a wound complication, but decreases the risk for late effects, which are generally irreversible. For retroperitoneal sarcomas, intraoperative radiotherapy can be used to safely escalate the radiation dose to the tumor bed. Patients with newly diagnosed sarcoma should be evaluated before surgery by a multidisciplinary team that includes a radiation oncologist.

Effect of combined neoadjuvant chemoradiation on overall survival for patients with locally advanced rectal cancer

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Background: Prospective randomized trials have demonstrated that neoadjuvant chemoradiation improves local control and results in a higher rate of sphincter-sparing surgery for patients with locally advanced rectal cancer. However, neoadjuvant therapy utilization and population-based outcomes are not well defined. Methods: Adults with stage II/III rectal adenocarcinoma within the National Cancer Data Base undergoing surgery between 2006-2012 were analyzed. Patients were grouped by type of neoadjuvant therapy received: no therapy, chemotherapy only, radiotherapy only, or concomitant chemoradiation. Multivariable modeling was used to compare perioperative outcomes and overall survival between groups. Results: Among 32,978 patients included, 9,714 (29.5%) received no neoadjuvant therapy, 890 (2.7%) chemotherapy only, 1,170 (3.5%) radiotherapy only, and 21,204 (64.3%) concomitant chemoradiation. 5-year overall survival among groups was 62%, 69%, 71%, and 74%, respectively. Compared to no therapy, chemotherapy or radiotherapy alone was not associated with any differences in perioperative or oncologic outcomes (all p > 0.05). With adjustment for patient and disease characteristics, neoadjuvant chemoradiation was associated with a lower likelihood of margin positivity (OR 0.74, p < 0.001), need for permanent colostomy (OR 0.77, 95% CI 0.70-0.85, p < 0.001), 30-day mortality (OR 0.67, p = 0.003), and overall survival (HR 0.69, p < 0.001). When compared to chemotherapy or radiotherapy alone, neoadjuvant chemoradiation was still associated with improved overall survival (vs. chemotherapy: HR 0.83, p = 0.04; vs. radiotherapy: HR 0.75, p < 0.001). Conclusions: Neoadjuvant chemoradiation, not chemotherapy or radiotherapy alone, is important for sphincter-preservation and survival for patients with locally advanced rectal cancer. Despite this finding, one third of patients with locally advanced rectal cancer are failing to receive this therapy in the United States.

Evaluation of Adjuvant Radiation Therapy for Resected Gallbladder Carcinoma: A Multi-institutional Experience

PURPOSE

The role of adjuvant radiation for gallbladder carcinoma (GBC) is uncertain. We combine the experience of six National Cancer Institute-designated cancer centers to explore the impact of adjuvant radiation following oncologic resection of GBC.

METHODS

Patients who underwent extended surgery for GBC at Johns Hopkins, Mayo Clinic, Duke University, Oregon Health & Science University, University of Michigan, and University of Texas MD Anderson between 1985 and 2008 were reviewed. Patients with metastatic disease at surgery, gross residual disease, or missing pathologic information were excluded.

RESULTS

Of the 112 patients identified, 61 % received adjuvant radiation, 93 % of whom received concurrent chemotherapy. Median follow-up of surviving patients was 47.3 (range 2.2-167.7) months. Patients who received adjuvant radiation had a higher rate of advanced T-stage (57 vs. 16 %, p < 0.01), lymph node involvement (63 vs. 18 %, p < 0.01), and positive microscopic margins (37 vs. 9 %, p < 0.01) compared with patients managed with surgery alone, but overall survival (OS) was comparable between the two cohorts (5-year OS: 49.7 vs. 52.5 %, p = 0.20). Lymph node involvement had the strongest association with poor OS (p < 0.01). Adjuvant radiation was associated with decreased isolated local failure (hazard ratio 0.17, 95 % confidence interval 0.05-0.63, p = 0.01). However, 71 % of recurrences included distant failure.

CONCLUSIONS

Following oncologic resection for GBC, adjuvant radiation may offer improved local control compared with observation. The benefit of adjuvant radiation beyond chemotherapy alone should therefore be explored. Certainly, the high rate of distant failure highlights the need for more effective systemic therapy.

T2-weighted four dimensional magnetic resonance imaging with result-driven phase sorting

PURPOSE

T2-weighted MRI provides excellent tumor-to-tissue contrast for target volume delineation in radiation therapy treatment planning. This study aims at developing a novel T2-weighted retrospective four dimensional magnetic resonance imaging (4D-MRI) phase sorting technique for imaging organ/tumor respiratory motion.

METHODS

A 2D fast T2-weighted half-Fourier acquisition single-shot turbo spin-echo MR sequence was used for image acquisition of 4D-MRI, with a frame rate of 2-3 frames/s. Respiratory motion was measured using an external breathing monitoring device. A phase sorting method was developed to sort the images by their corresponding respiratory phases. Besides, a result-driven strategy was applied to effectively utilize redundant images in the case when multiple images were allocated to a bin. This strategy, selecting the image with minimal amplitude error, will generate the most representative 4D-MRI. Since we are using a different image acquisition mode for 4D imaging (the sequential image acquisition scheme) with the conventionally used cine or helical image acquisition scheme, the 4D dataset sufficient condition was not obviously and directly predictable. An important challenge of the proposed technique was to determine the number of repeated scans (NR) required to obtain sufficient phase information at each slice position. To tackle this challenge, the authors first conducted computer simulations using real-time position management respiratory signals of the 29 cancer patients under an IRB-approved retrospective study to derive the relationships between NR and the following factors: number of slices (NS), number of 4D-MRI respiratory bins (NB), and starting phase at image acquisition (P0). To validate the authors' technique, 4D-MRI acquisition and reconstruction were simulated on a 4D digital extended cardiac-torso (XCAT) human phantom using simulation derived parameters. Twelve healthy volunteers were involved in an IRB-approved study to investigate the feasibility of this technique.

RESULTS

4D data acquisition completeness (Cp) increases as NR increases in an inverse-exponential fashion (Cp = 100 - 99 × exp(-0.18 × NR), when NB = 6, fitted using 29 patients' data). The NR required for 4D-MRI reconstruction (defined as achieving 95% completeness, Cp = 95%, NR = NR,95) is proportional to NB (NR,95 ∼ 2.86 × NB, r = 1.0), but independent of NS and P0. Simulated XCAT 4D-MRI showed a clear pattern of respiratory motion. Tumor motion trajectories measured on 4D-MRI were comparable to the average input signal, with a mean relative amplitude error of 2.7% ± 2.9%. Reconstructed 4D-MRI for healthy volunteers illustrated clear respiratory motion on three orthogonal planes, with minimal image artifacts. The artifacts were presumably caused by breathing irregularity and incompleteness of data acquisition (95% acquired only). The mean relative amplitude error between critical structure trajectory and average breathing curve for 12 healthy volunteers is 2.5 ± 0.3 mm in superior-inferior direction.

CONCLUSIONS

A novel T2-weighted retrospective phase sorting 4D-MRI technique has been developed and successfully applied on digital phantom and healthy volunteers.

Neoadjuvant radiation therapy does not increase perioperative morbidity among patients undergoing gastrectomy for gastric cancer

BACKGROUND

Neoadjuvant radiation therapy (RT) as a component of the multimodality treatment of gastric cancer has demonstrated promising results. Data regarding its effect on perioperative safety are limited.

METHODS

Adults undergoing gastrectomy for gastric cancer in the 2005-2011 National Surgical Quality Improvement Program were included. Groups were defined by neoadjuvant RT use, and then propensity-matched based on preoperative variables. Multivariable logistic regression was performed to assess neoadjuvant RT as an independent predictor of outcomes.

RESULTS

Among 2,764 patients identified, 55 (2.0%) were treated with neoadjuvant RT. Patients who received neoadjuvant RT were more likely to have received preoperative chemotherapy and steroids, and experienced weight loss (all P < 0.01). After matching, however, there were no preoperative differences. At time of surgery, total (vs. partial) gastrectomy was more common among patients who underwent neoadjuvant RT (70.9 vs. 46.7%, P < 0.01), and operative time was longer (290 vs. 236 min, P < 0.01). There were no differences in overall complications (23.6 vs. 29.7%, P = 0.49) or 30-day mortality (3.6 vs. 3.6%, P = 0.99).

CONCLUSIONS

Neoadjuvant RT was not associated with increased morbidity or mortality following resection for gastric cancer. These findings support the ongoing investigation of neoadjuvant RT as part of the multidisciplinary management of resectable gastric cancer.

Investigation of sagittal image acquisition for 4D-MRI with body area as respiratory surrogate

PURPOSE

The authors have recently developed a novel 4D-MRI technique for imaging organ respiratory motion employing cine acquisition in the axial plane and using body area (BA) as a respiratory surrogate. A potential disadvantage associated with axial image acquisition is the space-dependent phase shift in the superior-inferior (SI) direction, i.e., different axial slice positions reach the respiratory peak at different respiratory phases. Since respiratory motion occurs mostly in the SI and anterior-posterior (AP) directions, sagittal image acquisition, which embeds motion information in these two directions, is expected to be more robust and less affected by phase-shift than axial image acquisition. This study aims to develop and evaluate a 4D-MRI technique using sagittal image acquisition.

METHODS

The authors evaluated axial BA and sagittal BA using both 4D-CT images (11 cancer patients) and cine MR images (6 healthy volunteers and 1 cancer patient) by comparing their corresponding space-dependent phase-shift in the SI direction (δSPS (SI)) and in the lateral direction (δSPS (LAT)), respectively. To evaluate sagittal BA 4D-MRI method, a motion phantom study and a digital phantom study were performed. Additionally, six patients who had cancer(s) in the liver were prospectively enrolled in this study. For each patient, multislice sagittal MR images were acquired for 4D-MRI reconstruction. 4D retrospective sorting was performed based on respiratory phases. Single-slice cine MRI was also acquired in the axial, coronal, and sagittal planes across the tumor center from which tumor motion trajectories in the SI, AP, and medial-lateral (ML) directions were extracted and used as references from comparison. All MR images were acquired in a 1.5 T scanner using a steady-state precession sequence (frame rate ∼ 3 frames/s).

RESULTS

4D-CT scans showed that δSPS (SI) was significantly greater than δSPS (LAT) (p-value: 0.012); the median phase-shift was 16.9% and 7.7%, respectively. Body surface motion measurement from axial and sagittal MR cines also showed δSPS (SI) was significantly greater than δSPS (LAT). The median δSPS (SI) and δSPS (LAT) was 11.0% and 9.2% (p-value = 0.008), respectively. Tumor motion trajectories from 4D-MRI matched with those from single-slice cine MRI: the mean (±SD) absolute differences in tumor motion amplitude between the two were 1.5 ± 1.6 mm, 2.1 ± 1.9 mm, and 1.1 ± 1.0 mm in the SI, ML, and AP directions from this patient study.

CONCLUSIONS

Space-dependent phase shift is less problematic for sagittal acquisition than for axial acquisition. 4D-MRI using sagittal acquisition was successfully carried out in patients with hepatic tumors.

Human papillomavirus tumor infection in esophageal squamous cell carcinoma

The association between human papillomavirus (HPV) and esophageal squamous cell carcinoma (ESCC) has been recognized for over three decades. Recently, multiple meta-analyses have drawn upon existing literature to assess the strength of the HPV-ESCC linkage. Here, we review these analyses and attempt to provide a clinically-relevant overview of HPV infection in ESCC. HPV-ESCC detection rates are highly variable across studies. Geographic location likely accounts for a majority of the variation in HPV prevalence, with high-incidence regions including Asia reporting significantly higher HPV-ESCC infection rates compared with low-incidence regions such as Europe, North America, and Oceania. Based on our examination of existing data, the current literature does not support the notion that HPV is a prominent carcinogen in ESCC. We conclude that there is no basis to change the current clinical approach to ESCC patients with respect to tumor HPV status.

The safety and tolerability of veliparib (V) plus capecitabine (C) and radiation (RT) in subjects with locally advanced rectal cancer (LARC): Results of a phase 1b study

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Background: Patients (pts) with LARC treated with neoadjuvant C/RT and then surgery have low rates of pathologic complete response (ypCR) and significant relapse rates. V is a potent, orally bioavailable PARP inhibitor that has been shown to enhance the efficacy of chemotherapy and RT in preclinical models. This study sought to establish the recommended phase 2 dose (RPTD), as well as to assess safety, pharmacokinetics (PK), and preliminary activity of V + RT/C in pts with LARC. Methods: Pts with stage II-III rectal cancer received RT (50.4Gy/1.8Gy/fraction) with C (825 mg/m2 BID) five days per week (W) for 5.5W. Dosing of V (BID, 20mg-400mg) continued from W1D2 to 2 days past RT. Pts underwent surgery 5-10W following RT. Assessments included identification of RPTD with the Exposure Adjusted Continual Reassessment Method, adverse events (AEs), PK, and pathological response (ypCR and tumor downstaging rates). Results: As of August 5, 2014, 30 pts have been enrolled, 24/6 male/female, median age 58 yrs; 1 pt discontinued due to an AE. The most common treatment-emergent AEs possibly or probably related to V (>15% pts, n >4) were nausea (40%), fatigue (37%), diarrhea (30%), vomiting (20%), and dysgeusia (17%). One grade 3/4 event each of anemia and lymphopenia and 2 grade 3/4 events of diarrhea were deemed at least possibly related to V. Two dose limiting toxicities (DLTs) occurred: 1 at 70 mg BID V (radiation skin injury requiring dose interruption); 1 at 400 mg BID (nausea and vomiting requiring discontinuation). The RPTD is 400 mg BID of V in combination with RT/C. PK results from 16 pts suggest that V PK was approximately dose proportional when administered with RT/C and that V had no effect on the PK of C. To date, 18/25 (72%) pts have been downstaged post-surgery; with 7/25 (28%) achieving ypCR. Conclusions: V at 400 mg in combination with RT/C has an acceptable safety profile. 72% of 25 evaluable patients had tumor downstaging post-surgery, including 28% with ypCR. Dose escalation of V resulted in approximately dose-proportional increases in the V PK with no clear effect on C PK. Clinical trial information: NCT01589419.

Patterns of failure for stage I ampulla of Vater adenocarcinoma: a single institutional experience

BACKGROUND

Ampullary adenocarcinoma is a rare malignancy associated with a relatively favorable prognosis. Given high survival rates in stage I patients reported in small series with surgery alone, adjuvant chemoradiotherapy (CRT) has traditionally been recommended only for patients with high risk disease. Recent population-based data have demonstrated inferior outcomes to previous series. We examined disease-related outcomes for stage I tumors treated with pancreaticoduodenectomy, with and without CRT.

METHODS

All patients with stage I ampullary adenocarcinoma treated from 1976 to 2011 at Duke University were reviewed. Disease-related endpoints including local control (LC), metastasis-free survival (MFS), disease-free survival (DFS) and overall survival (OS) were analyzed using the Kaplan-Meier method.

RESULTS

Forty-four patients were included in this study. Thirty-one patients underwent surgery alone, while 13 also received adjuvant CRT. Five-year LC, MFS, DFS and OS for patients treated with surgery only and surgery with CRT were 56% and 83% (P=0.13), 67% and 83% (P=0.31), 56% and 83% (P=0.13), and 53% and 68% (P=0.09), respectively.

CONCLUSIONS

The prognosis for patients diagnosed with stage I ampullary adenocarcinoma may not be as favorable as previously described. Our data suggests a possible benefit of adjuvant CRT delivery.

Incidence and prognostic impact of high-risk HPV tumor infection in cervical esophageal carcinoma

BACKGROUND

Cervical esophageal carcinoma (CEC) is an uncommon malignancy. Limited data supports the use of definitive chemoradiotherapy (CRT) as primary treatment. Furthermore, the role of human papillomavirus (HPV) tumor infection in CEC remains unknown. This study retrospectively analyzes both outcomes of CEC patients treated with CRT and the incidence and potential role of HPV tumor infection in CEC lesions.

METHODS

A total of 37 CEC patients were treated with definitive CRT at our institution between 1987 and 2013. Of these, 19 had tumor samples available for high-risk HPV (types 16 and 18) pathological analysis.

RESULTS

For all patients (n=37), 5-year overall survival (OS), disease-free survival (DFS), and loco-regional control (LRC) rates were 34.1%, 40.2%, and 65.6%, respectively. On pathological analysis, 1/19 (5.3%) patients had an HPV-positive lesion.

CONCLUSIONS

Definitive CRT provides disease-related outcomes comparable to surgery. Moreover, HPV tumor infection in CEC is uncommon and its prognostic role is unclear. Our data contribute to the construction of an anatomical map of HPV tumor infection in squamous cell carcinomas (SCC) of the upper aerodigestive tract, and suggest a steep drop in viral infection rates at sites distal to the oropharynx, including the cervical esophagus.

Radiosensitive orbital metastasis as presentation of occult colonic adenocarcinoma

An 82-year-old man presented with progressive right frontal headaches. The patient's history was significant for benign polyps on surveillance colonoscopy 2 years prior, without high-grade dysplasia or carcinoma. MRI revealed an enhancing lesion arising within the superomedial aspect of the right orbit. Lesion biopsy demonstrated histological appearance and immunophenotype suggestive of colonic adenocarcinoma. Staging positron emission tomography/CT showed visceral metastases and diffuse activity in the posterior rectosigmoid, consistent with metastatic colon cancer. Treatment of the orbital lesion with external beam radiotherapy to 30 Gy resulted in significant palliation of the patient's headaches. The patient expired 2 months following treatment completion due to disease progression. Orbital metastasis as the initial presentation of an occult colorectal primary lesion is exceedingly rare, and occurred in this patient despite surveillance colonoscopy. Radiotherapy remains an efficacious modality for treatment of orbital metastases.

Is diaphragm motion a good surrogate for liver tumor motion?

PURPOSE

To evaluate the relationship between liver tumor motion and diaphragm motion.

METHODS AND MATERIALS

Fourteen patients with hepatocellular carcinoma (10 of 14) or liver metastases (4 of 14) undergoing radiation therapy were included in this study. All patients underwent single-slice cine-magnetic resonance imaging simulations across the center of the tumor in 3 orthogonal planes. Tumor and diaphragm motion trajectories in the superior-inferior (SI), anterior-posterior (AP), and medial-lateral (ML) directions were obtained using an in-house-developed normalized cross-correlation-based tracking technique. Agreement between the tumor and diaphragm motion was assessed by calculating phase difference percentage, intraclass correlation coefficient, and Bland-Altman analysis (Diff). The distance between the tumor and tracked diaphragm area was analyzed to understand its impact on the correlation between the 2 motions.

RESULTS

Of all patients, the mean (±standard deviation) phase difference percentage values were 7.1% ± 1.1%, 4.5% ± 0.5%, and 17.5% ± 4.5% in the SI, AP, and ML directions, respectively. The mean intraclass correlation coefficient values were 0.98 ± 0.02, 0.97 ± 0.02, and 0.08 ± 0.06 in the SI, AP, and ML directions, respectively. The mean Diff values were 2.8 ± 1.4 mm, 2.4 ± 1.1 mm, and 2.2 ± 0.5 mm in the SI, AP, and ML directions, respectively. Tumor and diaphragm motions had high concordance when the distance between the tumor and tracked diaphragm area was small.

CONCLUSIONS

This study showed that liver tumor motion had good correlation with diaphragm motion in the SI and AP directions, indicating diaphragm motion in the SI and AP directions could potentially be used as a reliable surrogate for liver tumor motion.

Patterns of recurrence after trimodality therapy for esophageal cancer

BACKGROUND

Patterns of failure after neoadjuvant chemoradiotherapy and surgery for esophageal cancer are poorly defined.

METHODS

All patients in the current study were treated with trimodality therapy for nonmetastatic esophageal cancer from 1995 to 2009. Locoregional failure included lymph node failure (NF), anastomotic failure, or both. Abdominal paraaortic failure (PAF) was defined as disease recurrence at or below the superior mesenteric artery.

RESULTS

Among 155 patients, the primary tumor location was the upper/middle esophagus in 18%, the lower esophagus in 32%, and the gastroesophageal junction in 50% (adenocarcinoma in 79% and squamous cell carcinoma in 21%) of patients. Staging methods included endoscopic ultrasound (73%), computed tomography (46%), and positron emission tomography/computed tomography (54%). Approximately 40% of patients had American Joint Committee on Cancer stage II disease and 60% had stage III disease. The median follow-up was 1.3 years. The 2-year locoregional control, event-free survival, and overall survival rates were 86%, 36%, and 48%, respectively. The 2-year NF rate was 14%, the isolated NF rate was 3%, and the anastomotic failure rate was 6%. The 2-year PAF rate was 9% and the isolated PAF rate was 5%. PAF was found to be increased among patients with gastroesophageal junction tumors (12% vs 6%), especially for the subset with ≥ 2 clinically involved lymph nodes at the time of diagnosis (19% vs 4%).

CONCLUSIONS

Few patients experience isolated NF or PAF as their first disease recurrence. Therefore, it is unlikely that targeting additional regional lymph node basins with radiotherapy would significantly improve clinical outcomes.

Four-dimensional magnetic resonance imaging using axial body area as respiratory surrogate: initial patient results

PURPOSE

To evaluate the feasibility of a retrospective binning technique for 4-dimensional magnetic resonance imaging (4D-MRI) using body area (BA) as a respiratory surrogate.

METHODS AND MATERIALS

Seven patients with hepatocellular carcinoma (4 of 7) or liver metastases (3 of 7) were enrolled in an institutional review board-approved prospective study. All patients were simulated with both computed tomography (CT) and MRI to acquire 3-dimensional and 4D images for treatment planning. Multiple-slice multiple-phase cine-MR images were acquired in the axial plane for 4D-MRI reconstruction. Image acquisition time per slice was set to 10-15 seconds. Single-slice 2-dimensional cine-MR images were also acquired across the center of the tumor in orthogonal planes. Tumor motion trajectories from 4D-MRI, cine-MRI, and 4D-CT were analyzed in the superior-inferior (SI), anterior-posterior (AP), and medial-lateral (ML) directions, respectively. Their correlation coefficients (CC) and differences in tumor motion amplitude were determined. Tumor-to-liver contrast-to-noise ratio (CNR) was measured and compared between 4D-CT, 4D-MRI, and conventional T2-weighted fast spin echo MRI.

RESULTS

The means (± standard deviations) of CC comparing 4D-MRI with cine-MRI were 0.97 ± 0.03, 0.97 ± 0.02, and 0.99 ± 0.04 in SI, AP, and ML directions, respectively. The mean differences were 0.61 ± 0.17 mm, 0.32 ± 0.17 mm, and 0.14 ± 0.06 mm in SI, AP, and ML directions, respectively. The means of CC comparing 4D-MRI and 4D-CT were 0.95 ± 0.02, 0.94 ± 0.02, and 0.96 ± 0.02 in SI, AP, and ML directions, respectively. The mean differences were 0.74 ± 0.02 mm, 0.33 ± 0.13 mm, and 0.18 ± 0.07 mm in SI, AP, and ML directions, respectively. The mean tumor-to-tissue CNRs were 2.94 ± 1.51, 19.44 ± 14.63, and 39.47 ± 20.81 in 4D-CT, 4D-MRI, and T2-weighted MRI, respectively.

CONCLUSIONS

The preliminary evaluation of our 4D-MRI technique results in oncologic patients demonstrates its potential usefulness to accurately measure tumor respiratory motion with improved tumor CNR compared with 4D-CT.