A Retrospective Study on the Clinicopathologic Characteristics and Outcomes of 179 Cases of Synchronous and Metachronous Bilateral Breast Cancer in China

OBJECTIVE

To investigate the clinicopathologic characteristics and outcome of bilateral breast cancer (BBC) in the Chinese population.

METHODS

A retrospective study was conducted on 7797 cases with primary breast cancer, including 7618 cases of unilateral breast cancer (UBC) and 179 cases of BBC. Among the latter, there were 108 cases of synchronous BBC (SBBC) and 71 cases of metachronous BBC (MBBC).

RESULTS

In the present study, the incidence of SBBC and MBBC are 1.39% and 0.91% among the general population, respectively. In comparison of UBC and BBC, SBBC and MBBC, there are significant differences in the common clinicopathological characteristics, such as pathologic stage, hormone receptor (HR) status and molecular type. In respect of the surgical treatment of BBC, 49.72% of the patients chose mastectomy. The 3-year disease free survival (DFS) for SBBC and MBBC are 94.4% and 96.9%, respectively. There is no difference in the overall survival (OS) and DFS between SBBC and MBBC. The histological grade and type of surgery on tumors of both sides are important influencing factors of DFS in the BBC patients.

CONCLUSION

There are statistical differences in the clinicopathological characteristics and outcomes between SBBC and MBBC among the Chinese population. Therefore, the treatment of BBC patients should be individualized.

Bilateral breast cancer in China: A 10-year single-center retrospective study (2006-2016)

Bilateral breast cancer (BBC) is an uncommon subset of breast cancer (BC), and it may present as synchronous bilateral breast cancer (sBBC) or metachronous bilateral breast cancer (mBBC). Through this study, we aimed to evaluate the proportion of BBC in BC and compare the clinicopathological characteristics, treatment, and outcomes of sBBC and mBBC at an academic cancer center in China. Patients with BC consecutively treated between 2006 and 2016 were retrospectively reviewed. Patients with BBC were included. In total, 3924 patients with BC were analyzed and 127 patients with BBC (28 sBBC, 99 mBBC) with a median follow-up of 98 months were identified. The proportion of BBC was 3.2% (0.7%, sBBC; 2.5%, mBBC). The median age at the first diagnosis of mBBC was significantly younger than that at the first diagnosis of sBBC (p = 0.027). Patients diagnosed as having sBBC were more likely to have a positive family history (p = 0.047). The first tumors of mBBC were detected at a significantly earlier tumor stage compared with those of sBBC (p = 0.028). The concordance rates of histopathologic type in the first and second tumors were 60.7% and 58.0% in sBBC and mBBC, respectively. sBBC had a significantly poorer disease-free survival than mBBC did (p = 0.001). BBC is a rare disease affecting the Chinese population. sBBC is associated with a greater prevalence of a family history of breast cancer and poorer prognosis, compared with mBBC.

Distribution of tumor subtypes in bilateral breast cancer: Comparison between synchronous and metachronous cancer

AIM

This study was performed to evaluate patterns of breast cancer subtypes in Korean patients with synchronous (SBC) or metachronous bilateral breast cancer (MBC).

METHODS

We retrospectively reviewed records of 302 patients with SBC (n = 161) or MBC (n = 141) who received curative surgery at our hospital between 1995 and 2013. Expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) was determined by immunohistochemistry (IHC) staining. We categorized breast cancers into the following subtypes: ER+ or PR+, HER2- (i.e., luminalA); ER+ or PR+, HER2+ (i.e., luminalB HER2+); ER-, PR- and HER2+ (i.e., HER2-enriched); ER-, PR- and HER2- (i.e., triple negative, TN).

RESULTS

More patients with MBC were ≤40 years at the time of breast cancer diagnosis than patients with SBC (34.6% vs. 19.3%, P < 0.01). The proportion of subtypes in SBC and MBC were as follows: luminalA, 65.8% vs. 45.0%; luminalB, HER2+, 9.0% vs. 8.5%; HER2-enriched, 4.1% vs. 12.1%; and TN, 11.2% vs. 31.2%, respectively (P < 0.01). The 10-year overall survival rate in patients with SBC and MBC was 89.0% and 93.6%, respectively. The 10-year disease-free survival rate in patients with SBC and MBC was 79.6% and 80.9%, respectively. Locoregional recurrence was found in 2.5% of patients with SBC and 9.9% of patients with MBC. Distant metastasis occurred in 8.7% of patients with SBC and 4.9% of patients with MBC.

CONCLUSION

The distribution of breast cancer subtypes was different between SBC and MBC. TN-subtype was profoundly more frequent in MBC whereas luminal-subtype was most frequently found among SBC.

Breast cancer with an intraductal component that was proven genetically to be metastasis of contralateral breast cancer: a case report

Background

When diagnosing patients with bilateral breast cancer, it is challenging to determine the relationship between multiple breast cancer lesions at the individual patient level with certainty.

Case presentation

A 35-year-old Japanese woman was diagnosed with a left breast cancer. She was previously diagnosed with right pT3N3M0 stage IIIC breast cancer and underwent chemotherapy with targeted therapy, radiotherapy, and endocrine therapy as adjuvant treatment after mastectomy and axillary lymph node dissection. Approximately 2 years after the first surgery, her left breast cancer was preoperatively diagnosed as a contralateral primary breast cancer, and left mastectomy and axillary lymph node dissection were performed. Histopathologically, the tumor was determined to be invasive ductal carcinoma accompanied with several intraductal components. After a second surgery, mutation analysis of her bilateral breast cancer was performed in a clinical study, which revealed that her metachronous bilateral breast tumors had the same GATA3 and CSMD1 mutations. Thus, mutation analysis strongly supported her latter left breast cancer being a metastatic lesion from the former right breast cancer. Some difficulties in diagnosing bilateral breast cancer exist when determining whether they are double primary cancers or represent contralateral breast metastasis. The existence of intraductal components is a critical piece of information for suspecting primary lesions. However, this case demonstrated that metastatic contralateral breast lesions can have intraductal components.

Conclusion

Herein we report a genetically proven contralateral breast metastasis with some intraductal components.

Concordance of Hormone Receptor Status and BRCA1/2 Mutation Among Women With Synchronous Bilateral Breast Cancer

Goals: BRCA1/2 mutations are associated with bilateral breast cancer. The extent of concordance between synchronous bilateral breast cancer (SBBC) tumors with respect to hormone receptor expression and BRCA1/2 mutations is unknown. We investigated the distribution of BRCA1/2 mutations and bilateral estrogen receptor (ER) status in SBBC. Methods: A retrospective analysis was performed on 15,337 patients with primary breast cancer who underwent surgical treatment at the Fudan University Shanghai Cancer Center between 2007 and 2014. We included 163 patients with synchronous bilateral breast cancer who had germline BRCA1/2 mutations testing. BRCA1/2 pathogenic/likely pathogenic mutations and other clinicopathological characteristics were studied in further analyses. Results: Patients with SBBC developed breast cancer at an older age and had a higher rate of ER positivity than patients with UBC (p < 0.001, separately). In contrast, 14.1% of SBBC patients had carcinomas with a lobular component in either breast based on pathological reports (p < 0.001). Twelve patients had BRCA1 mutations, and 14 patients had BRCA2 mutations, while no patients had mutations in both genes. The BRCA1/2 mutation rate was higher in younger patients (23.4 vs. 11.1%, p = 0.036). SBBC patients with a family history of breast cancer or bilateral ER-negative disease had a higher frequency of BRCA1/2 mutations than the cohort without a history of these conditions. SBBC with a bilateral ER-discordant status had a very low frequency of BRCA1/2 mutations (5.6%). Patients with an ER-positive (concordant or discordant) status had better 3-year disease-free survival than patients with a concordant ER-negative status (HR = 0.324, 95% CI: 0.126-0.837, P = 0.020). However, the outcomes were similar during long-term follow-up. Pathological lymph node stage was the only prognostic factor for SBBC in both univariate and multivariate Cox analyses. Conclusions: Our study shows that Chinese women with SBBC have different characteristics from their UBC counterparts. SBBC patients with a younger age, family history of breast cancer, or bilateral ER-negative disease are more likely to have BRCA1/2 mutations. SBBC patients with a concordant ER-negative status had worse early outcomes. Our results suggest that there may be additional factors underlying the tumor biology and genetics of SBBC.

Whole Exome Sequencing in the Accurate Diagnosis of Bilateral Breast Cancer: a Case Study

When faced with a case of bilateral breast cancer (BBC), understanding how to differentiate bilateral primary breast cancer from contralateral metastatic breast cancer is essential for treatment, but clear identification criteria have not been established to date. Diverse events play different roles in the therapy and prognosis of BBC; hence, it is of great significance to detect a more comprehensive and convincing technique to make an accurate differential diagnosis. We report a rare case of synchronous BBC in a 61-year-old Chinese woman. Based on her clinical and pathological features and the use of whole exome sequencing and cancer genome analysis, we concluded that the patient developed contralateral metastatic breast cancer which metastasized from left to right. Therefore, together with clinical, pathological and cancer genomics information, we could precisely define the origin and evolution of BBC.

Functional recovery after bilateral extended autologous latissimus dorsi breast reconstruction: A prospective observational study

BACKGROUND

The impact of unilateral extended autologous latissimus dorsi (EALD) flap harvest and axillary surgery on shoulder function has been well described, but the impact of bilateral EALD flap harvest has not been clearly defined nor is it clear whether reconstructions should be synchronous or staged.

METHODS

In this prospective observational study, patients undergoing bilateral EALD breast reconstruction (February 2003-December 2009) completed the disability, arm, shoulder and hand (DASH) questionnaire preoperatively and at five post-operative timepoints. Intensive shoulder physiotherapy was offered to those whose DASH score was >30 at 6 weeks or >20 at 12 weeks post-operatively.

RESULTS

Sixty patients underwent bilateral EALD flap breast reconstruction (51 synchronous, 9 metachronous). Patients with pre-existing shoulder pathology (n = 1) and those who failed to return any post-operative DASH questionnaire (n = 10) were excluded from initial DASH analysis. However, these eleven patients were included in a separate analysis as an intention-to-treat analysis. Statistical analysis was performed using non-parametric, Friedman test and multiple comparison model. Forty-nine patients' DASH scores were analysed. DASH score initially increased after surgery and then returned to functionally normal within 3-6 months (median DASH: preoperative = 1 vs 6 weeks post-operation = 26, p = <0.001; vs 3 months = 19, p = <0.001; vs 6 months = 13, p = <0.001); thereafter, the scores remained less than 12 (p = <0.001). Median DASH score after synchronous reconstruction was not higher than that after metachronous reconstructions, although the metachronous sample size was small.

CONCLUSION

With appropriate patient selection and intensive physiotherapy, bilateral EALD breast reconstruction does not appear to cause significant long-term impairment of shoulder function, and patients can now be counselled about the likely timecourse of shoulder recovery. There seems no reason to stage bilateral reconstruction to reduce shoulder morbidity.

pCR rates in patients with bilateral breast cancer after neoadjuvant anthracycline-taxane based-chemotherapy - A retrospective pooled analysis of individual patients data of four German neoadjuvant trials

PURPOSE

Patients with bilateral breast cancer (BBC) are usually excluded from participating in clinical trials and little is known about the response and outcome of BBC to neoadjuvant chemotherapy compared to unilateral BC (UBC).

METHODS

We prospectively captured the information on patients with BBC in our database treated within four neoadjuvant chemotherapy trials and collected retrospectively the rate of pathological complete response (pCR) defined as ypT0 ypN0, ypT0/is ypN0, ypT0 ypNX, clinical and histologic parameters. Synchronous carcinoma in the contralateral breast was considered as the non-indicator lesion. Patients with UBC only treated within the same neoadjuvant trials performed the control group.

RESULTS

From the 6727 patients treated within 4 German neoadjuvant trials 119 (1.8%) patients have been identified with the diagnosis of BBC. The pCR rate (ypT0 ypN0) was 12.6% in the non-indicator lesion group versus 10.9% the indicator lesion group versus 20.9% for patients with unilateral disease (p = 0.003). There were more advanced tumor stages and positive axillary lymph nodes in the indicator lesion than in the nonindicator lesion or in UBC. In 52.5% the molecular subtype was identical between indicator and non-indicator lesion with more triple negative and HER2 positive BC in the group of UBC. The disease free survival rate (DFS) was 25.8% for patients with UBC versus 39.6% for patients with BBC.

CONCLUSION

The selection for the indicator lesion was based on tumor size, nodal status and inclusion criteria. Patients with BBC patients had a lower pCR rate and a lower DFS.

[Synchronous bilateral breast cancer in Morocco: epidemiological and clinical characteristics]

Préciser la fréquence, les facteurs de risque et le pronostic du cancer du sein bilatéral, à partir d'une étude rétrospective de 22 cas de cancer du sein bilatéral synchrone dans un pays du Maghreb. De 2002 à 2010, 625 patientes étaient prises en charge pour cancer du sein au service de Gynécologie-Obstétrique «C» du centre hospitalier universitaire de Casablanca. 22 cas de cancer bilatéral synchrone étaient diagnostiqués. Nos résultats sont comparés avec ceux de la littérature. La fréquence de la bilatéralité du cancer du sein synchrone était de 3,52% (22/625). L'intervalle de temps moyen entre les deux cancers est de 4 mois (0 à 6 mois). Les patientes âgées de moins de 40 ans lors du premier cancer avaient six fois plus de risque de développer un cancer au niveau du sein controlatéral que les femmes âgées de plus de 40 ans. Les patientes atteintes d'une tumeur T3 ou T4 avaient un risque neuf fois plus élevé que les autres. 90,9% (2/22) des cas des premiers cancers sont des adénocarcinomes infiltrants. Les types histologiques du premier et du douzième cancer étaient identiques dans 86,4% (19/22) des cas. Quant au pronostic, il dépend à la fois du stade du premier et du deuxième cancer et le traitement de ce dernier doit obéir aux mêmes règles du traitement du premier cancer. L'incidence du cancer bilatéral synchrone du sein est de 3,52% dans notre série. Le cancer du sein unilatéral constitue un facteur de risque de développement d'un cancer du sein controlatéral. Une surveillance à vie est nécessaire au cours d'un cancer du sein pour détecter un cancer controlatéral.

Are bilateral breast cancers and breast cancers coexisting with ovarian cancer different from solitary tumors? A pair-matched immunohistochemical analysis aimed at intrinsic tumor phenotype

Patients with bilateral breast cancer (BBC) and breast-ovarian cancer syndrome (BOCS) constitute populations potentially enriched for molecular defects involved in the pathomechanisms of these malignancies. The aim of our study was to compare tumor morphology and expression of estrogen and progesterone receptor, HER2, Ki67, cytokeratin 5/6, E-cadherin, vimentin and epidermal growth factor receptor in tissue microarrays from 199 tumors from BBC or BOCS patients and 199 age-matched solitary tumors. Compared to controls, BBC and BOCS considered jointly had lower incidence of DCIS, lower expression of PgR and HER2, and higher expression of Ki67 and vimentin. BOCS tumors were of higher grade, had lower expression of ER and PgR and higher expression of Ki67, CK5/6, vimentin and EGFR. BBC had less DCIS component, lower HER2 expression and higher Ki67 expression. Metachronous BBC (mBBC) had lower expression of ER, PgR and HER2, and higher expression of Ki67 and vimentin. Synchronous BBC (sBBC) had less DCIS component, higher expression of ER, and lower expression of CK5/6, EGFR and E-cadherin. BBC and breast cancers in BOCS differ in many aspects from solitary tumors. BBC are a heterogeneous group of tumors, differing between sBBC and mBBC. mBBC phenotype shares many features with BOCS tumors.

Is symptom-oriented follow-up still up to date?

The main objective of following patients after the primary treatment of breast cancer is the detection of potentially curable events, particularly the detection of local recurrences and contralateral breast cancer. Additionally, medical counseling on therapies, psychosocial aspects, side effects of therapies, and lifestyle interventions is important to improve the quality of life. There is an ongoing discussion about whether early detection of asymptomatic metastasis could improve the course of disease. Today, the follow-up is still symptom-orientated. Intensified imaging and laboratory check-ups have not been beneficial for the patients' survival. A follow-up in the first 2-3 years is recommended every 3 months. Because of the decreasing incidence of recurrence from year 4, 6-monthly screening intervals are recommended. The screening should include a history, physical examination, and a consultation. Routine diagnostic imaging - except for mammography/ultrasound - is not indicated in asymptomatic patients. Innovative therapies for patients with metastatic breast cancer have been introduced. Therefore, measures of an intensified follow-up could change in the future as novel endocrine combination or targeted therapies in molecular subtypes could significantly improve the survival in early detected metastasis. In the future, more individualized follow-up programs are conceivable. However, this idea is so far not supported by the available data.

Incidence of occult contralateral carcinomas of the breast following mastoplasty aimed at symmetrization

INTRODUCTION

Breast carcinomas are the most frequent form of cancer in French women. Following a total mastectomy, only an estimated 25% of patients wish to undergo breast reconstruction. After mammary volume reconstitution, the plastic surgeon often attempts to harmonize the two breasts by carrying out contralateral reduction mammaplasty (CRM). In the literature, the incidence of occult contralateral carcinomas incidentally discovered in surgical specimens ranges from 1.12 to 4.5%. The main objective of this study was to evaluate occurrence of carcinoma in the CRM specimens in the framework of a breast reconstruction operation. The secondary objective was to determine the consequences of the incidentally discovered carcinoma in the contralateral breast.

MATERIAL AND METHODS

This was a 6-year, bicentric, retrospective study involving women having undergone breast cancer surgery who later underwent contralateral reduction mammaplasty (CRM), that is to say reconstruction aimed at harmonization of the two breasts.

RESULTS

Three hundred and nineteen patients were included in the study. Mean age during the CRM was 55years (29-79). Mean weight of the surgical specimens was 323grams (12-2500). Incidence of occult carcinomas found in the specimens was 0.94% (3 patients). The mean age for these 3 cases was 58years (47-64). All 3 patients had superior pedicle mammaplasty. One of the patients benefited from monobloc resection with orientation of the surgical specimen. In the other 2 cases, there existed 3 surgical resection specimens; in one case, they were oriented; in the other, they were not. In all 3 cases, the histological findings were unifocal ductal carcinomas in situ (DCIS). Mean tumor size was 5.7mm (3-9). Only the patient having had monobloc resection with orientation of the specimen underwent salvage surgery, which consisted in partial mastectomy, otherwise known as secondary lumpectomy. Adjuvant radiotherapy was administered to all of the patients. After 17months of mean follow-up (12-22), no recurrence was found in any of the three cases.

CONCLUSION

Incidence of occult contralateral breast carcinomas after symmetrization CRM approximates 1%. Our observations are in agreement with the data in the literature. Incidence is greater than in mammaplasty carried out for esthetic or functional reasons; this is probably due to the higher age and the previous breast cancer history of the breast reconstruction population. Monobloc resection and orientation of the surgical specimens with surgeon's knots facilitate precise pinpointing of the occult carcinoma. A secondary lumpectomy may take place when margins of excision are invaded or inadequate.

Histo-biological comparative analysis of bilateral breast cancer

Bilateral breast cancer occurs in approximately 7% of surviving breast cancer patients. However, a dilemma exists concerning the notion of whether this represents a de novo second primary tumor versus a breast metastasis. We analyzed 81 patients with bilateral breast cancer, 47 (58%) synchronous tumors and 34 (42%) metachronous tumors. Additionally, charts were reviewed for age, family history, full histology data and biological receptors. We found there were no significant differences in concordance between the first and second primary tumors (in both synchronous and metachronous bilateral breast cancer) with respect to histology; grade; T-category; N-category; ER, PR and HER-2 status. In addition, there was no significant difference in the strength of correlation between ER and PR in the first and secondary primary tumors. Our findings suggest that the differentiation of the origin of contralateral breast cancer based on routine histological and biological concordance is inconclusive. Furthermore, the dilemma will continue to exist until additional molecular approaches are applied routinely for research purposes to resolve the debate.

Histo-biological comparative analysis of bilateral breast cancer

Bilateral breast cancer occurs in approximately 7% of surviving breast cancer patients. However, a dilemma exists concerning the notion of whether this represents a de novo second primary tumor versus a breast metastasis. We analyzed 81 patients with bilateral breast cancer, 47 (58%) synchronous tumors and 34 (42%) metachronous tumors. Additionally, charts were reviewed for age, family history, full histology data and biological receptors. We found there were no significant differences in concordance between the first and second primary tumors (in both synchronous and metachronous bilateral breast cancer) with respect to histology; grade; T-category; N-category; ER, PR and HER-2 status. In addition, there was no significant difference in the strength of correlation between ER and PR in the first and secondary primary tumors. Our findings suggest that the differentiation of the origin of contralateral breast cancer based on routine histological and biological concordance is inconclusive. Furthermore, the dilemma will continue to exist until additional molecular approaches are applied routinely for research purposes to resolve the debate.

A population perspective to mitigating risk for second primary breast cancer

SUMMARY There are more than 2 million breast cancer survivors in the USA. Approximately 5–10% of survivors will develop a second, metachronous breast cancer within 10 years’ time; a risk two- to six-times higher than that in the general population. Women who develop metachronous cancer are more likely to die from the disease compared with women with unilateral cancer. Risk factors for metachronous cancer include BRCA mutation status, young age, family history and tumor phenotype, while adjuvant chemotherapy and endocrine therapy may attenuate the risk. Surveillance guidelines recommend annual mammography, but MRI is not currently indicated for most women. An increasing number of women are choosing prophylactic contralateral mastectomy, although it is not likely to be beneficial for most women. Improved strategies are needed for identifying survivors at an increased risk in order to help guide clinical decisions regarding follow-up care. This review presents an overview of the burden and risk factors for metachronous breast cancer and discusses challenges and opportunities for a population approach to mitigating risk and adverse outcomes from these cancers.

Prognostic implications of estrogen receptor pattern of both tumors in contralateral breast cancer

Estrogen receptor (ER) status is important for breast cancer survival, it is however unclear how prognosis of contralateral breast cancer (CBC) is affected by ER-status of the two tumors. We conducted a large, population-based study of ER-status of both tumors in CBC patients and its influence on prognosis. The cohort consisted of all women diagnosed with CBC in Stockholm, Sweden during 1976-2005, with information on ER-status from medical records (N = 933). Prognosis was modeled as incidence rates of distant metastasis via Poisson regression. The proportion of CBCs with both cancers of the same ER-status was significantly larger than expected by chance. For synchronous (simultaneous) cancers the prognosis was significantly affected by the combined ER-status of both tumors (p = 0.01). Compared to unilateral breast cancer patients the incidence rate ratio (IRR) for patients with double ER-positive tumors was 1.25 (95 % CI: 0.88-1.76), for ER-discordant tumors 2.19 (95 % CI: 1.18-4.08) and for double ER-negative tumors 3.95 (95 % CI: 1.77-8.81). For metachronous (non-simultaneous) cancers, women with double ER-positive tumors had similarly bad prognosis (IRR = 2.95; 95 % CI: 2.39-3.64) as women with double ER-negative tumors (IRR = 2.88; 95 % CI: 1.83-4.52). Both shorter time span between first and second cancer and endocrine therapy for the first cancer further worsened prognosis of women with double ER-positive metachronous CBC. For synchronous CBC patients, ER-pattern of both tumors is an important prognosticator, while among metachronous CBC patients, double ER-positive tumors confer equally bad prognosis as double ER-negative cancers. Our results indicate that this might be due to endocrine therapy resistance.

Prognosis of metachronous contralateral breast cancer: importance of stage, age and interval time between the two diagnoses

Studies comparing the prognosis after contralateral breast cancer (CBC) with that after unilateral breast cancer (UBC) shows conflicting results. We assessed the risk of breast cancer-specific death for women with metachronous CBC compared to those with a UBC in 8,478 women with invasive primary breast cancer registered in the Guy's and St. Thomas' Breast Cancer Tissue and Data Bank. Risk factors associated with breast cancer-specific death for women with CBC were estimated using Cox proportional hazards modelling. Prognoses after UBC and CBC were compared, with survival time for women with CBC calculated: (i) from CBC, (ii) from the initial cancer with CBC as a time-dependent covariate. Women diagnosed with CBC within 5 years after the initial primary breast cancer had a worse prognosis than those with CBC after 5 years and those with UBC. Women with CBC who had positive lymph nodes at the initial breast cancer diagnosis were at an increased risk of dying from breast cancer compared to those without [HR 2.5 (95% CI 1.5-4.0)]. For all stages of the initial breast cancer, a worse prognosis was observed after CBC. CBC increased the hazard originating from the initial cancer at any follow-up time, but the highest hazards were associated with a short interval to CBC. Metachronous CBC adds to the risk of dying from breast cancer. The risk increases substantially when it occurs shortly after the initial cancer, indicating a CBC in some instances may be an indicator of active distant disease. The occurrence of CBC implies a new surveillance and therapeutic situation.

Electron arc therapy for bilateral chest wall irradiation: treatment planning and dosimetric study

AIMS

The treatment of patients with synchronous bilateral breast cancer is a challenge. We present a report of dosimetric data of patients with bilateral chest walls as the target treated with electron arc therapy.

MATERIALS AND METHODS

Ten consecutive patients who had undergone electron arc therapy to the bilateral chest wall for breast cancer were analysed. After positioning and immobilisation, patients underwent computed tomography scans from the neck to the upper abdomen. Electron arc plans were generated using the PLATO RTS (V1.8.2 Nucletron) treatment planning system. Electron energy was chosen depending upon the depth and thickness of the planning target volume (PTV). For all patients, the arc angle ranged between 80 and 280° (start angle 80°, stop angle 280°). The homogeneity index, coverage index and doses to organs at risk were evaluated. The patient-specific output factor and thermoluminescence dosimetry (TLD) measurements were carried out for all patients. The total planned dose to the PTV was 50Gy/25 fractions/5 weeks.

RESULTS

The mean PTV (± standard deviation) was 568.9 (±116)cm(3). The mean PTV coverage was 89 (±5.8)% of the prescribed dose. For the right lung, the mean values of D(1) and D(10) were 46 (±7.6) and 30 (±9)Gy, respectively. For the left lung, the mean values of D(1) and D(10) were 45 (±7) and 27 (±8)Gy, respectively. For the heart, the mean values of D(1), D(5) and D(10) were 21 (±15), 13.5 (±12) and 9 (±9)Gy, respectively. The mean values of TLD at various pre-specified locations on the chest wall surface were 1.84, 1.82, 1.82, 1.89 and 1.78Gy, respectively

CONCLUSION

The electron arc technique for treating the bilateral chest wall is a feasible and pragmatic technique. This technique has the twin advantages of adequate coverage of the target volume and sparing of adjacent normal structures. However, compared with other techniques, it needs a firm quality assurance protocol for dosimetry and treatment delivery.