Postmastectomy Radiation in HER-2 Positive Breast Cancer after Neoadjuvant Therapy: Secondary Analysis of Two Randomized Trials

PURPOSE/OBJECTIVE(S)

The role of postmastectomy radiation therapy (PMRT) following primary systemic therapy (PST) in HER-2 positive breast cancer (Her2+BC) remains poorly understood. The current study evaluates PMRT based on the pathological response to PST in Her2+BC.

MATERIALS/METHODS

TRYPHAENA and NeoSphere are randomized phase II trials that investigated PST for Her2+BC. Our study is a pooled analysis of both trials, including 312 node-positive patients treated with HER-2 targeted PST followed by mastectomy with or without PMRT. The primary endpoint is loco-regional recurrence-free survival (LRRFS).

RESULTS

Our analysis included 172 (55%) patients who achieved nodal pCR and 140 (45%) patients who did not. Patients with nodal pCR had a 5-year LRRFS of 97% with PMRT delivered in 98 patients (57%). Patients without nodal pCR had a 5-year LRRFS of 87% with PMRT delivered in 93 patients (66%). Patients with ypN1 (n = 62) disease who received PMRT (n = 40) had a 5-year LRRFS of 85% as compared to 89% in those who did not (n = 22); (p = 0.60). A significant LRRFS difference was noted in patients with ypN2-3 (n = 78) disease who received PMRT (n = 53) compared to those who did not (n = 25) (5-year LRRFS 92% vs. 75%; p = 0.019). On multivariate analysis, clinical nodal disease at diagnosis and nodal pCR were significantly associated with loco-regional recurrence (LRR).

CONCLUSION

Her2+BC patients who achieve nodal pCR after PST have excellent loco-regional control which supports de-escalation of PMRT.

Radiation nephropathy: Mechanisms of injury and recovery in a murine model

BACKGROUND

Radiation nephropathy (RN) can be a severe late complication for patients treated with radiotherapy (RT) targeting abdominal and paraspinal tumors. Recent studies investigating the mechanisms of RT-mediated injury in the kidney have demonstrated that RT disrupts the cellular integrity of renal podocytes leading to cell death and loss of renal function.

AIM

To determine if RT-induced renal dysfunction is associated with alterations in podocyte and glomerular function, and whether RT-induced podocyte alterations were associated with changes in the glomerular basement membrane (GBM).

METHODS

C57BL/6 mice were treated with focal bilateral X-irradiation using a single dose (SD) of 4 Gy, 10 Gy, or 14 Gy or fractionated dosing (FD) of 5x6Gy or 24x2Gy. Then, 10-40 weeks after RT parameters of renal function were measured, along with glomerular filtration rate (GFR) and glomerular histology, as well as ultrastructural changes in GBM by transmission electron microscopy.

RESULTS

RT treatment resulted in persistent changes in renal function beginning at 10 weeks with little recovery up to 40 weeks post RT. Dose dependent changes were seen with increasing SD but no functional sparing was evident after FD. RT-induced loss of renal function was associated with expansion of the GBM and significant increases in foot process width, and associated with significant reduction in GFR, podocyte loss, and renal fibrosis.

CONCLUSION

For the first time, these data show that expansion of the GBM is one consequence of radiation injury, and disarrangement of the GBM might be associated with the death of podocytes. These data shed new light on the role podocyte injury and GBM in RT-induced renal dysfunction.

Radiotherapy Use and Incidence of Locoregional Recurrence in Patients With Favorable-Risk, Node-Positive Breast Cancer Enrolled in the SWOG S1007 Trial

Importance

Little is known about regional nodal irradiation (RNI) practice patterns or rates of locoregional recurrence (LRR) with and without RNI in patients with limited nodal disease and favorable biology treated with modern surgical and systemic therapy, including approaches that de-escalate those latter treatments.

Objective

To investigate how often patients with low-recurrence score breast cancer with 1 to 3 nodes involved receive RNI, incidence and predictors of LRR, and associations between locoregional therapy and disease-free survival.

Design, Setting, and Participants

In this secondary analysis of the SWOG S1007 trial, patients with hormone receptor-positive, ERBB2-negative breast cancer, and a Oncotype DX 21-gene Breast Recurrence Score assay result of no more than 25, were randomized to endocrine therapy alone vs chemotherapy then endocrine therapy. Prospectively collected radiotherapy information was collected from 4871 patients treated in diverse settings. Data were analyzed June 2022 to April 2023.

Exposure

Receipt of RNI (targeting at least the supraclavicular region).

Main Outcome(s) and Measure(s)

Cumulative incidence of LRR was calculated by locoregional treatment received. Analyses were assessed for associations between invasive disease-free survival (IDFS) and locoregional therapy, adjusted for menopausal status, treatment group, recurrence score, tumor size, nodes involved, and axillary surgery. Radiotherapy information was recorded in the first year after randomization, so survival analyses were landmarked as starting at 1 year among those still at risk.

Results

Of 4871 female patients (median [range] age, 57 [18-87] years) with radiotherapy forms, 3947 (81.0%) reported radiotherapy receipt. Of 3852 patients who received radiotherapy and had complete information on targets, 2274 (59.0%) received RNI. With a median follow-up of 6.1 years, the cumulative incidence of LRR by 5 years was 0.85% among patients who received breast-conserving surgery and radiotherapy with RNI; 0.55% after breast-conserving surgery with radiotherapy without RNI; 0.11% after mastectomy with postmastectomy radiotherapy; and 1.7% after mastectomy without radiotherapy. Similarly low LRR was observed within the group assigned to endocrine therapy without chemotherapy. The rate of IDFS did not differ by RNI receipt (premenopausal: hazard ratio [HR], 1.03; 95% CI, 0.74-1.43; P = .87; postmenopausal: HR, 0.85; 95% CI, 0.68-1.07; P = .16).

Conclusions and Relevance

In this secondary analysis of a clinical trial, RNI use was divided in the setting of biologically favorable N1 disease, and rates of LRR were low even in patients who did not receive RNI. Disease-free survival was not associated with RNI receipt; omission of chemotherapy among patients similar to those enrolled in the S1007 trial is not an independent indication for use of RNI.

Glioblastoma multiforme metastasizing to the skin, a case report and literature review

Glioblastoma Multiforme (GBM) is the most common primary central nervous system (CNS) malignancy in adults. It is very aggressive and is notorious for its fast and local invasion of nearby brain parenchyma. Consequently, the overall survival (OS) of patients with GBM is short despite resection, radiotherapy and chemotherapy regimens. The most common sites of metastasis of GBM are the lungs and pleura, cervical lymph nodes, and bone. Metastasis to the skin is a rare event and to our knowledge, there are less than 30 cases of GBM metastasizing to cutaneous or subcutaneous tissue described in the literature. None of these cases were diagnosed and/or treated in the Middle East region; and the majority of the metastases found were adjacent to the site of surgery undergone to remove the primary malignancy. We present the case of a 53-year-old male diagnosed with GBM and later showing signs of metastases at the anterio-auricular side of his face near-distant from the site of previous surgery done to remove the primary tumor.

Neoadjuvant chemotherapy and Avelumab in early stage resectable nonsmall cell lung cancer

Multiple randomized studies have shown that combination of chemotherapy and immune checkpoint inhibitors (ICIs) leads to better response rates and survival as compared to chemotherapy alone in the advanced stage of NSCLC. Data suggesting a benefit to using ICIs in the neoadjuvant therapy of patients with early stage NSCLC are emerging. Eligible subjects were treatment naïve patients with stage IB, II, and resectable IIIA NSCLC. Patients received three cycles of neoadjuvant chemotherapy with four doses of avelumab every 2 weeks. Patients with squamous cell cancer received cisplatin or carboplatin on day 1 and gemcitabine on days 1 and 8 of each cycle of chemotherapy. Patients with nonsquamous histology received cisplatin or carboplatin with pemetrexed on day 1 of each cycle. Patients then proceeded to their planned surgery. Out of 15 patients accrued as part of stage 1 of the study, four had a radiologic response (1 complete response), lower than the minimum of six responses needed to continue to phase 2 of the study. The study was therefore terminated. Majority had adenocarcinoma histology and stage IIIA disease. The treatment was well tolerated with no unexpected side effects. Four patients (26.7%) had grade III/IV CTCAE toxicity. This study confirms that the preoperative administration of chemotherapy and avelumab is safe. There was no indication of increased surgical complications. The benefit of adding immunotherapy to chemotherapy did not appear to enhance the overall response rate of patients in the neoadjuvant setting in patients with resectable NSCLC because this study failed to meet its primary endpoint.

Short-course radiation followed by mFOLFOX-6 plus avelumab for locally advanced rectal adenocarcinoma

139

Background: Total neoadjuvant treatment (TNT) for locally advanced rectal cancer is becoming an accepted approach over the last few years with increasing pathologic complete response (pCR) and compliance of patients for chemotherapy in comparison with the current standard of care i.e., fluoropyrimidine based chemoradiation followed by surgery and adjuvant chemotherapy. Sequential use checkpoint inhibitors after radiation therapy (RT) has demonstrated synergistic effect in vivo leading to decrease in size of irradiated and non-irradiated secondary tumors outside the radiation field (abscopal effect). Methods: This is an investigator initiated; open-label, single-arm multicenter phase II study, adopting Simon’s two-stage aiming at evaluating the pCR rate and safety of using short-course radiation therapy (25 Grays in 5 fractions), followed by 6 cycles of mFOLFOX-6 plus Avelumab (anti PDL1), then total mesorectal excision(TME) in patients with locally-advanced, potentially resectable rectal adenocarcinoma. Results: 13 out of 44 patients were accrued from 20, July till 28, Dec 2018 in the first stage of the study (30% from total sample size). They all met the inclusion criteria and received full protocol treatment. 12 out of the 13 completed TME. 1 of the 13 had progression of disease, so surgery was aborted and patient was dropped out the study. The sample consisted of 9 (69%) males and 4 (31%) females with median age of 62 (33.0, 73.0) years. The first interim analysis revealed 3 patients (25%) achieved pCR (tumor regression grade: TRG = 0) out of 12 as compared to the historical control group with pCR of 16%. For the rest of the patients, 3 (25%) had major pathologic response rate (pRR) with TRG = 1 (< 10% viable cells is tumor bed).In total, 6 out of 12 patients (50%) had major pathologic response rate. As for safety, no serious adverse events of grade 3 and 4 were reported. Conclusions: Based on the first interim analysis results, incorporation of Avelumab and short course radiotherapy is tolerable in patients with locally advanced rectal cancer treated with TNT. The study will resume recruitment to reach the target accrual. Clinical trial information: NCT03503630.

Abstract 4161: Protecting Sphingomyelin Phosphodiesterase Acid Like 3B (SMPDL3b) enhances kidney function and reduces concurrent chemoradiotherapy-induced nephrotoxicity

Background: Cisplatin is a widely used radiosensitizer. Dose-related and cumulative renal insufficiency, including acute renal failure, are the primary dose-limiting toxicities of cisplatin. The lipid-modulating enzyme sphingomyelin phosphodiesterase acid-like 3B (SMPDL3b) and Sphingosine 1-Phosphate Receptor-1 (S1P1) are critical determinants of renal podocyte injury. In the current study, we investigated the functions of SMPDL3b and S1P in cisplatin and radiation-induced renal injury, and the use of rituximab (RTX) to attenuate nephrotoxicity.

Material/Methods: Podocytes were incubated for 2 h with S1P (100 nM) or vehicle (2% dodecane/98% ethanol) and irradiated with 0-8 Gy, or podocytes were irradiated (8 Gy) in the presence of RTX (100 mg/ml) or IgG (100 mg/ml). In other experiments, 10-14-week old C57BL/6 mice were given bilateral kidney X-irradiation (4 Gy) using an image-guided small animal arc radiation treatment system (iSMAART), 6mg/kg cisplatin or combined cisplatin plus radiation. Some animals received a single intravenous (IV) injection of rituximab mAb or IgG (50 mg/kg) prior to treatment. Functional kidney parameters and immuno-histopathological assessments of renal damage (e.g. oil red staining, H & E, Periodic Acid-Schiff (PAS) and SMPDL3B expression) were measured post-RT. iSMAART dynamic contrast-enhanced (DCE) imaging was used for estimating glomerular filtration rate 20 weeks post radiation.

Results: Exogenous S1P rescued podocytes from concurrent chemoradiotherapy-induced cellular cytoskeletal remodeling, and RTX pretreatment mitigated podocytopathy in vitro. iSMAART dynamic contrast-enhanced (DCE) imaging analysis showed that rituximab pretreatment improved the GFR and kidney function parameters post concurrent chemoradiotherapy. SMPDL3b expression at the protein level and podocyte counts dropped significantly in irradiated kidney post-RT in cisplatin-treated mice. Rituximab pretreatment in cisplatin-treated mice, improved GFR, kidney functional parameters, vascular structure, normalization of pericyte coverage, suppress the development of fibrosis and tubular damage post-irradiation.

Conclusion: This study shows that rituximab pretreatment protects mice against concurrent chemoradiation induced kidney injury. SMPDL3b and Sphingosine 1-Phosphate Receptor-1 may be important therapeutic targets for radiation-induced kidney injuries in cancer patients.

Citation Format: Anis Ahmad, Alla Mitrofanova, Saba Ansari, Junwei Shi, Yidong Yang, Sandra Merscher, Alessia Fornoni, Youssef Zeidan, Brian Marples. Protecting Sphingomyelin Phosphodiesterase Acid Like 3B (SMPDL3b) enhances kidney function and reduces concurrent chemoradiotherapy-induced nephrotoxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4161.

Abstract 904: Podocyte-specific SMPDl3b modulates radiation-induced renal dysfunction

Background: The underlying mechanisms responsible for the renal failure and proteinuria in radiation nephropathy remain largely unknown. Radiotherapy with or without chemotherapy may result in radiation-induced kidney injury in pelvic malignancies such as gynecologic cancers, lymphomas, gastrointestinal cancers, sarcomas of the upper abdomen and during total body irradiation. The current study investigates the role of sphingolipids in radiation-induced podocytopathy using a murine model. The molecular and functional effects of kidney irradiation were evaluated after single-dose exposures.

Material/Methods: In cell culture, SMPDL3b expression post radiation (8Gy) was determined by real-time PCR (RT-PCR) and Western blotting. Morphological changes and DNA damage were detected post radiation using immunofluorescence microscopy. Wild-type C57BL/6 male and female mice (age 10-14 weeks) were irradiated with a single dose of X-ray (14 Gy) using an image guided small animal arc radiation treatment system (iSMAART). Rituximab/IgG was administered (50 mg/kg, intraperitoneal injection) 30 min before the single dose of irradiation. Functional kidney parameters, kidney histology, and gene expression were analyzed at 20, 30 and 40 weeks after irradiation.

Results: Following irradiation, SMPDL3b expression at protein level was significantly reduced in vitro and in vivo. However, no significant changes were observed at the transcriptional level. Podocyte number also decreased significantly post radiation in vivo. iSMAART dynamic contrast enhanced (DCE) imaging data analysis showed reduced glomerular filtration rate post radiation. In agreement with the functional data, hematoxylin and eosin staining of kidney sections showed a multifocal increase in the number of pericytes, tubular atrophy, and glomerular damage. Periodic Acid-Schiff (PAS) staining showed an increase in glomerular mesangial matrix accumulation post radiation. Sirius red staining showed diffuse intertubular fibrosis, especially in the renal cortex post radiation. These histological changes were paralleled by the change in serum Creatinine, urine albumin. Rituximab pretreatment to mice, improved kidney functional parameters, vascular structure, normalization of pericyte coverage, suppress the development of fibrosis and tubular damage post irradiation.

Conclusion: This study shows that rituximab pretreatment protects mice against radiation-induced nephrotoxicity, which may have therapeutic implications for radiation-induced injuries in cancer patients.

Citation Format: Anis Ahmad, Alla Mitrofanova, Saba Ansari, Thirupandiyur Udayakumar, Jacek Bielawski, Alan Pollack, Alesia Fornoni, Brian Marples, Youssef Zeidan. Podocyte-specific SMPDl3b modulates radiation-induced renal dysfunction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 904. doi:10.1158/1538-7445.AM2017-904

New insights on the use of desipramine as an inhibitor for acid ceramidase

Treatment of different cancer cell lines with desipramine induced a time- and dose-dependent downregulation of acid ceramidase. Desipramine's effect on acid ceramidase appeared specific for amphiphilic agents (desipramine, chlorpromazine, and chloroquine) but not other lysomotropic agents such as ammonium chloride and bafilomycin A1, and was not transcriptionally regulated. The cathepsin B/L inhibitor, CA074ME, but not the cathepsin D inhibitor, pepstatin A, blocked desipramine's effect on acid ceramidase. Desipramine led to a more pronounced downregulation of sphingosine compared to ceramide suggesting acid ceramidase inhibition is important to desipramine's mechanism of action. This study reveals a new mechanism of action for desipramine.