Small Breast Volume Research Articles

VMAT Radiation Therapy (VMAT) Versus Intensity Modulated Radiation Therapy (IMRT) for Small-Sized Breast

Purpose/Objective(s): This study aims to analyze the dosimetric difference between VMAT therapy and intensity modulated therapy (IMRT) on small breast volume after receiving breast cancer conservation surgery. Materials/Methods: All patients underwent CT simulation for RT planning using the AAA algorithm with a calculation gird of 2.5 mm. All patients were treated with VMAT technique and a corresponding Intensity modulated radiation therapy (IMRT) plan was generated for comparison. These 10 small size breast (cup size 32A, 32B, 34A, 34B) patients had received breast conservation surgery prior to radiation therapy. VMAT using 6 MV x-rays simultaneous integrated field boost technique were given to irradiate the whole breast with 50 Gy and a concomitant boost irradiation to the surgical bed for 60.2 Gy in 28 fractions. The planning objectives were: PTV V95% >95%, Dmax <107%; Mean lung dose (MLD) <15 Gy, V20 Gy <20%. Heart dose should be 10 Gy. Results: The minimum follow-up was 6 months. Comparison between VMAT and IMRT revealed significant dose-volume differences for PTV dose coverage, treatment time in terms of MU, and dose to ipsilateral lung tissue. Dose-volume distribution to the heart, spine, contralateral lung, normal tissue, and normal breast was similar for both VMAT and IMRT technique with no significant difference. The mean VPTV95% was 98.6% 0.002(VMAT) and 98.8% 0.003 (IMRT). The mean V107% was higher for the VMAT (43.9% 12.1) when compared with IMRT (14.8% 27.4). The mean conformity index was similar for VMAT (0.742 0.09) and IMRT (0.748 0.07). The mean homogeneity index was similar for RA (1.08 0.017) and IMRT (1.096 0.011). The mean ipsilateral lung dose was higher for the VMAT technique (11.7 Gy 2.8) compared with the IMRT technique (9.3 Gy 1.9). However, the D2% (Gy) and V20 Gy (%) was higher for the IMRT than the VMAT technique (40.7 Gy 1.9, 17.9% 0.05 vs 38.4 Gy 2.5, 15.1% 2.5 respectively). Treatment time in terms of monitor unit (MU) was found to be significantly lower for the RA technique when compared with IMRT (791 MU vs 1337 MU, p Z 0.007). Conclusions: IMRT is a mature and well-accepted technique for breast cancer irradiation; VMAT is a recent development that is also suitable for breast irradiation. We found in this study that VMAT is comparable with IMRT in terms of PTV coverage, tumor dose conformity and homogeneity index for small sized breast. This study also found that VMAT is an

Dosimetric comparison between intensity-modulated radiotherapy and standard wedged tangential technique for whole-breast radiotherapy in Asian women with relatively small breast volumes

We sought to investigate whether intensity-modulated radiotherapy (IMRT) has a dosimetric advantage compared to the standard wedged tangential technique (SWT) for whole-breast radiotherapy (WBRT) in Asian women with relatively small breast volume. Computed tomography images of 25 Asian patients with early-stage breast cancer (right 15, left 10) used for WBRT planning were examined. After contouring the target volumes and bilateral lungs and, for left-side treatment, the heart, 4 plans were made for each patient: namely, SWT, tangential-field IMRT (T-IMRT), 3-field IMRT (3F-IMRT), and 4-field IMRT (4F-IMRT). The prescribed dose was 5000 cGy. The median planning target volume (PTV) for WBRT was 552.6 cc (range 288.8-1518.4 cc). Compared to SWT, (1) T-IMRT achieved significant improvement for dose homogeneity in the PTV (p < 0.001) and the dose received by 2% (D2) of the PTV (p < 0.001). T-IMRT also reduced the bilateral lung mean dose (p < 0.001) and the ipsilateral lung volume which received more than 20 Gy (V20) (p = 0.01). (2) 3F-IMRT resulted in a significant increase in the mean dose to the ipsilateral lung (p < 0.001) and to the contralateral lung (p < 0.001). (3) 4F-IMRT also resulted in a significant increase in the mean dose to the ipsilateral lung (p < 0.001) and to the contralateral lung (p < 0.001). Tangential-field IMRT provided an improved dose distribution compared with SWT for WBRT in Asian women with a relatively small breast volume.

MRI volumetric analysis of fibroglandular tissue to assess risk of the spared nipple in BRCA 1/2 patients who are considering prophylactic nipple-sparing mastectomy.

1507 Background: Prophylactic nipple sparing mastectomy (NSM) in BRCA 1/2 mutation carriers is an option for risk reduction but is controversial over concern that residual fibroglandular tissue (FGT) with malignant potential remains in the spared nipple. Since the volume of FGT in the nipple has not been formally evaluated, the objective of this study is to measure the residual volume of FGT in the spared nipple at a standard retroareolar margin (5mm) and identify sources of variability, including a greater margin and patient factors. Methods: A segmentation protocol was applied to breast MRIs from 105 consecutive BRCA 1/2patients. The MRI segmentation quantified volumes for total breast and nipple FGT. The nipple FGT volume was determined by setting the retroareolar margin (depth on MRI). The proportion of FGT in the nipple with 5mm retroareolar margin relative to the breast was calculated as the primary outcome and compared to 10mm margins. Associations between the proportion of FGT in the nipple (5mm) and patient characteristics were examined using uni- and multivariable analyses. Effect size was measured where appropriate. Results: At 5mm and 10mm retroareolar thickness, residual FGT comprised 0.24% (0.02-0.9%) and 0.42% (0.0.2-01.2%), respectively, of the total breast FGT (p &lt; 0.001, Cohen d = 0.03). Smaller breast volume, lower BMI and parity (p &lt; 0.001, p &lt; 0.009, p &lt; 0.009 respectively) were predictive of greater proportion of residual FGT on univariate analysis, while breast volume and parity were predictive with multivariate (R2 = 0.28, F = 16.5, p &lt; 0.0005). Conclusions: The proportion of FGT remaining in the spared nipple with a 5mm margin is extremely small, suggesting very little added risk over a skin sparing mastectomy. This proportion may be influenced by breast volume and childbearing. Doubling the retroareolar margin statistically increases the proportion, yet this likely does not translate into a clinically meaningful increase and may support a slightly thicker retroareolar margin. Overall, our findings support safety of the current trend toward increased rates of prophylactic NSM performed in the BRCA 1/2 patient population.

Association of single nucleotide polymorphisms in the genes ATM, GSTP1, SOD2, TGFB1, XPD and XRCC1 with risk of severe erythema after breast conserving radiotherapy

PurposeTo examine the association of polymorphisms in ATM (codon 158), GSTP1 (codon 105), SOD2 (codon 16), TGFB1 (position −509), XPD (codon 751), and XRCC1 (codon 399) with the risk of severe erythema after breast conserving radiotherapy.Methods and materialsRetrospective analysis of 83 breast cancer patients treated with breast conserving radiotherapy. A total dose of 50.4 Gy was administered, applying 1.8 Gy/fraction within 42 days. Erythema was evaluated according to the Radiation Therapy Oncology Group (RTOG) score. DNA was extracted from blood samples and polymorphisms were determined using either the Polymerase Chain Reaction based Restriction-Fragment-Length-Polymorphism (PCR-RFL) technique or Matrix-Assisted-Laser-Desorption/Ionization –Time-Of-Flight-Mass-Spectrometry (MALDI-TOF). Relative excess heterozygosity (REH) was investigated to check compatibility of genotype frequencies with Hardy-Weinberg equilibrium (HWE). In addition, p-values from the standard exact HWE lack of fit test were calculated using 100,000 permutations. HWE analyses were performed using R.ResultsFifty-six percent (46/83) of all patients developed erythema of grade 2 or 3, with this risk being higher for patients with large breast volume (odds ratio, OR = 2.55, 95% confidence interval, CI: 1.03–6.31, p = 0.041). No significant association between SNPs and risk of erythema was found when all patients were considered. However, in patients with small breast volume the TGFB1 SNP was associated with erythema (p = 0.028), whereas the SNP in XPD showed an association in patients with large breast volume (p = 0.046). A risk score based on all risk alleles was neither significant in all patients nor in patients with small or large breast volume. Risk alleles of most SNPs were different compared to a previously identified risk profile for fibrosis.ConclusionsThe genetic risk profile for erythema appears to be different for patients with small and larger breast volume. This risk profile seems to be specific for erythema as compared to a risk profile for fibrosis.

3D-conformal accelerated partial breast irradiation treatment planning: the value of surgical clips in the delineation of the lumpectomy cavity.

BackgroundAccurate localisation of the lumpectomy cavity (LC) volume is one of the most critical points in 3D-conformal Partial breast irradiation (3D-APBI) treatment planning because the irradiated volume is restricted to a small breast volume. Here, we studied the role of the placement of surgical clips at the 4 cardinal points of the lumpectomy cavity in target delineation.MethodsForty CT-based 3D-APBI plans were retrieved on which a total of 4 radiation oncologists, two trainee and two experienced physicians, outlined the lumpectomy cavity. The inter-observer variability of LC contouring was assessed when the CTV was defined as the delineation that encompassed both surgical clips and remodelled breast tissue.ResultsThe conformity index of tumour bed delineation was significantly improved by the placement of surgical clips within the LC (median at 0.65). Furthermore, a better conformity index of LC was observed according to the experience of the physicians (median CI = 0.55 for trainee physicians vs 0.65 for experienced physicians).ConclusionsThe placement of surgical clips improved the accuracy of lumpectomy cavity delineation in 3D-APBI. However, a learning curve is needed to improve the conformity index of the lumpectomy cavity.

Round Gel Breast Implants or Anatomic Gel Breast Implants: Which is the Best Choice?

Since their introduction in 1993, anatomic implants have been popularized by numerous surgeons, but very little literature compares the precise indications, advantages, and disadvantages between round implants and anatomic implants. A retrospective analysis was performed for all the patients who underwent breast implantation by the main author over a 15-year period. The number of implanted patients, the shape of the implants placed, the approach routes, and the placement plane were determined as well as the relationship between the shape of the implant and the approach route. The aesthetic results obtained were analyzed in detail based on the shape of the implant used. Over a 15-year period, 932 patients underwent surgery for breast implants. During the first 6 years, only round implants were used, and during the last 9 years, both anatomic and round implants were used. A total of 787 pairs of round implants and 145 pairs of anatomic implants were placed. The indications based on the postoperative aesthetic analysis suggest the use of implants according to their shape. The use of anatomic implants is suggested for patients with significant differences in chest height and width measurements, for cases of significant mammary asymmetry, for patients with a small breast volume or a prominent thorax, and for breasts with a significant deficit of inferior mammary volume or significant shortening of the breast. The authors recommend round implants for patients with a superior pole deficit or moderate breast pseudoptosis, for patients who have a breast that will cover the implant, and for patients who present with a small asymmetry.

SU‐GG‐J‐175: Target Registration Error Analysis Via KV Imaging and Conebeam CT in Accelerated Partial Breast Irradiation

Purpose: In accelerated partial breast irradiation (APBI), accurate localization of the lumpectomy cavity is important. We are investigating daily localization of the lumpectomy cavity in patients with implanted surgical clips by kV imaging followed by conebeam CT (CBCT). Initial data based on 2 patients are presented here. Target registration error (TRE) analysis was performed to assess the accuracy of available image‐guidance techniques for target localization during APBI. Method and Materials: APBI patients were positioned to the treatment isocenter initially by laser alignment to skin tattoos, followed by orthogonal kV radiographs to visualize bony anatomy and surgical clips and then by CBCT (once daily) to visualize both surgical clips and soft tissue architecture. Couch shifts were performed based on matching surgical clip position and lumpectomy cavity architecture (when visible) to the planned setup. The lumpectomy cavity position was assumed to be represented by the surgical clips. The TRE is defined as the residual setup error following isocenter alignment. Surface topology analysis on the serial CBCT datasets was performed post‐treatment by co‐registering the breast surfaces, as defined by CBCT, and then measuring the clip misalignment. Results: The average laser setup TREs (determined by kV imaging) for patients 1 (breast volume = 1335.5cc) and 2 (breast volume = 404.7cc) were 3.7mm and 6.1mm, respectively. The average kV imaging TREs (determined by CBCT, post‐kV imaging shifts) for patients 1 and 2 were 4.9mm and 1.4mm, respectively. The average surface topology TREs for patients 1 and 2 were 4.9mm and 1.6mm, respectively. Conclusion: Even after kV imaging, TREs around 0.5cm were detected using CBCT in the larger breast volume. Therefore, CBCT may improve targeting in APBI for patients with large breast volumes. Surface alignment may be more suitable for patients with small breast volumes and is currently under further investigation.

Breast carcinoma in men

We read with interest the recent article by Giordano et al.1 Utilizing the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database for breast carcinoma cases diagnosed among men between 1973–1998 (August 2000 submission), they reported a 26% increase in the overall incidence rate of male breast carcinoma, based on 5-year increments and including in situ tumors. The explanation for this increase was unclear, meriting further investigation. Using the more recent SEER database for breast carcinoma cases diagnosed through 2001 (November 2003 submission), we added 3 years of observation and compared stage-specific trends among male and female breast carcinoma cases. Overall breast carcinoma rates were found to have increased 29% for men and 58% for women, based on 5-year increments and including in situ tumors. During the last three decades there were temporal increases for in situ and invasive localized breast carcinomas with decreases for invasive regional and distant tumors among both men and women. Rates of in situ tumors increased the most rapidly: 123% and 555% among men and women, respectively. Invasive localized disease rates were found to have increased a more modest 37% and 78% among men and women, respectively. Conversely, the disease rates of invasive regional and distant breast carcinoma declined for men and women during the 1980s and 1990s. For example, the distant disease rate was found to have decreased 41% among men from 0.09 per 100,000 man-years during 1975–1980 to 0.053 per 100,000 man-years during 1997–2001. The rapid rise in early-stage female breast carcinomas diagnosed during the 1980s undoubtedly resulted from increases in screened-derived “occult” in situ and invasive localized tumors.2 Advances in screening mammography could not account for the dramatic increases noted in early-stage breast carcinoma among men, given that men are not routinely screened for breast carcinoma. However, a heightened awareness of male breast carcinoma might result in the earlier detection of “symptomatic” in situ and invasive localized tumors because of the easier detection of small lesions in men with a small breast volume.3 Male breast carcinoma is a rare disease and the absolute numbers for breast carcinoma cases among men were low for certain stages of disease. Therefore, we must interpret stage-specific male breast carcinoma rates with caution. Nonetheless, temporal trends for male breast carcinoma have remained essentially stable for decades whereas those for female breast carcinoma have increased worldwide.4, 5 Additional surveillance is certainly warranted to determine whether the recent report by Giordano et al.1 foreshadows a change in the risk of male breast carcinoma or simply reflects earlier detection over time. William F. Anderson M.D.*, Susan S. Devesa Ph.D. , * Division of Cancer Prevention, National Cancer Institute, Bethesda, Maryland, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland.

Dosimetric comparison of xr 4 mv, cobalt and xr 6 mv after conservative surgery in breast cancer

Purpose/Objective: Abstract # 2039 of the ASTRO meeting 2001 demonstrated that local failure rate was increased with XR 6 MV as compared to cobalt in a large retrospective series of patients with breast carcinoma. The aim of this study was to compare dosimetric differences between XR 4 MV, XR 6 MV and cobalt.Materials/Methods: 50 patients treated with conservative surgery for primary breast cancer were randomly selected. Breast CT-scan slice separation and thickness was 8 mm. Clinical Target Volume (CTV) was outlined on each slice with Focus 3.0.0 software (Computerized Medical System). The CTV was assumed to start 5 mm below the skin. Internal limit encompassed thoracic wall. Upper limit was upper border of sternum. Lower border was inferior part of the breast . Dose-Volume Histogram were determined for each patient using 3 different energies : XR 4 MV, XR 6 MV and cobalt, and 2 wedges : 0 or 20°. Paired T test was used for statistical analysis.Results: Median CTV was 650 ml (160-2300). Using 20° wedge, 100% isodose encompassed 79% of CTV for XR 4 MV as compared to 65% for cobalt (p<0.00001) and to 51% for XR 6MV (p<0.00001). Difference was significant between cobalt and XR 6MV (p<0.00001). Same difference was observed using 0° wedge (57% XR 4 MV, 44% cobalt and 33% XR 6 MV, p<0.00001 for each). Same difference was observed with 95% isodose (87% XR 4 MV, 78% cobalt, 75% XR 6 MV, p<0.00001 for each). For patients with small breast volume (CTV < 650 ml) or patients with large volume (CTV>650 ml), difference remained the same.Conclusions: Breast dosimetry using XR 4 MV is more homogenous than cobalt or XR 6 MV, independently of breast volume and wedge. Breast dosimetry using cobalt is more homogenous than XR 6 MV, that probably explained local relapse differences previously described. This results led us to recommend the use of the lowest available photon energy to treat breast carcinoma. Purpose/Objective: Abstract # 2039 of the ASTRO meeting 2001 demonstrated that local failure rate was increased with XR 6 MV as compared to cobalt in a large retrospective series of patients with breast carcinoma. The aim of this study was to compare dosimetric differences between XR 4 MV, XR 6 MV and cobalt. Materials/Methods: 50 patients treated with conservative surgery for primary breast cancer were randomly selected. Breast CT-scan slice separation and thickness was 8 mm. Clinical Target Volume (CTV) was outlined on each slice with Focus 3.0.0 software (Computerized Medical System). The CTV was assumed to start 5 mm below the skin. Internal limit encompassed thoracic wall. Upper limit was upper border of sternum. Lower border was inferior part of the breast . Dose-Volume Histogram were determined for each patient using 3 different energies : XR 4 MV, XR 6 MV and cobalt, and 2 wedges : 0 or 20°. Paired T test was used for statistical analysis. Results: Median CTV was 650 ml (160-2300). Using 20° wedge, 100% isodose encompassed 79% of CTV for XR 4 MV as compared to 65% for cobalt (p<0.00001) and to 51% for XR 6MV (p<0.00001). Difference was significant between cobalt and XR 6MV (p<0.00001). Same difference was observed using 0° wedge (57% XR 4 MV, 44% cobalt and 33% XR 6 MV, p<0.00001 for each). Same difference was observed with 95% isodose (87% XR 4 MV, 78% cobalt, 75% XR 6 MV, p<0.00001 for each). For patients with small breast volume (CTV < 650 ml) or patients with large volume (CTV>650 ml), difference remained the same. Conclusions: Breast dosimetry using XR 4 MV is more homogenous than cobalt or XR 6 MV, independently of breast volume and wedge. Breast dosimetry using cobalt is more homogenous than XR 6 MV, that probably explained local relapse differences previously described. This results led us to recommend the use of the lowest available photon energy to treat breast carcinoma.

Why change a good thing? Revisiting the fleur-de-lis reconstruction of the breast.

Although the latissimus flap is known for its simplicity and reliability, use of the fleur-de-lis pattern was plagued by undesirable T-shaped donor sites and small breast volumes in thin patients. We report a modified technique for optimal shaping of the standard latissimus with the successful application of a modified fleur-de-lis pattern. Because a "wet" tumescent infiltration was utilized and large amounts of subcutaneous fat were harvested, these changes permitted application to a wide variety of patients, with generous breast volumes reducing the size of the implant placed and resulting in excellent donor-site scars. This is a retrospective cohort study of 53 delayed or immediate reconstructions performed consecutively by the principal author (M.E.A.) on 48 patients at a university-based, urban hospital. Each case was analyzed between April of 1995 and February of 1999, with a follow-up from 2.5 to 44 months. All patients underwent injection of tumescent solution into the subcutaneous plane and harvest of large amounts of subcutaneous fat with the neurologically intact latissimus muscle. The last 25 reconstructions utilized the modified fleur-de-lis skin pattern, an inferiorly based vertical limb and replacement of skin deficiency in both axes. Of 11 perioperatively irradiated patients, none required skin grafting, whereas 6 percent of all native mastectomy flaps were grafted. There was one instance of minor distal tip flap necrosis in a nonirradiated patient. No implants became infected or were extruded. Donor sites were without wound complications and unveiled a 16 percent overall seroma rate.Through selective addition of harvested tissue, this modified technique, particularly the fleur-de-lis pattern, permits improved volume and projection in the inferior pole. The T-shaped donor-site closure is not only acceptable, but is also desirable, with reduced wound tension and minimization of dog-ear formation. With a relative paucity of complications, this conceptually ideal modification is technically simple and aesthetically comparable to our transverse rectus abdominis muscle flap results.

Determination of optimal radiation energy for different breast sizes using CT-simulator [correction of simulatior] in tangential breast irradiation.

The purpose of this study is to determine and recommend the optimal radiation source according to breast size for tangential irradiation in breast conserving therapy. Twenty-eight patients treated at our department from January 1994 to January 1996 were studied. The dose distribution within the irradiated breast was calculated using a (60)Co-gamma ray and 6 MV-X ray. Then we compared 3-D dose distributions of the (60)Co-gamma ray and 6 MV-X ray in different-sized breasts. Three parameters (breast volume, chest wall separation, and breast height) were adopted as representative of breast size. We also examined correlations among the three parameters. When the breast size was large (breast volume >400 cm(3), chest wall separation > 19.5 cm, or breast height > 6.5 cm), the average volume of normal tissue which received more than 110% of the isocenter dose ("hot spot") was significantly greater with the (60)Co-gamma ray than with the 6 MV-X ray (p < 0.05). A similar result was obtained with regard to hot spots in the clinical target volume. The cold area that received less than 95% of the isocenter dose was greater using a 6 MV-X ray when the breast size was small (breast volume <200 cm(3), chest wall separation <17.5 cm, or breast height <5.0 cm). However, the difference was not significant. There was a significant correlation between breast volume and chest wall separation (r =0.849, p <0.001). Breast volume and breast height were also significantly correlated (r =0.813, p <0.001). Since breast volume and shape are different in each patient, the optimal energy should be selected for each case to obtain uniform dose distribution in breast-conserving therapy. Chest wall separation or breast height, which are measurable without a 3-D planning system, can substitute for breast volume as parameters for breast size. We recommend that the (60)Co-gamma ray not be used for treating large breasts, those with chest wall separation > or =19.5 cm or breast height > or =6.5 cm.