Investigation of conformal and intensity-modulated radiation therapy techniques to determine the absorbed fetal dose in pregnant patients with breast cancer

Öğretici, Akın; Akbas, Ugur; Koksal, Canan; Bilge, Hatice

doi:10.1016/j.meddos.2015.10.001

Cited by 10 publications

(4 citation statements)

References 11 publications

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“…We did not attempt 3-dimensional conformal radiotherapy (3D-CRT) in our case, though IMRT has scatter and leakage issues compared to 3D-CRT [10]. We hoped to use IMRT to decrease the risk of adverse effects, especially brain necrosis.…”

Section: Discussionmentioning

confidence: 99%

Case Report: Anaplastic Astrocytoma Treated with Postoperative Radiotherapy Using Flattening Filter-Free Volumetric Arc Therapy (FFF-VMAT) during Pregnancy—Acceptable Fetal Dosimetry

Noyama¹,

Takahashi²,

Nozawa³

et al. 2020

JCT

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Background: Postoperative irradiation for brain tumor in pregnant women is a matter of concern. Aim: We aimed to assess the safety of radiotherapy for brain tumors in pregnancy. We here report a successful treatment for anaplastic astrocytoma during pregnancy: surgery + postoperative irradiation. We wish to emphasize how we devised irradiation procedure to achieve both therapeutic effectiveness and safety to the fetus/infant. Case Presentation: A 34-year-old pregnant woman suffered with brain anaplastic astrocytoma. Tumor resection under craniotomy was performed with success. We decided to conduct postoperative radiotherapy at 25 weeks of gestation to reduce the risk of recurrence. We used a flattening filter-free volumetric arc therapy (FFF-VMAT) technique, which can achieve lower out-of-field dose than VMAT with a flattening filter or helical tomotherapy. We prescribed 60 Gy over 30 fractions. During actual beam delivery, surface and rectal dose to the patient (mother) were measured. The total fetal dose was estimated at 0.006-0.018 Gy, which is under the threshold set by the ICRP. A male healthy infant was born vaginally at the 37th week of pregnancy. The patient (mother) and the infant are healthy at the time of writing. Conclusion: FFF-VMAT is a good choice for brain tumors during pregnancy.

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Section: Discussionmentioning

confidence: 99%

Case Report: Anaplastic Astrocytoma Treated with Postoperative Radiotherapy Using Flattening Filter-Free Volumetric Arc Therapy (FFF-VMAT) during Pregnancy—Acceptable Fetal Dosimetry

Noyama¹,

Takahashi²,

Nozawa³

et al. 2020

JCT

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“…The treatment dose was 68 Gy in 34 fractions using IMRT with 4 MV photons from a Varian Clinac 2300; the fetal dose was estimated to be between 9 and 14 cGy using a very large metal block cantilevered from the face of the treatment system as shielding. Numerous reports also exist for fetal dose from radiation therapy for breast cancer, showing fetal doses of 1.0 cGy (for shielded electron treatment) up through 8.5 cGy (for photon IMRT) 27, 28, 29…”

Section: Discussionmentioning

confidence: 99%

Radiation treatment planning and delivery strategies for a pregnant brain tumor patient

Labby

Barraclough

Bayliss

et al. 2018

J Applied Clin Med Phys

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The management of a pregnant patient in radiation oncology is an infrequent event requiring careful consideration by both the physician and physicist. The aim of this manuscript was to highlight treatment planning techniques and detail measurements of fetal dose for a pregnant patient recently requiring treatment for a brain cancer. A 27‐year‐old woman was treated during gestational weeks 19–25 for a resected grade 3 astrocytoma to 50.4 Gy in 28 fractions, followed by an additional 9 Gy boost in five fractions. Four potential plans were developed for the patient: a 6 MV 3D‐conformal treatment plan with enhanced dynamic wedges, a 6 MV step‐and‐shoot (SnS) intensity‐modulated radiation therapy (IMRT) plan, an unflattened 6 MV SnS IMRT plan, and an Accuray TomoTherapy HDA helical IMRT treatment plan. All treatment plans used strategies to reduce peripheral dose. Fetal dose was estimated for each treatment plan using available literature references, and measurements were made using thermoluminescent dosimeters (TLDs) and an ionization chamber with an anthropomorphic phantom. TLD measurements from a full‐course radiation delivery ranged from 1.0 to 1.6 cGy for the 3D‐conformal treatment plan, from 1.0 to 1.5 cGy for the 6 MV SnS IMRT plan, from 0.6 to 1.0 cGy for the unflattened 6 MV SnS IMRT plan, and from 1.9 to 2.6 cGy for the TomoTherapy treatment plan. The unflattened 6 MV SnS IMRT treatment plan was selected for treatment for this particular patient, though the fetal doses from all treatment plans were deemed acceptable. The cumulative dose to the patient's unshielded fetus is estimated to be 1.0 cGy at most. The planning technique and distance between the treatment target and fetus both contributed to this relatively low fetal dose. Relevant treatment planning strategies and treatment delivery considerations are discussed to aid radiation oncologists and medical physicists in the management of pregnant patients.

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“…While several previous studies have reported the peripheral dose to the pelvic region during breast external radiation therapy [33][34][35][36][37][38][39], to the best of our knowledge, the current study is the first report on the peripheral dose to the pelvic region during a breast intraoperative electron radiation therapy (IOERT) boost in the absence of an abdominal shielding apron. Also, obtained dose values were compared with those of external beam radiation therapy.…”

Section: Introductionmentioning

confidence: 89%

Measurement of peripheral dose to the pelvic region and the associated risk for cancer development after breast intraoperative electron radiation therapy

et al. 2019

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This study aimed to measure the received dose to the pelvic region of patients during breast intraoperative electron radiation therapy (IOERT). Furthermore, we compared the findings with those of external beam radiation therapy. Finally, secondary ovarian and uterus cancer risks following breast IOERT were estimated. In the current study, the received dose to the pelvic surface of 18 female patients during breast IOERT boosts were measured by thermoluminescent dosimeter (TLD-100) chips. All patients were treated with 12 Gy given in a single fraction. To estimate the dose to the ovary and uterus of the patients, conversion coefficients for depth from the surface dose were obtained in a Rando phantom. Given the received dose to the pelvic region of the patients, secondary ovarian and uterus cancer risks following breast IOERT were estimated. The received doses to the ovary and uterus surface of the patients were 0.260 ± 0.155 mGy to 31.460 ± 6.020 mGy and 0.485 ± 0.122 mGy to 22.387 ± 15.476 mGy, respectively. Corresponding intra-pelvic (ovary and uterus) regional doses were 0.012 ± 0.007 mGy to 1.479 ± 0.283 mGy and 0.027 ± 0.001 mGy to 1.164 ± 0.805 mGy, respectively. Findings demonstrated that the ratio of the received dose by the pelvic surface to the regional dose during breast IOERT was much less than external beam radiation therapy. The mean of the secondary cancer risks for the ovary in 8 and 10 MeV electron beam energies were 135.722 ± 117.331 × 10−6 and 69.958 ± 28.072 × 10−6, and for the uterus were 17.342 ± 10.583 × 10−6 and 2.971 ± 3.604 × 10−6, respectively. According to our findings, the use of breast IOERT in pregnant patients can be considered as a safe radiotherapeutic technique, because the received dose to the fetus was lower than 50 mGy. Furthermore, IOERT can efficiently reduce the unnecessary dose to the pelvic region and lowers the risk of secondary ovarian and uterus cancer following breast irradiation.

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Investigation of conformal and intensity-modulated radiation therapy techniques to determine the absorbed fetal dose in pregnant patients with breast cancer

Cited by 10 publications

References 11 publications

Case Report: Anaplastic Astrocytoma Treated with Postoperative Radiotherapy Using Flattening Filter-Free Volumetric Arc Therapy (FFF-VMAT) during Pregnancy—Acceptable Fetal Dosimetry

Case Report: Anaplastic Astrocytoma Treated with Postoperative Radiotherapy Using Flattening Filter-Free Volumetric Arc Therapy (FFF-VMAT) during Pregnancy—Acceptable Fetal Dosimetry

Radiation treatment planning and delivery strategies for a pregnant brain tumor patient

Measurement of peripheral dose to the pelvic region and the associated risk for cancer development after breast intraoperative electron radiation therapy

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