10-Year results after sector resection with or without postoperative radiotherapy for stage I breast cancer: a randomized trial

Negative effect of seroma on breast balloon brachytherapy dosimetry

PURPOSE

Balloon brachytherapy is commonly used to deliver Accelerated Partial Breast Irradiation (APBI). Seroma interference is a relatively common phenomenon during APBI. The negative effect of seroma accumulation on the planning target volume evaluation (PTV_Eval) coverage is not well understood.

METHODS AND MATERIALS

This is a dosimetric replanning study on 10 patients with evidence of seroma collection at time of initial computed tomographic simulation around the catheter. Total dose was 34 Gy given at 3.4 Gy twice a day over 5 treatment days. A total of 20 plans were generated, 10 plans without accounting for and 10 after subtracting the seroma. We then compared the changes seen in PTV_Eval between plans as a factor of the seroma volume.

RESULTS

Median age was 62 years (51-83). Histology was invasive in 7/10 cases and in situ in 3/10. Median balloon to skin distance was 8.5 mm (3-14). Median balloon volume was 39 cc (30-104). Median seroma volume was 3.34 cc (1.13-13.71). For every 1 cc of accumulated seroma the percentage of PTV_Eval coverage by the 90% isodose line (V90) was found to decrease by 2.45% (P < .0001; confidence interval [CI], 1.87-3.03) and coverage by the 100% isodose line (V100) was decreased by 1.11% (P < .0001; CI, 0.81-1.41). Fifty percent (5/10) of previously acceptable plans with seroma not accounted for failed to meet the V90 ≥90% requirement after subtracting the seroma.

CONCLUSIONS

Accumulation of seroma was associated with a considerable negative impact on PTV_Eval dosimetry with a greater impact on V90 compared with the V100. Clinicians must be careful in detecting and accounting for such accumulation in treatment plans to prevent underdosing of the at risk target breast tissue.

Sector Resection With or Without Postoperative Radiotherapy for Stage I Breast Cancer: 20-Year Results of a Randomized Trial

Purpose

To investigate how radiotherapy (XRT) adds to tumor control using a standardized surgical technique with meticulous control of surgical margins in a randomized trial with 20 years of follow-up.

Patients and Methods

Three hundred eighty-one women with pT1N0 breast cancer were randomly assigned to sector resection with (XRT group) or without (non-XRT group) postoperative radiotherapy to the breast. With follow-up through 2010, we estimated cumulative proportion of recurrence, breast cancer death, and all-cause mortality.

Results

The cumulative probability of a first breast cancer event of any type after 20 years was 30.9% in the XRT group and 45.1% in the non-XRT group (hazard ratio [HR], 0.58; 95% CI, 0.41 to 0.82). The benefit of radiotherapy was achieved within the first 5 years. After 20 years, 50.4% of the women in the XRT group died compared with 54.0% in the non-XRT group (HR, 0.92; 95% CI, 0.71 to 1.19). The cumulative probability of contralateral cancer or death as a result of cancer other than breast cancer was 27.1% in the XRT group and 24.9% in the non-XRT group (HR, 1.17; 95% CI, 0.77 to 1.77). In an anticipated low-risk group, the cumulative incidence of first breast cancer of any type was 24.8% in the XRT group and 36.1% in the non-XRT group (HR, 0.61; 95% CI, 0.35 to 1.07).

Conclusion

Radiotherapy protects against recurrences during the first 5 years of follow-up, indicating that XRT mainly eradicates undetected cancer foci present at primary treatment. The similar rate of recurrences beyond 5 years in the two groups indicates that late recurrences are new tumors. There are subgroups with clinically relevant differences in risk.

Brachytherapy in breast cancer: an effective alternative

Breast conserving surgery (BCS) with following external beam radiation therapy (EBRT) of the conserved breast has become widely accepted in the last decades for the treatment of early invasive breast cancer. The standard technique of EBRT after BCS is to treat the whole breast up to a total dose of 42.5 to 50 Gy. An additional dose is given to treated volume as a boost to a portion of the breast. In the early stage of breast cancer, research has shown that the area requiring radiation treatment to prevent the cancer from local recurrence is the breast tissue that surrounds the area where the initial cancer was removed. Accelerated partial breast irradiation (APBI) is an approach that treats only the lumpectomy bed plus a 1-2 cm margin rather than the whole breast and as a result allows accelerated delivery of the radiation dose in four to five days. There has been a growing interest for APBI and various approaches have been developed under phase I-III clinical studies; these include multicatheter interstitial brachytherapy, balloon catheter brachytherapy, conformal external beam radiation therapy (3D-EBRT) and intra-operative radiation therapy (IORT). Balloon-based brachytherapy approaches include MammoSite, Axxent electronic brachytherapy, Contura, hybrid brachytherapy devices. Another indication for breast brachytherapy is reirradiation of local recurrence after mastectomy. Published results of brachytherapy are very promising. We discuss the current status, indications, and technical aspects of breast cancer brachytherapy.

Shortened radiation therapy schedules for early-stage breast cancer: a review of hypofractionated whole-breast irradiation and accelerated partial breast irradiation

Breast-conserving therapy consisting of segmental mastectomy followed by whole-breast irradiation (WBI) has become widely accepted as an alternative to mastectomy as a treatment for women with early-stage breast cancer. WBI is typically delivered over the course of 5-6 weeks to the whole breast. Hypofractionated whole-breast irradiation and accelerated partial breast irradiation have developed as alternative radiation techniques for select patients with favorable early-stage breast cancer. These radiation regimens allow for greater patient convenience and the potential for decreased health care costs. We review here the scientific rationale behind delivering a shorter course of radiation therapy using these distinct treatment regimens in this setting as well as an overview of the published data and pending trials comparing these alternative treatment regimens to WBI.

Progress and controversies: radiation therapy for invasive breast cancer

Radiation therapy is a critical component of the multidisciplinary management of invasive breast cancer. In appropriately selected patients, radiation not only improves local control, sparing patients the morbidity and distress of local recurrence, but it also improves survival by preventing seeding and reseeding of distant metastases from persistent reservoirs of locoregional disease. In recent years, considerable progress has been made toward improving our ability to select patients most likely to benefit from radiotherapy and to administer treatment in ways that maximize clinical benefit while minimizing toxicity and burden. This article reviews the role of radiation therapy in invasive breast cancer management, both after breast-conserving surgery and after mastectomy. It focuses particularly on emerging evidence that helps to define the clinical situations in which radiotherapy is indicated, the appropriate targets of treatment, and optimal approaches for minimizing both the toxicity and the burden of treatment, all in the context of the evolving surgical and systemic management of this common disease. It includes a discussion of new approaches in breast cancer radiotherapy, including hypofractionation and intensity modulation, as well as a discussion of promising avenues for future research.

Partial–breast irradiation: towards a replacement for whole–breast irradiation?

Largely thanks to all of the investigators and patients who have participated in randomized breast-conservation trials, many women facing a diagnosis of breast cancer today can conserve their breast with the help of adjuvant radiation therapy. A standard course of radiation consists of 5-7 weeks of daily radiation treatments delivered to the whole breast. The success of this treatment has led investigators to attempt to determine whether the same control can be achieved while decreasing the volume of breast tissue irradiated, thus allowing treatment to be delivered in a shorter period of time. This approach could alleviate time and logistical problems faced by patients during their course of treatment as well as improving overall cost-effectiveness. It can also allow complete avoidance of the adjacent heart and lung tissue in the radiation treatment portal. Partial-breast irradiation (the delivery of radiation to the resection cavity, plus a safety margin) delivered in just hours or days, is currently under investigation. Although relatively new, its use is growing rapidly and many institutional and cooperative group trials are quickly enlisting patients, while physicians are gaining experience in a variety of partial-breast irradiation techniques.

Dosimetric evaluation of multilumen intracavitary balloon applicator rotation in high-dose-rate brachytherapy for breast cancer

The objective of this work is to evaluate dosimetric impact of multilumen balloon applicator rotation in high-dose-rate (HDR) brachytherapy for breast cancer. Highly asymmetrical dose distribution was generated for patients A and B, depending upon applicator proximity to skin and rib. Both skin and rib spacing was ≤ 0.7 cm for A; only rib spacing was ≤ 0.7 cm for B. Thirty-five rotation scenarios were simulated for each patient by rotating outer lumens every 10° over ± 180° range with respect to central lumen using mathematically calculated rotational matrix. Thirty-five rotated plans were compared with three plans: 1) original multidwell multilumen (MDML) plan, 2) multidwell single-lumen (MDSL) plan, and 3) single-dwell single-lumen (SDSL) plan. For plan comparison, planning target volume for evaluation (PTV_EVAL) coverage (dose to 95% and 90% volume of PTV_EVAL) (D95 and D90), skin and rib maximal dose (Dmax), and normal breast tissue volume receiving 150% (V150) and 200% (V200) of prescribed dose (PD) were evaluated. Dose variation due to device rotation ranged from -5.6% to 0.8% (A) and -6.5% to 0.2% (B) for PTV_EVAL D95; -5.2% to 0.4% (A) and -4.1% to 0.7% (B) for PTV_EVAL D90; -2.0 to 18.4% (A) and -7.8 to 17.5% (B) for skin Dmax; -11.1 to 22.8% (A) and -4.7 to 55.1% (B) of PD for rib Dmax, respectively. Normal breast tissue V150 and V200 variation was &lt; 1.0 cc, except for -0.1 to 2.5cc (B) of V200. Furthermore, 30° device rotation increased rib Dmax over 145% of PD: 152.9% (A) by clockwise 30° rotation and 152.5% (B) by counterclockwise 30° rotation. For a highly asymmetric dose distribution, device rotation can outweigh the potential benefit of improved dose shaping capability afforded by multilumen and make dosimetric data worse than single-lumen plans unless it is properly corrected.

Real-world outcomes of postmastectomy radiotherapy in breast cancer patients with 1-3 positive lymph nodes: a retrospective study

OBJECTIVE

To assess the treatment outcomes and to explore the determinants of clinical outcome in breast cancer patients with 1-3 positive nodes who did or did not receive postmastectomy radiotherapy (PMRT) in a tertiary care referral cancer center in Northern Thailand.

METHODS

We investigated a retrospective cohort of registered breast cancer patients at the Faculty of Medicine, Chiang Mai University, Thailand from 2001-2007. Analysis was performed using Cox regression models to identify factors affecting the overall survival (OS) and relapse-free survival (RFS) rates. Comparisons were made between two cohorts: women who received adjuvant PMRT (74 patients) and women who did not receive adjuvant PMRT (81 patients).

RESULTS

A total of 155 patients were included with a median follow-up period of 4.45 years. There was a statistically significant 4-year OS difference between the two groups of patients: 100% for the PMRT group and 93.1% for the non-PMRT group (P = 0.044). The 4-year RFS was 85.9% for patients receiving PMRT and 78.3% for patients who did not receive PMRT (P = 0.291). On multivariate analysis of OS, using hormonal treatment was the only significant independent factor associated with improved OS. On multivariate analysis of RFS, none of the variables were significantly associated with improved RFS. PMRT was notfound to be a prognostic variable related to the outcome of patients using a logistic regression model.

CONCLUSION

Our retrospective, hospital-based analysis demonstrated that PMRT improved the treatment outcome in terms of OS for women with 1-3 node positive early-stage breast cancer.

GammaPod-a new device dedicated for stereotactic radiotherapy of breast cancer

PURPOSE

This paper introduces a new external beam radiotherapy device named GammaPod that is dedicated for stereotactic radiotherapy of breast cancer.

METHODS

The design goal of the GammaPod as a dedicated system for treating breast cancer is the ability to deliver ablative doses with sharp gradients under stereotactic image guidance. Stereotactic localization of the breast is achieved by a vacuum-assisted breast immobilization cup with built-in stereotactic frame. Highly focused radiation is achieved at the isocenter due to the cross-firing from 36 radiation arcs generated by rotating 36 individual Cobalt-60 beams. The dedicated treatment planning system optimizes an optimal path of the focal spot using an optimization algorithm borrowed from computational geometry such that the target can be covered by 90%-95% of the prescription dose and the doses to surrounding tissues are minimized. The treatment plan is intended to be delivered with continuous motion of the treatment couch. In this paper the authors described in detail the gamma radiation unit, stereotactic localization of the breast, and the treatment planning system of the GammaPod system.

RESULTS

A prototype GammaPod system was installed at University of Maryland Medical Center and has gone through a thorough functional, geometric, and dosimetric testing. The mechanical and functional performances of the system all meet the functional specifications.

CONCLUSIONS

An image-guided breast stereotactic radiotherapy device, named GammaPod, has been developed to deliver highly focused and localized doses to a target in the breast under stereotactic image guidance. It is envisioned that the GammaPod technology has the potential to significantly shorten radiation treatments and even eliminate surgery by ablating the tumor and sterilizing the tumor bed simultaneously.

Accelerated partial breast irradiation for breast cancer: a meta-analysis

To evaluate the long-term effect of breast conservation with accelerated partial breast irradiation (APBI) for early-stage breast cancer, PubMed, EMBASE, Cochrane Library, Web of Science, Chinese Biomedical Literature Database, Chinese Scientific Journals Full-text Database, and China Journal Full-text Database were searched to identify relevant original published trials. Randomized controlled trials in any language comparing APBI with whole-breast radiotherapy in patients with early-stage breast cancer were included. RevMan 5 software was used for statistical analysis. Four trials involving 919 patients were included. The rate of 5- and 7-year excellent/good cosmetic results was significant {odds ratio (OR) = 2.09 [95% confidence interval (CI) = 1.21-3.62]} between two groups. The 5- and 8-year overall survival had no significant difference [OR = 1.76 (95% CI = 0.67-4.62) and OR = 0.86 (95% CI = 0.44-1.66)]. The 10-year overall survival had significant differences [OR = 0.56 (95% CI = 0.35-0.91)]. There were no differences in the 5-year local recurrence (LR)-free survival [OR = 0.65 (95% CI = 0.18-2.34)], cancer-specific survival [OR = 1.67 (95% CI = 0.39-7.12)], disease-free survival [OR = 0.84 (95% CI = 0.38-1.84)], LR [OR = 1.36 (95% CI = 0.46-3.99)], the rate of contralateral breast cancer [OR = 2.82 (95% CI = 0.73-10.89)], and distant metastasis [OR = 0.71 (95% CI = 0.22-2.31)]. APBI significantly improved the rate of excellent/good cosmetic results anywhere in the breast, shortened the treatment time, alleviated the pain, and improved the quality of life. Future large-scale, high-quality, and double-blind trials are needed.

RB1 status in triple negative breast cancer cells dictates response to radiation treatment and selective therapeutic drugs

Triple negative breast cancer (TNBC) includes basal-like and claudin-low subtypes for which only chemotherapy and radiation therapy are currently available. The retinoblastoma (RB1) tumor suppressor is frequently lost in human TNBC. Knockdown of RB1 in luminal BC cells was shown to affect response to endocrine, radiation and several antineoplastic drugs. However, the effect of RB1 status on radiation and chemo-sensitivity in TNBC cells and whether RB1 status affects response to divergent or specific treatment are unknown. Using multiple basal-like and claudin-low cell lines, we hereby demonstrate that RB-negative TNBC cell lines are highly sensitive to gamma-irradiation, and moderately more sensitive to doxorubicin and methotrexate compared to RB-positive TNBC cell lines. In contrast, RB1 status did not affect sensitivity of TNBC cells to multiple other drugs including cisplatin (CDDP), 5-fluorouracil, idarubicin, epirubicin, PRIMA-1^met, fludarabine and PD-0332991, some of which are used to treat TNBC patients. Moreover, a non-biased screen of ∼3400 compounds, including FDA-approved drugs, revealed similar sensitivity of RB-proficient and -deficient TNBC cells. Finally, ESA⁺/CD24^−/low/CD44⁺ cancer stem cells from RB-negative TNBC lines were consistently more sensitive to gamma-irradiation than RB-positive lines, whereas the effect of chemotherapy on the cancer stem cell fraction varied irrespective of RB1 expression. Our results suggest that patients carrying RB-deficient TNBCs would benefit from gamma-irradiation as well as doxorubicin and methotrexate therapy, but not necessarily from many other anti-neoplastic drugs.

Breast-conservative surgery with and without radiotherapy in patients aged 55-75 years with early-stage breast cancer: a prospective, randomized, multicenter trial analysis after 108 months of median follow-up

OBJECTIVES

Breast-conserving therapy (BCT), including postoperative whole breast irradiation (WBI), is generally accepted as the treatment of choice for most patients with early-stage breast cancer. The question whether WBI is mandatory in all patients remains one of the most controversial issues in BCT. To answer this question, a randomized, prospective, multicentre study was launched in January 2001. Primary endpoints of the study were to assess the cumulative incidence of in-breast-recurrences (IBR) and overall survival (OAS) after conservative surgery (BCS) with or without WBI.

METHODS

From January 2001 until December 2005, 749 patients with unifocal infiltrating breast cancer up to 25 mm, 0-3 positive axillary lymph nodes, no extensive intraductal component or lymphvascular invasion from 11 centres in Italy, were randomly assigned to BCS+WBI (arm 1:373 patients) or BCS alone (arm 2:376 patients). Treatment arms were well balanced in terms of baseline characteristics. Systemic adjuvant therapy was administered according to the institutional policies. Kaplan-Meier method was used for survival analysis and log-rank test to evaluate the difference between the two arms. RESULTS (Last analysis 31.12.2012): After median follow-up of 108 months, 12 (3.4%) IBR were observed in arm 1 and 16 (4.4%) in arm 2. OAS was 81.4% in arm 1 and 83.7% in arm 2. There was no statistically significant difference regarding IBR and death in the two treatment groups.

CONCLUSIONS

These data are promising and suggest that WBI after BCS can be omitted in selected patients with early stage breast cancer without exposing them to an increased risk of local recurrence and death. Longer follow-up is needed to further consolidate these results.

Displacement of the lumpectomy cavity defined by surgical clips and seroma based on 4D-CT scan for external-beam partial breast irradiation after breast-conserving surgery: a comparative study

OBJECTIVE

To compare the displacements of the lumpectomy cavity delineated by the surgical clips and the seroma based on four-dimensional CT (4D-CT) for external-beam partial breast irradiation (EB-PBI) after breast-conserving surgery (BCS).

METHODS

14 breast cancer patients after BCS were recruited for EB-PBI and undertook 4D-CT simulation. On the 10 sets of the 4D-CT images, all the surgical clips in the cavity were delineated. The gross tumour volume (GTV) formed by the clips, the seroma, and both the clips and the seroma were defined as GTVc, GTVs and GTVc+s, respectively. The displacements of the centre of mass (COM) of the clips, GTVc, GTVs, GTVc+s and the selected clips in the three-dimensional (3D) directions were recorded and compared.

RESULTS

In the left-right, anterior-posterior and superior-inferior directions, the displacements were 2.20, 1.80 and 2.70 mm for the clip COM; 0.90, 1.05 and 1.20 mm for GTVc; 0.80, 1.05 and 0.80 mm for GTVs; and 0.90, 1.20 and 1.40 mm for GTVc+s, respectively. In the 3D directions, the displacements of the clip COM were greater than the GTVc, GTVs, GTVc+s, and the displacements of the clip COM, GTVc+s, GTVc and GTVs were significantly greater than the displacements of the selected clips (p<0.05).

CONCLUSION

The displacements of the clip COM were greater than that of the GTVc, GTVs, GTVc+s and the four selected clips. The optimal internal target volume should be defined based on the boundary displacements.

ADVANCES IN KNOWLEDGE

When the GTV was delineated using the clips and/or the seroma, there was displacement difference between the lumpectomy cavity centre and the boundary for the EB-PBI. The optimal internal target volume should be defined based on the boundary displacements of the lumpectomy cavity.

Use of boost radiotherapy in oncoplastic breast-conserving surgery - a systematic review

BACKGROUND

The use of local boost radiotherapy to the tumour bed has been demonstrated in randomised-controlled trials to reduce local recurrence rates following breast-conserving surgery (BCS) and is the standard of care. Oncoplastic BCS techniques with parenchymal rearrangement present new challenges to the localisation of the tumour bed and therefore delivery of local boost radiotherapy. The aim of this review was to evaluate the reporting of boost radiotherapy in the oncoplastic BCS literature.

METHODS

Pubmed, Ovid MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews were searched for studies reporting oncoplastic BCS using volume displacement techniques.

RESULTS

24 studies met the inclusion criteria (n = 1933 patients). Use of boost radiotherapy was reported in 11 studies, in 2 of which it was for the treatment of incomplete or close margins, and marking of the tumour bed was only reported in 8 studies. None of the studies reported the number of patients where the tumour bed could not be localised.

CONCLUSIONS

The use of local boost radiotherapy and tumour bed marking was not reported in the majority of studies of oncoplastic BCS. Future studies need to provide detailed information regarding the use of boost radiotherapy and difficulties determining the target volume so that current radiotherapy approaches can be reviewed and improved for these advanced techniques.

Radiation therapy in the management of breast cancer

Radiation therapy (RT) plays an essential role in the management of breast cancer by eradicating subclinical disease after surgical removal of grossly evident tumor. Radiation reduces local recurrence rates and increases breast cancer-specific survival in patients with early-stage breast cancer after breast-conserving surgery and in node-positive patients who have undergone mastectomy. This article reviews the following topics: (1) the rationale for adjuvant RT and the evidence for its use in noninvasive and invasive breast cancer, (2) RT delivery techniques for breast-conserving therapy such as hypofractionated RT, partial breast irradiation, and prone irradiation, and (3) indications for PMRT.

Validation of a Web-Based Tool to Predict the Ipsilateral Breast Tumor Recurrence (IBTR! 2.0) after Breast-Conserving Therapy for Korean Patients

Purpose

IBTR! 2.0 is a web-based nomogram that predicts the 10-year ipsilateral breast tumor recurrence (IBTR) rate after breast-conserving therapy. We validated this nomogram in Korean patients.

Methods

The nomogram was tested for 520 Korean patients, who underwent breast-conserving surgery followed by radiation therapy. Predicted and observed 10-year outcomes were compared for the entire cohort and for each group, predefined by nomogram-predicted risks: group 1, <3%; group 2, 3% to 5%; group 3, 5% to 10%; group 4, >10%.

Results

In overall patients, the overall 10 year predicted and observed estimates of IBTR were 5.22% and 5.70% (p=0.68). In group 1, (n=124), the predicted and observed estimates were 2.25% and 1.80% (p=0.73), in group 2 (n=177), 3.95% and 3.90% (p=0.97), in group 3 (n=181), 7.14% and 8.80% (p=0.42), and in group 4 (n=38), 11.66% and 14.90% (p=0.73), respectively.

Conclusion

In a previous validation of this nomogram based on American patients, nomogram-predicted IBTR rates were overestimated in the high-risk subgroup. However, our results based on Korean patients showed that the observed IBTR was higher than the predicted estimates in groups 3 and 4. This difference may arise from ethnic differences, as well as from the methods used to detect IBTR and the healthcare environment. IBTR! 2.0 may be considered as an acceptable nomogram in Korean patients with low- to moderate-risk of in-breast recurrence. Before widespread use of this nomogram, the IBTR! 2.0 needs a larger validation study and continuous modification.

Target localisation for tumour bed radiotherapy in early breast cancer

INTRODUCTION

To compare clinical and CT techniques in localisation of the tumour bed in patients undergoing adjuvant breast radiotherapy for breast cancer.

METHODS

Patients were CT scanned in the treatment position following clinical delineation of the whole breast, surgical scar and boost volume. Computed tomography boost volumes were contoured in three dimensions. A definitive treatment plan was generated to encompass the CT-localised planning target volume (PTV) with ≥90% isodose using electrons. A hypothetical plan was also generated to cover the clinically determined boost field for comparison. The primary end point was the difference in PTV coverage by the 90% isodose between the plans based on clinically and CT localised boost volumes.

RESULTS

The plans for 50 patients were evaluated. The median percentage of PTV encompassed by the 90% isodose using the clinical and CT techniques was 29% (range 5-90%) and 83% (range 25-100%), respectively. PTV coverage by the 90% isodose using the clinical technique was at least 10% less than that using CT technique in 88% of patients (95% confidence interval 77-95%; P < 0.0001).

CONCLUSION

Tumour bed boost PTV coverage was insufficient using clinical determination as compared with CT localisation. This study supports CT planning for target volume localisation of the tumour bed boost in patients treated with breast-conserving therapy for breast cancer.

Impact of interfraction seroma collection on breast brachytherapy dosimetry - a mathematical model

Purpose

Balloon brachytherapy is a widely accepted modality for delivery of accelerated partial breast irradiation (APBI). Our hypothesis was that inter-fraction seroma collection around the balloon surface would have an adverse effect on dosimetry of the target.

Material and methods

This is a dosimetric re-planning study using two volumetric models (30 cc and 45 cc) in a Contura^® multi-lumen balloon (MLB) catheter. In a previously treated patient, two customized baseline plans were generated using multiple channels of the Contura^® catheter prescribed to the Planning Target Volume Evaluation (PTV_Eval). Symmetric expansions of 1.0 mm (0-9 mm) increments around the balloon surface were performed to simulate a “Virtual Seroma” (VS) accumulation for both balloon volumes and plans were obtained for each expansion using Eclipse Brachyvision™. An analysis of these plans was then performed to evaluate the effect of seroma accumulation on dosimetric parameters of V100 and V90.

Results

20 plans were generated and analyzed (10 plans for each balloon volume), representing VS of 6.0-66.0 cc. There was a commensurate decrease in the dose delivered to the PTV_Eval V100 and V90 (as defined by the original treatment plan) with increasing VS accumulation leading to a sub-optimal coverage of the PTV_Eval. For 30 cc MLB catheter, V100 decreased by 1.4% and V90 decreased by 0.9% for every 1 cc of VS. For 45cc MLB catheter, V100 decreased by 1.3% and V90 decreased by 1.15% for every 1.0 cc accumulation of VS.

Conclusions

Balloon catheter-tissue adherence ensures daily dose delivery to the planned PTV_Eval. Accumulation of seroma, hematoma or air between HDR fractions can significantly impact PTV_Eval dosimetry. Vacuum-port aspiration prior to delivery of each fraction, if available, should be considered to minimize the risk of geographic under dosing.

Multidisciplinary care of patients with early-stage breast cancer

There is a compelling need for close coordination and integration of multiple specialties in the management of patients with early-stage breast cancer. Optimal patient care and outcomes depend on the sequential and often simultaneous participation and dialogue between specialists in imaging, pathologic and molecular diagnostic and prognostic stratification, and the therapeutic specialties of surgery, radiation oncology, and medical oncology. These are but a few of the various disciplines needed to provide modern, sophisticated management. The essential role for coordinated involvement of the entire health care team in optimal management of patients with early-stage breast cancer is likely to increase further.

Clinical significance following breast conservation therapy with or without irradiation in breast cancer patients

BACKGROUND

We retrospectively examined the clinical outcome of irradiated versus non-irradiated groups of Japanese breast cancer patients according to their clinical and histopathological characteristics following breast-conserving therapy.

METHODS

We retrospectively evaluated a total of 1197 Japanese female breast cancer patients (598 irradiated and 599 non-irradiated) who received breast-conserving therapy. The median age of the patients was 54 years (range: 24-99 years). We retrospectively examined the local recurrence-free survival rates in those with or without post-operative irradiation according to age, surgical margin status and histopathological characteristics including histological grade, estrogen receptor expression and HER2 status.

RESULTS

Local recurrence-free survival rates in the irradiated group were significantly higher than those in the non-irradiated group, especially in surgical margin-positive [hazard ratio (HR): 0.334, 95% confidence interval: 0.14-0.79, P = 0.001], estrogen receptor-positive (HR: 0.249, 95% confidence interval: 0.11-0.54, P < 0.001), HER2-negative (HR: 0.382, 95% confidence interval: 0.21-0.69, P = 0.001) and non-triple-negative (HR: 0.382, 95% confidence interval: 0.21-0.69, P = 0.001) breast cancer patients.

CONCLUSION

The results indicated that irradiation after breast-conserving therapy is strongly recommended in Japanese breast cancer patients, especially those with surgically positive margins, estrogen receptor-positive tumors and HER2-negative invasive breast cancers.

Uncommon Breast Malignancies: Presentation Pattern, Prognostic Issue and Treatment Outcome in an Italian Single Institution Experience

Aims and background

Often neglected by large clinical trials, patients with uncommon breast malignancies have been rarely analyzed in large series.

Patients and methods

Of 2,052 patients diagnosed with breast cancer and followed in our Institution from January 1985 to December 2009, we retrospectively collected data on those with uncommon histotypes, with the aim of investigating their presentation characteristics and treatment outcome.

Results

Rare histotypes were identified in 146 patients (7.1% of our total breast cancer population), being classified as follows: tubular carcinoma in 75 (51.4%), mucinous carcinoma in 36 (24.7%), medullary carcinoma in 25 (17.1%) and papillary carcinoma in 10 patients (6.8%). Whereas age at diagnosis was not significantly different among the diverse diagnostic groups, patients with medullary and papillary subtypes had a higher rate of lymph node involvement, similar to that of invasive ductal carcinoma. Early stage diagnosis was frequent, except for medullary carcinoma. Overall, in comparison with our invasive ductal carcinoma patients, those with rare histotypes showed a significantly lower risk of recurrence, with a hazard ratio of 0.28 (95% CI, 0.12–0.62; P = 0.002).

Conclusions

According to our analysis, patients with uncommon breast malignancies are often diagnosed at an early stage, resulting in a good prognosis with standard treatment.

Adjuvant radiotherapy in the management of axillary node negative invasive breast cancer: a qualitative systematic review

PURPOSE

To actualize and to detail guidelines used in technical radiotherapy and indications for innovative radiation technologies in early axillary node negative breast cancer (BC).

METHODS

Dosimetric and treatment planning studies, phase II and III trials, systematic reviews and retrospective studies were all searched (Medline(®) database). Their quality and clinical relevance were also checked against validated checklists. A level of evidence was associated for each result.

RESULTS

A total of 75 references were included. Adjuvant BC radiotherapy (50Gy/25 fractions/5 weeks followed by a tumor boost of 16Gy/8 fractions) is still the standard of care. Overall treatment time could be shortened for patients who present with low local relapse risk BC by using either hypofractionated whole breast irradiation; or accelerated partial breast irradiation. BC IMRT is not used in current practice.

CONCLUSION

Our group aimed to provide guidelines for technical and clinical applications of innovative BC radiation technologies.

Brachytherapy in accelerated partial breast irradiation (APBI) - review of treatment methods

Breast conserving surgery (BCS) with following radiotherapy (EBRT) of the conserved breast became widely accepted in the last decades as the treatment of early invasive breast cancer. In an early stage of breast cancer, research has shown that the area requiring radiation treatment to prevent cancer from local recurrence is the breast tissue that surrounds the area where the initial cancer was removed. Accelerated partial breast irradiation (APBI) is an approach that treats only the lumpectomy bed with 1-2 cm margin, rather than the whole breast and as a result allows accelerated delivery of the radiation dose in four to five days. Published results of APBI are very promising. It is evident that APBI will play a role in the management of a selected group of early breast cancer. We discuss current status, indications, technical aspects and recently published results of APBI using different brachytherapy techniques.

Feasibility of eradication of breast cancer cells remaining in postlumpectomy cavity and draining lymph nodes following intracavitary injection of radioactive immunoliposomes

Most diagnosed early stage breast cancer cases are treated by lumpectomy and adjuvant radiation therapy, which significantly decreases the locoregional recurrence but causes inevitable toxicity to normal tissue. By using a technique of preparing liposomes carrying technetium-99m ((99m)Tc), rhenium-186 ((186)Re), or rhenium-188 ((188)Re) radionuclides, as well as chemotherapeutic agents, or their combination, for cancer therapy with real time image-monitoring of pharmacokinetics and prediction of therapy effect, this study investigated the potential of a novel targeted focal radiotherapy with low systemic toxicity using radioactive immunoliposomes to treat both the surgical cavity and draining lymph nodes in a rat breast cancer xenograft positive surgical margin model. Immunoliposomes modified with either panitumumab (anti-EGFR) or bevacizumab (anti-VEGF) were remote loaded with (99m)Tc diagnostic radionuclide, and injected into the surgical cavity of female nude rats with positive margins postlumpectomy. Locoregional retention and systemic distribution of (99m)Tc-immunoliposomes were investigated by nuclear imaging, stereofluorescent microscopic imaging, and gamma counting. Histopathological examination of excised draining lymph nodes was performed. The locoregional retention of (99m)Tc-immunoliposomes in each animal was influenced by the physiological characteristics of the surgical site of individual animals. Panitumumab- and bevacizumab-liposome groups had higher intracavitary retention compared with the control liposome groups. Draining lymph node uptake was influenced by both the intracavitary radioactivity retention level and metastasis status. The panitumumab-liposome group had higher accumulation on the residual tumor surface and in the metastatic lymph nodes. Radioactive liposomes that were cleared from the cavity were metabolized quickly and accumulated at low levels in vital organs. Therapeutic radionuclide-carrying specifically targeted panitumumab- and bevacizumab-liposomes have increased potential compared to non-antibody targeted liposomes for postlumpectomy focal therapy to eradicate remaining breast cancer cells inside the cavity and draining lymph nodes with low systemic toxicity.

Effectiveness of radiation for prevention of mastectomy in older breast cancer patients treated with conservative surgery

BACKGROUND

A recent clinical trial concluded that radiation therapy (RT) does not lower the risk of mastectomy and, thus, may be omitted in older women with stage I, estrogen receptor (ER)-positive breast cancer who undergo conservative surgery (CS). However, it is not known whether this finding applies to patients outside of clinical trials. Accordingly, we used the Surveillance, Epidemiology, and End Results-Medicare observational cohort to determine the effect of RT on the risk of mastectomy among older women with stage I, ER-positive breast cancer.

METHODS

The authors identified 7403 women ages 70 to 79 years who underwent CS between 1992 and 2002. Claims were used to determine RT status and to identify women who underwent mastectomy subsequent to initial treatment. The Kaplan-Meier method was used to estimate the risk of subsequent mastectomy, and Cox regression analysis was used to determine the effect of RT adjusted for clinical-pathologic covariates.

RESULTS

At a median follow-up of 7.3 years, the risk of subsequent mastectomy within 10 years of diagnosis was 3.2% for patients who received RT versus 6.3% for patients who did not receive RT (P < .001). In adjusted analyses, RT was associated with a lower risk of mastectomy (hazard ratio, 0.33; 95% confidence interval, 0.22-0.48; P < .001). RT provided no benefit for patients ages 75 to 79 years without high-grade tumors who had a pathologic lymph node assessment (P = .80); however, for all other subgroups, RT was associated with an absolute reduction in risk of mastectomy that ranged from 4.3% to 9.8% at 10 years.

CONCLUSIONS

Outside of a clinical trial, the receipt of RT after CS was associated with a greater likelihood of ultimate breast preservation for most older women with early breast cancer.

Nomogram to predict the benefit of radiation for older patients with breast cancer treated with conservative surgery

PURPOSE

The role of radiation therapy (RT) after conservative surgery (CS) remains controversial for older patients with breast cancer. Guidelines based on recent clinical trials have suggested that RT may be omitted in selected patients with favorable disease. However, it is not known whether this recommendation should extend to other older women. Accordingly, we developed a nomogram to predict the likelihood of long-term breast preservation with and without RT.

METHODS

We used Surveillance, Epidemiology, and End Results-Medicare data to identify 16,092 women age 66 to 79 years treated with CS between 1992 and 2002, using claims to identify receipt of RT and subsequent mastectomy. Time to mastectomy was estimated using the Kaplan-Meier method. Cox proportional hazards models determined the effect of covariates on mastectomy-free survival (MFS). A nomogram was developed to predict 5- and 10-year MFS, given associated risk factors, and bootstrap validation was performed.

RESULTS

With a median follow-up of 7.2 years, the overall 5- and 10-year MFS rates were 98.1% (95% CI, 97.8% to 98.3%) and 95.4% (95% CI, 94.9% to 95.8%), respectively. In multivariate analysis, age, race, tumor size, estrogen receptor status, and receipt of RT were predictive of time to mastectomy and were incorporated into the nomogram. Nodal status was also included given a significant interaction with RT. The resulting nomogram demonstrated good accuracy in predicting MFS, with a bootstrap-corrected concordance index of 0.66.

CONCLUSION

This clinically useful tool predicts 5- and 10-year MFS among older women with early breast cancer using readily available clinicopathologic factors and can aid individualized clinical decision making by estimating predicted benefit from RT.

Utilization of breast conserving therapy in stages 0, I, and II breast cancer patients in New Jersey: an American College of Surgeons National Cancer Data Base (NCDB) analysis

BACKGROUND

The purpose of the study was to determine the use of breast conservation surgery (BCS) followed by whole breast irradiation [BCS+radiation therapy (RT)] in stages 0, I, and II breast cancer patients treated in New Jersey using the National Cancer Database.

MATERIALS AND METHODS

A retrospective analysis was conducted using the data from 13 hospitals in New Jersey certified by the American College of Surgeons Commission on Cancer and members of the Cancer Institute of New Jersey's Network affiliates. Subjects with a first primary malignancy of the breast (stages 0, I, and II) treated from 2000 to 2006 were included in the analysis.

RESULTS

A total of 11,146 patients with stage 0 (n=2843), stage I (n=4757), and stage II (n=3546) were treated for their breast cancer. Of stage 0, I, and II patients, 72% (n=2053), 73% (n=3482), and 53% (n=1865) received BCS, respectively. Of these patients, 40% (n=826), 67.6% (n=2353), and 63% (n=1177) received adjuvant RT after BCS for their stages 0, I, and II, respectively. Use of BCS+RT was equivalent across racial groups and all ages, except patients above 70 years of age (61% <40 y, 57% 40 to 49 y, 60% 50 to 59 y, 65% 60 to 69 y, and 51% >70 y).

CONCLUSIONS

These data report an underutilization of RT after BCS in patients with stage 0 breast cancer treated across 13 hospitals in New Jersey. The Commission on Cancer's Rapid Quality Reporting System may be one method of identifying groups of patients not receiving care according to evidence-based guidelines.

Long-term outcome of hypofractionated radiotherapy to the whole breast of Japanese women after breast-conserving surgery

BACKGROUND

In Japan, there are still no reports of long-term outcome for hypofractionated radiotherapy to the whole breast after breast-conserving surgery (BCS). We report our institution's results from evaluation of the efficacy and safety of hypofractionated radiotherapy for Japanese women.

METHODS

Data in the medical records of 327 patients were retrospectively reviewed. The patients were treated with hypofractionated radiotherapy between January 2003 and December 2006 at the Kawasaki Medical School Hospital and were followed for more than 3 years. The median age was 54 years old (the age range was 28-80 years). The whole breast was irradiated with a total dose of 42.56 Gy/16 fx with boost irradiation to positive margins. Adjuvant therapy consisted of chemotherapy and/or hormone therapy and was administered to 300 patients, based on their stage or pathological findings.

RESULTS

Follow-up periods ranged from 21 to 92 months; the median follow-up period was 60 months. At 5-year follow-up, overall survival, cause-specific survival, relapse-free survival, and local control were 96.0, 97.5, 95.3, and 99.7% respectively. Grade 2 radiation pneumonitis occurred in five patients. Grade 2 radiation dermatitis occurred in 17 patients. Severe late complications were not observed.

CONCLUSIONS

In our study, hypofractionated radiotherapy led to good results without severe toxicity. We believe hypofractionated radiotherapy after BCS is safe and efficient treatment for Japanese women.

[Modern radiotherapy after breast-conserving surgery]

In the last four decades breast-conserving surgery followed by whole breast irradiation has become the standard of care for the treatment of early-stage (0-I-II) breast carcinoma. With the advent of breast-screening, incidence of breast carcinomas with more favorable prognostic characteristics has increased significantly. This change in the prognostic profile of newly diagnosed breast cancers opened a new horizon for clinical research seeking for individual risk-adapted protocols of breast cancer radiotherapy. Several groups have been tested the efficacy of accelerated (partial or whole) breast irradiation, which has become the new treatment paradigm in the radiotherapy of early-stage breast cancers. Furthermore, others have attempted to identify subgroups of patients for whom radiotherapy after breast-conserving surgery could be safely omitted. Recently molecular gene expression assays have emerged as promising prognostic and predictive markers for local recurrence. This article reviews the results of these studies focusing on individual risk-adapted radiotherapy after breast-conserving surgery for patients with early-stage breast carcinoma.

The prognostic significance of lymphovascular invasion in invasive breast carcinoma

BACKGROUND

Although lymphovascular invasion (LVI) has been associated with a poor outcome in patients with breast cancer, it is not included in most internationally recognized staging systems, including the American Joint Committee on Cancer tumor, lymph node, metastasis (TNM) classification. This is mainly because it remains unclear whether the presence of LVI is an independent, high-risk criterion in clinically relevant staging subgroups.

METHODS

The current study was based on a large and well characterized consecutive series of patients who had operable (pathologic T1 [pT1]-pT2, pathologic N0 [pN0]-pN3, M0) breast cancer (3812 informative cases) who were treated according to standard protocols at a single institution and who had long-term follow-up to assess the prognostic value of definite LVI in clinically and molecularly relevant staging subgroups.

RESULTS

LVI was strongly associated with both breast cancer-specific survival (BCSS) and distant metastasis-free survival (DMFS) in the entire series and in different subgroups. Multivariate analyses identified LVI as an independent predictor of both BCSS and DMFS in patients with operable breast cancer overall; in the TNM clinical subgroups pT1a-pT1c/pN0 and pT2/pN0; and in the molecular classes estrogen receptor (ER)-positive, ER-negative, human epidermal growth factor 2 [HER2]-negative, and triple-negative. In patients who had lymph node-negative tumors, LVI could be used as a high-risk criterion providing survival disadvantage equivalent to that provided by 1 or 2 involved lymph nodes (pN0 to pN1) and to that provided by 1 size category (pT1 to pT2). The use of immunohistochemistry for detecting an endothelial-specific marker contributed to the prognostic significance of LVI when applied to routine LVI negative/possible cases.

CONCLUSIONS

LVI provided a strong predictor of outcome in patients with invasive breast cancer and should be incorporated into breast cancer staging systems.

Tumor bed-to-skin distance using accelerated partial-breast irradiation with the strut-adjusted volume implant device

PURPOSE

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

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.

The evolution of the locoregional therapy of breast cancer

Breast-conserving therapy (BCT) and mastectomy have equal survival outcomes. Rates of local recurrence after BCT have declined steadily, largely as a result of the widespread use of systemic therapy. Sentinel node biopsy has replaced axillary dissection for staging the axilla, and in women undergoing BCT with whole-breast irradiation (WBI), axillary dissection is not needed for local control or survival in those with fewer than three involved sentinel nodes. Alternatives to 6 weeks of WBI have been shown to be safe and effective for subsets of breast cancer patients, and the use of preoperative chemotherapy allows BCT in some women who require mastectomy if surgery is the initial step in treatment. The combination of the smaller cancers detected with screening and the routine use of multimodality therapy has resulted in a decrease in the morbidity of local therapy and improved cancer treatment outcomes.

Omission of radiation therapy after breast-conserving surgery in the United States: a population-based analysis of clinicopathologic factors

BACKGROUND

Radiation therapy (RT) after breast-conserving surgery (BCS) is associated with a significant reduction in ipsilateral breast tumor recurrence and breast cancer mortality rates in patients with early stage breast cancer. The authors of this report sought to determine which patients with breast cancer do not receive RT after BCS in the United States.

METHODS

The Surveillance, Epidemiology, and End Results registry was used to determine the rates of RT after BCS for women with stage I through III breast cancer in the United States from 1992 through 2007. A multivariate analysis was performed to identify independent predictors of omission of RT.

RESULTS

In total, 294,254 patients with invasive, nonmetastatic breast cancer were identified who underwent surgery from 1992 through 2007. Most patients (57%) underwent BCS; among those, 21.1% did not receive RT after BCS. The omission of RT increased significantly from 1992 (15.5%) to 2007 (25%). The receipt of RT also decreased significantly for patients with increased cancer stage, age <55 years, high-grade tumors, large tumors, positive or untested lymph node status, African American or Hispanic race, and negative or unknown estrogen receptor status. Significant geographic variation was observed in the rates of RT after BCS.

CONCLUSIONS

The omission of RT after BCS was more common in recent years, especially among women who had an increased risk of breast cancer recurrence. This trend represents a serious health care concern because of the potential increased risk of local recurrence and breast cancer mortality.

Lobular breast cancer: same survival and local control compared with ductal cancer, but should both be treated the same way? analysis of an institutional database over a 10-year period

BACKGROUND

Invasive lobular carcinoma (ILC) is believed to be more often multicentric and bilateral compared with invasive ductal cancer (IDC), leading clinicians to pursue a more aggressive local and contralateral approach.

METHODS

Retrospective review of a consecutive cohort of breast cancer patients operated at one institution from January 2000 to January 2010 was performed. Median follow-up was 4 years.

RESULTS

There were 171 ILC (14.5%) and 1,011 IDC patients in the study period. Median age (63 vs. 65 years) and tumor diameter (1.7 cm) were similar in the two groups. Diagnoses of ILC were more frequent in the second half of the study period (55/465 vs. 116/662, p<0.01). Multicentricity was reported in 108/1,011 (10.6%) IDC and in 31/171 (18.1%) ILC patients (p<0.01). A positive margin of resection at initial surgery was documented in 71/1,011 (7%) IDC and in 21/171 (12.3%) ILC patients (p<0.001). Although the rate of mastectomy decreased over time in both groups, this was more pronounced for ILC patients (p<0.001). Locoregional control, contralateral cancer, overall survival, disease-free survival, and survival according to diameter, nodal status, and type of surgical intervention did not differ between IDC and ILC. On multivariate analysis, stage of disease and hormone receptor status were associated with disease-free survival, but histology was not.

CONCLUSIONS

Although ILC is more often multicentric, bilateral, and associated with a positive margin of resection, local control and survival are similar to IDC. ILC can be treated similarly to IDC with good results.

Interfraction accumulation of seroma during accelerated partial breast irradiation: preliminary results of a prospective study

PURPOSE

To quantify and characterize the process of seroma accumulation during accelerated partial breast irradiation using multicatheter balloon brachytherapy.

MATERIALS AND METHODS

Twenty-two patients were treated using the Contura Multilumen brachytherapy catheter to a dose of 34Gy in 10 fractions over 5 treatment days. Serial aspirations of the vacuum port of the catheter were performed at the time of CT simulation and before each treatment. Volume and characteristics of fluid drawn were recorded. Univariate analysis was performed to evaluate various factors predictive of seroma formation.

RESULTS

Median patient age was 59.5 years, body mass index was 31, and volume of surgical specimen was 62.4cm(3). Median time from breast conservation surgery to placement of Contura catheter was 18.5 days. Pericatheter seroma, typically scant with a median volume of 0.75mL, was noted in 91% of patients at CT simulation. A total of 203 aspirations were performed with a median-aspirated seroma volume of 4.05mL. There was no significant correlation between the volume of seroma and histology (invasive vs. in situ), quadrant of location, body mass index, reexcision or reoperation, days from breast conservation surgery to balloon placement, or the volume of specimen removed. Radiation treatment factors, including balloon volume, balloon to skin distance, and planning target volume evaluation, also did not correlate with aspirated seroma.

CONCLUSIONS

Interfraction seroma accumulation has a variable pattern of development with no discernible predictors of occurrence. Routine pretreatment aspirations via vacuum port may potentially improve dosimetric reproducibility for a minority of patients.

Video surface image guidance for external beam partial breast irradiation

OBJECTIVE

Accelerated partial breast irradiation is an emerging treatment option for early stage breast cancer. With accelerated partial breast irradiation, patient setup, and target registration accuracy is vital. The current study compared various methods for isocenter placement accuracy.

METHODS AND MATERIALS

Twenty-three patients treated on an institutional-approved partial breast irradiation protocol were monitored at each treatment fraction. All patients included in this study underwent clip placement at the time of surgery. Patients underwent computed tomographic simulation and surface contours were used to reconstruct a reference surface map. At the treatment machine, patients were initially positioned by laser alignment to tattoos. Orthogonal kilovoltage imaging of the chest wall, followed by video surface mapping of the breast, was performed. This video surface map was matched to the reference surface map to adjust the couch position. Verification orthogonal chest wall imaging and video surface mapping was again performed. The accuracy of setup by laser, orthogonal imaging of the chest wall, and surface alignment was retrospectively compared using the centroid clip position as the reference standard. The impact of setup error by surface alignment and by orthogonal kilovoltage imaging on planning target volume coverage was then calculated.

RESULTS

Laser-based positioning resulted in a residual setup error of 3.9 ± 3.7 mm, 4.6 ± 3.9 mm, and 4.3 ± 4.5 mm in the posterior-anterior (P-A), inferior-superior (I-S), and left-right (L-R) directions, respectively, using clips as the reference standard. Setup based on bony anatomy with orthogonal imaging resulted in residual setup error of 3.2 ± 2.9 (P-A), 4.2 ± 3.5 (I-S), and 4.7 ± 5.3 mm (L-R). Setup with video surface mapping resulted in a residual setup error of 1.9 ± 2.2, 1.8 ± 1.9, and 1.8 ± 2.1 mm in the P-A, I-S, and L-R directions, respectively. Vector spatial deviation was 8.8 ± 4.2, 8.3 ± 3.8, and 4.0 ± 2.3 mm with laser, chest wall on board imaging, and video surface mapping based setup, respectively. Setup by video surface mapping resulted in improved dosimetric coverage of the planning target volume when compared with orthogonal imaging of the chest wall (V100 96.0% ± 0.1% vs 89.3% ± 0.2%; V95 99.7% ± 0.01% vs 98.6% ± 0.01%, P < .05).

CONCLUSIONS

Video surface mapping of the breast is a more accurate method for isocenter placement in comparison to conventional laser-based alignment or orthogonal kilovoltage imaging of the chest wall.

Local control following single-dose intraoperative radiotherapy prior to surgical excision of early-stage breast cancer

BACKGROUND

Multiple partial breast radiotherapy techniques are available. We have previously presented the technical details of our procedure of delivering partial breast irradiation with a single fraction of intraoperative radiotherapy (IORT) targeting the tumor in situ prior to partial mastectomy. This study details our completed, single-institution trial.

MATERIALS AND METHODS

An IRB-approved, DSMB-monitored phase II trial was performed with the following inclusion criteria: women age ≥48, ultrasound-visible invasive ductal cancers <3 cm, clinically negative axillary nodes. IORT was delivered using mobile electron irradiator, at least a 1.5-cm radial and 1-cm deep margin; patients received 15 Gy and immediately underwent partial mastectomy. Ipsilateral breast recurrence was classified as true/marginal, elsewhere in the breast or nodal basin. Kaplan-Meier methods were used to estimate survival functions and exact 95% confidence intervals are reported.

RESULTS

Between 2003 and 2007, 71 women underwent IORT (median follow-up: 3.5 years). For patients with tumor-involved or close margins, additional therapy was required: 7 patients, total mastectomy; 11, whole breast radiation. Four women experienced invasive ipsilateral breast failures (1 new primary, 3 margin recurrences) for a 3-year local control rate of 49 of 53 (94.8%; 95% confidence interval 92.4% [95% CI] 84.2–98.3%), actuarial three-year in breast recurrence was 8% (95% CI 2–18%), and breast cancer-specific survival was 100%.

CONCLUSIONS

Intraoperative radiotherapy delivered to an in situ tumor is feasible, but our local control rate at 3.5 years is concerning. Possible changes to this technique to improve local control rates include better preoperative imaging (MRI), routine intraoperative ultrasound, and improved IORT delivery (larger cone, increased dose).