Dosimetric comparison between proton beam therapy, intensity modulated radiation therapy, and 3D conformal therapy for soft tissue extremity sarcoma

PURPOSE/OBJECTIVES

Proton beam therapy (PBT) may provide a dosimetric advantage in sparing soft tissue and bone for selected patients with extremity soft sarcoma (eSTS). We compared PBT with photons plans generated using intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3D-CRT).

MATERIALS/METHODS

Seventeen patients previously treated with pencil beam scanning PBT were included in this study. Of these patients, 14 treated with pre-operative 50 Gy in 25 fractions were analyzed. IMRT and 3D-CRT plans were created to compare against the original PBT plans. Dose-volume histogram (DVH) indices were evaluated amongst PBT, IMRT, and 3D plans. Kruskal-Wallis rank sum tests were used to get the statistical significance. A p value smaller than .05 was considered to be statistically significant.

RESULTS

For the clinical target volume (CTV), D2%, D95%, D98%, D_min, D_max, and V50Gy, were assessed. D_min, D1%, D_max, D_mean, V1Gy, V5Gy, and V50Gy were evaluated for the adjacent soft tissue. D1%, D_max, D_mean, and V35-50% were evaluated for bone. All plans met CTV target coverage. The PBT plans delivered less dose to soft tissue and bone. The mean dose to the soft tissue was 2 Gy, 11 Gy, and 13 Gy for PBT, IMRT, and 3D, respectively (p < .001). The mean dose to adjacent bone was 15 Gy, 26 Gy, and 28 Gy for PBT, IMRT, and 3D, respectively (p = .022).

CONCLUSION

PBT plans for selected patients with eSTS demonstrated improved sparing of circumferential soft tissue and adjacent bone compared to IMRT and 3D-CRT. Further evaluation will determine if this improved dosimetry correlates with reduced toxicity and improved quality of life.

CTNI-16. NRG-RTOG 9802 OBSERVATION ARM - LONG TERM RESULT

BACKGROUND

Radiation Therapy Oncology Group 9802 was a phase III trial for patients with centrally confirmed LGG (WHO grade II). Participants ³ 40 years or those with neurosurgeon defined less than gross total resection (GTR) were randomized to radiotherapy (RT) +/- PCV. In a separate cohort, adults age &lt; 40 years with neurosurgeon defined GTR were observed by MRI every 6 months without adjuvant therapy. At last report, outcome for the observation cohort was immature with median follow-up of only 4.4 years. Here, we present mature outcomes for the observation arm.

METHODS

Eligible adults (as above) were observed by MRI every 6 months. OS and PFS were estimated by Kaplan-Meier method and estimated hazard ratios to characterize the prognostic variables.

RESULTS

There were 111 eligible patients (median age 30; median KPS = 100). Median follow-up was 16.1 years with 71 (64%) alive at the last follow-up. 79 patients (71%) had progressed with median PFS of 6.9 years. 5, 10, and 15 year-PFS and OS rates were 54%, 39%, 28% and 94%, 77%, and 65%. 1p19q status was codeleted in 32%, IDH1/2 mutant in 78% and MGMT promoter methylated in 39% of tested cases. Multivariate Cox analyses showed that preoperative tumor size ³ 4 cm (HR = 2.43 for PFS, p = 0.001; HR = 2.58 for death, p = 0.016) and residual disease on imaging ³ 1 cm (HR = 2.97 for PFS, P &lt; 0.001; HR = 2.02 for death, p = 0.05) were associated with worse outcomes. Analyses based on molecular results will be presented.

CONCLUSION

A subset of low-grade gliomas can be observed after the initial resection based on younger age, smaller tumor size, and no residual disease on neuroimaging. This can likely be further refined by prognostic molecular markers. Patients with the most favorable prognostic factors can avoid or delay the acute and long-term side effects of RT and chemotherapy for several years.

Potential Molecular Targets in the Setting of Chemoradiation for Esophageal Malignancies

Although the development of effective combined chemoradiation regimens for esophageal cancers has resulted in statistically significant survival benefits, the majority of patients treated with curative intent develop locoregional and/or distant relapse. Further improvements in disease control and survival will require the development of individualized therapy based on the knowledge of host and tumor genomics and potentially harnessing the host immune system. Although there are a number of gene targets that are amplified and proteins that are overexpressed in esophageal cancers, attempts to target several of these have not proven successful in unselected patients. Herein, we review our current state of knowledge regarding the molecular pathways implicated in esophageal carcinoma, and the available agents for targeting these pathways that may rationally be combined with standard chemoradiation, with the hope that this commentary will guide future efforts of novel combinations of therapy.

Margin reduction from image guided radiation therapy for soft tissue sarcoma: Secondary analysis of Radiation Therapy Oncology Group 0630 results

PURPOSE

Six imaging modalities were used in Radiation Therapy Oncology Group (RTOG) 0630, a study of image guided radiation therapy (IGRT) for primary soft tissue sarcomas of the extremity. We analyzed all daily patient-repositioning data collected in this trial to determine the impact of daily IGRT on clinical target volume-to-planning target volume (CTV-to-PTV) margin.

METHODS AND MATERIALS

Daily repositioning data, including shifts in right-left (RL), superior-inferior (SI), and anterior-posterior (AP) directions and rotations for 98 patients enrolled in RTOG 0630 from 18 institutions were analyzed. Patients were repositioned daily on the basis of bone anatomy by using pretreatment images, including kilovoltage orthogonal images (KVorth), megavoltage orthogonal images (MVorth), KV fan-beam computed tomography (KVCT), KV cone beam CT (KVCB), MV fan-beam CT (MVCT), and MV cone beam CT (MVCB). Means and standard deviations (SDs) for each shift and rotation were calculated for each patient and for each IGRT modality. The Student's t tests and F-tests were performed to analyze the differences in the means and SDs. Necessary CTV-to-PTV margins were estimated.

RESULTS

The repositioning shifts and day-to-day variations were large and generally similar for the 6 imaging modalities. Of the 2 most commonly used modalities, MVCT and KVorth, there were no statistically significant differences in the shifts and rotations (P = .15 and .59 for the RL and SI shifts, respectively; and P = .22 for rotation), except for shifts in AP direction (P = .002). The estimated CTV-to-PTV margins in the RL, SI, and AP directions would be 13.0, 10.4, and 11.7 mm from MVCT data, respectively, and 13.1, 8.6, and 10.8 mm from KVorth data, respectively, indicating that margins substantially larger than 5 mm used with daily IGRT would be required in the absence of IGRT.

CONCLUSIONS

The observed large daily repositioning errors and the large variations among institutions imply that daily IGRT is necessary for this tumor site, particularly in multi-institutional trials. Otherwise, a CTV-to-PTV margin of 1.5 cm is required to account for daily setup variations.

Efficacy endpoints of radiation therapy group protocol 0247: a randomized, phase 2 study of neoadjuvant radiation therapy plus concurrent capecitabine and irinotecan or capecitabine and oxaliplatin for patients with locally advanced rectal cancer

PURPOSE

To report secondary efficacy endpoints of Radiation Therapy Oncology Group protocol 0247, primary endpoint analysis of which demonstrated that preoperative radiation therapy (RT) with capecitabine plus oxaliplatin achieved a pathologic complete remission prespecified threshold (21%) to merit further study, whereas RT with capecitabine plus irinotecan did not (10%).

METHODS AND MATERIALS

A randomized, phase 2 trial evaluated preoperative RT (50.4 Gy in 1.8-Gy fractions) with 2 concurrent chemotherapy regimens: (1) capecitabine (1200 mg/m(2)/d Monday-Friday) plus irinotecan (50 mg/m(2)/wk × 4); and (2) capecitabine (1650 mg/m(2)/d Monday-Friday) plus oxaliplatin (50 mg/m(2)/wk × 5) for clinical T3 or T4 rectal cancer. Surgery was performed 4 to 8 weeks after chemoradiation, then 4 to 6 weeks later, adjuvant chemotherapy (oxaliplatin 85 mg/m(2); leucovorin 400 mg/m(2); 5-fluorouracil 400 mg/m(2); 5-fluorouracil 2400 mg/m(2)) every 2 weeks × 9. Disease-free survival (DFS) and overall survival (OS) were estimated univariately by the Kaplan-Meier method. Local-regional failure (LRF), distant failure (DF), and second primary failure (SP) were estimated by the cumulative incidence method. No statistical comparisons were made between arms because each was evaluated individually.

RESULTS

A total of 104 patients (median age, 57 years) were treated; characteristics were similar for both arms. Median follow-up for RT with capecitabine/irinotecan arm was 3.77 years and for RT with capecitabine/oxaliplatin arm was 3.97 years. Four-year DFS, OS, LRF, DF, and SP estimates for capecitabine/irinotecan arm were 68%, 85%, 16%, 24%, and 2%, respectively. The 4-year DFS, OS, LRF, DF, and SP failure estimates for capecitabine/oxaliplatin arm were 62%, 75%, 18%, 30%, and 6%, respectively.

CONCLUSIONS

Efficacy results for both arms are similar to other reported studies but suggest that pathologic complete remission is an unsuitable surrogate for traditional survival metrics of clinical outcome. Although it remains uncertain whether the addition of a second cytotoxic agent enhances the effectiveness of fluorouracil plus RT, these results suggest that further study of irinotecan may be warranted.

Hydronephrosis in patients with cervical cancer: an assessment of morbidity and survival

PURPOSE

Hydronephrosis is a frequently observed but understudied complication in patients with cervical cancer. To better characterize hydronephrosis in cervical cancer patients, the current study sought (1) to describe hydronephrosis-associated morbidity and (2) to analyze the prognostic effect of hydronephrosis in patients with a broad range of cancer stages over time.

METHODS

The Mayo Clinic Tumor Registry was interrogated for all invasive cervical cancer patients seen at the Mayo Clinic from 2008 through 2013 in Rochester, Minnesota; these patients' medical records were then reviewed in detail.

RESULTS

Two hundred seventy-nine cervical cancer patients with a median age of 49 years and a range of cancer stages were included. Sixty-five patients (23 %) were diagnosed with hydronephrosis at some point during their disease course. In univariate analyses, hydronephrosis was associated with advanced cancer stage (p < 0.0001), squamous histology (p = 0.0079), and nonsurgical cancer treatment (p = 0.0039). In multivariate analyses, stage and tumor histology were associated with hydronephrosis. All but one patient underwent stent placement or urinary diversion; hydronephrosis-related morbidity included pain, urinary tract infections, nausea and vomiting, renal failure, and urinary tract bleeding. In landmark univariate survival analyses, hydronephrosis was associated with worse survival at all time points. In landmark multivariate analyses (adjusted for patient age, stage, cancer treatment, and tumor histology), hydronephrosis was associated with a trend toward worse survival over time (hazard ratios ranged from 1.47 to 4.69).

CONCLUSION

Hydronephrosis in cervical cancer patients is associated with notable morbidity. It is also associated with trends toward worse survival-even if it occurs after the original cancer diagnosis.

Radiation Therapy Oncology Group 0247: a randomized Phase II study of neoadjuvant capecitabine and irinotecan or capecitabine and oxaliplatin with concurrent radiotherapy for patients with locally advanced rectal cancer

PURPOSE

To evaluate the rate of pathologic complete response (pCR) and the toxicity of two neoadjuvant chemoradiotherapy (chemoRT) regimens for Stage T3-T4 rectal cancer in a randomized Phase II study.

METHODS AND MATERIALS

Patients with Stage T3 or T4 rectal cancer of <12 cm from the anal verge were randomized to preoperative RT (50.4 Gy in 1.8-Gy fractions) with concurrent capecitabine (1,200 mg/m(2)/d Mondays through Friday) and irinotecan (50 mg/m(2) weekly in four doses) (Arm 1) or concurrent capecitabine (1,650 mg/m(2)/d Monday through Friday) and oxaliplatin (50 mg/m(2) weekly in five doses) (Arm 2). Surgery was performed 4-8 weeks after chemoRT, and adjuvant chemotherapy 4-6 weeks after surgery. The primary endpoint was the pCR rate, requiring 48 evaluable patients per arm.

RESULTS

A total of 146 patients were enrolled. The protocol chemotherapy was modified because of excessive gastrointestinal toxicity after treatment of 35 patients; 96 were assessed for the primary endpoint-the final regimen described above. The patient characteristics were similar for both arms. After chemoRT, the rate of tumor downstaging was 52% and 60% and the rate of nodal downstaging (excluding N0 patients) was 46% and 40%, for Arms 1 and 2, respectively. The pCR rate for Arm 1 was 10% and for Arm 2 was 21%. For Arm 1 and 2, the preoperative chemoRT rate of Grade 3-4 hematologic toxicity was 9% and 4% and the rate of Grade 3-4 nonhematologic toxicity was 26% and 27%, respectively.

CONCLUSIONS

Preoperative chemoRT with capecitabine plus oxaliplatin for distal rectal cancer has significant clinical activity (10 of 48 pCRs) and acceptable toxicity. This regimen is currently being evaluated in a Phase III randomized trial (National Surgical Adjuvant Breast and Bowel Project R04).

RTOG sarcoma radiation oncologists reach consensus on gross tumor volume and clinical target volume on computed tomographic images for preoperative radiotherapy of primary soft tissue sarcoma of extremity in Radiation Therapy Oncology Group studies

OBJECTIVE

To develop a Radiation Therapy Oncology Group (RTOG) atlas delineating gross tumor volume (GTV) and clinical target volume (CTV) to be used for preoperative radiotherapy of primary extremity soft tissue sarcoma (STS).

METHODS AND MATERIALS

A consensus meeting was held during the RTOG meeting in January 2010 to reach agreement about GTV and CTV delineation on computed tomography (CT) images for preoperative radiotherapy of high-grade large extremity STS. Data were presented to address the local extension of STS. Extensive discussion ensued to develop optimal criteria for GTV and CTV delineation on CT images.

RESULTS

A consensus was reached on appropriate CT-based GTV and CTV. The GTV is gross tumor defined by T1 contrast-enhanced magnetic resonance images. Fusion of magnetic resonance and images is recommended to delineate the GTV. The CTV for high-grade large STS typically includes the GTV plus 3-cm margins in the longitudinal directions. If this causes the field to extend beyond the compartment, the field can be shortened to include the end of a compartment. The radial margin from the lesion should be 1.5 cm, including any portion of the tumor not confined by an intact fascial barrier, bone, or skin surface.

CONCLUSION

The consensus on GTV and CTV for preoperative radiotherapy of high-grade large extremity STS is available as web-based images and in a descriptive format through the RTOG. This is expected to improve target volume consistency and allow for rigorous evaluation of the benefits and risks of such treatment.

Is a solitary inguinal lymph node metastasis from adenocarcinoma of the rectum really a metastasis?

OBJECTIVE

Metastatic involvement of inguinal lymph nodes (ILN) from rectal adenocarcinoma is unusual, particularly without signs of distant spread to other organ sites. By current convention, ILN involvement, including solitary involvement, is classified as metastatic disease (M). However, anecdotal reports suggest that such patients are a distinct entity and should be managed differently. The aim of this study was to gain further insight regarding this seemingly distinct patient subset.

METHOD

This case series provides a descriptive report of patients with rectal adenocarcinoma and solitary inguinal lymph node metastasis (SILNM).

RESULTS

Upon retrospective review of medical records from 4480 patients with rectal adenocarcinoma seen at Mayo Clinic Rochester from 1995 to 2004, six patients (0.13%) with SILNM were identified. Three had metachronous and three had synchronous SILNM (four left sided, one right sided, and one bilateral). The mean age at SILNM diagnosis was 61.3 years, and three patients had originally stage II (and three had stage III disease). Five patients received concurrent chemo-radiation therapy and one declined treatment. Among those with metachronous SILNM, the mean survival after diagnosis of rectal cancer was 42 months. By comparison, all three patients with synchronous SILNM were still alive after a mean duration of 40 months of follow up.

CONCLUSION

Solitary involvement of ILNs might represent a distinct subset of patients with metastatic rectal adenocarcinoma who have a more favourable prognosis. If confirmed by larger studies, our data suggest that alternate management algorithms might be reasonable for such patients.

Locally advanced primary colorectal cancer: intraoperative electron and external beam irradiation +/- 5-FU

PURPOSE

For locally advanced primary colorectal cancer, our institution has combined intraoperative electron irradiation (IOERT) with external beam irradiation (EBRT) +/- 5-fluorouracil (5-FU) and surgical resection. Disease control and survival were compared with the current IOERT and prior non-IOERT regimens.

METHODS AND MATERIALS

From April 1981 through August 1995, 61 patients received an IOERT dose of 10-20 Gy, usually combined with 45-55 Gy of fractionated EBRT; 56 had minimum follow-up of 18 months. The amount of residual disease remaining at IOERT after exploration and maximal resection in the 56 patients was gross in 16, < or = microscopic in 39, and unresected in 1.

RESULTS

Survival (SR) and disease control were analyzed as a function of potential prognostic factors. Factors that achieved statistical significance for improved overall survival included treatment sequence of preop EBRT + 5-FU (vs. postoperative EBRT + 5-FU, p = 0.003) and < or = microscopic residual disease after maximal resection (vs. gross residual, p = 0.005). Those that appeared to favorably impact disease-free survival included EBRT + 5-FU (vs. EBRT alone, p = 0.01), < or = microscopic residual (vs. gross, p = 0.0014), and colon site of primary (vs. rectum, p = 0.009). Failures within an irradiation field have occurred in 4 of 16 patients (25%) who presented with gross residual after partial resection vs. 2 of 39 (5%) with < or = microscopic residual after gross total resection (p = 0.01). The significant prognostic factors for a decrease in distant metastases were the same as for disease-free SR with respective p-values of 0.013 (EBRT + 5-FU), 0.008 (microscopic residual), and 0.03 (colon primary). The current data suggests a relationship between IOERT dose and incidence of Grade 2 or 3 neuropathy (< or = 12.5 Gy--1 of 29 or 3%, > or = 15 Gy--6 of 26 or 23%, p = 0.03).

CONCLUSIONS

Both overall survival and disease control appear to be improved with the addition of IOERT to standard treatment. More routine use of systemic therapy is indicated as a component of IOERT containing treatment regimens because the incidence of distant metastases was 50% of patients at risk.

Intraoperative electron and external beam irradiation with or without 5-fluorouracil and maximum surgical resection for previously unirradiated, locally recurrent colorectal cancer

PURPOSE/OBJECTIVE

1) Disease control and survival will be evaluated for treatment regimens containing intraoperative electron irradiation (IOERT) for locally recurrent, previously unirradiated colorectal cancers. 2) Various prognostic factors will be evaluated to determine whether they have an impact on disease control or survival.

MATERIALS AND METHODS

From April 1981 through August 1995, 123 patients with previously unirradiated locally recurrent colorectal cancers received IOERT at our institution, usually as a supplement to external beam irradiation (EBRT) and maximum resection. All received EBRT with or without concomitant 5-fluorouracil-based chemotherapy. Forty-five Gy in 25 fractions was given to the tumor or tumor bed plus 3-cm to 5-cm margins in 121 of 123 patients and a boost of 5.4 to 9 Gy in 3 to 5 fractions to the tumor plus 2-cm margins. Maximum resection was performed before or after EBRT. IOERT doses ranged from 10 to 20 Gy in 119 of 123 patients, with dose dependent on resection margins (130 fields in 123 patients). Maintenance chemotherapy was given to only two patients.

RESULTS

Disease relapse and survival were evaluated. Central failure (within the IOERT field) was documented in 13 of 123 patients (11 percent) with a five-year actuarial rate of 26 percent. Local relapse (in EBRT field) occurred in 24 patients (20 percent); five-year rate was 37 percent. Distant metastases occurred in 66 patients (54 percent); five-year rate was 72 percent. Median survival was 28 months, with overall survival at two, three, and five years of 62, 39, and 20 percent, respectively. Tolerance data suggest a relationship between IOERT dose and incidence of Grade 2 or 3 neuropathy (< or = 12.5 Gy, 2 of 29 or 7 percent; > or = 15 Gy, 19 of 101 or 19 percent; P = 0.12). Survival and disease control were analyzed as a function of potential prognostic factors. None of the prognostic factors had a significant impact on disease control or survival. Although there was a trend for reduction in local relapse rates with gross total vs. partial resection, this neither achieved statistical significance nor translated into improved survival. Patients with gross residual disease after maximum resection had three-year and five-year survival rates of 36 and 18 percent, respectively, which paralleled results for patients with gross total resection at 41 and 24 percent, respectively.

CONCLUSION

Encouraging trends for improved local control with or without survival exist in separate locally recurrent colorectal IOERT analyses from our institution and other institutions. Therefore, continued evaluation of IOERT approaches seems warranted. Disease control within the IOERT and external fields is decreased when the surgeon is unable to accomplish a gross total resection. Therefore, it is reasonable to consistently add 5-fluorouracil or other dose modifiers during EBRT and to evaluate the use of dose modifiers in conjunction with IOERT (sensitizers and hyperthermia). In view of high systemic failure rates of > 50 percent in patients with locally recurrent disease, more routine use of systemic therapy is indicated as a component of IOERT-containing treatment regimens (use existent chemotherapy and/or develop effective immunotherapy and gene transfer therapy). Even with locally recurrent lesions, the aggressive multimodality approaches including IOERT have resulted in improved local control and long-term survival rates of 20 percent vs. an expected 5 percent with conventional techniques.

Protamine reaction in a patient undergoing coronary artery bypass grafting

The neutralization of heparin anticoagulation is accomplished by the administration of protamine. While the administration of protamine is generally uneventful, allergic reactions can occur. This article describes such a reaction in a patient having cardiac surgery. Classification of protamine reactions and signs and symptoms are discussed. Treatment and management of high risk patients is highlighted.

The effects of two methods of pelvic examination instruction on student performance and anxiety

The impact of two methods of pelvic examination instruction on student performance and anxiety was examined. Forty second-year medical students were randomly assigned either to an experimental group which received initial pelvic examination instruction from professional patients or to a control group which received this instruction from a gynecologist with a clinic patient. Results revealed no significant difference between experimental and control subjects in subsequent performance of the pelvic examination, on heart rate, or on perceived anxiety using one anxiety inventory. However, significant differences were found using a second anxiety instrument. The cost per student examination was twice as much for the clinic-patient group as for the professional-patient group. These findings are discussed in relation to prior research and instructional practices.