Faculty Bibliography

BACKGROUND:During the breast lumpectomy procedure, surgeons traditionally elect to use either a superficial or full-thickness closure when sealing the wound depending on surgeon preference as well as desired outcomes. The purpose of this study was to examine dosimetric endpoints in patients with superficial versus full-thickness closures with accelerated partial breast irradiation (APBI). METHODS:Patients who underwent breast conservation surgery followed by 3D conformal external-beam APBI were identified (n = 45) and were separated according to the type of cavity closure performed: superficial and full thickness. Data gathered from the retrospective review of patient charts was analyzed according to criteria in the NSABP B-39 protocol in order to quantify the amount of radiation delivered to organs at risk. The patient seroma cavity was further given a cavity visualization score to assess the impact of wound closure on treatment planning. RESULTS:There was no significant difference in the mean CVS score for the 2 groups. There were no statistical differences in all dosimetric endpoints compared for the 2 types of closure, and both groups met NSABP B-39 guidelines for the ipsilateral breast, heart, and ipsilateral lung dosimetry. CONCLUSIONS:We found no significant difference in dosimetric outcomes in either the superficial or deep closure treatment groups. Breast surgeons should not alter their preferred closure strategy in anticipation of 3D-CRT APBI.

PURPOSE/OBJECTIVE:Because of the risk of skin toxicity with single dwell position, single-lumen brachytherapy devices are sometimes contraindicated for tumor cavities 5-7mm from the skin surface. We discuss the use of multicatheter device to treat patients with tumor bed-to-skin distances <7mm. METHODS AND MATERIALS/METHODS:We treated 117 patients with accelerated partial-breast irradiation brachytherapy: 77 single-lumen and 40 multicatheter devices. A subset of 12 patients treated with SAVI(®) had bed-to-skin spacing <7mm. All patients had Tis-2N0 ductal carcinoma with negative margins. A total dose of 34.0Gy in 10 fractions was delivered twice daily. Planning target volume was created using computed tomography-based three-dimensional planning with a 1.0-cm expansion of the lumpectomy cavity. Skin dose was measured dosimetrically, with skin constraints <125% of the prescription. Toxicities were graded, and patients were assessed at various intervals. RESULTS:Of the patients treated with the multicatheter device, 0% (0/12) had their device pulled. At 2 weeks after treatment, fewer than 50% of the patients had skin toxicities of Grades 1-2, all of which resolved by 6 months. The cosmetic outcome was good to excellent at followup. CONCLUSIONS:Multicatheter devices permit well-tolerated accelerated partial-breast irradiation in patients with tumor cavities near the skin surface for which the single-lumen device may not be appropriate.

PURPOSE/OBJECTIVE:To determine, whether the presence of gold fiducial markers would improve the inter- and intraphysician accuracy in the delineation of the surgical cavity compared with a matched group of patients who did not receive gold fiducial markers in the setting of accelerated partial-breast irradiation (APBI). METHODS AND MATERIALS/METHODS:Planning CT images of 22 lumpectomy cavities were reviewed in a cohort of 22 patients; 11 patients received four to six gold fiducial markers placed at the time of surgery. Three physicians categorized the seroma cavity according to cavity visualization score criteria and delineated each of the 22 seroma cavities and the clinical target volume. Distance between centers of mass, percentage overlap, and average surface distance for all patients were assessed. RESULTS:The mean seroma volume was 36.9 cm(3) and 34.2 cm(3) for fiducial patients and non-fiducial patients, respectively (p = ns). Fiducial markers improved the mean cavity visualization score, to 3.6 ± 1.0 from 2.5 ± 1.3 (p < 0.05). The mean distance between centers of mass, average surface distance, and percentage overlap for the seroma and clinical target volume were significantly improved in the fiducial marker patients as compared with the non-fiducial marker patients (p < 0.001). CONCLUSIONS:The placement of gold fiducial markers placed at the time of lumpectomy improves interphysician identification and delineation of the seroma cavity and clinical target volume. This has implications in radiotherapy treatment planning for accelerated partial-breast irradiation and for boost after whole-breast irradiation.