Neoadjuvant durvalumab with or without stereotactic body radiotherapy in patients with early-stage non-small-cell lung cancer: a single-centre, randomised phase 2 trial.

BACKGROUND: Previous phase 2 trials of neoadjuvant anti-PD-1 or anti-PD-L1 monotherapy in patients with early-stage non-small-cell lung cancer have reported major pathological response rates in the range of 15-45%. Evidence suggests that stereotactic body radiotherapy might be a potent immunomodulator in advanced non-small-cell lung cancer (NSCLC). In this trial, we aimed to evaluate the use of stereotactic body radiotherapy in patients with early-stage NSCLC as an immunomodulator to enhance the anti-tumour immune response associated with the anti-PD-L1 antibody durvalumab. METHODS: We did a single-centre, open-label, randomised, controlled, phase 2 trial, comparing neoadjuvant durvalumab alone with neoadjuvant durvalumab plus stereotactic radiotherapy in patients with early-stage NSCLC, at NewYork-Presbyterian and Weill Cornell Medical Center (New York, NY, USA). We enrolled patients with potentially resectable early-stage NSCLC (clinical stages I-IIIA as per the 7th edition of the American Joint Committee on Cancer) who were aged 18 years or older with an Eastern Cooperative Oncology Group performance status of 0 or 1. Eligible patients were randomly assigned (1:1) to either neoadjuvant durvalumab monotherapy or neoadjuvant durvalumab plus stereotactic body radiotherapy (8 Gy × 3 fractions), using permuted blocks with varied sizes and no stratification for clinical or molecular variables. Patients, treating physicians, and all study personnel were unmasked to treatment assignment after all patients were randomly assigned. All patients received two cycles of durvalumab 3 weeks apart at a dose of 1·12 g by intravenous infusion over 60 min. Those in the durvalumab plus radiotherapy group also received three consecutive daily fractions of 8 Gy stereotactic body radiotherapy delivered to the primary tumour immediately before the first cycle of durvalumab. Patients without systemic disease progression proceeded to surgical resection. The primary endpoint was major pathological response in the primary tumour. All analyses were done on an intention-to-treat basis. This trial is registered with ClinicalTrial.gov, NCT02904954, and is ongoing but closed to accrual. FINDINGS: Between Jan 25, 2017, and Sept 15, 2020, 96 patients were screened and 60 were enrolled and randomly assigned to either the durvalumab monotherapy group (n=30) or the durvalumab plus radiotherapy group (n=30). 26 (87%) of 30 patients in each group had their tumours surgically resected. Major pathological response was observed in two (6·7% [95% CI 0·8-22·1]) of 30 patients in the durvalumab monotherapy group and 16 (53·3% [34·3-71·7]) of 30 patients in the durvalumab plus radiotherapy group. The difference in the major pathological response rates between both groups was significant (crude odds ratio 16·0 [95% CI 3·2-79·6]; p<0·0001). In the 16 patients in the dual therapy group with a major pathological response, eight (50%) had a complete pathological response. The second cycle of durvalumab was withheld in three (10%) of 30 patients in the dual therapy group due to immune-related adverse events (grade 3 hepatitis, grade 2 pancreatitis, and grade 3 fatigue and thrombocytopaenia). Grade 3-4 adverse events occurred in five (17%) of 30 patients in the durvalumab monotherapy group and six (20%) of 30 patients in the durvalumab plus radiotherapy group. The most frequent grade 3-4 events were hyponatraemia (three [10%] patients in the durvalumab monotherapy group) and hyperlipasaemia (three [10%] patients in the durvalumab plus radiotherapy group). Two patients in each group had serious adverse events (pulmonary embolism [n=1] and stroke [n=1] in the durvalumab monotherapy group, and pancreatitis [n=1] and fatigue [n=1] in the durvalumab plus radiotherapy group). No treatment-related deaths or deaths within 30 days of surgery were reported. INTERPRETATION: Neoadjuvant durvalumab combined with stereotactic body radiotherapy is well tolerated, safe, and associated with a high major pathological response rate. This neoadjuvant strategy should be validated in a larger trial. FUNDING: AstraZeneca.

MRI-LINAC: A transformative technology in radiation oncology.

Advances in radiotherapy technologies have enabled more precise target guidance, improved treatment verification, and greater control and versatility in radiation delivery. Amongst the recent novel technologies, Magnetic Resonance Imaging (MRI) guided radiotherapy (MRgRT) may hold the greatest potential to improve the therapeutic gains of image-guided delivery of radiation dose. The ability of the MRI linear accelerator (LINAC) to image tumors and organs with on-table MRI, to manage organ motion and dose delivery in real-time, and to adapt the radiotherapy plan on the day of treatment while the patient is on the table are major advances relative to current conventional radiation treatments. These advanced techniques demand efficient coordination and communication between members of the treatment team. MRgRT could fundamentally transform the radiotherapy delivery process within radiation oncology centers through the reorganization of the patient and treatment team workflow process. However, the MRgRT technology currently is limited by accessibility due to the cost of capital investment and the time and personnel allocation needed for each fractional treatment and the unclear clinical benefit compared to conventional radiotherapy platforms. As the technology evolves and becomes more widely available, we present the case that MRgRT has the potential to become a widely utilized treatment platform and transform the radiation oncology treatment process just as earlier disruptive radiation therapy technologies have done.

Neoadjuvant durvalumab plus radiation versus durvalumab alone in stages I-III non-small cell lung cancer: survival outcomes and molecular correlates of a randomized phase II trial.

We previously reported the results of a randomized phase II trial (NCT02904954) in patients with early-stage non-small cell lung cancer (NSCLC) who were treated with either two preoperative cycles of the anti-PD-L1 antibody durvalumab alone or combined with immunomodulatory doses of stereotactic radiation (DRT). The trial met its primary endpoint of major pathological response, which was significantly higher following DRT with no new safety signals. Here, we report on the prespecified secondary endpoint of disease-free survival (DFS) regardless of treatment assignment and the prespecified exploratory analysis of DFS in each arm of the trial. DFS at 2 and 3 years across patients in both arms of the trial were 73% (95% CI: 62.1-84.5) and 65% (95% CI: 52.5-76.9) respectively. For the exploratory endpoint of DFS in each arm of the trial, three-year DFS was 63% (95% CI: 46.0-80.4) in the durvalumab monotherapy arm compared to 67% (95% CI: 49.6-83.4) in the dual therapy arm. In addition, we report post hoc exploratory analysis of progression-free survival as well as molecular correlates of response and recurrence through high-plex immunophenotyping of sequentially collected peripheral blood and gene expression profiles from resected tumors in both treatment arms. Together, our results contribute to the evolving landscape of neoadjuvant treatment regimens for NSCLC and identify easily measurable potential biomarkers of response and recurrence.

Glamour, expression, and consequences of tattoos in radiation treatment.

It is estimated that approximately 24% of the US population has at least one tattoo. However, tattoo ink ingredients include heavy metals (high atomic number Z) that are not regulated, which can cause skin reactions. This study investigates the dosimetric effects in surface dose due to high-Z elements in tattoo ink under electron beam irradiation. Four commercially available tattoo ink colors, black, red, yellow, and blue were chosen. The elemental composition of the tattoo ink samples was analyzed using X-ray Fluorescence (XRF). An ultrathin-window parallel plate ion chamber was used to measure the surface dose perturbation (ratio of ionizations with and without tattoo ink) for 6 - 20 MeV electron beams. The elemental concentration in the tattoo ink samples showed high-Z elements, with Z ranging from 11 to 92. The dose perturbation ranged from 1.4% up to 6% for the yellow ink for the 6 MeV electron beam, with similar values across the rest of the electron energies, whereas the black, red, and blue inks presented up to 3% dose perturbation for the same range of energies. Based on this initial study, we conclude that commercially available tattoo inks contain large amounts of high-Z metals that may contribute to dose perturbation. Therefore treatment of superficial lesions with electron beams in a tattooed area should be monitored for signs of early skin reaction during radiation therapy treatments.

Dosimetric assessment of tumor control probability in intensity and volumetric modulated radiotherapy plans.

OBJECTIVE:: Radiobiological models have been used to calculate the outcomes of treatment plans based on dose-volume relationship. This study examines several radiobiological models for the calculation of tumor control probability (TCP) of intensity modulated radiotherapy plans for the treatment of lung, prostate, and head and neck (H&N) cancers. METHODS:: Dose volume histogram (DVH) data from the intensity modulated radiotherapy plans of 36 lung, 26 prostate, and 87 H&N cases were evaluated. The Poisson, Niemierko, and Marsden models were used to calculate the TCP of each disease group treatment plan. The calculated results were analyzed for correlation and discrepancy among the three models, as well as different treatment sites under study. RESULTS:: The median value of calculated TCP in lung plans was 61.9% (34.1-76.5%), 59.5% (33.5-73.9%) and 32.5% (0.0-93.9%) with the Poisson, Niemierko, and Marsden models, respectively. The median value of calculated TCP in prostate plans was 85.1% (56.4-90.9%), 81.2% (56.1-88.7%) and 62.5% (28.2-75.9%) with the Poisson, Niemierko, and Marsden models, respectively. The median value of calculated TCP in H&N plans was 94.0% (44.0-97.8%) and 94.3% (0.0-97.8%) with the Poisson and Niemierko models, respectively. There were significant differences between the calculated TCPs with the Marsden model in comparison with either the Poisson or Niemierko model (p < 0.001) for both lung and prostate plans. The TCPs calculated by the Poisson and Niemierko models were significantly correlated for all three tumor sites. CONCLUSION:: There are variations with different radiobiological models. Understanding of the correlation and limitation of a TCP model with dosimetric parameters can help develop the meaningful objective functions for plan optimization, which would lead to the implementation of outcome-based planning. More clinical data are needed to refine and consolidate the model for accuracy and robustness. ADVANCES IN KNOWLEDGE:: This study has tested three radiobiological models with varied disease sites. It is significant to compare different models with the same data set for better understanding of their clinical applicability.

Concurrent chemoradiation for high-risk prostate cancer.

There are estimated to be 220800 cases of prostate cancer diagnosed in 2015, making up 26% of all cancer diagnoses. Fortunately, adenocarcinoma of the prostate is often a highly treatable malignancy. Even though the majority of prostate cancer patients present with localized disease, prostate cancer still accounts for over 27000 deaths a year. There is a subset of patients that are likely to recur after locoregional treatment that is thought of as a "high-risk" population. This more aggressive subset includes patients with clinical stage greater than T2b, Gleason score greater than 7, and prostate specific antigen greater than 20 ng/dL. The rate of biochemical relapse in this high risk group is 32%-70% within five years of definitive focal therapy. Given these discouraging outcomes, attempts have been made to improve cure rates by radiation dose escalation, addition of androgen depravation therapy, and addition of chemotherapy either sequentially or concurrently with radiation. One method that has been shown to improve clinical outcomes is the addition of chemotherapy to radiotherapy for definitive treatment. Concurrent chemoradiation with 5-fluorouracil, estramustine phosphate, vincristine, docetaxel, and paclitaxel has been studied in the phase I and/or II setting. These trials have identified the maximum tolerated dose of chemotherapy and radiation that can be safely delivered concurrently and established the safety and feasibility of this technique. This review will focus on the addition of concurrent chemotherapy to radiotherapy in the definitive management of high-risk prostate cancer.

Predictors of Complete Response and Disease Recurrence Following Chemoradiation for Rectal Cancer.

OBJECTIVE: Approximately 10-40% of rectal patients have a complete response (CR) to neoadjuvant chemoradiation (CRT), and these patients have improved survival. Thus, non-operative management ("watch-and-wait" approach) may be an option for select patients. We aimed to identify clinical predictors of CR following CRT. METHODS: Patients treated with definitive CRT for T3-T4, locally unresectable T1-T2, low-lying T2, and/or node-positive rectal cancer from August 2004 to February 2015 were retrospectively reviewed. Most patients were treated with 50.4 Gy radiation and concurrent 5-fluoruracil or capecitabine. Patients were considered to have a CR if surgical pathology revealed ypT0N0M0 (operative management), or if they had no evidence of residual disease on clinical and radiographic assessment (non-operative management). Statistical analysis was carried out to determine predictors of CR and long-term outcomes. RESULTS: Complete records were available on 138 patients. The median follow-up was 24.5 months. Thirty-six patients (26.3%) achieved a CR; 30/123 operatively managed patients (24.5%) and 6/15 (40%) non-operatively managed patients. None of the 10 patients with mucinous adenocarcinoma achieved a CR. Carcinoembryonic antigen (CEA) ≥5 µg/L at diagnosis (OR 0.190, 95% CI 0.037-0.971, p = 0.046), tumor size ≥3 cm (OR 0.123, 95% CI 0.020-0.745, p = 0.023), distance of tumor from the anal verge ≥3 cm (OR 0.091, 95% CI 0.013-0.613, p = 0.014), clinically node-positive disease at diagnosis (OR 0.201, 95% CI 0.045-0.895, p = 0.035), and interval from CRT to surgery ≥8 weeks (OR 5.267, 95% CI 1.068-25.961, p = 0.041) were independent predictors of CR. The CR group had longer 3-year distant metastasis-free survival (DMFS) (93.7 vs. 63.7%, p = 0.016) and 3-year disease-free survival (DFS) (91.1 vs. 67.8%, p = 0.038). Three-year locoregional control (LRC) (96.6 vs. 81.3%, p = 0.103) and overall survival (97.2 vs. 87.5%, p = 0.125) were higher in the CR group but this did not achieve statistical significance. CR was not an independent predictor of LRC, DMFS, or DFS. CONCLUSION: CEA at diagnosis, tumor size, tumor distance from the anal verge, node positivity at diagnosis, and interval from CRT to surgery were predictors of CR. These clinical variables may offer insight into patient selection and timing of treatment response evaluation in the watch-and-wait approach.

Comparison of anal cancer outcomes in public and private hospital patients treated at a single radiation oncology center.

OBJECTIVE: To compare clinical and treatment characteristics and outcomes in locally advanced anal cancer, a potentially curable disease, in patients referred from a public or private hospital. METHODS: We retrospectively reviewed 112 anal cancer patients from a public and a private hospital who received definitive chemoradiotherapy at the same cancer center between 2004 and 2013. Tumor stage, radiotherapy delay, radiotherapy duration, and unplanned treatment breaks ≥10 days were compared using t-test and χ(2) test. Overall survival (OS), disease free survival (DFS), and colostomy free survival (CFS) were examined using the Kaplan-Meier method and compared with the log-rank test. Cox proportional hazard models for OS and DFS were developed. RESULTS: The follow-up was 14.9 months (range, 0.7-94.8 months). Public hospital patients presented with significantly higher clinical T stage (P<0.05) and clinical stage group (P<0.05), had significantly longer radiotherapy delays (P<0.05) and radiotherapy duration (P<0.05), and had more frequent radiation therapy (RT) breaks ≥10 days (P<0.05). Three-year OS showed a marked trend in favor of private hospital patients for 3-year OS (72.8% vs. 48.9%; P=0.171), 3-year DFS (66.3% vs. 42.7%, P=0.352), and 3-year CFS (86.4% vs. 68.9%, P=0.299). Referral hospital was not predictive of OS or DFS on multivariate analysis. CONCLUSIONS: Public hospital patients presented at later stage and experienced more delays in initiating and completing radiotherapy, which may contribute to the trend in poorer DFS and OS. These findings emphasize the need for identifying clinical and treatment factors that contribute to decreased survival in low socioeconomic status (SES) populations.

Hypofractionated radiation therapy for prostate cancer: biologic and technical considerations.

The optimal radiation schedule for the curative treatment of prostate cancer is not known. The dose-response of tumors and normal tissues to fractionated irradiation can be described according to a parameter called the alpha-beta ratio (α/ß). In the past several years numerous reports have been published that suggest that the alpha-beta ratio for prostate cancer may be quite low; between 1 and 3. If this hypothesis is true, then a radiation therapy schedule that employs less frequent and larger fractions, termed hypofractionation, may be more efficacious. Multiple randomized trials have been conducted comparing moderate (less than 5 Gy/day) hypofractionated radiation therapy and standard radiation therapy in men with prostate cancer. In the majority of these studies the moderate hypofractionated arm had equivalent efficacy with a similar or improved side effect profile. One area to use caution may be in patients with compromised (IPSS > 12) urinary function at baseline due to an increase in urinary toxicity observed in patients treated with hypofractionated radiation in one study. Extreme hypofractionation (greater than or equal to 5 Gy/day), is currently being compared in a randomized trial. Early prospectively collected data from multiple institutions demonstrates efficacy and toxicity that compares favorably with historical controls. The cost savings from hypofractionation could be profound on a national level and only increases the necessity of testing hypofractionated treatment schedules. Long term data and future trials will help radiation oncologists determine the ideal fractionation scheme based on cost, efficacy, and toxicity.

Toxicity and disease-related outcomes after radiotherapy for head and neck cancer in human immunodeficiency virus-positive patients.

BACKGROUND: Human immunodeficiency virus (HIV) seropositivity may be associated with higher risk of local recurrence and poor survival in multiple malignancies. However, long-term disease control in HIV-positive patients with head and neck cancer (HNC) is not well described. The purpose of this study is to review the disease-related outcomes of HIV-positive patients who underwent radiotherapy (RT) or chemoradiotherapy (CRT) at our institution. METHODS: We retrospectively reviewed 24 HIV-positive patients who underwent RT for HNC between 2004 and 2013. Patient characteristics, treatment details, and outcomes were collected. Overall survival (OS) and local recurrence-free survival (LRFS) were investigated. Kaplan-Meier estimated survival was calculated. RESULTS: Median follow-up was 21 months. All patients were treated with curative intent. Eighty-three percent had stage III-IV. Primary sites of disease included oropharynx (n = 12), larynx (n = 6), oral cavity (n = 2), unknown primary (n = 2), nasal cavity (n = 1), and paranasal sinuses (n = 1). Four patients (17%) had definitive RT alone and nine had definitive CRT (38%; eight cisplatin and one cetuximab). Eleven (46%) were treated in the adjuvant setting after surgical resection; six with RT alone and five with concurrent cisplatin. Eight patients had acute Grade 3 toxicity with no acute Grade 4 or 5 toxicities. Fifteen patients (63%) were alive and disease-free. Two- and 5-year OS was 67 and 59%, respectively. LRFS at 2-years was 82%. Median OS was 83 months. CONCLUSION: In this cohort, HIV-positive patients treated aggressively with curative intent had excellent OS and local control following RT or CRT for HNC compared to historical controls. Treatment was relatively well tolerated. This group of patients should be managed aggressively with intent to cure.

Feasibility and efficacy of local radiotherapy with concurrent novel agents in patients with multiple myeloma.

INTRODUCTION: This study evaluated the safety and efficacy of radiotherapy (RT) with concurrent novel agents (NAs), cytotoxic therapy (CTx), or both in the management of osteolytic bone lesions in multiple myeloma (MM). PATIENTS AND METHODS: A total of 39 patients with MM received RT to 64 different bone sites during the 2007-2012 period, with a dose of 8 to 37.5 Gy (mean, 26.8 Gy) delivered in 1 to 15 fractions (median, 10 fractions). Of these patients, 21 also received concurrent NAs or CTx. Pain response, M protein and κ light chain response, and adverse events were evaluated. RESULTS: RT was completed in 35 of 39 patients (89.7%) in this study. Pain relief was observed in 30 of 31 patients (96.7%). Hematologic toxicity (grade 3 or 4 by the Radiation Therapy Oncology Group system) was seen in 43.2% of treated patients, and NA therapy was stopped in 2 patients owing to grade 4 toxicity. RT adverse effects resolved at 4 to 6 weeks posttreatment. Changes in pre- and posttreatment levels of M protein trended toward significance in patients treated with RT + systemic therapy (ST) versus. RT alone (ΔM ProteinRT+ST = 5.6 g/L; ΔM ProteinRT = 0 g/L; P = .089). CONCLUSION: Treating MM with RT concurrently with CTx including NAs was safe and well tolerated in the majority of patients (14 of 16 [87.5%] for those taking NAs and 19 of 21 [90.5%] for all patients). Excellent clinical pain response (> 95%) was also seen in patients regardless if they were treated with RT + ST or RT alone.

Squamous cell carcinoma of the prostate.

Squamous cell carcinoma of the prostate is a rare tumor, making up 0.5% to 1% of all prostate carcinomas. It is typically described as an aggressive cancer, with a median postdiagnosis survival of 14 months. Presented here is a case of primary squamous cell carcinoma of the prostate, with a complicated presentation of metastatic disease. Due to the extent of the patient's disease, he was treated with palliative radiation therapy using a four-field technique (AP/PA and left and right lateral fields) with 18 mV photons prescribed to the 100% isodose line. The prescription dose was 4000 cGy in 16 fractions of 250 cGy per fraction. No definitive treatment of squamous cell carcinoma of the prostate exists but varying approaches including surgical intervention, chemotherapy, and radiation therapy have been implemented without durable response. However, multimodal treatments appear to be the most promising with longer durations of survival.

Toxicity of head-and-neck radiation therapy in human immunodeficiency virus-positive patients.

PURPOSE: To examine the acute morbidity of high dose head and neck RT and CRT in patients with infected with HIV. METHODS AND MATERIALS: All HIV-positive patients who underwent radiation therapy for head and neck cancer in our department between 2004 and 2008 were reviewed. Treatment related data were examined. All treatments were delivered with megavoltage photon beams or electron beams. Patients were evaluated by an attending radiation oncologist for toxicity and response on a weekly basis during therapy and monthly after treatment in a multidisciplinary clinic. Acute toxicities were recorded using the Radiation Therapy and Oncology Group (RTOG) common toxicity criteria. Response to treatment was based on both physical exam as well as post-treatment imaging as indicated. RESULTS: Thirteen patients who underwent RT with a diagnosis of HIV were identified. Median age was 53 years and median follow-up was 22 months. Twelve had squamous cell carcinoma and one had lymphoproliferative parotiditis. Median radiation dose was 66.4 Gy and median duration of treatment was 51 days. The median number of scheduled radiotherapy days missed was zero (range 0 to 7). One patient (8%) developed Grade 4 confluent moist desquamation. Eight patients (61%) developed Grade 3 toxicity. CONCLUSION: Based on our results, HIV-positive individuals appear to tolerate treatment for head and neck cancer, with toxicity similar to that in HIV-negative individuals.

Phase I/II study of biweekly paclitaxel and radiation in androgen-ablated locally advanced prostate cancer.

PURPOSE: To determine the maximum-tolerated dose (MTD) of concurrent paclitaxel and radiation therapy (RT) in patients with locally advanced prostate cancer. MATERIALS AND METHODS: Eligible patients had T2-4 tumors with Gleason scores greater than 7 and/or PSA levels greater than 10 ng/mL and/or had tumors with pathologic stage TxN1. Hormonal ablation was initiated 3 months before RT and was given for 9 months. RT was delivered daily (1.8 Gy) with concurrent twice-weekly paclitaxel (30 mg/m(2)). The whole pelvis was irradiated to 39.6 Gy. The radiation dose was escalated as follows: 63 Gy, 66.6 Gy, 70.2 Gy, and 73.8 Gy. The last RT dose level was fixed at 73.8 Gy. RESULTS: Between January 2000 and October 2006, 22 patients were enrolled. The median age was 59 years (range, 48 to 72 years); the median PSA level was 22.4 ng/mL (range, 2.8 to 113 ng/mL). The number of patients per stage was as follows: three with T1, eight with T2, 11 with T3, and five with pN1 = 5. No grade 3 toxicities occurred at 63 Gy. Grade 3 diarrhea occurred in three patients at 66.6 Gy. The protocol then was amended to treat the prostate volume first followed by the whole pelvis. No grade 3 toxicities were observed at 70.2 Gy. One patient experienced grade 3 diarrhea at 73.8 Gy. Five additional patients were treated to 73.8 Gy without grade 3 toxicity, which established the MTD for combined paclitaxel and RT at 73.8 Gy. At 38 months median follow-up (range, 9 to 87 months), 21 (95%) of 22 patients are alive. Six (27%) of 22 experienced recurrence. CONCLUSION: Concurrent biweekly paclitaxel with RT is feasible, with an MTD of 73.8 Gy. Recovery of gonadal function occurs in the majority of patients. These results encourage testing in a phase III setting.

Sclerosis of the pterygoid process in untreated patients with nasopharyngeal carcinoma.

PURPOSE: To retrospectively evaluate the prevalence of pterygoid process sclerosis in patients with untreated nasopharyngeal carcinoma. MATERIALS AND METHODS: This retrospective HIPAA-compliant study was performed after the institutional review board deemed it to be exempt from review and patient informed consent. Contrast material-enhanced computed tomographic (CT) scans of the neck obtained in 31 patients (22 men, nine women; mean age, 42 years; age range, 27-68 years) with untreated nasopharyngeal carcinoma and in 31 control subjects (17 men, 14 women; mean age, 43 years; age range, 19-62 years) were evaluated independently by two neuroradiologists. The presence of sclerosis of the pterygoid process-defined as increased attenuation in the medullary cavity and/or thickening of the cortical bone-was assessed. Other findings noted included pterygoid process erosion, enhancing tumor adjacent to the pterygoid process, and CT evidence of parapharyngeal extension of the tumor. The data were evaluated by using generalized estimating equations based on a binary logistic regression model. RESULTS: The prevalence of pterygoid process sclerosis averaged for the two readers was 60% (37 of 62 subjects) among the patients with nasopharyngeal carcinoma but only 3% (two of 62 subjects) among the control subjects, indicating a highly significantly increased prevalence (P < .001) of this finding in the patients with nasopharyngeal carcinoma. The overall prevalences of pterygoid process erosion, parapharyngeal extension of tumor, and enhancing tumor adjacent to the pterygoid process were 27% (17 of 62 subjects), 47% (29 of 62 subjects), and 77% (48 of 62 subjects), respectively. Pterygoid process sclerosis was the sole skull base abnormality in 36% (11 of 31) of the patients with nasopharyngeal carcinoma. CONCLUSION: Sclerosis of the pterygoid process, which was present in about half of the patients with untreated nasopharyngeal carcinoma, may reflect tumor proximity to or tumor invasion of the pterygoid process.