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

Accelerated partial breast irradiation is safe and effective using intensity-modulated radiation therapy in selected early-stage breast cancer

PURPOSE

To report the feasibility, toxicity, cosmesis, and efficacy of using intensity-modulated radiation therapy (IMRT) with respiratory gating to deliver accelerated partial breast irradiation (APBI) in selected Stage I/II breast cancer after breast-conserving surgery.

METHODS AND MATERIALS

Eligible patients with node-negative Stage I/II breast cancer were prospectively enrolled in an institutional review board approved protocol to receive APBI using IMRT after breast-conserving surgery. The target volume was treated at 3.8 Gy/fraction twice daily for 5 days, to a total dose of 38 Gy.

RESULTS

Thirty-six patients were enrolled for a median follow-up time of 44.8 months. The median tumor size was 0.98 cm (range, 0.08-3 cm). The median clinical target volume (CTV) treated was 71.4 cc (range, 19-231 cc), with the mean dose to the CTV being 38.96 Gy. Acute toxicities included Grade 1 erythema in 44% of patients and Grade 2 in 6%, Grade 1 hyperpigmentation in 31% of patients and Grade 2 in 3%, and Grade 1 breast/chest wall tenderness in 14% of patients. No Grade 3/4 acute toxicities were observed. Grade 1 and 2 late toxicities as edema, fibrosis, and residual hyperpigmentation occurred in 14% and 11% of patients, respectively; Grade 3 telangiectasis was observed in 3% of patients. The overall cosmetic outcome was considered "excellent" or "good" by 94% of patients and 97% when rated by the physician, respectively. The local control rate was 97%; 1 patient died of a non-cancer-related cause.

CONCLUSIONS

APBI can be safely and effectively administered using IMRT. In retrospective analysis, IMRT enabled the achievement of normal tissue dose constraints as outlined by Radiation Therapy Oncology Group 04-13/NSABP B-13 while providing excellent conformality for the CTV. Local control and cosmesis have remained excellent at current follow-up, with acceptable rates of acute/late toxicities. Our data suggest that cosmesis is dependent on target volume size. Further prospective multi-institutional trials should be performed to evaluate IMRT to deliver APBI.

Intratumoral Immune Responses Can Distinguish New Primary and True Recurrence Types of Ipsilateral Breast Tumor Recurrences (IBTR)

Ipsilateral breast tumor recurrence (IBTR) is an increasingly common clinical challenge. IBTRs include True Recurrences (TR; persistent disease) and New Primaries (NP; de novo tumors), but discrimination between these is difficult. We assessed tumor infiltrating leukocytes (TIL) as biomarkers for distinguishing these types of IBTR using primary tumors and matched IBTRs from 24 breast cancer patients, half of which were identified as putative TRs and half as NPs using a previously reported clinical algorithm. Intratumoral lymphocyte populations (CD3, CD8, CD4, CD25, FOXP3, TIA1, CD20) and macrophages (CD68) were quantified by immunohistochemistry in each tumor. Compared to matched primaries, TRs showed significant trends towards increased CD3(+) and CD8(+) TIL, while these populations were often diminished in NPs. Comparison of IBTRs showed that TRs had significantly higher levels of CD3(+) (P = 0.0136), CD8(+) (P = 0.0092), and CD25(+) (P = 0.0159) TIL than NPs. We conclude that TIL may be a novel diagnostic biomarker to distinguish NP from TR IBTRs.

Reirradiation as a component of the multidisciplinary management of locally recurrent breast cancer

BACKGROUND AND PURPOSE

Our intent was to review a modern multidisciplinary institutional experience involving reirradiation of the breast, chest wall, and lymphatics for locoregional recurrences of breast cancer and report toxicity and clinical outcomes.

MATERIALS AND METHODS

Between 1995 and 2009, 12 locoregional recurrences were reirradiated in 8 patients. The mean dose of initial radiotherapy was 57.1 Gy (range, 50.4-60.6 Gy), and the mean dose of reirradiation was 46.7 Gy (range, 30-62.1 Gy). The second course of radiotherapy was delivered using daily radiotherapy to 5 recurrences, twice-daily radiotherapy to 5 recurrences (1 with mold brachytherapy boost), and a combination of once- and twice-daily radiotherapy to 2 recurrences.

RESULTS

The median follow-up from time of completion of reirradiation was 30 months (range, 1.5-67 months). Local control was achieved in 7 of 8 patients and 11 of 12 recurrences. Regional control was achieved in 5 of 8 patients and 6 of 12 recurrences. Distant control was achieved in 5 of 8 patients. At time of analysis, 5 of 8 patients were alive. Median survival since reirradiation completion was 36 months (range, 4.5-47 months). Acute toxicity included grade 2 dermatitis in 4 patients, ipsilateral shoulder pain in 1 patient, and ipsilateral pleurisy in 1 patient. Late skin and soft tissue toxicity manifested as fibrosis in 4 patients, hyperpigmentation in 3 patients, and telangiectasia in 3 patients. Three patients reported lymphedema, 1 patient reporting chest wall pain and 1 patient with an ipsilateral rib fracture.

CONCLUSIONS

Multidisciplinary management of locoregional recurrence of breast cancer using reirradiation is well tolerated as salvage treatment and provides durable locoregional control.

Radiobiological characterization of post-lumpectomy focal brachytherapy with lipid nanoparticle-carried radionuclides

Post-operative radiotherapy has commonly been used for early stage breast cancer to treat residual disease. The primary objective of this work was to characterize, through dosimetric and radiobiological modeling, a novel focal brachytherapy technique which uses direct intracavitary infusion of β-emitting radionuclides (186Re/188Re) carried by lipid nanoparticles (liposomes). Absorbed dose calculations were performed for a spherical lumpectomy cavity with a uniformly injected activity distribution using a dose point kernel convolution technique. Radiobiological indices were used to relate predicted therapy outcome and normal tissue complication of this technique with equivalent external beam radiotherapy treatment regimens. Modeled stromal damage was used as a measure of the inhibition of the stimulatory effect on tumor growth driven by the wound healing response. A sample treatment plan delivering 50 Gy at a therapeutic range of 2.0 mm for 186Re-liposomes and 5.0 mm for 188Re-liposomes takes advantage of the dose delivery characteristics of the β-emissions, providing significant EUD (58.2 Gy and 72.5 Gy for 186Re and 188Re, respectively) with a minimal NTCP (0.046%) of the healthy ipsilateral breast. Modeling of kidney BED and ipsilateral breast NTCP showed that large injected activity concentrations of both radionuclides could be safely administered without significant complications.

True recurrence versus new primary: an analysis of ipsilateral breast tumor recurrences after breast-conserving therapy

PURPOSE

Ipsilateral breast tumor recurrence (IBTR) can occur in 5-20% of women with early-stage breast cancer treated with breast-conserving therapy. Two entities of IBTR have been described: true recurrence (TR), suggested to be regrowth of disease at the tumor bed, and new primary (NP), distinct from the index lesion in histology and location. This study compared survival outcomes between two patient cohorts classified clinically as having either TR or NP.

METHODS AND MATERIALS

Between 1989 and 1999, 6,020 women were referred to the BC Cancer Agency with newly diagnosed pT1-2, N0-1, M0 invasive breast cancer, treated with breast-conserving surgery. Of these, 289 patients had pathologically confirmed IBTR. Retrospective analysis was performed, and a set of decision rules was applied to classify cases as TR or NP based on change in histology, grade, hormone receptor status, and tumor location. Of 289 patients, 129 (45%) were classified as having TR and 139 (48%) as having NP; 21 (7%) were unclassified.

RESULTS

The distributions of age at diagnosis, age at recurrence, and histopathologic factors were similar in the TR and NP cohorts (all p > 0.05). The mean time to recurrence was shorter in TR patients than in NP patients (4.8 years vs. 6.3 years, p = 0.001). Treatment of the IBTR did not differ between the two groups. In the TR and NP cohorts, breast cancer-specific survival was 55.7% vs. 61.3% (p = 0.93), and overall survival was 43.7% vs. 54.8% (p = 0.53).

CONCLUSIONS

Time to recurrence is significantly shorter in patients with IBTR classified as true recurrence compared to new primary. Non-statistically significant trends for less favorable survival were observed for patients with TR. Further investigation of the hypothesis that TR and NP tumors are distinct entities with different survival prognoses will require standardized pathology review and molecular analyses.

Post-lumpectomy intracavitary retention and lymph node targeting of (⁹⁹m)Tc-encapsulated liposomes in nude rats with breast cancer xenograft

Liposomes are recognized drug delivery systems with tumor-targeting capability. In addition, therapeutic or diagnostic radionuclides can be efficiently loaded into liposomes. This study investigated the feasibility of utilizing radiotherapeutic liposomes as a new post-lumpectomy radiotherapy for early-stage breast cancer by determining the locoregional retention and systemic distribution of liposomes radiolabeled with technetium-99m ((⁹⁹m)Tc) in an orthotopic MDA-MB-231 breast cancer xenograft nude rat model. To test this new brachytherapy approach, a positive surgical margin lumpectomy model was set up by surgically removing the xenograft and deliberately leaving a small tumor remnant in the surgical cavity. Neutral, anionic, and cationic surface-charged fluorescent liposomes of 100 and 400 nm diameter were manufactured and labeled with (⁹⁹m)Tc-BMEDA. Locoregional retention and systemic distribution of (⁹⁹m)Tc-liposomes injected into the post-lumpectomy cavity were determined using non-invasive nuclear imaging, ex vivo tissue gamma counting and fluorescent stereomicroscopic imaging. The results indicated that (⁹⁹)Tc-liposomes were effectively retained in the surgical cavity (average retention was 55.7 ± 24.2% of injected dose for all rats at 44 h post-injection) and also accumulated in the tumor remnant (66.9 ± 100.4%/g for all rats). The majority of cleared (⁹⁹m)Tc was metabolized quickly and excreted into feces and urine, exerting low radiation burden on vital organs. In certain animals (⁹⁹m)Tc-liposomes significantly accumulated in the peripheral lymph nodes, especially 100 nm liposomes with anionic surface charge. The results suggest that post-lumpectomy intracavitary administration of therapeutic radionuclides delivered by 100-nm anionic liposome carrier is a potential therapy for the simultaneous treatment of the surgical cavity and the draining lymph nodes of early-stage breast cancer.

Achieving autologous breast reconstruction for breast cancer patients in the setting of post-mastectomy radiotherapy

INTRODUCTION

Breast cancer is now associated with long-term disease-free and overall survival, and in the setting of mastectomy, long term psycho-sexual health becomes an important consideration. To this end, breast reconstruction has been shown to significantly improve quality of life for mastectomy patients. With adjuvant radiotherapy often required in the setting of breast reconstruction, it is unclear what interaction the two can have.

METHODS

A thorough literature review was undertaken to assess the impact of radiotherapy on autologous breast reconstruction, and in particular, the influence of its timing on vessel selection, post-operative complications and both oncologic and cosmetic outcomes.

RESULTS

A clear benefit was established for delaying reconstruction until after radiotherapy to improve cosmetic outcomes. Although the timing of radiotherapy administration may influence vessel selection and the nature of post-operative complications encountered, overall outcomes were not dissimilar. Likewise, oncologic outcomes have not been shown to be significantly affected by the timing of radiotherapy.

CONCLUSIONS AND IMPLICATIONS FOR CANCER SURVIVORS

Both immediate and delayed breast reconstruction are safe modes of treatment, however patients that are expected to require adjuvant radiotherapy may benefit from delaying reconstruction until completion of oncologic treatment.

Relative biological effectiveness of photon energies used in brachytherapy and intraoperative radiotherapy techniques for two breast cancer cell lines

BACKGROUND

Partial breast irradiation (IORT or brachytherapy) differ from external radiation of whole breast in terms of irradiated volumes, fractionation, radiation energy and dose rate; all factors influencing the treatment outcome in a complex manner. Theoretically obtained RBE values comparing effects of radiation used in IORT and external therapy are published, but experimental studies are required to confirm these data. The aim of this study is to establish such RBE values for two breast cancer cell lines.

MATERIALS AND METHODS

Colony formation of breast cancer cell lines (MCF-7 and T-47D) were studied after photon irradiation with qualities and dose rates used in IORT, brachytherapy and external radiation. RBE values from survival data were used to compare effects.

RESULTS

Increasing the photon energy (dose rate 0.2 Gy/min) from 50 kV (Intrabeam) to 380 keV (¹⁹²Ir source) and 6 MV (linear accelerator) yielded an increase in the cell survival, whereas increasing the dose rate to 6 Gy/min had minor effect. Average RBE values for 50 kV with 6 MV as reference radiation varied from about 1.4 (for doses < 5 Gy) to > 1.9 (for doses < 0.02 Gy) for MCF-7 cells and from about 1.4 to > 3.1 for T-47D cells for the same dose levels. Corresponding RBE values for 380 keV radiation were about 1.4 for MCF-7 cells and 1.3-2.3 for T-47D cells.

CONCLUSION

RBE data for breast cancer cells exposed to radiation used in IORT, brachytherapy or external radiation differ among the cell lines tested. The values are in agreement with published theoretical and experimental work.

Hypofractionation should be the new 'standard' for radiation therapy after breast conserving surgery

Hypofractionated whole breast radiation therapy following breast conserving surgery (BCS) has been used in many institutions for several decades. Four randomized trials with 5-10-year follow-up, have demonstrated equivalent local control, cosmetic and normal tissue outcomes between 50 Gy in 25 fractions and various hypofractionated RT prescriptions employing 13-16 fractions. Indirect evidence suggests that hypofractionated RT may also be safe and effective for regional nodal RT. In the face of equivalent outcomes, patient convenience and health care utilization benefits, hypofractionated RT should be the new 'standard' following BCS.

Postlumpectomy focal brachytherapy for simultaneous treatment of surgical cavity and draining lymph nodes

PURPOSE

The primary objective was to investigate a novel focal brachytherapy technique using lipid nanoparticle (liposome)-carried β-emitting radionuclides (rhenium-186 [(186)Re]/rhenium-188 [(188)Re]) to simultaneously treat the postlumpectomy surgical cavity and draining lymph nodes.

METHODS AND MATERIALS

Cumulative activity distributions in the lumpectomy cavity and lymph nodes were extrapolated from small animal imaging and human lymphoscintigraphy data. Absorbed dose calculations were performed for lumpectomy cavities with spherical and ellipsoidal shapes and lymph nodes within human subjects by use of the dose point kernel convolution method.

RESULTS

Dose calculations showed that therapeutic dose levels within the lumpectomy cavity wall can cover 2- and 5-mm depths for (186)Re and (188)Re liposomes, respectively. The absorbed doses at 1 cm sharply decreased to only 1.3% to 3.7% of the doses at 2 mm for (186)Re liposomes and 5 mm for (188)Re liposomes. Concurrently, the draining sentinel lymph nodes would receive a high focal therapeutic absorbed dose, whereas the average dose to 1 cm of surrounding tissue received less than 1% of that within the nodes.

CONCLUSIONS

Focal brachytherapy by use of (186)Re/(188)Re liposomes was theoretically shown to be capable of simultaneously treating the lumpectomy cavity wall and draining sentinel lymph nodes with high absorbed doses while significantly lowering dose to surrounding healthy tissue. In turn, this allows for dose escalation to regions of higher probability of containing residual tumor cells after lumpectomy while reducing normal tissue complications.

Second conservative treatment for ipsilateral breast cancer recurrence using high-dose rate interstitial brachytherapy: preliminary clinical results and evaluation of patient satisfaction

PURPOSE

To assess early clinical results and evaluate patient satisfaction in case of second conservative treatment (2nd CT) combining lumpectomy plus high-dose rate (HDR) interstitial brachytherapy for patients (pts) presenting with ipsilateral breast cancer recurrence (IBCR).

METHODS AND MATERIALS

From June 2005 to July 2009, 42 pts presenting with an IBCR underwent a second lumpectomy with intraoperative implantation of plastic tubes in the tumor bed. After performing the dose distribution analysis on the postimplant CT scan, a total dose of 34 Gy in 10 fractions over 5 consecutive days was delivered. Toxicity evaluation was based on the Common Terminology Criteria for Adverse Events v3.0 criteria. Applying a visual analogic scale (VAS) analysis, patient satisfaction regarding cosmetic result and 2nd CT possibility was performed after the end of brachytherapy.

RESULTS

Median followup was 21 months (range, 6-50 months) and median age at the time of local recurrence was 65 years (range, 30-85 years). Median delay between primary and recurrence was 11 years (range, 1-35 years). Median recurrence tumor size was 12 mm (range, 2-30 mm). Median number of plastic tubes and planes were nine (range, 5-12) and two (range, 1-3), respectively. Median clinical target volume was 68 cc (range, 31.2-146 cc). Second local control rate was 97%. Twenty-two pts (60%) developed complications. Cutaneous and subcutaneous fibrosis was the most frequent side effect. Median VAS satisfaction score regarding cosmetic result was 7 of 10 (range, 4-9), whereas median VAS satisfaction score for 2nd CT was 10 of 10 (range, 8-10).

CONCLUSION

A 2nd CT for IBCR using high-dose rate brachytherapy seems feasible with encouraging results in terms of second local control with an acceptable toxicity. Patient satisfaction regarding the possibility of second breast preservation should be considered.

Accelerated partial breast irradiation with interstitial implants: risk factors associated with increased local recurrence

PURPOSE

To analyze patient, disease, and treatment-related factors regarding their impact on local control after interstitial multicatheter accelerated partial breast irradiation (APBI).

METHODS AND MATERIALS

Between November 2000 and April 2005, 274 patients with early breast cancer were recruited for the German-Austrian APBI Phase II trial (ClinicalTrials.gov identifier: NCT00392184). In all, 64% (175/274) of the patients received pulsed-dose-rate (PDR) brachytherapy and 36% (99/274) received high-dose-rate (HDR) brachytherapy. Prescribed reference dose for HDR brachytherapy was 32 Gy in eight fractions of 4 Gy, twice daily. Prescribed reference dose in PDR brachytherapy was 49.8 Gy in 83 consecutive fractions of 0.6 Gy each hour. Total treatment time was 3 to 4 days.

RESULTS

The median follow-up time was 64 months (range, 9-110). The actuarial 5-year local recurrence free survival rate (5-year LRFS) was 97.7%. Comparing patients with an age <50 years (49/274) vs. ≥50 years (225/274), the 5-year LRFS resulted in 92.5% and 98.9% (exact p = 0.030; 99% confidence interval, 0.029-0.032), respectively. Antihormonal treatment (AHT) was not applied in 9% (24/274) of the study population. The 5-year LRFS was 99% and 84.9% (exact p = 0.0087; 99% confidence interval, 0.0079-0.0094) in favor of the patients who received AHT. Lobular histology (45/274) was not associated with worse local control compared with all other histologies (229/274). The 5-year LRFS rates were 97.6% and 97.8%, respectively.

CONCLUSIONS

Local control at 5 years is excellent and comparable to therapeutic successes reported from corresponding whole-breast irradiation trials. Our data indicate that patients <50 years of age ought to be excluded from APBI protocols, and that patients with hormone-sensitive breast cancer should definitely receive adjuvant AHT when interstitial multicatheter APBI is performed. Lobular histology need not be an exclusion criterion for future APBI trials.

Accelerated Partial Breast Irradiation: Potential Roles following Breast-Conserving Surgery

Background

Multiple randomized trials comparing mastectomy to lumpectomy and whole breast irradiation (WBI) have shown equivalent survival outcomes in early-stage breast cancer. WBI requires a treatment course of several weeks, which has resulted in limited access to breast-conserving therapy in certain populations. A shorter accelerated course of partial breast irradiation (APBI) has been investigated recently.

Methods

This article reviews the current medical literature, including randomized trials and prospective institutional studies of APBI and the current recommendations regarding the use of this emerging technique.

Results

Several APBI techniques have been developed, including brachytherapy and external beam methods. The longest follow-up data are available for multicatheter interstitial brachytherapy, a technique that is not commonly used. Other methods, including balloon brachytherapy and external beam three-dimensional conformal techniques, have limited follow-up that shows similar local control rates to whole breast irradiation in highly selected patients. Guidelines for the appropriate use of APBI have been published.

Conclusions

While APBI may increase access to breast conservation therapy for some women with early-stage breast cancer, follow-up data demonstrating the efficacy of this relatively new treatment approach are limited. Therefore, strict evidence-based selection criteria should be applied when evaluating patients who may be appropriate for APBI.

Accelerated partial breast irradiation: 5-year results of the German-Austrian multicenter phase II trial using interstitial multicatheter brachytherapy alone after breast-conserving surgery

PURPOSE

To evaluate the impact of accelerated partial breast irradiation on local control, side effects, and cosmesis using multicatheter interstitial brachytherapy as the sole method for the adjuvant local treatment of patients with low-risk breast cancer.

METHODS AND MATERIALS

274 patients with low-risk breast cancer were treated on protocol. Patients were eligible for the study if the tumor size was < 3 cm, resection margins were clear by at least 2 mm, no lymph node metastases existed, age was >35 years, hormone receptors were positive, and histologic grades were 1 or 2. Of the 274 patients, 175 (64%) received pulse-dose-rate brachytherapy (D(ref) = 50 Gy). and 99 (36%) received high-dose-rate brachytherapy (D(ref) = 32.0 Gy).

RESULTS

Median follow-up was 63 months (range, 9-103). Only 8 of 274 (2.9%) patients developed an ipsilateral in-breast tumor recurrence at the time of analysis. The 5-year actuarial local recurrence-free survival probability was 98%. The 5- year overall and disease-free survival probabilities of all patients were 97% and 96%, respectively. Contralateral in-breast malignancies were detected in 2 of 274 (0.7%) patients, and distant metastases occurred in 6 of 274 (2.2%). Late side effects ≥ Grade 3 (i.e., breast tissue fibrosis and telangiectasia) occurred in 1 patient (0.4%, 95%CI:0.0-2.0%) and 6 patients (2.2%, 95%CI:0.8-4.7%), respectively. Cosmetic results were good to excellent in 245 of 274 patients (90%).

CONCLUSIONS

The long-term results of this prospective Phase II trial confirm that the efficacy of accelerated partial breast irradiation using multicatheter brachytherapy is comparable with that of whole breast irradiation and that late side effects are negligible.

Radiation therapy and tamoxifen after breast-conserving surgery: updated results of a 2 x 2 randomised clinical trial in patients with low risk of recurrence

To study the role of radiotherapy and tamoxifen after breast-conserving surgery (BCS) in patients with a favourable prognosis, a clinical trial was initiated by the German Breast Cancer Study Group (GBSG-V). Between 1991 and 1998, 361 patients (pT 1pN0M0, aged 45-75 years, receptor positive, grades I and II) were randomised to radiotherapy (yes/no) and tamoxifen for 2 years (yes/no) in a 2 x 2-factorial design; the exclusion of seven centres (14 patients) left 347 patients for the analysis. First results after a median follow-up of 5.9 years were published. Herein we present updated results after a median follow-up of about 10 years. Hundred and eleven events concerning event-free survival (EFS) have been observed. Since a strong interactive effect between radiotherapy and tamoxifen has been established, the results are presented in terms of the treatment effects for all four treatment groups separately. Mainly due to the presence of local recurrences, the event rate was much higher in the group with BCS only than in the other three groups. No significant difference could be established between the four treatment groups for distant disease-free survival rates (DDFS). Updated results give further evidence that even in patients with a favourable prognosis, the avoidance of radiotherapy and tamoxifen after BCS increases the rate of local recurrences substantially. Rates are about three times higher in the BCS only group. For the two outcomes EFS and DDFS, no important difference could be seen between the three groups with an additional treatment. However, because of the limited sample size with corresponding low power the strength of evidence for such a comparison is weak.

Validation of a web-based predictive nomogram for ipsilateral breast tumor recurrence after breast conserving therapy

PURPOSE IBTR! version 1.0 is a web-based tool that uses literature-derived relative risk ratios for seven clinicopathologic variables to predict ipsilateral breast tumor recurrence (IBTR) after breast-conserving therapy (BCT). Preliminary testing demonstrated over-estimation in high-risk subgroups. This study uses two independent population-based datasets to create and validate a modified nomogram, IBTR! version 2.0. METHODS Cox regression modeling was performed on 7,811 patients treated with BCT at the British Columbia Cancer Agency (median follow-up, 9.4 years). Population-based hazard ratios were generated for the seven variables in the original nomogram. A modified nomogram was then tested against 664 patients from Massachusetts General Hospital (median follow-up, 9.3 years). The mean predicted and observed 10-year estimates were compared for the entire cohort and for four groups predefined by nomogram-predicted risks: group 1: less than 3%; group 2: 3% to 5%; group 3: 5% to 10%; and group 4: more than 10%. Results IBTR! version 2.0 predicted an overall 10-year IBTR estimate of 4.0% (95% CI, 3.8 to 4.2), while the observed estimate was 2.8% (95% CI, 1.6 to 4.7; P = .10). The predicted and observed IBTR estimates were: group 1 (n = 283): 2.2% versus 1.3%, P = .40; group 2 (n = 237): 3.8% versus 3.5%, P = .80; group 3 (n = 111): 6.7% versus 3.2%, P = .05; and group 4 (n = 33): 12.5% versus 8.7%, P = .50. CONCLUSION IBTR! version 2.0 is accurate in the majority of patients with a low to moderate risk of in-breast recurrence. The nomogram still overestimates risk in a minority of patients with higher risk features. Validation in a larger prospective data set is warranted.

[Local control in breast cancer: constant importance, changing radiotherapy practice]

Local control is of primary importance when treating operable breast cancer. Local relapse serves as a secondary source of distant metastases, and compromises survival. Postoperative radiotherapy improves local control after mastectomy or breast conserving surgery, however, sometimes it leads to overtreatment. The risk of local relapse may be estimated based on different correlated factors, such as the type of the surgery, the size and stage of the tumor, the nodal status, the histological type, multifocality and biological features of the cancer, the margin status, the age and the mammographic appearance of the lesion. Late radiogenic sequelae appearing 5-10 years after radiotherapy are sometimes fatal, but may be prevented if radiotherapy is delivered at a high standard. Systemic therapies contribute to local control, and in some cases may substitute radiotherapy. In other low risk cases, radiotherapy may be either omitted or lessened. Local therapies in breast cancer should be tailored individually.

Verification in the water phantom of the irradiation time calculation done by the algorithm used in intraoperative radiotherapy

AIM

The investigation of the irradiation time calculation accuracy of the GGPB algorithm used for IORT.

BACKGROUND

Conventionally, breast conserving therapy consists of breast conserving surgery followed by postoperative whole breast irradiation and boost. The use of intraoperative radiotherapy (IORT) enables the boost to be delivered already during the surgery. In this case, the treatment dose for IORT can be calculated by use of General Gaussian Pencil Beam (GGPB) algorithm, which is implemented in TPS Eclipse.

MATERIALS AND METHODS

PDDs and OFs for electron beams from Mobetron and all available applicators were measured in order to configure the GGPB algorithm. Afterwards, the irradiation times for the prescribed dose of 3 Gy were calculated by means of it. The results of calculations were verified in the water phantom using the Marcus ionization chamber.

RESULTS

The results differed between energies. For 6 MeV the irradiation times calculated by the GGPB algorithm were correct, for the energy of 9 MeV they were too small and for the energy of 4 MeV they were too large for applicators with smaller diameters, while acceptable for the remaining ones.

CONCLUSION

The GGPB algorithm can be used in intraoperative radiotherapy for energy and applicator sets for which no significant difference between the measured and the prescribed dose was obtained. For the rest of energy-applicator sets the configuration should be verified and possibly repeated.

Conservative surgery with and without radiotherapy in elderly patients with early-stage breast cancer: a prospective randomised multicentre trial

Breast conserving therapy (BCT) including postoperative irradiation of the remaining breast tissue is generally accepted as the best treatment for the majority of patients with early-stage breast cancer. The question is whether there is a necessity for irradiating all patients. Between 2001 and 2005, 749 women aged 55-75 years with infiltrating breast carcinoma were randomly assigned to breast conservative surgery, with or without radiotherapy (RT), to evaluate the incidence of in-breast recurrence (IBR). After 5 years of median follow-up, the cumulative incidence of IBR was 2.5% in the surgery-only arm and 0.7% in the surgery plus RT arm. There are no differences in terms of overall survival and distant disease-free survival. The preliminary evaluation suggests that breast irradiation after conservative surgery can be avoided without exposing these patients to an increased risk of distant-disease recurrence. Prolonged follow-up will further clarify the possible risks and late sequelae potentially induced by breast RT.

Ipsilateral breast tumor recurrence: is there any evidence for benefit of further systemic therapy?

To date, there are no standard guidelines for treating patients with ipsilateral breast tumor recurrence (IBTR). Current practice is to resect the recurrence with a radical intent followed possibly by radiotherapy if the patient has not received this before, but the role of further adjuvant medical (hormone or chemotherapy) therapy remains undefined. Currently Phase III trials are underway to answer this question. In this review, we will focus on published data relating to IBTR and discuss recent trials. The results from the Phase III trials will not be available for sometime. At the time of IBTR, it is reasonable to change the endocrine therapy with indirect evidence from sequencing of impact on outcome. There is currently no conclusive evidence to suggest that further adjuvant chemotherapy post loco-regional recurrence impacts on survival, though the use of noncross-resistant chemotherapy drugs may make sense in those at highest risk. Biopsy at IBTR is helpful to distinguish whether it is a true recurrence or a new primary tumor and receptor phenotyping may be helpful for HER2. Future trials in IBTR need to address the following issues: to be able to distinguish between true recurrence and new primary (consensus required on definitions); pathologic processing relating to margins needs to be standardized (1 or 5 mm wide specimens); documentation of the pattern of IBTR in relation to each histopathologic subtype and methods used for pathologic examination by centers. Regional nodal recurrence including supraclavicular node recurrence is not dealt with in this review.

Local relapse after breast-conserving surgery and radiotherapy: effects on survival parameters

PURPOSE

This retrospective analysis of 1,610 women treated for breast cancer and 88 patients with local relapse aims to show the poor survival parameters after local failure and to evaluate risk factors and compare them with other studies and analyses published.

PATIENTS AND METHODS

Between 1984 and 1997, 1,610 patients presenting with a total of 1,635 pT1-2 invasive and noninvasive carcinomas of the breast were treated at the authors' institution. The mean age was 57.1 years (range 25-85 years). Treatment protocols involved breast-conserving surgery with or without systemic therapy and whole-breast radiotherapy in all women, followed by a boost dose to the tumor bed according to risk factors for local recurrence. All axillary node-positive patients underwent systemic therapy (six cycles of classic CMF or tamoxifen 20 mg/day for 2-5 years). The time of diagnosis of local relapse was defined as time 0 for the survival curves after local failure. The association of clinicopathologic factors was studied using uni- and multivariate analyses. Survival and local control were calculated by the Kaplan-Meier actuarial method and significance by the log-rank test.

RESULTS

After a mean follow-up of 104 months, 88 local failures were recorded (5.4%). Calculated from the time of diagnosis of local relapse, 5-year overall survival (OS) was 62.8%, metastasis-free survival 60.6%, and disease-specific survival 64.2%. In patients with failure during the first 5 years after treatment, the survival parameters were worse (OS 50.6%) compared to those who relapsed after 5 years (OS 78.8%; p < 0.028). Significances were also found for initial T- and N-stage and type of failure (solid tumor vs. diffuse spread).

CONCLUSION

This analysis again shows that the survival parameters are worsening after local relapse, especially in case of early occurrence. In breast cancer treatment, therefore, the goal remains to avoid local failure.

Accelerated partial breast irradiation with IMRT: new technical approach and interim analysis of acute toxicity in a phase III randomized clinical trial

PURPOSE

To evaluate with a randomized clinical trial the possibility of treating the index quadrant with external intensity-modulated radiotherapy (IMRT) in a selected group of patients with early-stage breast cancer and to analyze the acute toxicity.

METHODS AND MATERIALS

From September 2005, a randomized Phase III clinical trial has been conducted to compare conventional (tangential field) fractionated whole breast treatment (Arm A) with accelerated partial breast irradiation plus intensity-modulated radiotherapy (Arm B). For intensity-modulated radiotherapy, the clinical target volume was drawn with a uniform 1-cm margin around the surgical clips in three dimensions. The ipsilateral and contralateral breast, ipsilateral and contralateral lung, heart, and spinal cord were contoured as organs at risk. All the regions of interest were contoured according to the International Commission on Radiation Units and Measurements reports 50 and 62 recommendations.

RESULTS

In September 2008, 259 patients were randomized and treated. The mean clinical target volume in Arm B was 44 cm(3) and the mean planning target volume was 123 cm(3). The mean value of the ratio between the planning target volume and the ipsilateral breast volume was 21%. The rate of Grade 1 and Grade 2 acute skin toxicity was 22% and 19% in Arm A (Radiation Therapy Oncology Group scale), respectively. The tolerance in Arm B was excellent with only 5% Grade 1 and 0.8% Grade 2 acute skin toxicity. The planning constraints were fully satisfied in most patients. In a very few cases, this was not possible because of very unfavorable anatomy. Quality assurance procedures were performed according to our internal quality assurance protocol, with excellent results.

CONCLUSION

In the present preliminary analysis, we have demonstrated that accelerated partial breast irradiation is feasible, with very low acute toxicity.

Biologically effective dose-response relationship for breast cancer treated by conservative surgery and postoperative radiotherapy

PURPOSE

To find a biologically effective dose (BED) response for adjuvant breast radiotherapy (RT) for initial-stage breast cancer.

METHODS AND MATERIALS

Results of randomized trials of RT vs. non-RT were reviewed and the tumor control probability (TCP) after RT was calculated for each of them. Using the linear-quadratic formula and Poisson statistics of cell-kill, the average initial number of clonogens per tumor before RT and the average tumor cell radiosensitivity (alpha-value) were calculated. An alpha/beta ratio of 4 Gy was assumed for these calculations.

RESULTS

A linear regression equation linking BED to TCP was derived: -ln[-ln(TCP)] = -ln(No) + alpha(*) BED = -4.08 + 0.07 (*) BED, suggesting a rather low radiosensitivity of breast cancer cells (alpha = 0.07 Gy(-1)), which probably reflects population heterogeneity. From the linear relationship a sigmoid BED-response curve was constructed.

CONCLUSION

For BED values higher than about 90 Gy(4) the radiation-induced TCP is essentially maximizing at 90-100%. The relationship presented here could be an approximate guide in the design and reporting of clinical trials of adjuvant breast RT.

Mammographic findings of partial breast irradiation

RATIONALE AND OBJECTIVES

The aim of this study was to determine if patients who underwent partial-breast irradiation followed by segmental mastectomies had fewer mammographic changes on the first post-treatment mammogram than those who underwent segmental mastectomies followed by whole-breast irradiation.

MATERIALS AND METHODS

Subjects enrolled in a study of partial-breast irradiation therapy after segmental mastectomy (intraoperative radiation therapy) plus a random sample of patients who underwent segmental mastectomies followed by conventional whole-breast radiation therapy were identified through the institution's breast cancer database from March 2003 through February 2006. A radiologist specializing in breast imaging reviewed and recorded each patient's pretreatment mammogram for breast density and tumor location and the first post-treatment mammogram, obtained within the first year of treatment, for three common types of mammographic change seen after breast surgery and radiation treatment (breast edema, skin thickening, and surgical scarring), which when severe make it difficult to use mammography for continuing follow-up of the conserved breast. The extent of mammographic change was noted by the radiologist as minimal, moderate, or marked. The data were entered into a database, and statistical analysis was conducted using logistic regression models and chi(2) tests. The effect of breast density on mammographic change was also assessed.

RESULTS

The severity of edema was lower with decreasing breast density (P < .006). There was no apparent effect of breast density on the severity of skin thickening. The extent of surgical scarring decreased as breast density increased (P < .026). Analysis of the data from the cumulative logistic regression models demonstrated that even after controlling for breast density, patients who underwent whole-breast radiation therapy had significantly more edema (P = .003), skin thickening (P = .003), and surgical scarring than those who underwent intraoperative radiation therapy (P < .001).

CONCLUSION

Patients have a higher probability of having fewer post-treatment mammographic changes after partial-breast irradiation followed by segmental mastectomy than after breast conservation surgery followed by whole-breast irradiation.

Dose optimization of breast balloon brachytherapy using a stepping 192Ir HDR source

To develop dose optimization schemes of breast balloon brachytherapy using a stepping of Ir192 HDR source.

There is a considerable underdosage (11%–13%) of PTV due to anisotropy of a stationary source in breast balloon brachytherapy. We improved the PTV coverage by varying multiple dwell positions and weights. We assumed that the diameter of spherical balloons varied from 4.0 cm to 5.0 cm, that the PTV was a 1‐cm thick spherical shell over the balloon (reduced by the small portion occupied by the catheter path), and that the number of dwell positions varied from 2 to 13 with 0.25‐cm steps, oriented symmetrically with respect to the balloon center. By assuming that the perfect PTV coverage can be achieved by spherical dose distributions from an isotropic source, we developed an optimization program to minimize two objective functions defined as: (1) the number of PTV‐voxels having more than 10% difference between optimized doses and spherical doses, and (2) the difference between optimized doses and spherical doses per PTV‐voxel.

The optimal PTV coverage occurred when applying 8–11 dwell positions with weights determined by the optimization scheme. Since the optimization yields ellipsoidal isodose distributions along the catheter, there is relative skin sparing for cases with source movement approximately tangent to the skin. We also verified the optimization in CT‐based treatment planning systems.

Our volumetric dose optimization for PTV coverage showed close agreement to linear or multiple‐points optimization results from the literature. The optimization scheme provides a simple and practical solution applicable to the clinic.

PACS number: 87.55.de

The dynamic tumor bed: volumetric changes in the lumpectomy cavity during breast-conserving therapy

PURPOSE

To characterize the magnitude of volume change in the postoperative tumor bed before and during radiotherapy, and to identify any factors associated with large volumetric change.

METHODS AND MATERIALS

Thirty-six consecutive patients with early-stage or preinvasive breast cancer underwent breast-conserving therapy at our institution between June 2006 and October 2007. Computed tomography (CT) scans of the breast were obtained shortly after surgery, before the start of radiotherapy (RT) for treatment planning, and, if applicable, before the tumor bed boost. Postoperative changes, seroma, and surgical clips were used to define the tumor bed through consensus agreement of 3 observers (B.P., D.I., and J.L.). Multiple variables were examined for correlation with volumetric change.

RESULTS

Between the first and last scan obtained (median time, 7.2 weeks), the tumor bed volume decreased at least 20% in 86% of patients (n = 31) and at least 50% in 64% of patients (n = 23). From the postoperative scan to the planning scan (median time, 3 weeks), the tumor bed volume decreased by an average of 49.9%, or approximately 2.1% per postoperative day. From planning scan to boost scan (median interval, 7 weeks), the median tumor bed volume decreased by 44.6%, at an average rate of 0.95% per postoperative day. No single factor was significantly associated with a change in tumor bed volume greater than 20%.

CONCLUSIONS

The average postlumpectomy cavity undergoes dramatic volumetric change after surgery and continues this change during RT. The rate of change is inversely proportional to the duration from surgery. In this study no factors studied predicted large volumetric change.