Pembrolizumab-induced nephrotoxicity in a patient with breast cancer.

The introduction of immunotherapy has revolutionized the treatment and improved outcomes of multiple types of cancer. Although breast cancer is a less immune-responsive tumor type, the incorporation of pembrolizumab into chemotherapy regimens in the neoadjuvant and first-line metastatic setting for the triple-negative disease has improved outcomes. However, the use of this type of treatment is associated with a spectrum of adverse events. Although rarely affected, kidneys can be a target for immunotherapy, leading to irreversible injury if not recognized and addressed early. A 52-year-old woman presented with clinical stage II right breast cancer diagnosed at an outside facility. Neoadjuvant docetaxel/carboplatin/pembrolizumab every 3 weeks was started. Given the partial response on MRI after the 4th cycle, treatment was switched to doxorubicin/cyclophosphamide. However, pembrolizumab was held in cycle 2 due to the rash and then resumed in cycle 3 after the resolution of symptoms. Elevated creatinine was noted 3 weeks after the last dose of pembrolizumab without improvement despite adequate fluid resuscitation. Diagnostic workup was unremarkable except for pyuria and minimal albuminuria on urinalysis. In the absence of other risk factors and the temporal relationship between pembrolizumab administration and the onset of acute kidney injury (AKI), immune-related nephrotoxicity was the underlying diagnosis. After initiation of corticosteroids, creatinine decreased back to baseline without the need for kidney biopsy. An addendum to the original pathology report from the outside facility surfaced 5 months after starting treatment, revealing that the second breast lesion had a Fluorescence in situ hybridization (FISH) test performed that was positive. Given this fact, therapy was changed to two cycles of neoadjuvant paclitaxel/carboplatin/trastuzumab/pertuzumab, with approximately 8 weeks between the last pembrolizumab dose and the first dose of trastuzumab. Thereafter, she underwent a right breast mastectomy which showed residual invasive carcinoma with negative margins and lymph nodes. She completed 1 year of trastuzumab. Immune-related AKI is a rare, but potentially serious complication associated with an increase in mortality. Further research is needed in the development and early detection. There is promising research in the development of noninvasive biomarkers which has the added benefit of identifying patients who can be re-challenged with immunotherapy.

Primary Squamous Cell Biliary Carcinoma With Liver Metastasis Is Rare but Malicious.

Primary squamous cell carcinoma (SCC) of the liver is quite rare, and to our knowledge, very few cases have been reported in the literature. The exact pathogenesis of the disease is unestablished; however, it is mostly reported to be associated with hepatic cyst, Caroli's disease, hepatolithiasis, hepatic cirrhosis, and hepatic teratoma. We report a case of a 50-year-old woman with no prior medical history initially, who presented with postprandial epigastric and right upper quadrant pain that continued to worsen and was associated with early satiety, nausea, and weight loss of 25 pounds over 2 months, which prompted further evaluation by her primary care physician. Magnetic resonance imaging (MRI) examination a month later revealed a large heterogeneous area measuring 8.5 × 2.4 × 7.4 cm in the inferior right hepatic lobe with heterogeneous enhancement and involvement of the gallbladder, concerning for cholangiocarcinoma. Given radiographic findings, she underwent a computed tomography (CT)-guided core biopsy of the liver, which showed a necrotic malignant tumor favoring adenocarcinoma and was also found to have germline BRCA mutation. A positron emission tomography (PET) scan revealed a large partially necrotic fluorodeoxyglucose (FDG) avid mass, possibly arising from the gallbladder fossa with an invasion of both lobes of the liver and probable involvement of a portion of the ascending colon. There was no gross evidence of distant metastatic disease. The patient underwent staging laparoscopy prior to initiating chemotherapy, and another biopsy was done, which returned in favor of SCC, with immunohistochemical stains being positive for cytokeratin (CK)19, Ber-EP4 (epithelial antigen recognized by Ber-EP4 antibody), and P40 (DeltaNp63); while negative for CK7, CK20, caudal-type homeobox 2 (CDX-2), paired box 8 (PAX-8), and mucicarmine. The patient started platinum-based chemotherapy due to germline BRCA mutation. However, due to complications associated with therapy and the progression of the disease, the patient eventually chose hospice. Primary SSC remains an unexplored aggressive malignancy that carries an overall poor prognosis. Diagnosis can be challenging and requires high clinical suspicion due to the scarcity in specific laboratory workup. Pathological diagnosis remains the gold standard; however, it also carries its own challenges. Treatment is usually case-oriented, and definitive protocols have yet to be established.

Allogeneic stem cell transplant outcomes between TBI-containing reduced intensity and myeloablative conditioning regimens for ALL in complete remission.

Total-body irradiation (TBI)-based conditioning regimen is preferred in acute lymphoblastic leukemia (ALL). We retrospectively evaluated allogeneic stem cell transplant (alloSCT) outcomes of 86 adult ALL patients in complete remission (CR) who received TBI-containing reduced intensity (RIC) (Flu/Mel/TBI = 31) and myeloablative conditioning (MAC) (VP16/TBI = 47; CY/TBI = 8) between January 2005 and December 2019. All patients received peripheral blood allografts. Patients in the RIC group were older than the MAC group (61 years old versus 36 years, p < .001). Donor was 8/8 HLA-matched in 83% and unrelated in 65% of patients. Three-year survival was 56.04% for RIC and 69.9% for MAC (HR 0.64; p = .19). Propensity score-based multivariable Cox analyses (PSCA) did not demonstrate any difference in grade III-IV acute graft versus host disease (GVHD) (SHR 1.23, p = .91), chronic GVHD (SHR 0.92, p = .88), survival (HR 0.94, p = .92), and relapse-free survival (HR 0.66, p = .47) between both groups, while relapse rate was lower (SHR 0.21, p = .02) for MAC compared to RIC. Our study did not demonstrate any difference in survival for TBI-containing RIC and MAC alloSCT for adult ALL in CR.

The Role of Surgery in Stage I Small Cell Lung Cancer: A National VA Database Analysis.

BACKGROUND: Historically, limited stage Small Cell Lung Cancer (SCLC) has been treated with concurrent chemoradiation (CRT). While current NCCN guidelines recommend consideration of lobectomy in node-negative cT1-T2 SCLC, data regarding the role of surgery in very limited SCLC is lacking. METHODS: Data from the National VA Cancer Cube were compiled. A total of 1,028 patients with pathologically confirmed stage I SCLC were studied. Only 661 patients that either received surgery or CRT were included. Interval-censored Weibull and Cox proportional hazard regression models were used to estimate median overall survival (OS) and hazard ratio (HR), respectively. Two survival curves were compared by a Wald test. Subset analysis was performed based on the location of the tumor in the upper vs. lower lobe as delineated by ICD-10 codes C34.1 and C34.3. RESULTS: Four-hundred and forty-six patients received concurrent CRT; while 223 underwent treatment that contained surgery (93 surgery only, 87 surgery/chemo, 39 surgery/chemo/radiation and 4 surgery/radiation). The median OS for the surgery-inclusive treatment was 3.87 years (95% CI 3.21-4.48) while median OS for the CRT cohort was 2.45 years (95% CI 2.17-2.74). HR of death for surgery-inclusive treatment when compared to CRT is 0.67 (95% CI 0.55-0.81; P < .001). Subset analysis based on the location of the tumor in both the upper or lower lobes showed improved survival with surgery as compared to CRT regardless of the location. HR for the upper lobe was 0.63 (95% CI 0.50-0.80; P < .001) and lower lobe 0.61 (95% CI 0.42-0.87; P = .006). Multivariable regression analysis accounting for age and ECOG-PS shows a HR 0.60 (95% CI 0.43-0.83; P = .002) favoring surgery. CONCLUSIONS: Surgery was used in less than a third of patients with stage I SCLC who received treatment. Surgery-inclusive multimodality treatment was associated with a longer overall survival as compared to chemoradiation, independent of age, performance status or tumor location. Our study suggests a more expansive role for surgery in stage I SCLC.

Impact of Pre-transplant Induction Therapy on Outcomes of Patients Who Undergo Autologous Stem Cell Transplantation for Mantle Cell Lymphoma in First Complete Remission.

Mantle cell lymphoma is a rare subtype of non-Hodgkin's lymphoma with poor prognosis and continue to be challenging to treat. The choice of first line induction regimen remains a topic of debate due paucity of clinical trials. We retrospectively evaluated 66 patients diagnosed with mantle cell lymphoma who achieved first complete response after induction chemotherapy followed by autologous stem cell transplant. Treatment groups were divided into low-intensity versus high-intensity regimens. Our data showed the intensity of induction regimen does not impact posttransplant outcomes of mantle cell lymphoma who underwent autologous stem cell transplant in first complete response.

Immune Checkpoint Inhibitor-induced Pneumonitis: Incidence, Clinical Characteristics, and Outcomes.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are the newest class of anticancer drugs. Pneumonitis is increasingly being recognized as a potential complication of these agents. METHODS: We conducted a retrospective study of patients who received ICIs at a comprehensive cancer center. We collected data on demographics, type of malignancy, type of ICI agent, incidence of pneumonitis up to 6 weeks after receiving ICI agent, clinical characteristics, and risk factors for overall survival in patients who develop pneumonitis. RESULTS: A total of 654 patients received ICIs during the study period. The most common type of cancer for which ICI was given was adenocarcinoma of the lung (29%), followed by renal cell cancer (12%) and squamous cell lung cancer (12%). Among the study patients, 41% received nivolumab and 32% received pembrolizumab. Other patients in the study received combination of ICIs or ICI plus chemotherapeutic agent, or were part of clinical trial involving ICI. Overall 42 (6.4%) patients developed pneumonitis within 6 weeks after the last dose of treatment of any ICI agent. Of these, 81% of patients had Grade ≥ 2 pneumonitis and 45% of these required hospital admission for pneumonitis, with 10% of them requiring admission to intensive care unit. Overall, patients who received pembrolizumab-containing regimen, had prior chemotherapy, or who never had cancer-related surgery had increased risk of death. CONCLUSION: Our large retrospective study shows real-life data of incidence of pneumonitis in patients who are treated with ICIs for cancer treatment. Our data indicate that the incidence of pneumonitis is overall lower than that reported previously with relatively good outcomes.

Comparison of Carboplatin With Cisplatin in Small Cell Lung Cancer in US Veterans.

Importance: The current standard of care for the treatment of small cell lung cancer (SCLC) is concurrent chemoradiation for patients with limited-stage SCLC (LS-SCLC) and chemoimmunotherapy for extensive-stage SCLC (ES-SCLC). The backbone of chemotherapy regimens in both is a platinum-etoposide doublet: cisplatin is traditionally the preferred platinum agent in the curative intent setting, whereas carboplatin is preferred in ES-SCLC because of its favorable toxicity profile. Objective: To determine whether cisplatin is associated with better survival outcomes than carboplatin in treating LS-SCLC and ES-SCLC. Design, Setting, and Participants: In this cohort study, data were compiled from the National Veterans Affairs Central Cancer Registry for patients with SCLC who received platinum-based multiagent chemotherapy between 2000 and 2020 for ES-SCLC and 2000 and 2021 for LS-SCLC. Only patients with pathologically confirmed cases of LS-SCLC who received concurrent chemoradiation and ES-SCLC who received chemotherapy were included. Main Outcomes and Measures: The primary end point was overall survival (OS). The secondary end points included OS by Eastern Cooperative Oncology Group performance status, age, and laterality. Interval-censored Weibull and Cox proportional hazard regression models were used to estimate median OS and hazard ratios (HRs), respectively. Survival curves were compared by a Wald test. Results: A total of 4408 SCLC cases were studied. Most patients were White (3589 patients [81.4%]), male (4252 [96.5%]), and non-Hispanic (4142 [94.0%]); 2262 patients (51.3%) were 60 to 69 years old, followed by 1476 patients (33.5%) aged 70 years or older, 631 patients (14.3%) aged 50 to 59 years, and 39 patients (0.9%) aged 30 to 49 years. Among 2652 patients with ES-SCLC, 2032 were treated with carboplatin-based therapy and 660 received cisplatin; the median OS was 8.45 months (95% CI, 7.75-9.20 months) for cisplatin and 8.51 months (95% CI, 8.07-8.97 months) for carboplatin (HR, 1.01; 95% CI, 0.91-1.12; P = .90). Subset analysis showed no survival difference between the 2 agents in different age or performance status groups except for patients aged 70 years and older, for whom the median OS was 6.36 months (95% CI, 5.31-7.56 months) for cisplatin and 8.47 months (95% CI, 7.79-9.19 months) for carboplatin (HR, 0.77; 95% CI, 0.61-0.96; P = .02). Multivariable analysis of performance status and age did not show a significant difference in survival between the 2 groups (HR, 0.96; 95% CI, 0.83-1.10; P = .54). Of 1756 patients with LS-SCLC, 801 received carboplatin, and 1018 received cisplatin. The median OS was 26.92 months (95% CI, 25.03-28.81 months) for cisplatin and 25.58 months (95% CI, 23.64-27.72 months) for carboplatin (HR, 1.04; 95% CI, 0.94-1.16; P = .46). The median OS was not significantly different between 2 agents according to cancer stage (I-III), performance status, and age groups. A multivariable analysis of factors associated with OS accounting for stage (I-III), performance status, and age did not demonstrate a significant difference in survival between carboplatin and cisplatin in patients with LS-SCLC (HR, 0.995; 95% CI, 0.86-1.15; P = .95). Conclusions and Relevance: Cisplatin is not associated with a survival advantage over carboplatin among patients with either ES-SCLC or LS-SCLC, irrespective of performance status and age. The favorable toxicity profile of carboplatin and comparable OS support its use in both LS-SCLC and ES-SCLC in clinical practice and may allow more room for combination with novel treatment strategies in clinical trials.

Crescentic Glomerulonephritis and Membranous Nephropathy: A Rare Overlap.

Background: Membranous nephropathy (MN) is a disease that affects the basement membrane of the glomeruli of the kidney resulting in proteinuria. The concurrent incidence of vasculitic glomerulonephritis and MN in the same patient is unusual. Herein, we report a case with this unusual combination. Case: Our patient is a 53-year-old Hispanic male with a medical history of tobacco use, type 2 diabetes mellitus, and hypertension who presented with hematuria and was found to have nephrotic range proteinuria and renal impairment. Blood workup revealed positive ANCA serology, which led to a renal biopsy that showed crescentic vasculitis in addition to membranous nephropathy. The patient was started on intermittent hemodialysis (HD) and treated initially with intravenous (IV) pulse steroids; subsequently, oral prednisolone and IV cyclophosphamide were initiated. The patient remained HD dependent at the time of discharge with the resolution of hematuria. A follow-up with an outpatient nephrology clinic was arranged. Conclusion: Membranous nephropathy complicated by crescentic glomerulonephritis has a more aggressive clinical course and decline in renal function compared to MN alone which can lead to initiating renal replacement therapy. However, immunosuppressive drugs can result in significant improvement of renal function if started early enough.

Lutetium-177 Dotatate-Induced Hemolytic Anemia and Myelodysplastic Syndrome.

Lutetium-177 (177Lu) dotatate is a type of peptide receptor radioligand therapy (PRRT) using radiolabeled somatostatin for patients with progressive somatostatin receptor-positive gastrointestinal neuroendocrine tumors. While cases of therapy-related myeloid neoplasms (t-MN) have been described as a consequence of 177 Lu dotatate, there are no reports of hemolytic anemia associated with therapy. We present a case of a 68-year-old woman with metastatic low-grade neuroendocrine tumor who presented four weeks after the second dose of 177Lu dotatate with progressive fatigue and dyspnea. Laboratory workup was remarkable for hemolytic anemia. Lutetium-177 dotatate-induced hemolysis was suspected after ruling out other causes. Corticosteroid treatment was initiated with improvement in hemoglobin, and dose-reduced PRRT was planned upon discharge. Six months into the treatment course of 177Lu dotatate, macrocytic anemia was noticed on routine follow-up with normal vitamin B12 and folic acid levels. A bone marrow biopsy was done, revealing myelodysplastic syndrome (MDS) features. Given the temporal relationship between drug introduction and the objective findings, early-onset 177Lu dotatate-induced MDS was diagnosed with a plan for close hematologic follow-up. Myelodysplastic syndrome should be suspected when megaloblastic anemia develops in patients with previous 177Lu dotatate therapy. The latency period between initial treatment and MDS diagnosis reported in the literature ranges between 15 months to seven years. Apart from the unusually early onset of MDS, what is unique about our case is the development of hemolytic anemia after administration of PRRT. The clinical course and the brisk response to steroid therapy, suggest other mechanisms of PRRT toxicity besides DNA breaks, genetic mutations, and myelosuppression by an immune-mediated component that likely plays a role in 177Lu dotatate toxicity. Further investigation and monitoring are needed to identify the frequency of such adverse events and the pathophysiology of their occurrence.

Idiopathic portal vein thrombosis not related to hepatic disease or malignancy.

Acute portal vein thrombosis (PVT) is a rare disorder defined by the sudden occlusion of the portal vein, which could be partial or complete. Prothrombotic states, inherited or acquired, are thought to be the cause in patients without cirrhosis or malignancy. However, the aetiology of some cases remains idiopathic despite a multidisciplinary diagnostic approach. The initial diagnostic modality to confirm PVT is either contrast-enhanced abdominal (CT) or MRI; as it can identify predisposing factors, and detect evidence of complications. Eliciting the underlying aetiology is critical to guide overall management and prevent future recurrence. The purpose of treatment is to stop thrombus extension and achieve portal vein patency by anticoagulation to optimise outcomes. Herein, we present an unusual case of spontaneous PVT in a young woman. We will also discuss the evaluation of patients without obvious aetiology.

Spotlight on Trastuzumab Deruxtecan (DS-8201,T-DXd) for HER2 Mutation Positive Non-Small Cell Lung Cancer.

Human epidermal growth factor receptor 2 (HER2) is a proto-oncogene that, when mutated or overexpressed, plays an important role in oncogenesis. The landscape of HER2-positive breast cancer has changed dramatically over the past 2 decades with the FDA approval of a growing number of agents (antibodies, tyrosine kinase inhibitors, and antibody-drug conjugates) targeting the HER2 receptor. HER2 inhibition has also been approved for HER2-positive gastric cancer. HER2 is amplified in 9% and mutated in 3% of lung cancer. Historically, HER2-targeted therapy for lung cancer with trastuzumab, pertuzumab, and trastuzumab emtansine has failed to demonstrate a survival benefit. Trastuzumab deruxtecan (T-DXd) is a novel antibody-drug conjugate with a tetrapeptide linker, which delivers a topoisomerase I inhibitor with a drug-to-antibody ratio of 7~8. The potency of the active payload, as well as its significant bystander effect, resulted in significant anti-tumor activity. The DESTINY-Lung01 trial evaluated T-DXd in HER2-positive non-squamous non-small cell lung cancer (NSCLC) and reported a progression-free survival of 14 months in HER2-mutated NSCLC, earning its breakthrough designation by the FDA. In this review, we will discuss the structural characteristics, pharmacodynamics, and pharmacokinetics of T-DXd. We will also shed light on the preclinical and ongoing clinical trials of T-DXd along with future directions in the management of HER2 positive lung cancer.

SARS-CoV-2 infection: Initial viral load (iVL) predicts severity of illness/outcome, and declining trend of iVL in hospitalized patients corresponds with slowing of the pandemic.

BACKGROUND: Hospitalization of patients infected with the severe acute respiratory syndrome virus 2 (SARS-CoV-2) have remained considerable worldwide. Patients often develop severe complications and have high mortality rates. The cycle threshold (Ct) value derived from nasopharyngeal swab samples using real time polymerase chain reaction (RT-PCR) may be a useful prognostic marker in hospitalized patients with SARS-CoV-2 infection, however, its role in predicting the course of the pandemic has not been evaluated thus far. METHODS: We conducted a retrospective cohort study which included all patients who had a nasopharyngeal sample positive for SARS-CoV-2 between April 4 -June 5, 2020. The Ct value was used to estimate the number of viral particles in a patient sample. The trend in initial viral load on admission on a population level was evaluated. Moreover, patient characteristics and outcomes stratified by viral load categories were compared and initial viral load was assessed as an independent predictor of intubation and in-hospital mortality. RESULTS: A total of 461 hospitalized patients met the inclusion criteria. This study consisted predominantly of acutely infected patients with a median of 4 days since symptom onset to PCR. As the severity of the pandemic eased, there was an increase in the percentage of samples in the low initial viral load category, coinciding with a decrease in deaths. Compared to an initial low viral load, a high initial viral load was an independent predictor of in-hospital mortality (OR 5.5, CI 3.1-9.7, p < 0.001) and intubation (OR 1.82 CI 1.07-3.11, p = 0.03), while an initial intermediate viral load was associated with increased risk of inpatient mortality (OR 1.9, CI 1.14-3.21, p = 0.015) but not with increased risk for intubation. CONCLUSION: The Ct value obtained from nasopharyngeal samples of hospitalized patients on admission may serve as a prognostic marker at an individual level and may help predict the course of the pandemic when evaluated at a population level.

SARS-CoV-2 Viral Load and Myocardial Injury: Independent and Incremental Predictors of Adverse Outcome.

To evaluate the association of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) initial viral load (iVL) and the incidence of myocardial injury (MCI) in hospitalized patients with SARS-CoV-2 infection, we conducted a retrospective longitudinal study of hospitalized patients who had a nasopharyngeal swab sample on admission that returned a positive result for SARS-CoV-2 by polymerase chain reaction between April 4 and June 5, 2020. The cycle threshold (Ct) value was used as a surrogate for the iVL level, with a Ct level of 36 or less for elevated iVL and greater than 36 for low iVL. Myocardial injury was defined as an elevated high-sensitivity cardiac troponin I level that was higher than the 99th percentile upper reference limit. A total of 270 patients were included. Of these, 171 (63.3%) had an elevated iVL and 88 (32.6%) had MCI. There was no significant difference in the incidence of MCI in patients with low iVL compared to those with elevated iVL (28 of 99 [28.3%] vs 60 of 171 [35.1%]; P=.25). In a multivariable model, MCI (odds ratio, 3.86; 95% CI, 1.80 to 8.34; P<.001) and elevated iVL (odds ratio, 4.21; 95% CI, 2.06 to 8.61; P<.001) were independent and incremental predictors of in-hospital mortality. The SARS-CoV-2 iVL level is not associated with increased incidence of MCI, although both parameters are strong independent and incremental predictors of mortality. Understanding the MCI mechanisms allows for early focused interventions to improve survival, especially in patients with SARS-CoV-2 infection and high iVL.

Midostaurin-induced Sweet syndrome in a patient with FLT3-ITD-positive AML.

Sweet syndrome (SS), also referred as acute febrile neutrophilic dermatosis, is an inflammatory process characterised by the abrupt appearance of erythematous papules or nodules with predominant neutrophilic infiltration in the dermis. Fever and neutrophilia are common presenting features. However, extracellular manifestations, including ocular and musculoskeletal, may occur. SS is divided into three subtypes: classical (or idiopathic), malignancy associated and drug induced. Medication-induced subtype accounts for up to 26% of cases. In recent years, emerging evidence has showed that SS may also occur in neutropenic patients who underwent induction for acute myeloid leukemia (AML). The identification of FMS-like tyrosine kinase 3 (FLT3) gene mutation in approximately 30% of patients with AML has promoted the targeted therapy with FLT3-internal tandem duplication (ITD) inhibitors. Midostaurin, a recently Food and Drug Administration-approved medication for FLT3-ITD-positive AML, was reported once as cause for SS. We report a midostaurin-induced SS with neutropenia in a patient following induction chemotherapy of AML.

BRCA mutations in pancreatic cancer and progress in their targeting.

Introduction: Genomic instability resulting from DNA damage repair (DDR) deficiencies is a hallmark of cancer and offers treatment opportunities. Homologous recombination DDR defect is a result of multiple critical gene mutations, including BRCA1/2. Targeting DNA DDR defects in pancreatic cancer (PC) is emerging as a potential treatment strategy with current focus on BRCA mutations.Areas covered: Challenges in treating patients with PC are explained. We review DDR defects as a treatment target in PC, specifically, germline BRCA mutation and sensitivity to platinum compounds and exploiting the strategy of synthetic lethality using poly (ADP-ribose) polymerase (PARP) inhibition. Literature review was undertaken through PubMed, Google Scholar, and Clinicaltrials.gov website.Expert opinion: DDR defects are promising targets for novel therapies in PC. Early application of such strategy is in patient subgroup with BRCA germline mutation, which is seen in only 5-7% of the PC population. The oral PARP inhibitor olaparib in the maintenance setting represents the first targeted therapy in metastatic PC based on a phase 3 study. There is a very modest benefit for patients with PC using PARP inhibitors. Future work must improve our understanding of mechanisms of sensitivity and resistance to PARP inhibitors in PC and enhance the molecular selection of patients for such therapy.

Rectal Invasion by Metastatic Prostate Adenocarcinoma.

In men, prostate cancer is the second most diagnosed cancer worldwide. Typical sites for metastasis include bone, lung, and liver. Prostate cancer with gastrointestinal involvement, particularly rectal, has been rarely reported in the literature. As patients with prostate cancer with rectal invasion may present with symptoms similar to those of other gastrointestinal pathologies, such as anal fissures and rectal carcinoma itself, misdiagnosis and delays in care can result. Direct visualization of the rectum via endoscopy, along with biopsy, allows clinicians to make an accurate and timely diagnosis in patients with prostate cancer with rectal involvement, which in turn leads to broader available treatment options.

Atypical Hemolytic Uremic Syndrome in the Setting of Acute Clostridium difficile Colitis.

Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. HUS can be secondary to multiple etiologies such as infections, medications, and immune processes. A rare, yet significant, etiology of HUS includes acute Clostridium difficile colitis. Here, we present a case of atypical HUS secondary to acute C. difficile colitis, successfully treated with hemodialysis and systemic corticosteroids. It is imperative that clinicians are cognizant of C. difficile-associated HUS given the overall rising incidence of acute C. difficile infections.

Maintained Complete Response and Long-Term Survival in Epidermal Growth Factor Receptor Mutated Metastatic Non-Small Cell Lung Cancer with Erlotinib.

The prognosis of advanced non-small cell lung cancer (NSCLC) has significantly improved for certain patients with the development of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). However, metastatic NSCLC patients with long-term survival are still rare. Our 66-year-old male patient was admitted to the hospital for treatment of pneumonia. A chest CT scan done revealed a left upper lobe mass; computed tomography (CT)-guided fine-needle aspiration (FNA) was done in 2010 revealing adenocarcinoma. A staging positron emission tomography (PET) scan did not reveal evidence of metastatic disease. He underwent left upper lobectomy and the pathologic stage was IB, moderately differentiated adenocarcinoma with positive angiolymphatic invasion. He was offered adjuvant systemic therapy, but he opted for surveillance. In 2012, a CT scan showed disease recurrence in the left upper lobe, which was confirmed with a biopsy. He was deemed non-surgical by thoracic oncology. Systemic therapy was initiated with carboplatin/pemetrexed and Avastin; after four cycles of treatment, the CT scan showed stable disease. Mutation analysis sent before chemotherapy revealed EGFR mutation for which chemotherapy was stopped and he was started on switch maintenance with erlotinib 150 mg in October 2012, then the dose was reduced to 100 mg secondary to grades 2-3 acneiform rash. Follow-up CT scans in January 2016 showed complete remission, which is maintained with no evidence of disease as of today. Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related mortality in the United States. Surgical excision is the standard treatment for stage I disease. Despite the long-term survival without adjuvant therapy, the disease recurrence rate ranges between 27% and 38% after resection. Different histologic subtypes vary in pathologic and molecular features, leading to differences in treatment and prognosis. In the adenocarcinoma subtype, five-year progression-free survival in patients with EGFR mutation treated with an EGFR-TKI is 14.6% as compared to less than 5% in unselected patients with distant-stage NSCLC. The association between exon 19 deletions, which represent about 45% of overall EGFR mutations and half of the sensitizing ones, and prolonged survival in patients with advanced NSCLC treated with EGFR-TKIs has been reported by several groups. Our case reports long-term survival in a patient with EGFR mutation-positive NSCLC with no evidence of disease for eight years since he started erlotinib treatment. Is there an option to discontinue maintenance erlotinib at this point? The answer to this question is not known, but this is a remarkably maintained response that is a good area to study patient's characteristics leading to differences in response.