Omission of Axillary Dissection Following Nodal Downstaging With Neoadjuvant Chemotherapy.

Importance: Data on oncological outcomes after omission of axillary lymph node dissection (ALND) in patients with breast cancer that downstages from node positive to negative with neoadjuvant chemotherapy are sparse. Additionally, the best axillary surgical staging technique in this scenario is unknown. Objective: To investigate oncological outcomes after sentinel lymph node biopsy (SLNB) with dual-tracer mapping or targeted axillary dissection (TAD), which combines SLNB with localization and retrieval of the clipped lymph node. Design, Setting, and Participants: In this multicenter retrospective cohort study that was conducted at 25 centers in 11 countries, 1144 patients with consecutive stage II to III biopsy-proven node-positive breast cancer were included between April 2013 and December 2020. The cumulative incidence rates of axillary, locoregional, and any invasive (locoregional or distant) recurrence were determined by competing risk analysis. Exposure: Omission of ALND after SLNB or TAD. Main Outcomes and Measures: The primary end points were the 3-year and 5-year rates of any axillary recurrence. Secondary end points included locoregional recurrence, any invasive (locoregional and distant) recurrence, and the number of lymph nodes removed. Results: A total of 1144 patients (median [IQR] age, 50 [41-59] years; 78 [6.8%] Asian, 105 [9.2%] Black, 102 [8.9%] Hispanic, and 816 [71.0%] White individuals; 666 SLNB [58.2%] and 478 TAD [41.8%]) were included. A total of 1060 patients (93%) had N1 disease, 619 (54%) had ERBB2 (formerly HER2)-positive illness, and 758 (66%) had a breast pathologic complete response. TAD patients were more likely to receive nodal radiation therapy (85% vs 78%; P = .01). The clipped node was successfully retrieved in 97% of TAD cases and 86% of SLNB cases (without localization). The mean (SD) number of sentinel lymph nodes retrieved was 3 (2) vs 4 (2) (P < .001), and the mean (SD) number of total lymph nodes removed was 3.95 (1.97) vs 4.44 (2.04) (P < .001) in the TAD and SLNB groups, respectively. The 5-year rates of any axillary, locoregional, and any invasive recurrence in the entire cohort were 1.0% (95% CI, 0.49%-2.0%), 2.7% (95% CI, 1.6%-4.1%), and 10% (95% CI, 8.3%-13%), respectively. The 3-year cumulative incidence of axillary recurrence did not differ between TAD and SLNB (0.5% vs 0.8%; P = .55). Conclusions and Relevance: The results of this cohort study showed that axillary recurrence was rare in this setting and was not significantly lower after TAD vs SLNB. These results support omission of ALND in this population.

Proton Partial Breast Irradiation: Detailed Description of Acute Clinico-Radiologic Effects.

Introduction: Accelerated partial breast irradiation (APBI) with protons results in a very different acute effect profile than standard whole breast irradiation. We reviewed our initial experience with proton APBI and felt that a detailed description of these effects were needed to permit a common tool to compare experience with this developing technology. Methods: Sixty sequential patients treated with proton APBI on a prospective protocol were evaluated and 43 patients with a minimum six-month follow-up underwent detailed photographic and radiologic analysis. The tumorectomy cavity plus an additional 1.5 cm clinical target volume (CTV) was treated with two or three passively-scattered proton beams to a dose of 34 Gy in 10 fractions in one week. Photographs were taken at the end of radiation, at two weeks, six weeks, and every six months thereafter. Mammography was obtained at six months after radiation and annually thereafter. All visual changes were categorized using the smallest meaningful gradations in findings and are demonstrated herein. All treatment-related mammographic findings are reported. Findings: Visual and mammographic findings showed a clear time-dependent relationship and significant variation between individuals. Peak skin reaction occurred at two to six weeks after completion of therapy. At two weeks most patients had either no visible effects and patchy erythema involving <50% of the treated skin (60%). At six weeks most patients had either patchy erythema involving <50% of the overlying skin (33%) or patchy erythema involving >50% of the treated skin (28%). Only one patient developed any moist desquamation. At six months most patients had no visible skin changes (57%) or a small, circular area of mild hyperpigmentation (33%). Mammographic changes seen at six months were regional skin thickening (40%), residual seroma (14%), localized retraction (26%), and fat necrosis (2%). A subcategorized variant on the CTCAE 4.0 was developed to foster granular recording of these findings.

A 10-Year Experience with Mastectomy and Tissue Expander Placement to Facilitate Subsequent Radiation and Reconstruction.

BACKGROUND: An integrated approach to skin sparing mastectomy with tissue expander placement followed by radiotherapy and delayed reconstruction was initiated in our institution in 2002. The purpose of this study was to assess the surgical outcomes of this strategy. METHODS: Between September 2002 and August 2013, a total of 384 reconstructions had a tissue expander placed at the time of mastectomy and subsequently underwent radiotherapy. Rates and causes of tissue expander explantation before, during, and after radiotherapy, as well as tumor specific outcomes and reconstruction approaches, were collected. RESULTS: Median follow-up after diagnosis was 5.6 (range 1.3-13.4) years. In the study cohort, 364 patients (94.8%) had stage II-III breast cancer, and 7 patients (1.8%) had locally recurrent disease. The 5-year rates of actuarial locoregional control, disease-free survival, and overall survival were 99.2, 86.1, and 92.4%, respectively. The intended delayed-immediate reconstruction was subsequently completed in 325 of 384 mastectomies (84.6% of the study cohort). Of the remaining 59 tissue expanders, 1 was explanted before radiotherapy, 1 during radiotherapy, and 7 patients (1.8%) were lost to follow-up. Fifty patients (13.0%) required tissue expander explantation after radiation and before their planned final reconstruction, primarily due to cellulitis. Nonetheless, the cumulative rate of completed reconstructions was 89.6%. The median time from placement of the tissue expander until reconstruction was 12 (interquartile range 9-15) months. CONCLUSIONS: Tissue expander placement at skin-sparing mastectomy in patients who require radiotherapy appears to be a viable strategy for combining reconstruction and radiotherapy.

Proton partial breast irradiation in the supine position: Treatment description and reproducibility of a multibeam technique.

PURPOSE: Proton-accelerated partial breast irradiation (APBI) is early in its developmental phase without standardized treatment parameters. We report an approach to multibeam proton APBI using a universally available supine setup and deliberate beam arrangement strategy to limit the total area of skin receiving a full dose while being robust for interfraction variation. METHODS AND MATERIALS: Thirty-three American Society for Radiation Oncology consensus-suitable/cautionary APBI candidates were treated using a passively scattered proton beam between 2010 and 2014 to 34 Gy relative biological effectiveness in 10 fractions twice daily. All patients were immobilized in a Vac-Lok cradle, typically with the arm down, and adducted to mound the breast and facilitate multiple, optimal en face beams. Radiopaque wires were placed on the surgical scar and 3 markers separate from the scar were placed elsewhere on the breast. All markers were used for each setup and removed before treatment. Marker displacement, wire rotation, and wire displacement were recorded from 10 random patients (100 orthogonal films). A 15-mm expansion was made to the tumor bed to obtain a clinical target volume, and followed by a 5-mm skin contraction and exclusion of the chest wall. A radial planning target volume margin of 5 mm was used. RESULTS: Across 100 pretreatment images, median displacement of 3 distinct skin set-up markers was 3, 4, and 3 mm. Displacement of the scar wire in the X and Y direction was 0 and 1 mm, respectively. Among 28 verification scans performed, only 1 resulted in adaptive planning because of the initial presence of an air pocket in the lumpectomy cavity that resolved spontaneously during treatment. CONCLUSIONS: APBI proton treatment using a supine approach was largely reproducible. Inter-fraction variation demonstrates 5-mm radial planning margins were adequate; however, outliers do occur and films should be reviewed critically and in real time. This technique is straightforward and could be used at any proton facility without the need for specialized equipment.

Radio-chemotherapy in anal cancer: Institutional experience at a large radiation oncology center in Chile.

AIM: In this article the aim is to provide a concise narrative review and inform the institutional experience at a referral center in Chile with the use of radio-chemotherapy in anal cancer. BACKGROUND: Cancer of the anus and anal canal is mainly a loco-regional disease. For years the standard of care has been concomitant radio-chemotherapy, which permits organ preservation and better local control than alternative surgical procedures. MATERIALS AND METHODS: A retrospective analysis of 44 patients treated between 2002 and 2010 was performed. Local recurrence, distant recurrence and overall survival were analyzed with the Kaplan-Meier method. Relevant groups where compared with the log-rank test and univariate analysis were done with the Cox proportional hazards model. RESULTS: Median follow-up of the cohort was 56 months, with a minimum follow-up of at least 24 months. There was a significant difference between clinical stages in disease free survival (log-rank trend p < 0.001), and a significant difference in overall survival (OS) when comparing clinical stages that were grouped in stage I-IIIa and IIIB (log-rank p = 0.001). On univariate analysis, age older than 60, having received full treatment and dose above 45 Gy were all significantly related to OS (p < 0.05). An overall survival of 45% and disease free survival of 45% at 5 years were found in our series. CONCLUSIONS: Our findings show that results at the Instituto de Radiomedicina in Chile are comparable to published literature. Dismal results in stage IIIb cases indicate much work remains in therapies to achieve loco-regional control in locally advanced cases.