Fat necrosis of the breast: an unusual complication of lumpectomy and radiotherapy in breast cancer

Fat necrosis after accelerated partial breast irradiation or hypofractionated whole breast irradiation: A case-control study

PURPOSE

This study aimed to compare the incidence of fat necrosis after accelerated partial breast irradiation (APBI) vs hypofractionated whole breast irradiation (WBI) in patients with early-stage breast cancer.

MATERIALS AND METHODS

Data from early-stage breast cancer patients who underwent breast-conserving surgery and adjuvant radiotherapy between 2009 and 2022 were retrospectively collected. Radiation therapy consisted of APBI of 30 Gy in 5 daily fractions (Fx) (delivered in one week, consecutively) to the tumour bed or WBI (42.4 Gy in 16 Fx). Reports on fat necrosis were extracted from yearly mammograms and breast ultrasound imaging. The primary endpoint was the incidence of radiologically detected fat necrosis.

RESULTS

A total of 536 patients were included among the APBI and WBI cohorts, with 268 and 268 patients respectively. The three-year Kaplan-Meier actuarial rate of fat necrosis was 32.8% (95% CI: 30.0% - 35.6%) for APBI and 22.3% (95% CI: 19.7% - 24.9%) for WBI patients. Univariate Kaplan-Meier survival analysis revealed a Hazard Ratio of 1.6 [95% CI: 1.1 - 2.2; p = 0.0055] for the fat necrosis rate within the APBI group compared to WBI. Multivariate Cox proportional hazard regression confirmed significant associations between fat necrosis and APBI (HR = 2.2 95% CI: 1.2 - 4.0; p = 0.01).

CONCLUSIONS

The occurrence of radiologically diagnosed fat necrosis was higher in the APBI group compared to the WBI. Further investigations aiming to identify a lower-dose schedule with comparable efficacy to 30 Gy in 5 Fx but fewer toxicities, particularly for high-risk patients, are warranted.

Risk Factors for Fat Necrosis After Stereotactic Partial Breast Irradiation for Early-Stage Breast Cancer in a Phase 1 Clinical Trial

PURPOSE

This study reports predictive dosimetric and physiologic factors for fat necrosis after stereotactic-partial breast irradiation (S-PBI).

METHODS AND MATERIALS

Seventy-five patients with ductal carcinoma-in situ or invasive nonlobular epithelial histologies stage 0, I, or II, with tumor size <3 cm were enrolled in a dose-escalation, phase I S-PBI trial between January 2011 and July 2015. Fat necrosis was evaluated clinically at each follow-up. Treatment data were extracted from the Multiplan Treatment Planning System (Cyberknife, Accuray). Univariate and stepwise logistic regression analyses were conducted to identify factors associated with palpable fat necrosis.

RESULTS

With a median follow-up of 61 months (range: 4.3-99.5 months), 11 patients experienced palpable fat necrosis, 5 cases of which were painful. The median time to development of fat necrosis was 12.7 months (range, 3-42 months). On univariate analyses, higher V32.5-47.5 Gy (P < .05) and larger breast volume (P < .01) were predictive of any fat necrosis; higher V35-50 Gy (P < .05), receiving 2 treatments on consecutive days (P = .02), and higher Dmax (P = .01) were predictive of painful fat necrosis. On multivariate analyses, breast volume larger than 1063 cm³ remained a predictive factor for any fat necrosis; receiving 2 treatments on consecutive days and higher V45 Gy were predictive of painful fat necrosis. Breast laterality, planning target volume (PTV), race, body mass index, diabetic status, and tobacco or drug use were not significantly associated with fat necrosis on univariate analysis.

CONCLUSIONS

Early-stage breast cancer patients treated with breast conserving surgery and S-PBI in our study had a fat necrosis rate comparable to other accelerated partial breast irradiation modalities, but S-PBI is less invasive. To reduce risk of painful fat necrosis, we recommend not delivering fractions on consecutive days; limiting V42.5 < 50 cm³, V45 < 20 cm³, V47.5 < 1 cm³, Dmax ≤ 48 Gy and PTV < 100 cm³ when feasible; and counseling patients about the increased risk for fat necrosis when constraints are not met and for those with breast volume >1000 cm³.

Omentum for Mammary Disorders: A 30-Year Systematic Review

PURPOSE

Although the safety of applying omentum to the female breast for total breast reconstruction is controversial, it has recently been used to treat certain mammary disorders as well. A systematic review was therefore conducted to analyze and establish the suitability and safety of applying omentum to the breast.

METHODS

Covereing the interval from January 1984 to December 2013, we performed searches in MEDLINE, Embase, SciELO, and Google-Scholar for original articles describing the applicability of greater omentum to the breast and its clinical complications.

RESULTS

Sixty observational articles with 985 women were chosen. The main clinical indications were total breast reconstruction after mastectomy due to breast cancer (45 studies), radiation damage (23 studies), and congenital Poland syndrome (4 studies). Altogether, 273 complications were identified among the 985 women treated. The most frequent was flap necrosis (26.74 %). The most serious was injury to the digestive system (1.10 %). There was a 35.48 % incidence of local breast cancer recurrence in eight observational studies on oncological risk. Seven of the eight included only women with advanced cancer. One of these studies reported the incidence and relapse time predominantly according to the primary tumor size.

CONCLUSIONS

Although the oncological risk remains unclear, there was a high volume of complications that affected the digestive system. These findings suggest that omentum has well established applicability, but only for total breast reconstruction of huge defects, where muscular/myocutaneous or perforator flaps may be unsuitable.

Laser lipolysis without suction: reality or myth?

BACKGROUND AND OBJECTIVE

Liposuction is one of the most frequently performed aesthetic surgical procedures. Laser- and ultrasound-based systems have become especially popular in recent years, including laser lipolysis, which has a number of advantages over classic liposuction. Some researchers contend that the aspiration step is not necessary. Herein, we report a case that highlights the negative consequences when the basic surgical rule of not leaving any necrotic tissue is not followed.

MATERIALS AND METHODS

We report the case of a 50-year-old man who presented with a 15 cm mass in the right lower quadrant, located immediately subcutaneously, passing the midline infraumbilically, tender to touch, and with beginnings of abscess formation, who underwent laser lipolysis. The subcutaneous necrotic fat was removed with a skin island en bloc. No postoperative complications occurred and the patient was problem free 6 months post-surgery.

RESULTS

In the surgical literature, most studies on fat necrosis have focused on fat necrosis in the breast. Fat necrosis is usually a gradual process that is noticed by the patient or physician as a mass. Radiologically, it can imitate cancer, especially in breast tissue. Complications from fat necrosis are primarily linked to the amount of necrosis. Any amount of necrosis above the body's resorption capacity will lead the body into attempting self-limitation, with consequences to both the physical and psychological health of the patient.

CONCLUSIONS

We believe that claiming that no aspiration is required after laser lipolysis, without the necessary studies, has no scientific basis.

Infections associated with solid malignancies

Although solid tumors comprise the vast majority of cancers, the incidence of serious infectious complications in this population is much less than in patients with hematologic malignancies. Most infections involving patients with solid tumors comprise two groups. First, patients acquire infections as a result of the cancer itself, due to either mass effect that interrupts normal function or destruction of the normal barriers to infection. Second, patients acquire infections as a complication of the treatments they receive, such as chemotherapy, radiation, surgery, or medical devices. Advances in the management of cancer have resulted in a gradual stepwise improvement in survival for patients with most types of solid tumors. Much of this improvement has been attributed to advances in cancer screening, diagnosis, and therapeutic modalities. In addition, improvements in the prevention, diagnosis, and treatment of infections have likely contributed to this prolonged survival. This review highlights select articles in the medical literature that shed light on the epidemiology and pathophysiology of infections in patients with solid tumors. In addition, this review focuses upon the diagnosis and treatment of these infections and their recent advances.

Sonography of fat necrosis of the breast: correlation with mammography and MR imaging

Fat necrosis (FN) of the breast is a benign nonsuppurative inflammatory process of the adipose tissue. The radiologic appearance ranges from benign to suspicious for malignancy; therefore, it is very important to know the distinguishing radiologic features of FN on different modalities. Mammography is more helpful in identifying FN than ultrasonography in most of the cases, and MRI may also be used to rule out malignancy as an adjunct to mammography and sonography. Even when modern diagnostic modalities are used, biopsy may still be unavoidable for some cases. In conclusion, an accurate history and familiarity with the radiologic findings are crucial to recognizing FN and avoiding unnecessary interventions.

Fat necrosis simulating recurrent neoplasia following external beam radiotherapy in a dog

A 4.5-year-old neutered male dog was diagnosed with incompletely excised well-differentiated lymphangiosarcoma in the right inguinal subcutaneous region. The mass had metastasized to the right hypogastric and medial iliac lymph nodes. Surgery followed by definitive radiation therapy was administered to the primary site and the sites of metastasis. The dog had a complete response to radiotherapy, and minimal acute side effects. Doxorubicin was administered after radiotherapy. Approximately 4 months following radiation therapy, the dog developed a mass, presumed recurrent tumor, in the original site. In a biopsy only steatitis and fibrosis were found. The mass continued to grow and conservative surgical excision was elected. Histopathologically the diagnosis was fat necrosis and steatitis, with a microscopic focus of lymphangiosarcoma. Fat necrosis is an uncommon sequelum to breast irradiation in people and also appears to be rare in animals. Fat necrosis should be considered as a differential diagnosis when recurrent tumor is suspected in a previously irradiated subcutaneous site in a dog.

Fat necrosis of the breast—A review

Fat necrosis of the breast is a benign condition that most frequently affects peri-menopausal women. It can mimic breast cancer clinically or radiologically. In other cases it can obscure malignant lesions. The core of this review is derived from a MEDLINE database literature search from 1966-2004. Further references were from lateral search. In this paper, we review the pathogenesis and pathology clinical and radiological features of fat necrosis of the breast. The implication of fat necrosis in the management of patients with breast lump is also discussed. Fat necrosis of breast is a complex process. Therefore, a systematic review of this condition will enable surgeons, radiologists and oncologists working in the field of breast disease to understand it better and improve its management.

Image-guided breast brachytherapy: an alternative to whole-breast radiotherapy

Lumpectomy and whole-breast radiotherapy (ie, breast-conservation treatment) are accepted as viable alternatives to mastectomy in locoregional management of breast cancer. These techniques are used to keep morbidity to a minimum, optimise cosmesis, and maintain treatment outcomes. Pathological and clinical data suggest that most recurrences of cancer in the ipsilateral breast are in the vicinity of the index lesion, and that remote recurrences are uncommon, whether or not whole-breast radiotherapy is delivered. These data lend support to the idea of partial-breast radiotherapy. Such a restricted treatment volume allows safe delivery of an accelerated hypofractionated regimen over a shortened course of 1 week. This technique differs from that of standard whole-breast tangential external-beam radiotherapy and necessitates investigation of accelerated partial-breast irradiation (APBI). Several techniques of APBI are being investigated; however, most experience, and the most favourable early outcomes, has been obtained with image-guided breast brachytherapy. This review highlights the rationale and outcomes of brachytherapy techniques.

Spectrum of sonographic findings in superficial breast masses

OBJECTIVE

The purpose of this presentation is to show the sonographic findings of breast masses, which can occur in subcutaneous fat or in the cutaneous layer of the breast.

METHODS

We reviewed the sonographic findings of superficial breast masses, including the epidermal inclusion cyst, steatocystoma multiplex, fat necrosis, accessory breast, Mondor disease, sparganosis, neurofibroma, tuberculosis, mastitis, and breast malignancy.

RESULTS

Specific sonographic features of superficial breast masses have been illustrated.

CONCLUSIONS

Radiologists must be familiar with the sonographic findings of various diseases involving the superficial layer of the breast to avoid further patient workup.

Surgical considerations in the treatment of early stage breast cancer with accelerated partial breast irradiation (APBI) in breast conserving therapy via intersitial brachytherapy

OBJECTIVE

To examine early and late toxicities, evaluate cosmetic results, and determine the need for reoperation or additional diagnostic procedures in patients treated with accelerated partial breast irradiation (APBI) delivered by way of an interstitial implant in breast-conserving therapy.

METHODS

A total of 199 patients with stage I or II breast cancer were managed with lumpectomy followed by radiation restricted to the tumor bed using an interstitial implant (APBI). Retrospective analyses were performed for early and late toxicities (infection, fat necrosis, breast pain, edema, erythema, fibrosis, pigmentation changes, and telangiectasias), need for reoperation or additional diagnostic procedures, cosmetic results, and local control. Patient selection criteria by the surgeon for referral to RT for APBI included age, tumor size, histology, nodal status, margin status, and absence of extensive intraductal component. Treatment was delivered with either a low-dose or high-dose rate implant. Median follow-up was 5.7 years, and 54% of the patients were followed-up for >7 years.

RESULTS

Infections developed in 22 of 199 (11%) patients: 7% early (</=1 month after implant removal) and 4% late (>1 month after implant removal). Five of the 22 patients (2% of all patients) required operative intervention for the infection, either incision and drainage or debridement. There was a statistically significant difference between infection rates with open (8.5%) versus closed (2.5%) cavity placement of the interstitial needles (P = 0.005). There was no statistically significant difference between low-dose rate (inpatient) and high-dose rate (outpatient) treatment (P = 0.207). Forty-five patients (23%) had an additional diagnostic procedure to evaluate a suspicious or uncertain finding on physical examination or mammogram. Fibrosis and fat necrosis were found in 26 of the 45 patients. The incidence of fat necrosis increased with time. More patients were found to have fat necrosis after 5 years. One patient had fat necrosis diagnosed at <6 months; 8 patients (4% of total) at >/=6 months to <2 years; 10 patients (5% of total) at >/=2 years to <5 years; and 22 patients (11% of total) at >/=5 years. The majority of fat necrosis was detected on mammogram (80%) and was asymptomatic (78%). Cosmesis and toxicities were assessed at 3 defined time points: </=6 months, 2 years, and >/=5 years of follow-up. Using Harvard criteria, good to excellent cosmetic results were observed in >90% of patients. Breast pain, edema, and erythema diminished with time. Of the 199 cases, there were only 5 ipsilateral breast failures, yielding a 5-year actuarial local recurrence rate of 1.2%. Of these 5 failures, 2 were true recurrences/marginal misses, yielding a 5-year actuarial true recurrence/marginal miss rate of 0.5%. The 5-year actuarial cause-specific survival rate was 99% for APBI patients.

CONCLUSIONS

In selected patients with early-stage breast cancer, APBI with targeted interstitial brachytherapy offers 5-year results comparable with conventional breast-conserving therapy employing whole-breast radiation therapy. Minimal long-term toxicities were noted, most of which demonstrated continued resolution over time. Acceptable acute (7%) and delayed (4%) infection rates were observed. Fat necrosis was identified with increasing frequency with time, but the majority was asymptomatic. Cosmetic results are good to excellent (>90%). Continued follow-up by the surgeon will be required to determine the long-term efficacy of this alternative treatment approach.

3D CT–based high-dose-rate breast brachytherapy implants: treatment planning and quality assurance

PURPOSE

Although accelerated partial breast irradiation (APBI) as the sole radiation modality after lumpectomy has shown promising results for select breast cancer patients, published experiences thus far have provided limited information on treatment planning methodology and quality assurance measures. A novel three-dimensional computed tomography (CT)-based treatment planning method for accurate delineation and geometric coverage of the target volume is presented. A correlation between treatment volume and irradiation time has also been studied for quality assurance purposes.

METHODS AND MATERIALS

Between May 2002 and January 2003, 50 consecutive patients underwent an image-guided interstitial implant followed by CT-based treatment planning and were subsequently treated with APBI with a high-dose-rate (HDR) brachytherapy remote afterloader. Target volume was defined as the lumpectomy cavity +2 cm margin modified to >/=5 mm to the skin surface. Catheter reconstruction, geometric optimization, and manual adjustment of irradiation time were done to optimally cover the target volume while minimizing hot spots. Dose homogeneity index (DHI) and percent of target volume receiving 100% of the prescription dose (32 Gy in 8 fractions or 34 Gy in 10 fractions) was determined. Additionally, the correlation between the treatment volume and irradiation time, source strength, and dose was then analyzed for manual verification of the HDR computer calculation.

RESULTS

In all cases, the lumpectomy cavity was covered 100%. Target volume coverage was excellent with a median of 96%, and DHI had a median value of 0.7. For each plan, source strength times the treatment time for every unit of prescribed dose had an excellent agreement of +/-7% to the Manchester volume implant table corrected for modern units.

CONCLUSIONS

CT-based treatment planning allowed excellent visualization of the lumpectomy cavity and normal structures, thereby improving target volume delineation and optimal coverage, relative to conventional orthogonal film dosimetry. Using the Manchester volume implant table calculated irradiation time can be used as quality assurance for the HDR computed time. Thus dosimetric quality assurance and adequate target volume coverage can be concurrently confirmed, allowing prospective evaluation and optimization of implants.

Partial breast irradiation with interstitial 60CO brachytherapy results in frequent grade 3 or 4 toxicity. evidence based on a 12-year follow-up of 70 patients

PURPOSE

To investigate the radiation-induced toxicity and cosmesis of brachytherapy (BT) alone in early stage breast cancer.

METHODS AND MATERIALS

A total of 70 women diagnosed with Stage I or II breast carcinoma participated in a BT study at the Municipal Oncoradiological Center, Uzsoki Hospital, Budapest, Hungary, between November 1987 and June 1992. They had undergone breast-conserving surgery with an unknown surgical margin. The postoperative tumor bed irradiation was performed with interstitial (60)Co sources with an active length of 4 cm, with 10-mm center-to-center spacing arranged in a single plane. The median number of inserted sources was 5 (range, 2-8), with a linear activity of 133-137 MBq/cm at the beginning of the study. The 50 Gy delivered dose at 5 mm from the surface of the (60)Co sources was administered during 10-22 h to the virtual postoperative lumpectomy cavity (i.e., plane). For radiobiologic considerations, the clinical target volume (CTV) was calculated retrospectively with a 10-mm safety margin, resulting in a 72-cm(3) median CTV (range, 36-108 cm(3)) irradiated with a reference dose of 28 Gy. In the assessment of the skin and subcutaneous toxicity, the RTOG late radiation morbidity scoring system was applied. The radiosensitivity of the cultured fibroblasts was determined by clonogenic assay to check whether individual radiosensitivity played a role in the development and course of radiation-induced side-effects.

RESULTS

The median follow-up was 12 years (range, 10-15 years). The population of the final study (34 cases) comprised all survivors with tumor-free breasts (27 cases) and patients with breasts erroneously ablated/excised for misinterpreted radiation-induced sequelae (7 patients). A total of 97% of the cohort (33/34) had grade > or =2, and 59% (20/34) had grade > or =3 radiation-induced toxicity. By the end of the follow-up, 85% of the patients experienced Grade > or =2 telangiectasis and 41% had Grade 3 telangiectasis. Eighty-eight percent had fibrosis of some form, and 35% had grade > or =3 fibrosis. Forty-one percent of the cohort displayed fat necrosis, which was always accompanied by Grade > or =3 fibrosis or telangiectasis. The cosmetic results were poor in 50% (17/34) of the patients. The radiosensitivity of the fibroblasts was increased in only 2/24 patients (8% of the investigated cases, in agreement with data published for the general population). Comparisons of our fibrosis prevalence data with those of others allowed an estimate of 0.47 h(-1) for the rate of recovery of DNA damage in the fibroblasts.

CONCLUSIONS

Interstitial (60)Co BT of the breast tumor bed alone with a limited CTV (median, 72 cm(3)) and a total dose of 28 Gy is associated with a high rate (59%) of grade > or =3 radiation-induced toxicity and a high rate (50%) of poor cosmetic outcome at the end of a median follow-up of 12 years. A relatively high BT dose rate (1.3-2.8 Gy/h) applied during a short overall treatment time (10-22 h) and a possible geographic miss (close to skin implantation) might have contributed to the development of these sequelae.

Dynamic MRI of breast hardness following radiation treatment

PURPOSE

To evaluate functional microvascular characteristics of breast induration several years after radiation treatment using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) techniques.

MATERIALS AND METHODS

Fifteen women with moderate or marked breast induration after surgery and radiotherapy for breast cancer (2-15 years) were examined. Images of the irradiated breast (boost and nonboost sites) on short tau inversion recovery (STIR) and DCE-MRI sequences were subjectively evaluated for edema and the presence of enhancement and compared to the contralateral normal breast. Quantitative enhancement parameters-percent enhancing pixels, transfer constant (K(trans)), rate constant (k(ep)), leakage space (v(e)), and maximum contrast medium accumulation (MCMA)-were also compared.

RESULTS

No tumor recurrence was seen. Fat necrosis was seen in 2/15 cases. Increased parenchymal edema at the electron boost site was seen in 12/14 patients. Greater enhancement in the irradiated breast was seen in 11/14 evaluable patients. Kinetic parameter estimates including K(trans) were similar except for percent enhancing pixels, which was greater in the irradiated breast at both boost and nonboost sites (P = 0.03 and 0.04, respectively). v(e) and MCMA estimates were greater in breasts with marked induration compared to moderate grades (P = 0.002 and 0.01, respectively).

CONCLUSION

Parenchymal edema may be an important contributor to palpable induration several years after breast radiotherapy. Increased fluid content may be related to increased numbers of perfused microvessels and/or impaired lymphatic drainage.

Magnetic resonance imaging of induration in the irradiated breast

BACKGROUND

The causes of induration (hardness) in the breast many years after tumour excision and whole breast radiotherapy for early stage breast cancer are not well established. The purpose of this study is to describe morphological magnetic resonance imaging (MRI) appearances and MRI-derived microvascular functional characteristics of the indurated breast several years post-treatment.

PATIENTS AND METHODS

Fifteen women with moderate or marked induration at the electron boost site after breast preserving surgery and radiotherapy for early breast cancer (median 6 years; range, 2-15 years) underwent MRI, including 6/15 with very marked breast shrinkage and 8/15 with marked induration. Morphological T1- and T2-weighted and STIR images were obtained followed by a dynamic contrast medium enhanced sequence. The breast skin and underlying parenchyma of the irradiated breast were evaluated for thickening, oedema and the presence of enhancement compared to the contralateral breast. Particular note of boost site findings was made.

RESULTS

No evidence of tumour recurrence was seen. Fat necrosis was seen in 2/15 cases. Skin thickening and skin oedema not evident clinically were seen in 11/15 patients. Increased parenchymal oedema at the electron boost site was seen in 12/15 patients. The parenchymal oedema was not confined to the electron boost site, but was strongest in this location in 9/12 patients. Post-contrast images in 12/14 patients showed persistent parenchymal enhancement in nine (marked in three, who also had severe breast shrinkage and marked induration), a finding consistent with, but not diagnostic of tissue fibrosis.

CONCLUSIONS

Fat necrosis is not likely to contribute to breast induration several years after radiotherapy in more than a minority of patients. Increased fluid content in the breast parenchyma and skin oedema are likely to be more important contributors to palpable induration. Increased fluid content may be related to persistent capillary leakage even many years post-treatment, an expression of radiation-induced vascular injury. Fibrosis cannot be scored directly on MRI, but persistent parenchymal enhancement in a high proportion of post-contrast images is compatible with this pathology.

Fat necrosis of the female breast – Hadfield re-visited

Examination of pathology records from three hospitals over an 8-year period identified 42 cases of primary fat necrosis of the female breast. The mean age of the women was 56 (range 24-85) and the lump was most commonly in the upper, inner quadrant of the breast having been present for a mean of 11 weeks (range 1-56). Twenty-one percent of patients gave a history of trauma which had occurred a mean of 69 weeks (range 3-208) previously. The mammograms gave an appearance of malignancy in 12 of the 22 cases where they were performed. Cytology was suspicious in five cases. Thirty-seven patients subsequently underwent wide local excision to confirm the diagnosis. The histology was re-examined by a pathologist and a subgroup of patients were identified who had fat necrosis associated with periductal mastitis. Two patients who had a core biopsy diagnosis of fat necrosis were found to have malignancy on wide local excision. Here we review the changes in presentation since the original description of the condition, and highlight that although this series reflects difficult cases, fat necrosis remains a condition which can still be difficult to diagnose.

Fat necrosis of the breast: clinical, mammographic and sonographic features

OBJECTIVE

the purpose of this study was to describe and quantitate the clinical, mammographic and sonographic (US) features and to evaluate the evolution of fat necrosis in the breast.

MATERIALS AND METHODS

a retrospective review of the clinical, mammographic and US findings of 126 fat necrosis lesions in 94 patients, diagnosed between 1989 and 1999, was done. All the cases included in the study had at least 3 years follow-up mammograms. In addition, 48 patients with a total of 62 fat necrosis lesions, also had an US follow-up. Fat necrosis was diagnosed on the basis of histologic (n=25) and initial or follow-up imaging (n=69) findings.

RESULTS

the predominant mammographic features of the 114 lesions apparent on mammograms were radiolucent oil cyst (n=34, 26.9%), round opacity (n=16, 12.6%), asymmetrical opacity or heterogenicity of the subcutaneous tissues (n=20, 15.8%), dystrophic calcifications (n=34, 26.9%), clustered pleomorphic microcalcifications (n=5, 3.9%), and suspicious speculated mass (n=5, 3.9%). In five patients with 12 (9.5%) palpable masses, mammograms were normal. The predominant US features of the 112 lesions apparent on sonograms were solid (n=18, 14.2%), anechoic with posterior acoustic enhancement (n=21, 16.6%), anechoic with posterior acoustic shadowing (n=20, 15.8%), cystic with internal echoes (n=14, 11.1%), cystic with mural nodule (n=5, 3.9%) and increased echogenicity of the subcutaneous tissues (n=34, 26.9%). In five patients with 14 (11.1%) lesions, sonographic examination was normal. Mammographic follow-up showed that five of the radiolucent oil cysts developed curvilinear calcifications, six of the round opacities decreased in size and density, and another two disappeared. Eleven of the dystrophic calcifications became even more coarse. Six of the asymmetrical opacities became vague and one developed an oil cyst and coarse calcifications. The only nonoperated speculated mass developed a typical small radiolucent oil cyst in the centre. US follow-up showed that 18 of the 29 increased subcutaneous tissue echogenicity turned back to normal, while in the remaining 11 small cysts formed. In 19 solid appearing masses, 15 showed decrease in size, while four remained stable (biopsy disclosed fat necrosis). The four complex masses in two patients showed increase in size and appeared more cystic (FNAB was consistent with fat necrosis).

CONCLUSION

a spectrum of imaging findings is associated with fat necrosis. Knowledge of the mammographic and US appearance and evolution of these patterns may enable imaging follow-up of these lesions, reducing the number of unnecessary biopsies.

Improving the dosimetric coverage of interstitial high-dose-rate breast implants

PURPOSE/OBJECTIVE

We performed a retrospective computed tomography (CT)-based three-dimensional (3D) dose-volume analysis of high-dose-rate (HDR) interstitial breast implants to evaluate the adequacy of lumpectomy cavity coverage, and then designed a simple, reproducible algorithm for dwell-time adjustment to correct for underdosage of the lumpectomy cavity.

METHODS AND MATERIALS

Since March 1993, brachytherapy has been used as the sole radiation modality after lumpectomy in selected protocol patients with early-stage breast cancer treated with breast-conserving therapy. In this protocol, all patients received 32 Gy in 8 fractions of 4 Gy over 4 days. Eleven patients treated with HDR brachytherapy who underwent CT scanning after implant placement were included in this analysis. For each patient, the postimplant CT dataset was transferred to a 3D treatment planning system, and the relevant tissue volumes were outlined on each axial slice. The implant dataset, including the dwell positions and dwell times, were imported into the 3D planning system and then registered to the visible implant template in the CT dataset. The calculated dose distribution was analyzed with respect to defined volumes via dose-volume histograms. Due to the variability of lumpectomy cavity coverage discovered in this 3D quality assurance analysis, dwell times at selected positions were adjusted in an attempt to improve dosimetric coverage of the lumpectomy cavity. Using implant data from 5 cases, a dwell-time adjustment algorithm was designed and was then tested on 11 cases. In this algorithm, a point P was identified using axial CT images, which was representative of the underdosed region within the cavity. The distance (d) from point P to the nearest dwell position was measured. A number of dwell positions (N) nearest to point P were selected for dwell time adjustment. The algorithm was tested by increasing the dwell times of a variable number of positions (N = 1, 3, 5, 7, 10, and 20) by a weighting factor (alpha), where alpha = f(d) and alpha > 1, and subsequently performing 3D dose-volume analysis to evaluate the improvement in lumpectomy cavity coverage.

RESULTS

Before adjustment in the 11 implants, the median proportion of the lumpectomy cavity and target volume that received at least the prescription dose was 85% and 68%, respectively. After dwell-time adjustment, lumpectomy cavity coverage was significantly improved in all 11 cases. The median distance from point P to the nearest dwell position (d) was 1.4 cm (range 0.9-1.9). The median volume of the lumpectomy cavity receiving 32 Gy increased from 85.3% in the actual implant to 97.0% (range 74-100%) by increasing the dwell time of a single dwell position by a median factor (alpha) of 12.2 according to the above algorithm. With N = 3, the median proportion of the cavity volume receiving 32 Gy was improved to 97.5% (range 77-100%), with a median alpha of 5.7. Further improvement in lumpectomy cavity coverage was relatively small by increasing additional dwell times. In addition, with N = 20, the median absolute volume of breast tissue receiving 150% of the prescription dose was 70.3 cm3 compared to 26.3 cm3 in the actual implant; whereas with N = 1 or N = 3, this median volume was only 35.9 and 42.0 cm3, respectively.

CONCLUSION

Lumpectomy cavity coverage sometimes appears suboptimal with interstitial HDR breast brachytherapy using our current technique. A simple dwell-time increase at only 1-3 dwell positions can compensate for some underdosage without creating significant regions of overdosage. Using simple methodology, a single reference point representing the underdosed region can be utilized for initial selection of the dwell positions to be increased.

Positron emission tomography in breast cancer: a clinicopathological correlation of results

We conducted a retrospective study to evaluate the sensitivity, specificity and accuracy of positron emission tomography (PET) scans in 109 patients with primary recurrent or metastatic breast cancer. All patients had a PET scan, X-ray or CT scan of the chest, an ultrasound or CT scan of the liver and a bone scan. Mammography was available for 86 patients. Correlation between the PET scan result and histological findings were made. The sensitivity, specificity and accuracy of the PET scan were calculated for both the primary tumour (T) and lymph nodes (N). In patients with metastasis (M) the accuracy of the PET scan was compared with other imaging modalities. Histological results of the site in question were available in only 105 patients. Information for the primary tumour was available for 93 patients and for nodes in 74. The PET scan was accurate in 89.2% for (T), with 3.2% false positive and 7.6% false negative. For (N) the PET scan was accurate in 90.5% with 9.5% false negative. In the 86 patients who underwent both mammography and PET scanning, the PET scan was more accurate in 89.5% versus 72% (p = 0.0003). In the 19 patients with metastasis, the PET scan was in agreement with other imaging modalities in 100% of cases. PET scanning is the only non-invasive imaging procedure that will detect tumours in the breast, lymph nodes, lung, liver, bone and bone marrow with high sensitivity, specificity and accuracy. It is a valuable tool in the management of patients in all stages of breast cancer for diagnosis, staging and following treatment response.

Fat necrosis following breast reduction

Between 1984 and 1992, 300 patients underwent breast reduction in our unit. Three patients during the follow-up period were found to have a palpable mass in their breast. Excision biopsy revealed fat necrosis of the breast. The clinical, radiological and pathological features of fat necrosis of the breast are described.

Breast cellulitis after conservative surgery and radiotherapy

PURPOSE

Cellulitis is a previously unreported complication of conservative surgery and radiation therapy for early stage breast cancer. Patients who presented with breast cellulitis after conservative therapy are described.

METHODS AND MATERIALS

Eleven patients that developed cellulitis of the breast over a 38-month period of observation are the subject of this report. Clinical characteristics of patients with cellulitis and their treatment and outcome are reported. Potential patient and treatment-related correlates for the development of cellulitis are analyzed.

RESULTS

The risk of cellulitis persists years after initial breast cancer therapy. The clinical course of our patients was variable: some patients required aggressive, long-duration antibiotic therapy, while others had rapid resolution with antibiotics. Three patients suffered from multiple episodes of cellulitis.

CONCLUSION

Patients with breast cancer treated with conservative surgery and radiotherapy are at risk for breast cellulitis. Systematic characterization of cases of cellulitis may provide insight into diagnosis, prevention, and more effective therapy for this uncommon complication.

Clinical problems in follow-up of patients after conservative surgery and radiotherapy

Patients treated with conservative surgery and radiotherapy for early-stage breast carcinoma are at risk of developing an ipsilateral breast recurrence for a long period. Fortunately, few such patients present with an inoperable recurrence or simultaneous distant metastases. Salvage rates are high and may be improved by early detection. Although usually unambiguous, physical examination of the treated breast may reveal changes attributable to surgery and radiotherapy that can mimic a recurrent cancer. There also is substantial overlap in radiologic appearance between benign and malignant lesions. It may be necessary to perform a biopsy when there is a question of recurrence. Careful life-long follow-up of patients thus is a critical part of their care.

Radiation and other pathological changes in breast tissue after conservation treatment for carcinoma

Histological changes in breast tissue after radiotherapy were evaluated. Changes in tissue from 17 patients previously treated for breast cancer by surgery and radiotherapy were compared with those seen in a control group treated with surgery alone. Vascular and epithelial changes were seen only in tissue from patients who had received radiotherapy and, therefore, seemed to be relatively specific; stromal changes were seen in both groups and seemed, therefore, to be non-specific. Epithelial atypia is of particular importance as it may be severe and be confused with recurrent malignancy. The presence of other changes associated with radiotherapy, particularly those in vessels, should help to avoid such misdiagnosis.

Fat necrosis of the breast following lumpectomy and radiation therapy for early breast cancer

Between January 1980 and December 1985, 121 patients with early breast cancer were treated in the Department of Radiation Oncology at Westmead Hospital by external beam irradiation and an iridium wire boost following "lumpectomy". After a median follow-up of 26 months, 14 patients have developed recurrent masses in the treated breast. In four, recurrent carcinoma was strongly suspected and subsequently confirmed by fine needle aspiration biopsy, but in only two was a subsequent salvage mastectomy possible. The remaining 10 patients developed a nodule which was usually tender. With three exceptions, the nodule was at the primary tumour site and developed 4-43 months after treatment. In seven, tumour recurrence was suspected but not confirmed by biopsy and the other three were accepted as having post-treatment "radiation fibrosis". Excision biopsy was undertaken in eight of the 10 patients. Another patient underwent partial mastectomy for presumed local recurrence. The histological appearance in all cases was similar, with areas of fat necrosis and fibrosis with atypical stromal fibroblasts. Suture material was present microscopically in eight patients and was noted macroscopically (that is, by mammogram) in the one patient who did not undergo surgery. This complication is most likely caused by a combination of surgical and radiation factors. The difficulty in management is differentiation between tumour recurrence and a benign condition.

New lumps in the breast following conservation treatment for early breast cancer

A new lump in the breast following conservation treatment for early breast cancer may represent a recurrence of the disease or may be a benign lesion. Clinical evaluation of these lumps is often extremely difficult and, potentially, mammography would seem to be of great importance in the assessment. Between November 1981 and March 1986, 214 patients with operable breast cancers of 4 cm or less in diameter underwent conservative treatment. The conservation technique comprised synchronous excision of the primary tumour without a wide margin, axillary clearance, interstitial irradiation with iridium 192 (2000 cGy), and subsequent external beam radiotherapy to the breast (4600 cGy). After an average follow-up of 26 months, 17 patients developed a new lump in the treated breast necessitating further biopsy. Seven of these were malignant and 10 benign. In the latter category the most frequent finding was fat necrosis. Clinically, the lesions were indistinguishable from each other. The mammographic signs, which best predicted malignancy, were either of a mass or of a malignant type of microcalcification. This study illustrates the problems associated with deciding the nature of a new lump in the breast following conservation treatment. Mammography is complementary to physical examination, and a base-line mammogram six months after completion of therapy is helpful. Despite the use of mammography, biopsy is the only definitive way of excluding recurrence.