Purpose

Pancreatic fiducials have proven superior over other isocenter localization surrogates, including anatomical landmarks and intratumoral or adjacent stents. The more clinically relevant dosimetric impact of image guided radiation therapy (IGRT) using intratumoral fiducial markers versus bony anatomy has not yet been described and is therefore the focus of the current study.

Methods and materials

Using daily orthogonal kV or cone beam computed tomography (CBCT) images and positional and dosimetric data were analyzed for 12 consecutive patients treated with fiducial based IGRT and volumetric modulated arc therapy to the intact pancreas. The shifts from fiducial to bone (ΔFid-Bone) required to realign the daily fiducial-matched pretreatment images (kV, CBCTs) to the planning computed tomography (CT) using bony anatomic landmarks were recorded. The isocenter was then shifted by (ΔFid-Bone) for 5 evenly spaced treatments, and the dosimetric impact of ΔFid-Bone was calculated for planning target volume coverage (PTV50.4 and PTV47.9) and organs at risk (liver, kidney, and stomach/duodenum).

Results

The ΔFid-Bone were greatest in the superoinferior direction (ΔFid-Bone anteroposterior, 2.7 ± 3.0; left-right, 2.8 ± 2.8; superoinferior, 6.3 ± 7.9 mm; mean ± standard deviation; P = .03). PTV50.4 coverage was reduced by 13% (fiducial plan 95 ± 2.0 vs bone plan 82 ± 12%; P = .005; range, 5%-52%; >5% loss in all; and >10% loss in 42% of patients), and to a lesser degree for PTV47.9 (difference, -8%; range, 1%-30%; fiducial plan 100 ± 0.3% vs bone plan 92 ± 7.6%; P = .003; with reductions of >5% in 66% and >10% in 33% of patients). The dosimetric impact of ΔFid-Bone on the organs at risk was not significant. Positional shifts for kV- and CBCT-based realignments were nearly identical.

Conclusion

Compared with matching by fiducial markers, IGRT matched by bony anatomy substantially reduces the PTV50.4 and PTV47.9 coverage, supporting the use of intratumoral pancreatic markers for improved targeting in IGRT for pancreatic cancer.

Patients who develop locally recurrent uterine corpus or uterine cervix cancer after primary surgery are usually treated with radiotherapy. The optimal radiotherapeutic approach, however, has not been defined. We report the use of exploratory laparotomy, omental pedicle grafting, and intraoperative transperineal interstitial brachytherapy in the treatment of 28 such patients (10 with recurrent corpus and 18 with recurrent cervix cancer). In addition, 22 patients also received perioperative whole pelvic teletherapy while 21 also received a second closed interstitial application. Local control was achieved in 20 patients (71%), but only 10 (36%) continue to be alive without disease after a median of 44 months. Eighteen patients have died (17 of disease) a median of 13 months after open implant. Patients treated with a single implant (n = 7), with side wall involvement (n = 5), with tumors greater than 6 cm in size (n = 4), with a history of previous pelvic irradiation (n = 8), or with persistent disease after open interstitial therapy (n = 8), were not salvaged. Ten patients suffered acute morbidity which included deep venous thrombosis (n = 1), wound separation (n = 1), urinary infection (n = 2), wound infection (n = 2), pneumonia (n = 1), and fever (n = 3). Two other patients experienced chronic non-tumor-related comorbidities. These included a vesicovaginal fistula with a rectovaginal fistula in 1 patient and a small bowel obstruction with a ureteral stricture in another. A single individual suffered from both acute and chronic complications (fever, ureterointestinal fistula).(ABSTRACT TRUNCATED AT 250 WORDS)

Purpose

To investigate the relationship between abdominal chemoradiation (CRT) for locally advanced cancers and bone mineral density (BMD) reduction in the vertebral spine.

Materials and methods

Data from 272 patients who underwent abdominal radiation therapy from January 1997 to May 2015 were retrospectively reviewed. Forty-two patients received computed tomography (CT) scans of the abdomen prior to initiation and at least twice after radiation therapy. Bone attenuation (in Hounsfield unit) (HU) measurements were collected for each vertebral level from T7 to L5 using sagittal CT images. Radiation point dose was obtained at each mid-vertebral body from the radiation treatment plan. Percent change in bone attenuation (Δ%HU) between baseline and post-radiation therapy were computed for each vertebral body. The Δ%HU was compared against radiation dose using Pearson's linear correlation.

Results

Abdominal radiotherapy caused significant reduction in vertebral BMD as measured by HU. Patients who received only chemotherapy did not show changes in their BMD in this study. The Δ%HU was significantly correlated with the radiation point dose to the vertebral body (R=-0.472, P<0.001) within 4-8 months following RT. The same relationship persisted in subsequent follow up scans 9 months following RT (R=-0.578, P<0.001). Based on the result of linear regression, 5 Gy, 15 Gy, 25 Gy, 35 Gy, and 45 Gy caused 21.7%, 31.1%, 40.5%, 49.9%, and 59.3% decrease in HU following RT, respectively. Our generalized linear model showed that pre-RT HU had a positive effect (β=0.830) on determining post-RT HU, while number of months post RT (β=-0.213) and radiation point dose (β=-1.475) had a negative effect. A comparison of the predicted versus actual HU showed significant correlation (R=0.883, P<0.001) with the slope of the best linear fit=0.81. Our model's predicted HU were within ±20 HU of the actual value in 53% of cases, 70% of the predictions were within ±30 HU, 81% were within ±40 HU, and 90% were within ±50 HU of the actual post-RT HU. Four of 42 patients were found to have vertebral body compression fractures in the field of radiation.

Conclusions

Patients who receive abdominal chemoradiation develop significant BMD loss in the thoracic and lumbar vertebrae. Treatment-related BMD loss may contribute to the development of vertebral compression fractures. A predictive model for post-CRT BMD changes may inform bone protective strategies in patients planned for abdominal CRT.

Background and objectives

Radiation dermatitis occurs in a majority of patients with breast cancer who receive radiation therapy (RT), causes significant pain, and may necessitate treatment delay. Light emitting diode (LED) photomodulation has been reported to minimize radiation dermatitis. This study sought to further evaluate the efficacy of LED photomodulation in lessening radiation dermatitis.

Materials & methods

After surgery, patients with breast cancer received LED photomodulation or sham treatments in conjunction with three-dimensional conformal RT. Reactions were evaluated using standardized photographs graded according to National Cancer Institute criteria.

Results

In the LED treatment group (n=18), no patients had grade 0 reactions, six (33.3%) had grade 1 reactions, 12 (66.7%) had grade 2 reactions, and none had a grade 3 reaction. In the sham treatment group (n=15), one (6.6%) patient had a grade 0 reaction, four (26.7%) had grade 1 reactions, 9 (60.0%) had grade 2 reactions, and one (6.7%) had a grade 3 reaction. Two (11.1%) patients in the LED treatment group and one (6.7%) in the control group had to interrupt treatment. Differences between groups were not statistically significant.

Conclusion

LED photomodulation did not reduce the incidence of radiation-induced skin reactions or interruptions in therapy. .