Faculty Bibliography

BACKGROUND AND PURPOSE/OBJECTIVE:Quantifying radiation dose to cardiac substructures is important for research on the etiology and prevention of complications following radiotherapy; however, segmentation of substructures is challenging. In this study we demonstrate the application of our atlas-based automatic segmentation method to breast cancer radiotherapy plans for generating radiation doses in support of late effects research. MATERIAL AND METHODS/METHODS:We applied our segmentation method to contour heart substructures on the computed tomography (CT) images of 70 breast cancer patients who received external photon radiotherapy. Two cardiologists provided manual segmentation of the whole heart (WH), left/right atria, left/right ventricles, and left anterior descending artery (LAD). The automatically contours were compared with manual delineations to evaluate similarity in terms of geometry and dose. RESULTS:The mean Dice similarity coefficient between manual and automatic segmentations was 0.96 for the WH, 0.65 to 0.82 for the atria and ventricles, and 0.06 for the LAD. The mean average surface distance was 1.2 mm for the WH, 3.4 to 4.1 mm for the atria and ventricles, and 6.4 mm for the LAD. We found the dose to the cardiac substructures based on our automatic segmentation agrees with manual segmentation within expected observer variability. For left breast patients, the mean absolute difference in mean dose was 0.1 Gy for the WH, 0.2 to 0.7 Gy for the atria and ventricles, and 1.8 Gy for the LAD. For right breast patients, these values were 0.0 Gy, 0.1 to 0.4 Gy, and 0.4 Gy, respectively. CONCLUSION/CONCLUSIONS:Our automatic segmentation method will facilitate the development of radiotherapy prescriptive criteria for mitigating cardiovascular complications.

PURPOSE/OBJECTIVE:Mastectomy has long been the preferred approach for local salvage of recurrent breast cancer following breast-conservation therapy (BCT). Growing interest in avoiding mastectomy prompted RTOG 1014, a landmark phase two study demonstrating the feasibility of repeat BCT using a novel radiotherapy (RT) regimen (i.e., 45 Gy administered in 30 fractions of 1.5 Gy twice-daily to the partial breast, "rePBI"). We adopted this regimen as our institutional standard and report our observations regarding the safety and efficacy of rePBI as salvage therapy. METHODS:All patients at our institution who underwent repeat BCT and subsequently received rePBI from 2011 to 2019 were identified. Clinicopathologic features and treatment characteristics for both primary breast cancers and recurrences were collected, as were rates of subsequent recurrence and treatment-associated toxicities. RESULTS:The cohort included 34 patients with a median age of 65.8 (46.2-78.2) at the time of rePBI. At a median follow-up of 23.5 months, there were two subsequent locoregional recurrences (2-year local control rate 97%). There was no grade ≥ 3 toxicity. The most common acute toxicity (< 3 months) was radiation dermatitis (100%), and common grade 1-2 late toxicities (> 3 months) included fibrosis in 14 (41%), breast asymmetry in 12 (35%), and chest wall pain in 11 (32%). CONCLUSIONS:Repeat breast conservation using the hyperfractionated partial breast RT regimen defined by RTOG 1014 (45 Gy administered in 30 1.5 Gy twice-daily fractions) appears effective and well tolerated. No grade 3 or higher toxicities were observed and local control was excellent. Longer term follow-up among larger cohorts will define whether salvage mastectomy should remain the preferred standard.

Perineural invasion (PNI) is a pathologic finding observed across a spectrum of solid tumors, typically with adverse prognostic implications. Little is known about how the presence of PNI influences locoregional recurrence (LRR) among breast cancers. We evaluated the association between PNI and LRR among an unselected, broadly representative cohort of breast cancer patients, and among a propensity-score matched cohort. We ascertained breast cancer patients seen at our institution from 2008 to 2019 for whom PNI status and salient clinicopathologic features were available. Fine-Gray regression models were constructed to evaluate the association between PNI and LRR, accounting for age, tumor size, nodal involvement, estrogen receptor (ER), progesterone receptor (PR), HER2 status, histologic tumor grade, presence of lymphovascular invasion (LVI), and receipt of chemotherapy and/or radiation. Analyses were then refined by comparing PNI-positive patients to a PNI-negative cohort defined by propensity score matching. Among 8864 invasive breast cancers, 1384 (15.6%) were noted to harbor PNI. At a median follow-up of 6.3 years, 428 locoregional recurrence events were observed yielding a 7-year LRR of 7.1% (95% CI 5.5-9.1) for those with PNI and 4.7% (95% CI 4.2-5.3; p = 0.01) for those without. On univariate analysis throughout the entire cohort, presence of PNI was significantly associated with an increased risk of LRR (HR 1.39, 95% CI 1.08-1.78, p < 0.01). Accounting for differences in salient clinicopathologic and treatment parameters by multivariable Fine-Gray regression modeling, the association between PNI and LRR was potentiated (HR 1.57, 95% CI 1.2-2.07, p = 0.001). We further conducted propensity score matching to balance clinicopathologic parameters and treatments between the two groups (PNI vs not), again showing a similar significant association between PNI and LRR (HR 1.46, 95% CI 1.03-2.08, p = 0.034). PNI is significantly associated with LRR following the definitive treatment of invasive breast cancer. The excess risk conferred by PNI is similar in magnitude to that observed with LVI, or by ER/PR negativity. Breast cancer prognostication and therapeutic decision-making should consider the presence of PNI among other salient risk factors. Larger studies among more uniform breast cancer presentations may elucidate the extent to which these findings apply across breast cancer subtypes and stages.

BACKGROUND:For patients with breast cancer undergoing breast-conserving surgery (BCS), adjuvant radiation (RT) and hormonal therapy (HT) reduce the risk of locoregional recurrence (LRR). Although several studies have evaluated adjuvant HT ± RT, the outcomes of HT versus RT monotherapy remain less clear. In this study, the risk of LRR is characterized among older patients with early-stage breast cancer following adjuvant RT alone, HT alone, neither, or both. METHODS:This study included female patients from the Memorial Sloan Kettering Cancer Center (New York, New York) who were aged ≥65 years with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) T1N0 breast cancer treated with BCS. The primary endpoint was time to LRR evaluated by Cox regression analysis. RESULTS:There were 888 women evaluated with a median age of 71 years (range, 65-100 years) and median follow-up of 4.9 years (range, 0.0-9.5 years). There were 27 LRR events (3.0%). Five-year LRR was 11% for those receiving no adjuvant treatment, 3% for HT alone, 4% for RT alone, and 1% for HT and RT. LRR rates were significantly different between the groups (P < .001). Compared with neither HT nor RT, HT or RT monotherapy each yielded similar LRR reductions: HT alone (HR, 0.27; 95% CI, 0.10-0.68; P = .006) and RT alone (HR, 0.32; 95% CI, 0.11-0.92; P = .034). Distant recurrence and breast cancer-specific survival rates did not significantly differ between groups. CONCLUSIONS:LRR risk following BCS is low among women aged ≥65 years with T1N0, ER+/HER2- breast cancer. Adjuvant RT and HT monotherapy each similarly reduce this risk; the combination yields a marginal improvement. Further study is needed to elucidate whether appropriate patients may feasibly receive adjuvant RT monotherapy versus the current standards of HT monotherapy or combined RT/HT.

In an era of continued advancements in personalized medicine for the treatment of breast cancer, select patients with early stage breast cancer may be uniquely poised to benefit from partial breast irradiation (PBI) delivered with proton therapy. PBI presents an opportunity to improve quality of life during treatment with a significantly shorter treatment duration. By targeting less non-target breast tissue, excess radiation exposure and resulting toxicities are also reduced. Proton therapy represents a precision radiotherapy technology that builds on these advantages by further limiting the normal tissue exposure to unnecessary radiation dose not only to uninvolved breast tissue but also the underlying thoracic organs including the heart and lungs. Herein, we present a concise review of the rationale for the use of proton therapy for PBI, evidence available to date, and practical considerations in the implementation and use of proton therapy for this indication.

PURPOSE:Breast cancer diagnosis at a very young age has been independently correlated with worse outcomes. Appropriately intensifying treatment in these patients is warranted, even as we acknowledge the risks of potentially mutagenic adjuvant therapies. We examined local control, distant control, overall survival, and secondary malignancy rates by age cohort and by initial surgical strategy. METHODS AND MATERIALS:Female patients less than or equal to 35 years of age diagnosed with invasive breast cancer from January 1, 1990, to December 31, 2010, were identified. Control groups of those aged 36 to 50 years (n = 6246) and 51 to 70 years (n = 7294) were delineated from an institutional registry. Clinicopathologic and follow-up information was collected. Chi-squared test was used to compare frequencies of categorical variables. Survival endpoints were evaluated using Kaplan-Meier methodology. RESULTS:A total of 529 patients ≤35 years of age met criteria for analysis. The median age of diagnosis was 32 years (range 20-35). Median follow-up was 10.3 years. On multivariable analysis, factors associated with overall survival (OS) were tumor size (hazard ratio [HR] 1.14, P = .02), presence of lymphovascular invasion (HR 2.2, P <.001), estrogen receptor positivity (HR 0.64, P = .015), receipt of adjuvant chemotherapy (HR 0.52, P = .035), and black race (HR 2.87, P <.001). The ultra-young were more likely to experience local failure compared with the aged 36 to 50 group (HR 2.2, 95% CI 1.8-2.6, P < .001) and aged 51 to 70 group (HR 3.1, 95% CI 2.45 - 3.9, P <.001). The cumulative incidence of secondary malignancies at 5 and 10 years was 2.2% and 4.4%, respectively. Receipt of radiation was not significantly associated with secondary malignancies or contralateral breast cancer. CONCLUSION:Survival and recurrence outcomes in breast cancer patients ≤35 years are worse compared with those aged 36 to 50 or 51 to 70 years. Based on our data, breast conservation therapy is appropriate for these patients, and the concern for second malignancies should not impinge on the known indications for postoperative radiation therapy.

BACKGROUND:The COVID-19 pandemic has transformed cancer care with the rapid expansion of telemedicine, but given the limited use of telemedicine in oncology, concerns have been raised about the quality of care being delivered. We assessed the patient experience with telemedicine in routine radiation oncology practice to determine satisfaction, quality of care, and opportunities for optimization. PATIENTS AND METHODS:Patients seen within a multistate comprehensive cancer center for prepandemic office visits and intrapandemic telemedicine visits in December 2019 through June 2020 who completed patient experience questionnaires were evaluated. Patient satisfaction between office and telemedicine consultations were compared, patient visit-type preferences were assessed, and factors associated with an office visit preference were determined. RESULTS:In total, 1,077 patients were assessed (office visit, n=726; telemedicine, n=351). The telemedicine-consult survey response rate was 40%. No significant differences were seen in satisfaction scores between office and telemedicine consultations, including the appointment experience versus expectation, quality of physician's explanation, and level of physician concern and friendliness. Among telemedicine survey respondents, 45% and 34% preferred telemedicine and office visits, respectively, and 21% had no preference for their visit type. Most respondents found their confidence in their physician (90%), understanding of the treatment plan (88%), and confidence in their treatment (87%) to be better or no different than with an office visit. Patients with better performance status and who were married/partnered were more likely to prefer in-person office visit consultations (odds ratio [OR], 1.04 [95% CI, 1.00-1.08]; P=.047, and 2.41 [95% CI, 1.14-5.47]; P=.009, respectively). Patients with telephone-only encounters were more likely to report better treatment plan understanding with an office visit (OR, 2.25; 95% CI, 1.00-4.77; P=.04). CONCLUSIONS:This study is the first to assess telemedicine in routine radiation oncology practice, and found high patient satisfaction and confidence in their care. Optimization of telemedicine in oncology should be a priority, specifically access to audiovisual capabilities that can improve patient-oncologist communication.

BACKGROUND:Bone metastases cause significant morbidity in patients with cancer, and radiation therapy (RT) is an effective treatment approach. Indications for more complex ablative techniques are emerging. We sought to evaluate RT trends at a large multi-site tertiary cancer center. METHODS:Patients who received RT for bone metastases at a single institution (including regional outpatient clinics) from 2016 to 2018 were identified. Patients were grouped by RT regimen: single-fraction conventional RT (8 Gy × 1), 30 Gy in 10 fractions, SBRT, and "other". Multinomial logistic regression was performed to assess trends in regimens over time. Binary logistic regression was performed to evaluate factors associated with receipt of SBRT. RESULTS:Between 2016 and 2018, 5,952 RT episodes were received by 2,969 patients with bone metastases. Overall, 76% of episodes were ≤ 5 fractions. The median number of fractions planned for SBRT and non-SBRT episodes was 3 (IQR 3-3) and 5 (IQR 5-10), respectively. Use of SBRT increased from 2016 to 2018 (39% to 53%, p < 0.01) while use of 30 Gy in 10 fractions decreased (26% to 12%, p < 0.01), and 8 Gy × 1 was stable (5.3% to 6.9%, p = 0.28). SBRT was associated with higher performance status (p < 0.01) and non-radiosensitive histology (p < 0.01). Use of SBRT increased in the regional network (19% to 48%, p < 0.01) and at the main center (52% to 59%, p = 0.02), but did not increase within 30 days of death. More patients treated with 8 Gy × 1 than SBRT died within 30 days of treatment (24% vs 3.8%, respectively, p < 0.01). CONCLUSIONS:SBRT is replacing 30 Gy in 10 fractions for bone metastases, especially among patients with high performance status and non-radiosensitive histologies. Better prognostic algorithms could further improve patient-centered treatment selection at the end of life.

PURPOSE/OBJECTIVE:Telemedicine was rapidly implemented for initial consultations and radiation treatment planning in the wake of the coronavirus disease 2019 (COVID-19) pandemic. In this study, we explore utilization of and physician perspectives on this approach in an attempt to identify patient populations that may benefit most from virtual care. METHODS AND MATERIALS/METHODS:This is a mixed-methods study with a convergent design. Approximately 6 to 8 weeks after implementation of telemedicine, all radiation oncologists in a single academic radiation oncology department were invited to participate in either semistructured interviews with embedded survey questions or a concurrently administered survey only. Rapid qualitative analysis was used to identify common themes, and quantitative data was assessed using descriptive statistics and univariable analyses. RESULTS:At the apex of the pandemic, 92% of radiation oncology visits were conducted via telemedicine. In total, 51 of 61 radiation oncologists participated in the study (response rate 84%). Most (71%) reported no difference in ability to treat cancer appropriately via telemedicine, which was more common among specialized physicians (P = .01) but not those with higher visit volume or years of experience. Over half (55%) perceived no difference or even improvement in overall visit quality with telemedicine. Virtual visits were deemed acceptable for a median of 70% to 96% of patients, which varied by disease site. Need for physical examination, and availability of an acceptable proxy, factored into telemedicine acceptability. Most (88%) found telemedicine better than expected, but opinions were split on how telemedicine would affect physician burnout. Almost all (96%) foresaw a role for telemedicine beyond the pandemic and would opt for a median of 50% (interquartile range 20%-66%) of visits conducted via telemedicine. CONCLUSIONS:Among radiation oncologists in an academic setting, telemedicine was perceived to be highly appropriate and acceptable for most patients. Future studies should focus on identifying the 5% to 30% of patients whose care may be optimized with in-person visits, and if there is alignment with patient preferences.