Susan M. Hiniker

Abscopal effect in a patient with melanoma.

n engl j med 366;21 nejm.org may 24, 2012 2035 In the list of statements they believe to be incorrect in my editorial, Harrison et al. disregard published data on the long-term experience with ruxolitinib.2,3 Among 51 patients with myelofibrosis who received ruxolitinib at the Mayo Clinic from October 2007 through February 2009, a total of 49 (96%) had discontinued treatment at a median of less than 1 year, mostly for loss or lack of response, and risk-adjusted survival was not affected.2 In the study by Harrison and colleagues, the probability of maintained spleen response at 48 weeks was less than 60%, and more deaths were reported in patients assigned to the ruxolitinib group than in patients assigned to best available therapy (8% vs. 5%, P value not specified). In their defense of the drug, the authors misquote my comments on peripheral neuropathy and downplay the “ruxolitinib withdrawal syndrome.”3 The bottom line is that noncritical assessment of ruxolitinib cannot overcome its therapeutic limitations and potential harm to patients. I favor an approach wherein one points out the benefits and deficiencies of ruxolitinib in a balanced fashion. In my opinion, our patients deserve better than the ruxolitinib portfolio of symptomatic relief at the cost of treatment-associated induction or exacerbation of anemia or thrombocytopenia, and they should instead be encouraged to participate in clinical trials of potentially better drugs.

Role of Epidermal Growth Factor Receptor Degradation in Cisplatin-Induced Cytotoxicity in Head and Neck Cancer

Cisplatin and its analogues are the most commonly used agents in the treatment of head and neck squamous cell carcinoma. In this study, we investigated a possible role of epidermal growth factor (EGF) receptor (EGFR) phosphorylation and degradation in cisplatin-induced cytotoxicity. Cisplatin treatment led to an increase in initial EGFR phosphorylation at Y1045, the binding site of ubiquitin ligase, Casitas B-lineage lymphoma (c-Cbl), followed by ubiquitination in the relatively cisplatin-sensitive cell lines. However, cisplatin-resistant cell lines underwent minimal EGFR phosphorylation at the Y1045 site and minimal ubiquitination. We found that EGFR degradation in response to cisplatin was highly correlated with cytotoxicity in seven head and neck cancer cell lines. Pretreatment with EGF enhanced cisplatin-induced EGFR degradation and cytotoxicity, whereas erlotinib pretreatment blocked EGFR phosphorylation, degradation, and cisplatin-induced cytotoxicity. Expression of a mutant Y1045F EGFR, which is relatively resistant to c-Cbl-mediated degradation, in Chinese hamster ovary cells and the UMSCC11B human head and neck cancer cell line protected EGFR from cisplatin-induced degradation and enhanced cell survival compared with wild-type (WT) EGFR. Transfection of WT c-Cbl enhanced EGFR degradation and cisplatin-induced cytotoxicity compared with control vector. These results show that cisplatin-induced EGFR phosphorylation and subsequent ubiquitination and degradation is an important determinant of cisplatin sensitivity. Our findings suggest that treatment with an EGFR inhibitor before cisplatin would be antagonistic, as EGFR inhibition would protect EGFR from cisplatin-mediated phosphorylation and subsequent ubiquitination and degradation, which may explain the negative results of several recent clinical trials. Furthermore, they suggest that EGFR degradation is worth exploring as an early biomarker of response and as a target to improve outcome.

Role of Cell Cycle in Epidermal Growth Factor Receptor Inhibitor-Mediated Radiosensitization

Epidermal growth factor receptor (EGFR) inhibitors are increasingly used in combination with radiotherapy in the treatment of various EGFR-overexpressing cancers. However, little is known about the effects of cell cycle status on EGFR inhibitor-mediated radiosensitization. Using EGFR-overexpressing A431 and UMSCC-1 cells in culture, we found that radiation activated the EGFR and extracellular signal-regulated kinase pathways in quiescent cells, leading to progression of cells from G(1) to S, but this activation and progression did not occur in proliferating cells. Inhibition of this activation blocked S-phase progression and protected quiescent cells from radiation-induced death. To determine if these effects were caused by EGFR expression, we transfected Chinese hamster ovary (CHO) cells, which lack EGFR expression, with EGFR expression vector. EGFR expressed in CHO cells also became activated in quiescent cells but not in proliferating cells after irradiation. Moreover, quiescent cells expressing EGFR underwent increased radiation-induced clonogenic death compared with both proliferating CHO cells expressing EGFR and quiescent wild-type CHO cells. Our data show that radiation-induced enhancement of cell death in quiescent cells involves activation of the EGFR and extracellular signal-regulated kinase pathways. Furthermore, they suggest that EGFR inhibitors may protect quiescent tumor cells, whereas radiosensitization of proliferating cells may be caused by downstream effects such as cell cycle redistribution. These findings emphasize the need for careful scheduling of treatment with the combination of EGFR inhibitors and radiation and suggest that EGFR inhibitors might best be given after radiation in order to optimize clinical outcome.

Role of KEAP1/NRF2 and TP53 Mutations in Lung Squamous Cell Carcinoma Development and Radiation Resistance

Lung squamous cell carcinoma (LSCC) pathogenesis remains incompletely understood, and biomarkers predicting treatment response remain lacking. Here, we describe novel murine LSCC models driven by loss of Trp53 and Keap1, both of which are frequently mutated in human LSCCs. Homozygous inactivation of Keap1 or Trp53 promoted airway basal stem cell (ABSC) self-renewal, suggesting that mutations in these genes lead to expansion of mutant stem cell clones. Deletion of Trp53 and Keap1 in ABSCs, but not more differentiated tracheal cells, produced tumors recapitulating histologic and molecular features of human LSCCs, indicating that they represent the likely cell of origin in this model. Deletion of Keap1 promoted tumor aggressiveness, metastasis, and resistance to oxidative stress and radiotherapy (RT). KEAP1/NRF2 mutation status predicted risk of local recurrence after RT in patients with non-small lung cancer (NSCLC) and could be noninvasively identified in circulating tumor DNA. Thus, KEAP1/NRF2 mutations could serve as predictive biomarkers for personalization of therapeutic strategies for NSCLCs. SIGNIFICANCE We developed an LSCC mouse model involving Trp53 and Keap1, which are frequently mutated in human LSCCs. In this model, ABSCs are the cell of origin of these tumors. KEAP1/NRF2 mutations increase radioresistance and predict local tumor recurrence in radiotherapy patients. Our findings are of potential clinical relevance and could lead to personalized treatment strategies for tumors with KEAP1/NRF2 mutations. Cancer Discov; 7(1); 86-101. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 1.

Re-irradiation with stereotactic body radiation therapy as a novel treatment option for isolated local recurrence of pancreatic cancer after multimodality therapy: experience from two institutions

Limited treatment options exist for isolated local recurrence of pancreatic ductal adenocarcinoma (PDA) following surgical resection accompanied by neoadjuvant or adjuvant chemoradiation therapy (CRT). While select patients are eligible for re-resection, recurrent lesions are often unresectable. Stereotactic body radiation therapy (SBRT) represents a possible minimally invasive treatment option for these patients, although published data in this setting are currently lacking. This study examines the safety, efficacy, and palliative capacity of re-irradiation with SBRT for isolated local PDA recurrence. All patients undergoing SBRT at two academic centers from 2008-2012 were retrospectively reviewed to identify those who received re-irradiation with SBRT for isolated local recurrence or progression of PDA after previous conventionally fractionated CRT. Information regarding demographics, clinicopathologic characteristics, therapies received, survival, symptom palliation, and toxicity was obtained from patient charts. Kaplan-Meier statistics were used to analyze survival and the log-rank test was used to compare survival among patient subgroups. Eighteen patients were identified. Fifteen had previously undergone resection with neoadjuvant or adjuvant CRT, while 3 received definitive CRT for locally advanced disease. Median CRT dose was 50.4 Gy [interquartile range (IQR), 45.0-50.4 Gy] in 28 fractions. All patients subsequently received gemcitabine-based maintenance chemotherapy, but developed isolated local disease recurrence or progression without evidence of distant metastasis. Locally recurrent or progressive disease was treated with SBRT to a median dose of 25.0 Gy (range, 20.0-27.0 Gy) in 5 fractions. Median survival from SBRT was 8.8 months (95% CI, 1.2-16.4 months). Despite having similar clinicopathologic disease characteristics, patients who experienced local progression greater than vs. less than 9 months after surgery/definitive CRT demonstrated superior median survival (11.3 vs. 3.4 months; P=0.019) and progression-free survival (10.6 vs. 3.2 months; P=0.030) after SBRT. Rates of freedom from local progression at 6 and 12 months after SBRT were 78% (14 of 18 patients) and 62% (5 of 8 patients), respectively. Effective symptom palliation was achieved in 4 of 7 patients (57%) who reported symptoms of abdominal or back pain prior to SBRT. Five patients (28%) experienced grade 2 acute toxicity; none experienced grade ≥3 acute toxicity. One patient (6%) experienced grade 3 late toxicity in the form of small bowel obstruction. In conclusion, re-irradiation with hypofractionated SBRT in this salvage scenario appears to be a safe and reasonable option for palliation of isolated local PDA recurrence or progression following previous conventional CRT. Patients with a progression-free interval of greater than 9 months prior to isolated local recurrence or progression may be most suitable for re-irradiation with SBRT, as they appear to have a better prognosis with survival that is long enough for local control to be of potential benefit.

Primary squamous cell carcinoma of the vagina: Prognostic factors, treatment patterns, and outcomes

OBJECTIVE Primary squamous cell carcinoma (SCCA) of the vagina is a rare malignancy with limited data to guide treatment. We evaluated prognostic factors and outcomes for patients with primary vaginal SCCA treated with definitive radiation therapy at a single institution. METHODS A retrospective analysis was performed on patients treated for primary vaginal SCCA from 1959 to 2011. RESULTS Ninety-one patients with primary vaginal SCCA were treated with definitive radiation therapy. Thirty-eight patients had FIGO stage I, 28 stage II, 13 stage III, and 12 stage IV disease. The mean total dose was 70.1 Gy. Two-year overall survival (OS), locoregional control rate (LRC), and distant metastasis-free survival by stage were, respectively: stage I: 96.2%, 80.6%, 87.5%; stage II: 92.3%, 64.7%, 84.6%; stage III: 66.6%, 44.4%, 50.0%; and stage IV: 25.0%, 14.3%, 25.0%. Treatment with total dose over 70 Gy was associated with improved OS (p=0.0956) and LRC (p=0.055). There was a significant difference in median dose received by patients who developed grade 3/4 toxicity compared to those who did not (82.9 Gy versus 70.0 Gy, p=0.0019). None of the 10 patients treated with IMRT experienced locoregional recurrence or grade 3/4 toxicity. Tumor size larger than 4 cm was associated with worse OS (p=0.0034) and LRC (p=0.006). CONCLUSIONS Our analysis suggests that the optimal dose for definitive treatment of SCCA of the vagina lies between 70 and 80 Gy. Treatment with IMRT may allow for dose escalation with reduced toxicity and excellent LRC. Tumor size over 4 cm is associated with inferior outcomes and may require additional treatment modalities.

Sporadic versus Radiation-Associated Angiosarcoma: A Comparative Clinicopathologic and Molecular Analysis of 48 Cases

Angiosarcomas are aggressive tumors of vascular endothelial origin, occurring sporadically or in association with prior radiotherapy. We compared clinicopathologic and biologic features of sporadic angiosarcomas (SA) and radiation-associated angiosarcomas (RAA). Methods. From a University of Michigan institutional database, 37 SA and 11 RAA were identified. Tissue microarrays were stained for p53, Ki-67, and hTERT. DNA was evaluated for TP53 and ATM mutations. Results. Mean latency between radiotherapy and diagnosis of RAA was 11.9 years: 6.7 years for breast RAA versus 20.9 years for nonbreast RAA (P = 0.148). Survival after diagnosis did not significantly differ between SA and RAA (P = 0.590). Patients with nonbreast RAA had shorter overall survival than patients with breast RAA (P = 0.03). The majority of SA (86.5%) and RAA (77.8%) were classified as high-grade sarcomas (P = 0.609). RAA were more likely to have well-defined vasoformative areas (55.6% versus 27%, P = 0.127). Most breast SA were parenchymal in origin (80%), while most breast RAA were cutaneous in origin (80%). TMA analysis showed p53 overexpression in 25.7% of SA and 0% RAA, high Ki-67 in 35.3% of SA and 44.4% RAA, and hTERT expression in 100% of SA and RAA. TP53 mutations were detected in 13.5% of SA and 11.1% RAA. ATM mutations were not detected in either SA or RAA. Conclusions. SA and RAA are similar in histology, immunohistochemical markers, and DNA mutation profiles and share similar prognosis. Breast RAA have a shorter latency period compared to nonbreast RAA and a significantly longer survival.

Radiotherapy using a water bath in the treatment of Bowen's disease of the digit.

PURPOSE Bowens disease (BD), a form of squamous cell carcinoma in situ, can transform into invasive squamous cell carcinoma and should be treated aggressively. Although standard treatment for BD is electrodessication and curettage, radiotherapy (RT) can be used for those patients who are poor surgical candidates or when surgery could result in a poor cosmetic and functional outcome. Surgical treatment of BD of the digit can result in poor function and sometimes amputation. Here, we report our experience using a unique water bath technique to treat BD of the digit. MATERIALS AND METHODS This retrospective review evaluates the outcomes and toxicity of nine consecutive patients with BD of the digit treated with RT between 1999 and 2004. Fourteen digit lesions were immersed in a water bath and treated with photon irradiation. The median radiation dose delivered was 50Gy (range 25-66Gy) in 2.5Gy fractions (range 2-3Gy). RESULTS The median age of the patients treated was 77 years (range 29-87 years). Three patients (33%) had more than one digit treated. With a median follow-up of 25 months (range 0.4-52 months), all 14 digit lesions are locally controlled. The majority of lesions demonstrated mild to moderate erythema, desquamation, or edema (grade 1-2) acutely following RT which resolved within one month of treatment. Two digits (14%) developed ulcers (grade 4) which healed following RT. The only long-term toxicity was decreased sensation and strength in one patient who had three circumferential lesions. This toxicity was limited and did not appear to influence the patients daily activities (grade 2). CONCLUSIONS These preliminary results demonstrate high rates of tumor control with minimal morbidity following definitive RT in the treatment of BD of the digit, and suggest that RT may be a viable treatment alternative to surgery for selected lesions. Through a multidisciplinary assessment, treatment of BD of the digit can be individualized to optimize patient care.

Dose-Response Modeling of the Visual Pathway Tolerance to Single-Fraction and Hypofractionated Stereotactic Radiosurgery☆☆☆

Patients with tumors adjacent to the optic nerves and chiasm are frequently not candidates for single-fraction stereotactic radiosurgery (SRS) due to concern for radiation-induced optic neuropathy. However, these patients have been successfully treated with hypofractionated SRS over 2-5 days, though dose constraints have not yet been well defined. We reviewed the literature on optic tolerance to radiation and constructed a dose-response model for visual pathway tolerance to SRS delivered in 1-5 fractions. We analyzed optic nerve and chiasm dose-volume histogram (DVH) data from perioptic tumors, defined as those within 3mm of the optic nerves or chiasm, treated with SRS from 2000-2013 at our institution. Tumors with subsequent local progression were excluded from the primary analysis of vision outcome. A total of 262 evaluable cases (26 with malignant and 236 with benign tumors) with visual field and clinical outcomes were analyzed. Median patient follow-up was 37 months (range: 2-142 months). The median number of fractions was 3 (1 fraction n = 47, 2 fraction n = 28, 3 fraction n = 111, 4 fraction n = 10, and 5 fraction n = 66); doses were converted to 3-fraction equivalent doses with the linear quadratic model using α/β = 2Gy prior to modeling. Optic structure dose parameters analyzed included Dmin, Dmedian, Dmean, Dmax, V30Gy, V25Gy, V20Gy, V15Gy, V10Gy, V5Gy, D50%, D10%, D5%, D1%, D1cc, D0.50cc, D0.25cc, D0.20cc, D0.10cc, D0.05cc, D0.03cc. From the plan DVHs, a maximum-likelihood parameter fitting of the probit dose-response model was performed using DVH Evaluator software. The 68% CIs, corresponding to one standard deviation, were calculated using the profile likelihood method. Of the 262 analyzed, 2 (0.8%) patients experienced common terminology criteria for adverse events grade 4 vision loss in one eye, defined as vision of 20/200 or worse in the affected eye. One of these patients had received 2 previous courses of radiotherapy to the optic structures. Both cases were meningiomas treated with 25Gy in 5 fractions, with a 3-fraction equivalent optic nerve Dmax of 19.2 and 22.2Gy. Fitting these data to a probit dose-response model enabled risk estimates to be made for these previously unvalidated optic pathway constraints: the Dmax limits of 12Gy in 1 fraction from QUANTEC, 19.5Gy in 3 fractions from Timmerman 2008, and 25Gy in 5 fractions from AAPM Task Group 101 all had less than 1% risk. In 262 patients with perioptic tumors treated with SRS, we found a risk of optic complications of less than 1%. These data support previously unvalidated estimates as safe guidelines, which may in fact underestimate the tolerance of the optic structures, particularly in patients without prior radiation. Further investigation would refine the estimated normal tissue complication probability for SRS near the optic apparatus.

Value of surveillance studies for patients with stage I to II diffuse large B-cell lymphoma in the rituximab era.

BACKGROUND The role of surveillance studies in limited-stage diffuse large B-cell lymphoma (DLBCL) in the rituximab era has not been well defined. We sought to evaluate the use of imaging (computed tomography [CT] and positron emission tomography [PET]-CT) scans and lactate dehydrogenase (LDH) in surveillance of patients with stage I to II DLBCL. METHODS A retrospective analysis was performed of patients who received definitive treatment between 2000 and 2013. RESULTS One hundred sixty-two consecutive patients with stage I to II DLBCL were treated with chemotherapy +/- rituximab, radiation, or combined modality therapy. The 5-year rates of overall survival (OS) and freedom from progression (FFP) were 81.2% and 80.8%, respectively. Of the 162 patients, 124 (77%) were followed up with at least 1 surveillance PET scan beyond end-of-treatment scans; of those, 94 of 124 (76%) achieved a complete metabolic response on PET scan after completion of chemotherapy, and this was associated with superior FFP (P=.01, HR=0.3) and OS (P=.01, HR 0.3). Eighteen patients experienced relapse after initial response to therapy. Nine relapses were initially suspected by surveillance imaging studies (8 PET, 1 CT), and 9 were suspected clinically (5 by patient-reported symptoms and 4 by symptoms and physical examination). No relapses were detected by surveillance LDH. The median duration from initiation of treatment to relapse was 14.3 months among patients with relapses suspected by imaging, and 59.8 months among patients with relapses suspected clinically (P=.077). There was no significant difference in OS from date of first therapy or OS after relapse between patients whose relapse was suspected by imaging versus clinically. Thirteen of 18 patients underwent successful salvage therapy after relapse. CONCLUSIONS A complete response on PET scan immediately after initial chemotherapy is associated with superior FFP and OS in stage I to II DLBCL. The use of PET scans as posttreatment surveillance is not associated with a survival advantage. LDH is not a sensitive marker for relapse. Our results argue for limiting the use of posttreatment surveillance in patients with limited-stage DLBCL.