Irradiation with standard tangential breast fields in patients treated with conservative surgery and sentinel node biopsy: using a three-dimensional tool to evaluate the first level coverage of the axillary nodes

Should the management of radiation therapy for breast cancer be standardized? Results of a survey on current French practices in breast radiotherapy

Background

Breast cancer is the most frequent cancer in women in France. Its management has evolved considerably in recent years with a focus on reducing iatrogenic toxicity. The radiotherapy indications are validated in multidisciplinary consultation meetings; however, questions remain outstanding, particularly regarding hypofractionated radiotherapy, partial breast irradiation, and irradiation of the internal mammary chain and axillary lymph node area.

Materials and methods

An online survey was sent to 47 heads of radiotherapy departments in France. The survey consisted of 22 questions concerning indications for irradiation of the supraclavicular, internal mammary and axillary lymph node areas; irradiation techniques and modalities; prescribed doses; and fractionation.

Results

Twenty-four out of 47 centers responded (response rate of 51%). This survey demonstrated a wide variation in the prescribed dose regimen, monoisocentric radiotherapy, and indications of irradiation of the lymph node areas.

Conclusion

This survey provides insight into the current radiotherapy practice for breast cancer in France. It shows the need to standardize practices.

Oncoplastic Breast-Conserving Surgery for Synchronous Multicentric and Multifocal Tumors: Is It Oncologically Safe? A Retrospective Matched-Cohort Analysis

Background

Oncoplastic surgery is a well-established approach that combines breast-conserving treatment for breast cancer and plastic surgery techniques. Although this approach already has been described for multicentric and multifocal tumors, no long-term oncologic follow-up evaluation and no comparison with patients undergoing mastectomy have been published. This study aimed to evaluate whether oncoplastic surgery is a safe and reliable treatment for managing invasive primary multicentric and multifocal breast cancer.

Methods

The study compared a consecutive series of 100 patients with multicentric or multifocal tumors who had undergone oncoplastic surgery (study group) with 100 patients who had multicentric or multifocal tumors and had undergone mastectomy (control group) during a prolonged period. The end points evaluated were disease-free survival (DFS), overall survival (OS), cumulative incidence of local recurrence (CI-L), regional recurrence (CI-R), and distant recurrence (CI-D), all measured from the date of surgery.

Results

The OS and DFS were similar between the two groups. The incidence of local events was higher in the oncoplastic group, whereas the incidence of regional events was slightly higher in the mastectomy group. These differences were not statistically significant. The cumulative incidence of distant events was similar between the two groups.

Conclusions

To the authors’ knowledge, the current study provides the best available evidence suggesting that the oncoplastic approach is a safe and reliable treatment for managing invasive multifocal and multicentric breast cancers.

Incidental axillary dose delivery to axillary lymph node levels I-III by different techniques of whole-breast irradiation: a systematic literature review

BACKGROUND AND OBJECTIVE

In breast cancer treatment, radiotherapy is an essential component for locoregional management. Axillary recurrence in patients with invasive breast carcinoma remains an issue. The question of whether breast irradiation may unintentionally include levels I, II, and III, and may decrease the risk of axillary recurrence, remains a topic of discussion.

PATIENTS AND METHODS

A literature search was performed in PubMed and the Cochrane Library to identify articles that have published data regarding dose-volume analysis of axillary levels in breast irradiation. The following MESH terms were used: "breast cancer/lymph nodes" AND "radiotherapy dosage."

RESULTS

Thirteen articles were identified. The irradiation technique, initial dose prescribed to the breast, delineated volumes, and dose received at axillary levels were heterogeneous. The average dose delivered to axilla levels I, II, and III with three-dimensional conformal radiotherapy using standard fields (ST) ranged between 22 and 43.5 Gy, 3 and 35.6 Gy, and 1.0 and 20.5 Gy, respectively. The average doses delivered to axilla levels I, II, and III with three-dimensional conformal radiotherapy using "high tangential" fields (HT) ranged between 38 and 49.7 Gy, 11 and 47.1 Gy, and 5 and 44.7 Gy, respectively. Finally, the average doses delivered to axilla levels I, II, and III using intensity-modulated radiation therapy (IMRT) were between 14.5 and 42.6 Gy, 3.4 and 35 Gy, and 1.2 and 25.5 Gy, respectively.

CONCLUSION

Our literature review suggests that the incidental dose delivered to the axilla during whole-breast irradiation is heterogenous and dependent on the irradiation technique used. However, whether this observation can be translated into a therapeutic effect is still a matter of debate.

Radiation dose to the low axilla in patients treated for early-stage breast cancer by locoregional intensity-modulated radiotherapy (IMRT)

PURPOSE

To determine the dose received by the low axilla during locoregional radiotherapy (RT) for early-stage breast cancer and to assess the impact of the treatment technique (three-dimensional conformal radiotherapy (3D-CRT) or rotational IMRT (VMAT) or helical tomotherapy (HT).

MATERIALS AND METHODS

The dosimetric study was performed on patients receiving normofractionated (NFRT - 50Gy in 25 fractions) or hypofractionated (HFRT - 40Gy in 15 fractions) locoregional radiotherapy (breast or chest wall and internal mammary, supraclavicular and infraclavicular nodes±axillary nodes) by 3D-CRT or VMAT or HT at the Institut Curie Paris. Patients treated by breast-conserving surgery received a boost dose of 16Gy and 10Gy to the tumour bed, respectively.

RESULTS

Sixty-eight patients treated by RT from February 2017 to January 2019 were studied. The mean dose received by the low axilla when it was not part of the target volume was 30.8Gy, 41.0Gy and 44.4Gy by 3D-CRT, VMAT and HT, respectively for NFRT and 24.2Gy, 33.0Gy and 34.9Gy, respectively, for HFRT. With NFRT, 4.1% of the axilla received 95% (V95) of the prescribed dose by 3D-CRT compared to 24.5% and 33.6% by VMAT and HT, respectively; with HFRT, V95 was 3.9%, 19.5% and 24.1%, respectively.

CONCLUSION

The axilla receives a non-negligible dose during locoregional radiotherapy; this dose is greater when VMAT or HT are used. Prospective studies must be conducted to assess the impact of this axillary dose in terms of morbidity, which currently remains unknown.

[Diffusion prophylactic axillary irradiation in breast cancer - Literature review]

PURPOSE

In breast cancer, radiotherapy is an essential component of the treatment. However, indications of irradiation of the internal mammary chain and axillary area are debatables. Axillary recurrence in patients with invasive breast carcinoma remains an issue. Currently, the substitution of axillary lymph node dissection by sentinel node biopsy leads to revisit the role of axillary irradiation. Breast irradiation including level I, II and III might decrease the risk of axillary recurrence.

MATERIAL AND METHODS

A literature search was performed in PubMed and the Cochrane library to identify articles publishing data regarding dose-volume analysis of axillary levels in breast irradiation aiming to determine the potential therapeutic implications.

RESULTS

Eleven articles were retained. A total of 375 treatment plans were analyzed. The results concerning the irradiation technique, initial dose prescribed to breast, delineated volumes and dose received at axillary levels were heterogeneous. The average dose delivered to axilla levels I-III with 3D-conformal radiotherapy using standard fields were between 24Gy and 43.5Gy, 3Gy and 32.5Gy and between 1.0Gy and 20.5Gy respectively. The average doses delivered to axilla levels I-III with 3D-conformal radiotherapy using high tangential fields were between 38Gy and 49.7Gy, 11Gy and 47.1Gy and 5Gy 38.7Gy, 32.1Gy and 5Gy (result available for only one study) respectively. Finally, the average doses delivered to axilla levels I-III with intensity modulated radiation therapy were between 14.5Gy and 42.6Gy, 3.4Gy and 35Gy and between 1.2Gy and 25.5Gy respectively.

CONCLUSIONS

Incidental axillary dose seems insufficient to be therapeutic regardless of the irradiation technique. There are meaningful differences between intensity modulated radiation therapy and 3D-conformal radiotherapy.

Acute toxicity outcomes and dosimetric implications from incidental irradiation of adjacent tissues in tangent field hypofractionated breast radiotherapy

PURPOSE

Adjacent tissues-in-beam (TIB) may receive substantial incidental doses within standard tangent fields during hypofractioned whole breast irradiation (HF-WBI). To characterize the impact of dose to TIB, we analyzed dosimetric parameters of TIB and associated acute toxicity.

MATERIALS AND METHODS

Plans prescribed to 40.5 Gy/15 fractions from 4/2016-1/2018 were evaluated. Structures of interest were contoured: (1) TIB: all tissues encompassed by plan 30% isodose lines, (2) breast, (3) non-breast TIB (nTIB): TIB minus contoured breast. Volumes of TIB, breast, and nTIB receiving 100%-107% of prescription dose (V100-V107) were calculated. Twelve patient- and physician-reported acute toxicities were prospectively collected weekly. Correlations between volumetric and dosimetric parameters were assessed. Uni- and multivariable logistic regressions evaluated toxicity grade changes as a function of TIB, breast, and nTIB V100-V107 (in cm3).

RESULTS

We evaluated 137 plans. Breast volume was positively correlated with nTIB and nTIB V100 (rho = 0.52, rho = 0.30, respectively, both p < 0.001). V107 > 2 cm3 were noted in 14% of breast and 21% of nTIB volumes. On multivariable analyses, increasing breast and nTIB V100 significantly raised odds of grade 2+ dermatitis and burning/twinging pain, respectively; increasing nTIB V105 elevated odds of hyperpigmentation and burning pain; and increasing nTIB V107 raised odds of burning pain. Threshold volumes for >6-fold odds of developing burning pain were TIB V105 > 100 cm3 and V107 > 5 cm3.

CONCLUSIONS

For HF-WBI, doses to nTIB over the prescription predicted acute toxicities independent of breast doses. These data support inclusion of TIB as a region of interest in treatment planning and protocol design.

Breast-conserving surgery followed by whole-breast irradiation offers survival benefits over mastectomy without irradiation

Background

The prognostic equivalence between mastectomy and breast‐conserving surgery (BCS) followed by radiotherapy was shown in pivotal trials conducted decades ago. Since then, detection and treatment of breast cancer have improved substantially and recent retrospective analyses point towards a survival benefit for less extensive breast surgery. Evidence for the association of such survival data with locoregional recurrence rates is largely lacking.

Methods

The Swedish Multicentre Cohort Study prospectively included clinically node‐negative patients with breast cancer who had planned sentinel node biopsy between 2000 and 2004. Axillary lymph node dissection was undertaken only in patients with sentinel node metastases. For the present investigation, adjusted survival analyses were used to compare patients who underwent BCS and postoperative radiotherapy with those who received mastectomy without radiotherapy.

Results

Of 3518 patients in the Swedish Multicentre Cohort Study, 2767 were included in the present analysis; 2338 had BCS with postoperative radiotherapy and 429 had mastectomy without radiotherapy. Median follow‐up was 156 months. BCS followed by whole‐breast irradiation was superior to mastectomy without irradiation in terms of both overall survival (79·5 versus 64·3 per cent respectively at 13 years; P < 0·001) and breast cancer‐specific survival (90·5 versus 84·0 per cent at 13 years; P < 0·001). The local recurrence rate did not differ between the two groups. The axillary recurrence‐free survival rate at 13 years was significantly lower after mastectomy without irradiation (98·3 versus 96·2 per cent; P < 0·001).

Conclusion

The present data support the superiority of BCS with postoperative radiotherapy over mastectomy without radiotherapy. The axillary recurrence rate differed significantly, and could be one contributing factor in a complex explanatory model.

Radiotherapy to lower axilla key?

Loco-regional morbidity after breast conservation and axillary lymph node dissection for early breast cancer with or without regional nodes radiotherapy, perspectives in modern breast cancer treatment: the Skagen Trial 1 is active

BACKGROUND

Axillary lymph node dissection (ALND) and adjuvant radiotherapy (RT) in early breast cancer are associated with a risk of morbidity, including lymphedema and impaired shoulder mobility. The aim of this study was to evaluate loco-regional morbidity after breast conserving surgery (BCS), ALND, taxane-based chemotherapy and whole breast irradiation (WBI) with or without regional nodes RT.

MATERIAL AND METHODS

Eligible patients had BCS and ALND from 2007 to 2012 followed by adjuvant taxane-based chemotherapy and if indicated, trastuzumab and endocrine treatment. The RT consisted of WBI and regional nodes RT in case of ≥ pN1 disease (group 1) and WBI only in case of pN0-1(mic) disease (group 2). The dose was 50 Gy in 25 fractions. The patients were invited to participate in a cross-sectional study evaluating morbidity.

RESULTS

Of the 347 eligible patients, 277 patients (79%) accepted the invitation. Of these, 185 patients (67%) belonged to group 1 and 92 patients (33%) to group 2. The median time from RT to evaluation of morbidity was 3.3 years (group 1) and 4.3 years (group 2). In group 1, 34 patients (18%) and in group 2, 15 patients (16%) had ≥2 cm enlargement in circumference of ipsilateral upper or lower arm (p = .67). The frequence of impairment of ipsilateral shoulder abduction to ≤120° was 3% in both groups and of shoulder flexion to ≤120° was 1% and 2% (group 1 versus 2). No difference in patient reported outcome measure (PROM) data regarding heaviness or enlargement of ipsilateral upper and lower arm or mobility and sensory disturbances.

CONCLUSION

The risk of lymphedema was low in patients after ALND and not related to use of regional nodes RT. Impairment of shoulder function was rare, and no differences in PROM were detected regarding use or not of regional nodes RT.

Ipsilateral axillary recurrence after breast conservative surgery: The protective effect of whole breast radiotherapy

BACKGROUND AND PURPOSE

Whole breast radiotherapy (WBRT) is one of the possible reasons for the low rate of axillary recurrence after breast-conserving surgery (BCS).

PATIENTS AND METHODS

We retrospectively collected data from 4,129 consecutive patients with breast cancer ⩽2cm and negative sentinel lymph node who underwent BCS between 1997 and 2007. We compared the risk of axillary lymph node recurrence between patients treated by WBRT (n=2939) and patients who received partial breast irradiation (PBI; n=1,190) performed by a single dose of electron intraoperative radiotherapy.

RESULTS

Median tumour diameter was 1.1cm in both WBRT and PBI. Women who received WBRT were significantly younger and expressed significantly more multifocality, extensive in situ component, negative oestrogen receptor status and HER2 over-expression than women who received PBI. After a median follow-up of 8.3years, 37 and 28 axillary recurrences were observed in the WBRT and PBI arm, respectively, corresponding to a 10-year cumulative incidence of 1.3% and 4.0% (P<0.001). Multivariate analysis resulted in a hazard ratio of 0.30 (95% CI 0.17-0.51) in favour of WBRT.

CONCLUSIONS

In this large series of women with T1 breast cancer and negative sentinel lymph node treated by BCS, WBRT lowered the risk of axillary recurrence by two thirds as compared to PBI.

Dosimetric evaluation of incidental irradiation to the axilla during whole breast radiotherapy for patients with left-sided early breast cancer in the IMRT era

The purpose of this study was to compare the dosimetric parameters for incidental irradiation to the axilla during whole breast radiotherapy (WBRT) with 3-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT). Twenty left breast cancer patients treated with WBRT after breast-conserving surgery (BCS) were enrolled in this study. Remnant breast tissue, 3 levels of the axilla, heart, and lung were delineated. We used 2 different radiotherapy methods: 3D-CRT with field-in-field technique and 7-field fixed-beam IMRT. The target coverage of IMRT was significantly better than that of 3D-CRT (Dmean: 49.72 ± 0.64 Gy vs 50.24 ± 0.66 Gy, P < 0.001; V45: 93.19 ± 1.40% vs 98.59 ± 0.30%, P < 0.001; V47.5: 86.43 ± 2.72% vs 95.00 ± 0.02%, P < 0.001, for 3D-CRT and IMRT, respectively). In the IMRT plan, a lower dose was delivered to a wider region of the heart and lung. Significantly lower axillary irradiation was shown throughout each level of axilla by IMRT compared to 3D-CRT (Dmean for level I: 42.58 ± 5.31 Gy vs 14.49 ± 6.91 Gy, P < 0.001; Dmean for level II: 26.25 ± 10.43 Gy vs 3.41 ± 3.11 Gy, P < 0.001; Dmean for level III: 6.26 ± 4.69 Gy vs 1.16 ± 0.51 Gy, P < 0.001; Dmean for total axilla: 33.9 ± 6.89 Gy vs 9.96 ± 5.21 Gy, P < 0.001, for 3D-CRT and IMRT, respectively). In conclusion, the incidental dose delivered to the axilla was significantly lower for IMRT compared to 3D-CRT. Therefore, IMRT, which only includes the breast parenchyma, should be cautiously used in patients with limited positive sentinel lymph nodes and who do not undergo complete axillary lymph node dissection.

Dose coverage of axillary level I-III areas during whole breast irradiation with simplified intensity modulated radiation therapy in early stage breast cancer patients

PURPOSE

This study was designed to evaluate the dose coverage of axillary areas during whole breast irradiation with simplified intensity modulated radiation therapy (s-IMRT) and field-in-field IMRT (for-IMRT) in early stage breast cancer patients.

METHODS

Sixty-one consecutive patients with breast-conserving surgery and sentinel lymph node biopsy were collected. Two plans were created for each patient: the s-IMRT and for-IMRT plan. Dosimetric parameters of axillary areas were compared.

RESULTS

The average of mean doses delivered to the axillary level I areas in s-IMRT and for-IMRT plan were 27.7Gy and 29.1Gy (p = 0.011), respectively. The average of V47.5Gy, V45Gy and V40Gy (percent volume receiving≥ 47.5Gy, 45Gy and 40Gy) of the axillary level I in s-IMRT plan was significantly lower than that in for-IMRT plan (p < 0.001). For for-IMRT plans, patients with upper tangential border to humeral head ≤2cm, breast separation >19.3cm and body width >31.9cm had significantly higher mean dose in axillary level I area (p = 0.002, 0.007, 0.001, respectively).

CONCLUSION

Compared with for-IMRT plan, the s-IMRT plan delivered lower dose to axillary level I area. For centers using s-IMRT technique, caution should be exercised when selecting to omit axillary lymph node dissection for patients with breast conserving surgery and limited positive SLNs.

Axillary coverage by whole breast irradiation in 1 to 2 positive sentinel lymph nodes in breast cancer patients

PURPOSE

To evaluate the dosimetric coverage of axillary levels I, II, and III obtained with standard whole breast irradiation in 1 to 2 positive sentinel lymph nodes (SLNs) patients not submitted to axillary lymph nodes dissection (ALND), and to compare the lymph nodes areas coverage obtained with 3D conformal radiation therapy, intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT).

METHODS

Patients with 1 to 2 positive SLNs undergoing breast-conserving therapy, without ALND, were included in the analysis. For each patient, 3 treatment plans were performed: a 3D conventional tangential plan, a static IMRT plan, and a volumetric IMRT, designed to encompass the entire breast parenchyma. The volumes of axillary levels I, II, and III receiving 90% and 95% (V90, V95) of the whole breast prescribed dose were evaluated. Dose-volume histograms were compared by means of the Friedman test.

RESULTS

Ten patients were enrolled. All defined breast volumes received &gt;95% of the prescribed dose with the 3 techniques. Median V95 for axillary level I was 26.4% (range 4.7%-61.3%) for 3D plans, 8.6% (range 0.64%-19.1%) for static IMRT plans, and 2.6% (range 0.4%-4.7%) for volumetric IMRT plans (p&lt;0.001). Median V95 for axillary level II was 5.4% (range 0%-14.6%), 1.9% (range 0%-15%), and 2.6% (range 0.4%-4.7%) for 3D, static IMRT, and volumetric IMRT, respectively (p&lt;0.001).

CONCLUSIONS

Results of our analysis showed that standard 3D tangential whole breast irradiation failed to deliver a therapeutic dose to axillary levels I and II. The coverage was even lower using static and volumetric IMRT techniques.

Evaluation of Sentinel Lymph Node Dose Distribution in 3D Conformal Radiotherapy Techniques in 67 pN0 Breast Cancer Patients

Introduction. The anatomic position of the sentinel lymph node is variable. The purpose of the following study was to assess the dose distribution delivered to the surgically marked sentinel lymph node site by 3D conformal radio therapy technique. Material and Method. We retrospectively analysed 70 radiotherapy (RT) treatment plans of consecutive primary breast cancer patients with a successful, disease-free, sentinel lymph node resection. Results. In our case series the SN clip volume received a mean dose of 40.7 Gy (min 28.8 Gy/max 47.6 Gy). Conclusion. By using surgical clip markers in combination with 3D CT images our data supports the pathway of tumouricidal doses in the SN bed. The target volume should be defined by surgical clip markers and 3D CT images to give accurate dose estimations.

Breast radiotherapy (RT) using tangential fields (TgF): a prospective evaluation of the dose distribution in the sentinel lymph node (SLN) area as determined intraoperatively by clip placement

BACKGROUND

Randomized trials have established that patients with limited involvement of sentinel lymph node (SLN) do not require axillary lymph node dissection (ALND). The similar outcome in patients with ≤2 positive SLN with or without additional ALND is attributed, in part, to tangential fields (TgF) RT. We evaluated the dose distribution in the SLN biopsy area (SLNBa) as determined intraoperatively by clips placement for radiotherapy (RT) optimization.

METHODS

This prospective study included 25 patients who had breast conservation. Titanium clips were used intraoperatively to mark the SLNBa. All patients had 3D-conformal RT using standard (STgF) or high tangential fields (HTgF). Axillary levels, SLNBa, and organs at risk were contoured on a CT scan. Dose distribution and overlap between TgF and target volumes were analyzed.

RESULTS

The average doses delivered to axilla levels I-III and SLNBa were 25, 5, 2, and 33 Gy, respectively. The average dose delivered to SLNBa was higher using HTgF with better coverage of the axilla. Only 12 of 25 patients (48 %) had their SLNBa completely covered by the TgF. There was no impact of TgF size on ipsilateral lung dose. The mean heart dose delivered using STgF was lower than HTgF.

CONCLUSIONS

In the era of SLNB, axilla and SNLBa RT technique has to be standardized to deliver adequate dose. We recommend the use of HTgF or direct axillary RT techniques (such as in AMAROS trial) in patients with metastases in SLN without ALND completion, when only TgF are expected to cure potential residual disease in the axilla.

Tangential vs. defined radiotherapy in early breast cancer treatment without axillary lymph node dissection: a comparative study

PURPOSE

Recent studies have demonstrated low regional recurrence rates in early-stage breast cancer omitting axillary lymph node dissection (ALND) in patients who have positive nodes in sentinel lymph node dissection (SLND). This finding has triggered an active discussion about the effect of radiotherapy within this approach. The purpose of this study was to analyze the dose distribution in the axilla in standard tangential radiotherapy (SRT) for breast cancer and the effects on normal tissue exposure when anatomic level I-III axillary lymph node areas are included in the tangential radiotherapy field configuration.

PATIENTS AND METHODS

We prospectively analyzed the dosimetric treatment plans from 51 consecutive women with early-stage breast cancer undergoing radiotherapy. We compared and analyzed the SRT and the defined radiotherapy (DRT) methods for each patient. The clinical target volume (CTV) of SRT included the breast tissue without specific contouring of lymph node areas, whereas the CTV of DRT included the level I-III lymph node areas.

RESULTS

We evaluated the dose given in SRT covering the axillary lymph node areas of level I-III as contoured in DRT. The mean VD95% of the entire level I-III lymph node area in SRT was 50.28% (range, 37.31-63.24%), VD45 Gy was 70.1% (54.8-85.4%), and VD40 Gy was 83.5% (72.3-94.8%). A significant difference was observed between lung dose and heart toxicity in SRT vs. DRT. The V20 Gy and V30 Gy of the right and the left lung in DRT were significantly higher in DRT than in SRT (p<0.001). The mean heart dose in SRT was significantly lower (3.93 vs. 4.72 Gy, p=0.005).

CONCLUSION

We demonstrated a relevant dose exposure of the axilla in SRT that should substantially reduce local recurrences. Furthermore, we demonstrated a significant increase in lung and heart exposure when including the axillary lymph nodes regions in the tangential radiotherapy field set-up.

The standard tangential fields used for breast irradiation do not allow optimal coverage and dose distribution in axillary levels I-II and the sentinel node area

BACKGROUND

Recent data from ACOSOG Z0011 and NSABP B32 trials suggested no need for axillary lymph node dissection (ALND) in patients with micrometastatic involvement of the sentinel lymph node (SLN). The low rate of axillary recurrence was attributed to the axilla coverage by the tangential fields (TgFs) irradiation and systemic therapy. This study aimed to evaluate dose distribution and coverage of the axilla levels I-II and the SLN area.

PATIENTS AND METHODS

One hundred and nine patients were analyzed according to three groups: group 1 (50 Gy; n = 18), group 2 (60 Gy; n = 34) and group 3 (66 Gy; n = 57). Patients were treated using the standard (STgF; n = 22) or high (HTgF; n = 87) TgF.

RESULTS

The median doses delivered to level I using HTgF versus STgF were 33 and 20 Gy (P = 0.0001). The mean dose delivered to the SLN area was only 28 Gy. Additionally, the SLN area was totally included in the HTgF in 1 out of 12 patients who had intraoperative clip placement in the SNL area.

CONCLUSIONS

TgFs provide a limited coverage of the axilla and the SNLB area. This information should be considered when only TgFs are planned to target the axilla in patients with a positive SLN without ALND. Standardization of locoregional radiotherapy in this situation is urgently needed.

Complication rates in patients with negative axillary nodes 10 years after local breast radiotherapy after either sentinel lymph node dissection or axillary clearance

BACKGROUND

We assess complication rates in node negative breast cancer patients treated with breast radiotherapy (RT) only after sentinel lymph node dissection (SLND) or axillary lymph node dissection (ALND).

MATERIALS AND METHODS

Between 1995 and 2001, 226 women with AJCC stage I-II breast cancer were treated with lumpectomy, either SLND or SLND+ALND, and had available toxicities in follow-up: 111/136 (82%) and 115/129 (89%) in SLND and ALND groups, respectively. RT targeted the breast to median dose of 48.2 Gy (range, 46.0 to 50.4 Gy) without axillary RT. Chi-square tests compared complication rates of 2 groups for axillary web syndrome (AWS), seroma, wound infection, decreased range of motion of the ipsilateral shoulder, paresthesia, and lymphedema.

RESULTS

Median follow-up was 9.9 years (range, 8.3-15.3 y). Median number of nodes assessed was 2 (range, 1-5) in SLND and 18 (range, 7-36) in ALND (P < 0.0001). Acute complications occurred during the first 2 years and were AWS, seroma, and wound infection. Incidences of seroma 5/111 (4.5%) in SLND and 16/115 (13.9%) in ALND (P < 0.02, respectively) and wound infection 3/111 (2.7%) in SLND and 10/115 (8.7%) in ALND (P < 0.05, respectively) differed significantly. AWS was not statistically different between the groups. At 10 years, the only chronic complications decreased were range of motion of the shoulder 46/111 (41.4%) in SLND and 92/115 (80.0%) in ALND (P < 0.0001), paresthesia 12/111 (10.8%) in SLND and 39/115 (33.9%) in ALND (P < 0.0001), and lymphedema assessed by patients 10/111 (10.0%) in SLND and 39/115 (33.9%) in ALND (P < 0.0001). Chronic lymphedema, assessed by clinicians, occurred in 6/111 (5.4%) in SLND and 21/115 (18.3%) in ALND cohorts, respectively (P < 0.0001).

CONCLUSIONS

Our mature findings support that in patients with negative axillary nodal status SLND and breast RT provide excellent long-term cure rates while avoiding morbidities associated with ALND or addition of axillary RT field.

Axillary lymph node dose with tangential whole breast radiation in the prone versus supine position: a dosimetric study

Background

Prone breast positioning reduces skin reaction and heart and lung dose, but may also reduce radiation dose to axillary lymph nodes (ALNs).

Methods

Women with early stage breast cancer treated with whole breast irradiation (WBI) in the prone position were identified. Patients treated in the supine position were matched for treating physician, laterality, and fractionation. Ipsilateral breast, tumor bed, and Level I, II, and III ALNs were contoured according to the RTOG breast atlas. Clips marking surgically removed sentinel lymph nodes (SLN)s were contoured. Treatment plans developed for each patient were retrospectively analyzed. V90_% and V95_% was calculated for each axillary level. When present, dose to axillary surgical clips was calculated.

Results

Treatment plans for 46 women (23 prone and 23 supine) were reviewed. The mean V90_% and V95_% of ALN Level I was significantly lower for patients treated in the prone position (21% and 14%, respectively) than in the supine position (50% and 37%, respectively) (p < 0.0001 and p < 0.0001, respectively). Generally, Level II & III ALNs received little dose in either position. Sentinel node biopsy clips were all contained within axillary Level I. The mean V95_% of SLN clips was 47% for patients treated in the supine position and 0% for patients treated in the prone position (p < 0.0001). Mean V90_% to SLN clips was 96% for women treated in the supine position but only 13% for women treated in the prone position.

Conclusions

Standard tangential breast irradiation in the prone position results in substantially reduced dose to the Level I axilla as compared with treatment in the supine position. For women in whom axillary coverage is indicated such as those with positive sentinel lymph node biopsy who do not undergo completion axillary dissection, treatment in the prone position may be inappropriate.

How do I deal with the axilla in patients with a positive sentinel lymph node?

OPINION STATEMENT

Optimal management of the axilla in a patient with a positive sentinel node biopsy is not yet defined.These patients usually have Breast Conserving Surgery and receive adjuvant systemic therapy and whole breast radiation.Treatment options for the axilla include: no further surgery with or without radiation completion axillary nodal dissection with or without radiation Radiation options in addition to whole breast radiation include axillary and supraclavicular nodal irradiation regional nodal irradiationincludes supraclavicular and internal mammary nodes Completion axillary dissection has been standard practice in patients with positive sentinel nodes. the number of involved nodes provides prognostic information. theoretically improves local control, but may be obviated by systemic chemotherapy. but avoidance of dissection may not adversely affect locoregional control or survival. dissection has significant morbidity so safe avoidance is desirable. There is little worldwide concordance on the use of radiation: whole breast radiation (commonly used after breast conserving surgery) may radiate the lower axilla supraclavicular radiation is most commonly recommended for patients with four or more nodes but may confer a survival benefit on patients with lower risk disease. adding nodal irradiation reduces local recurrence with only modest toxicity. Adjuvant systemic therapy provides a survival benefit for patients with nodal disease. Most will receive cytostatic chemotherapy containing an anthracycline and a taxane. Hormone therapy is appropriate for estrogen receptor positive disease. The extent to which systemic therapy controls microscopic nodal disease is unknown. Node positive patients should generally receive adjuvant chemotherapy.A small group of patients benefit from specific nodal therapy. Further studies are needed to better identify these patients.

[Proposal for a new multidisciplinary therapeutic strategy in the breast cancer patient with sentinel lymph node metastasis]

Sentinel lymph node (SLN) biopsy is the standard of practice for assessing axillary spread in clinically node-negative breast cancer patients. On the other hand, axillary lymph node dissection (ALND) is the ideal procedure for patients with SLN metastasis. Different studies over the last few years have suggested that some patients with positive SLN can be treated without ALND. This article presents a literature review carried out by our multidisciplinary group and its strategy for avoiding routine ALND in women with SLN metastases. In this new strategy ALND should not be performed on women with T1 tumours, with 1-2 positive SLN and undergoing breast conservative surgery. On the other hand, ALND would be indicated in those patients with three or more positive SLN, presence of extracapsular invasion, mastectomised women and triple negative subtype or HER2+ tumours that have not received biological treatment with antibodies.

Axillary Irradiation as an Imperative Alternative to Axillary Dissection in Clinically Lymph Node-Negative but Sentinel Node-Positive Breast Cancer Patients?

At the moment, positive sentinel lymph node dissection (SLND) of the axilla is followed by axillary lymph node dissection (ALND) as standard of care. Recent data proves that omitting ALND after positive SLND in clinically lymph node-negative early stage breast cancer patients is feasible with low recurrence rates. The well known effect of radiotherapy to destroy occult tumor cells highly contributes to these results as a large extent of level I and II lymph nodes are unavoidably included in standard tangential radiation treatment fields. Reviewing the up to date published data on axillary lymph node treatment with radiotherapy, we hypothesize that full dosage coverage of level I and II of the axilla in early stage breast cancer will improve outcome and should be further evaluated.

Coverage of axillary lymph nodes with high tangential fields in breast radiotherapy

The aim of this study is to evaluate the coverage of axillary nodal volumes with high tangent fields (HTF) in breast radiotherapy and to determine the utility of customised blocking. The treatment plans of 30 consecutive patients with early breast cancer were evaluated. The prescription dose was 50 Gy to the whole breast. Axillary level I-II lymph node volumes were delineated and the cranial border of the tangential fields was set just below the humeral head to create HTF. Dose-volume histograms (DVH) were used to calculate the doses received by axillary nodal volumes. In a second planning set, HTF were modified with multileaf collimators (MLC-HTF) to obtain an adequate dose coverage of axillary nodes. The mean doses of the axillary nodes, the ipsilateral lung and heart were compared between the two plans (HTF vs MLC-HTF) using a paired sample t-test. The doses received by 95% of the breast volumes were not significantly different for the two plans. The doses received by 95% of the level I and II axillary volumes were 16.79 Gy and 11.59 Gy, respectively, for HTF, increasing to 47.2 Gy and 45.03 Gy, respectively, for MLC-HTF. Mean lung doses and per cent volume of the ipsilateral lung receiving 20 Gy (V20) were also increased from 6.47 Gy and 10.47%, respectively, for HTF, to 9.56 Gy and 16.77%, respectively, for MLC-HTF. Our results suggest that HTF do not adequately cover the level I and II axillary lymph node regions. Modification of HTF with MLC is necessary to obtain an adequate coverage of axillary levels without compromising healthy tissue in the majority of the patients.

A 10-year follow-up of treatment outcomes in patients with early stage breast cancer and clinically negative axillary nodes treated with tangential breast irradiation following sentinel lymph node dissection or axillary clearance

We compare long-term outcomes in patients with node negative early stage breast cancer treated with breast radiotherapy (RT) without the axillary RT field after sentinel lymph node dissection (SLND) or axillary lymph node dissection (ALND). We hypothesize that though tangential RT was delivered to the breast tissue, it at least partially sterilized occult axillary nodal metastases thus providing low nodal failure rates. Between 1995 and 2001, 265 patients with AJCC stages I-II breast cancer were treated with lumpectomy and either SLND (cohort SLND) or SLND and ALND (cohort ALND). Median follow-up was 9.9 years (range 8.3-15.3 years). RT was administered to the whole breast to the median dose of 48.2 Gy (range 46.0-50.4 Gy) plus boost without axillary RT. Chi-square tests were employed in comparing outcomes of two groups for axillary and supraclavicular failure rates, ipsilateral in-breast tumor recurrence (IBTR), distant metastases (DM), and chronic complications. Progression-free survival (PFS) was compared using log-rank test. There were 136/265 (51%) and 129/265 (49%) patients in the SLND and ALND cohorts, respectively. The median number of axillary lymph nodes assessed was 2 (range 1-5) in cohort SLND and 18 (range 7-36) in cohort ALND (P < 0.0001). Incidence of AFR and SFR in both cohorts was 0%. The rates of IBTR and DM in both cohorts were not significantly different. Median PFS in the SLND cohort is 14.6 years and 10-year PFS is 88.2%. Median PFS in the ALND group is 15.0 years and 10-year PFS is 85.7%. At a 10-year follow-up chronic lymphedema occurred in 5/108 (4.6%) and 40/115 (34.8%) in cohorts SLND and ALND, respectively (P = 0.0001). This study provides mature evidence that patients with negative nodes, treated with tangential breast RT and SLND alone, experience low AFR or SFR. Our findings, while awaiting mature long-term data from NSABP B-32, support that in patients with negative axillary nodal status such treatment provides excellent long-term cure rates while avoiding morbidities associated with ALND or addition of axillary RT field.

Prognostic significance of number of positive nodes: a long-term study of one to two nodes versus three nodes in breast cancer patients

PURPOSE

Previous reports of breast cancer have generally analyzed patients with one to three positive lymph nodes as a single group, often leading to controversy regarding the practical clinical applicability. The present study separately analyzed the survival outcomes of Stage T1-T2 breast cancer patients according to whether one, two, or three axillary nodes were pathologically positive.

METHODS AND MATERIALS

The records of 5,996 patients were available for analysis from the population-based Saskatchewan provincial registry between 1981 and 1995. Because the reliability of the nodal assessment depends on the number of lymph nodes sampled, only those 755 patients with Stage T1-T2 disease and eight or more nodes examined were analyzed further for overall survival and cause-specific survival (CSS).

RESULTS

Patients with one and two positive nodes had nearly indistinguishable survival plots, but those with three positive nodes had a distinct trend toward worse survival. The overall survival rate of patients with one, two, and three nodes at 5, 10, and 15 years was 82.7%, 77.0%, and 79.0%, 64.8%, 60.9%, and 52.8%, and 48.8%, 48.0%, and 40.9%, respectively (p = .11). The corresponding CSS rates at 5, 10, and 15 years were 89.4%, 82.0%, and 81.3%, 78.87%, 72.9%, and 62.1%, and 72.7%. 69.0%, and 55.6% (p = .0004). The use of regional radiotherapy did not confer any apparent survival benefit in terms of either overall survival or CSS.

CONCLUSION

Patients with one or two positive nodes had a similar CSS. However, those with three positive nodes fared worse, with a significantly reduced CSS compared with those with one or two involved nodes. Thus, the survival data among patients with one to three nodes positive reveals clearly relevant differences when analyzed separately.

Coverage of axillary lymph nodes in supine vs. prone breast radiotherapy

PURPOSE

To compare the dosimetry of target and normal tissue when tangents with the breast tissue were applied in a subset of breast cancer patients who had undergone computed tomography (CT) planning both supine and prone.

METHODS AND MATERIALS

The CT images of 20 patients who had undergone simulation in supine and prone positions were used for planning. The axillary lymph node regions (level I-III), breast tissue, tumor bed, heart, and bilateral lungs were manually contoured. Standard tangent fields were designed for the whole breast to deliver a prescribed dose of 50 Gy. Dose-volume histograms were compared between the two sets.

RESULTS

In each patient, coverage of breast tissue and tumor bed was readily achieved by either technique. In either position, treatment of the nodal regions was inadequate. On average, the mean dose to the nodal regions for levels I-III was approximately 50% less in the prone as compared with the supine position. The mean ipsilateral lung volume receiving 95% of the prescribed dose was 6.3% in the supine position compared to 0.43% in the prone position. When planned supine, the mean heart volume receiving 30 Gy was 0.56% compared with 0.30% in the prone position.

CONCLUSIONS

Planning in either position was found to achieve adequate coverage of the breast tissue and tumor bed for all patients. Lung was better spared prone. Coverage of axillary nodes was inadequate in either position, but further reduced in the prone vs. supine position. The choice of optimal setup should take into considerations stage and risk of nodal recurrence.

The impact of the number of excised axillary nodes and of the percentage of involved nodes on regional nodal failure in patients treated by breast-conserving surgery with or without regional irradiation

PURPOSE

After breast-conserving surgery, recommendations for regional nodal radiotherapy are usually based on the number of positive nodes. This number is dependent on the number of nodes removed during the axillary dissection. This study examines whether the percentage of positive nodes may help to select patients for regional radiotherapy.

METHODS AND MATERIALS

A retrospective study was conducted on 1,372 T1-T2 node-positive breast cancer patients treated at L'Hôtel-Dieu de Québec Hospital between 1972 and 1997.

RESULTS

Among the patients who did not receive regional radiotherapy, the percentage of involved nodes was significantly associated with axillary failure. Ten-year axillary control rates were 97% and 91% when the percentage of involved nodes was <50% and > or =50%, respectively (p = 0.007). In addition, regional radiotherapy is always significantly associated with a decrease in overall regional failure (axillary and/or supraclavicular), regardless of the percentage of involved nodes. However, regional radiotherapy reduced the axillary failure rate (2% vs. 9%, p = 0.007) only when more than a specific percentage of nodes was involved (> or =40% if N1-3 and > or =50% if N>3 nodes).

CONCLUSIONS

The percentage of involved nodes should be taken into consideration in selecting patients for regional radiotherapy. Irradiation of the axilla should be reserved for patients with a specific ratio: >40% involved nodes if N1-3 and > or =50% involved nodes if N>3 nodes.