John Waldron

Deintensification Candidate Subgroups in Human Papillomavirus-Related Oropharyngeal Cancer According to Minimal Risk of Distant Metastasis

PURPOSE To define human papillomavirus (HPV) -positive oropharyngeal cancers (OPC) suitable for treatment deintensification according to low risk of distant metastasis (DM). PATIENTS AND METHODS OPC treated with radiotherapy (RT) or chemoradiotherapy (CRT) from 2001 to 2009 were included. Outcomes were compared for HPV-positive versus HPV-negative patients. Univariate and multivariate analyses identified outcome predictors. Recursive partitioning analysis (RPA) stratified the DM risk. RESULTS HPV status was ascertained in 505 (56%) of 899 consecutive OPCs. Median follow-up was 3.9 years. HPV-positive patients (n = 382), compared with HPV-negative patients (n = 123), had higher local (94% v 80%, respectively, at 3 years; P < .01) and regional control (95% v 82%, respectively; P < .01) but similar distant control (DC; 90% v 86%, respectively; P = .53). Multivariate analysis identified that HPV negativity (hazard ratio [HR], 2.9; 95% CI, 2.0 to 5.0), N2b-N3 (HR, 2.9; 95% CI, 1.8 to 4.9), T4 (HR, 1.8; 95% CI, 1.2 to 2.9), and RT alone (HR, 1.8; 95% CI, 1.1 to 2.5) predicted a lower recurrence-free survival (RFS; all P < .01). Smoking pack-years > 10 reduced overall survival (HR, 1.72; 95% CI, 1.1 to 2.7; P = .03) but did not impact RFS (HR, 1.1; 95% CI, 0.7 to 1.9; P = .65). RPA segregated HPV-positive patients into low (T1-3N0-2c; DC, 93%) and high DM risk (N3 or T4; DC, 76%) groups and HPV-negative patients into different low (T1-2N0-2c; DC, 93%) and high DM risk (T3-4N3; DC, 72%) groups. The DC rates for HPV-positive, low-risk N0-2a or less than 10 pack-year N2b patients were similar for RT alone and CRT, but the rate was lower in the N2c subset managed by RT alone (73% v 92% for CRT; P = .02). CONCLUSION HPV-positive T1-3N0-2c patients have a low DM risk, but N2c patients from this group have a reduced DC when treated with RT alone and seem less suited for deintensification strategies that omit chemotherapy.

Comparative Prognostic Value of HPV16 E6 mRNA Compared With In Situ Hybridization for Human Oropharyngeal Squamous Carcinoma

PURPOSE A significant proportion of oropharyngeal squamous cell carcinomas (OSCC) are associated with the human papilloma virus (HPV), particularly HPV16. The optimal method for HPV determination on archival materials however, remains unclear. We compared a quantitative real-time polymerase chain reaction (qRT-PCR) assay for HPV16 mRNA to a DNA in situ hybridization (ISH) method, and evaluated their significance for overall (OS) and disease-free (DFS) survival. PATIENTS AND METHODS Matched, archival biopsies from 111 patients with OSCC were evaluated for HPV16 using a qRT-PCR for E6 mRNA and ISH for DNA. Immunohistochemistry for p16, p53, and epidermal growth factor receptor were also performed. RESULTS HPV16 E6 mRNA was positive in 73 (66%) of 111 samples; ISH was positive in 62 of 106 samples (58%), with 86% concordance. P16 was overexpressed in 72 samples (65%), which was strongly associated with HPV16 status by either method. E6 mRNA presence or p16 overexpression were significantly associated with superior OS; E6 mRNA, HPV16 ISH, or p16 were all significantly associated with DFS. On multivariate analysis adjusted for age, stage, and treatment, positive E6 mRNA was the only independent predictor for superior OS; for DFS, p16 expression or HPV16 status determined by either method was significant. CONCLUSION The prevalence of HPV16 in OSCC ranges from 58% to 66%, in a recently treated Canadian cohort. Classification of HPV-positivity by HPV16 E6 mRNA, HPV16 ISH or p16 immunohistochemistry (IHC) is associated with improved DFS. However, the latter two assays are technically easier to perform; hence, HPV16 ISH or p16 IHC should become standard evaluations for all patients with OSCC.

Refining American Joint Committee on Cancer/Union for International Cancer Control TNM Stage and Prognostic Groups for Human Papillomavirus–Related Oropharyngeal Carcinomas

PURPOSE To refine stage and prognostic group for human papillomavirus (HPV) -related nonmetastatic (M0) oropharyngeal cancer (OPC). METHODS All patients with nonmetastatic (M0) p16-confirmed OPC treated with radiotherapy with or without chemotherapy from 2000 to 2010 were included. Overall survival (OS) was compared among TNM stages for patients with HPV-related and HPV-unrelated OPC separately. For HPV-related OPC, recursive partitioning analysis (RPA) derived new RPA stages objectively. Cox regression was used to calculate adjusted hazard ratios (AHRs) to derive AHR stages. The performance of survival prediction of RPA stage and AHR stage was assessed against the current seventh edition TNM stages. Prognostic groups were derived by RPA, combining RPA stage and nonanatomic factors. RESULTS The cohort comprised 573 patients with HPV-related OPC and 237 patients with HPV-unrelated OPC, with a median follow-up of 5.1 years. Lower 5-year OS with higher TNM stage was evident for patients with HPV-unrelated OPC (stage I, II, III, and IV 5-year OS: 70%, 58%, 50%, and 30%, respectively; P = .004) but not for patients with HPV-related OPC (stage I, II, III, and IV 5-year OS: 88%, 78%, 71%, and 74%, respectively; P = .56). RPA divided HPV-related OPC into RPA-I (T1-3N0-2b), RPA-II (T1-3N2c), and RPA-III (T4 or N3; 5-year OS: 82%, 76%, and 54%, respectively; P < .001). AHR also yielded a valid classification, but RPA stage demonstrated better survival prediction. A further RPA (including RPA stage, age, and smoking pack-years [PYs]) derived the following four valid prognostic groups for survival: group I (T1-3N0-N2c_≤ 20 PY), group II (T1-3N0-N2c_> 20 PY), group III (T4 or N3_age ≤ 70), and group IVA (T4 or N3_age > 70; 5-year OS: 89%, 64%, 57%, and 40%, respectively; P < .001). CONCLUSION An RPA-based TNM stage grouping (stage I/II/III: T1-3N0-N2b/T1-3N2c/T4 or N3, with M1 as stage IV) is proposed for HPV-related OPC as a result of significantly improved survival prediction compared with the seventh edition TNM, and prognostication is further improved by an RPA-based prognostic grouping within the American Joint Committee on Cancer/Union for International Cancer Control TNM framework for HPV-related OPC.

T1/T2 GLOTTIC CANCER MANAGED BY EXTERNAL BEAM RADIOTHERAPY: THE INFLUENCE OF PRETREATMENT HEMOGLOBIN ON LOCAL CONTROL

Abstract Purpose: Pretreatment hemoglobin (Hb) level has been reported to be an important prognostic factor for local control and survival in various malignancies. However, in many settings, the adverse effect of a low Hb may be related to more advanced disease. The purpose of this analysis was to assess the influence of pretreatment Hb on local control in a large series of patients with a localized cancer (T1/T2 glottic cancer, AJCC 1992) treated in a standard fashion. Materials and Methods: Between January 1981 and December 1989, 735 patients (median age 63; 657 males, 78 females) with T1/T2 glottic cancer were treated with radiation therapy (RT). The standard RT prescription was 50 Gy in 20 fractions over 4 weeks (97% of patients). Factors studied for prognostic importance for local failure included pretreatment Hb, age, sex, T category, anterior commissure involvement, subglottic extension, and tumor bulk (presence of visible tumor vs. subclinical disease). Results: With a median follow-up of 6.8 years (range 0.2–14.3), 131 patients have locally relapsed for an actuarial 5-year relapse-free rate of 81.7%. The 5-year actuarial survival was 75.8%. The mean pretreatment hemoglobin level was 14.8 g/dl and was similar in all prognostic categories. On multivariate analysis, using the Cox proportional hazards model, pretreatment Hb predicted for local failure after RT. The hazard ratio (HR) for relapse was calculated for various Hb levels. For example, the HR for a Hb of 12 g/dl vs. a Hb of 15 g/dl was 1.8 (95% confidence interval 1.2–2.5). Previously established factors, including gender, T category, subglottic extension, as well as tumor bulk, were also prognostically important for local control. Conclusions: This analysis, in a large number of similarly treated patients, indicates that pretreatment Hb is an independent prognostic factor for local control in patients with T1/T2 carcinoma of the glottis treated with RT. The underlying biology of this observation needs to be explored, and using this information, it may be possible to develop strategies to improve treatment outcome.

The benefits and pitfalls of ipsilateral radiotherapy in carcinoma of the tonsillar region.

PURPOSE Ipsilateral techniques designed to restrict treatment to the primary tumor and neck on the same side have been used in selected cases of cases of carcinoma of the tonsillar region at our institution for many years. The primary purpose of this study is to evaluate the risk of failure in the opposite neck in cases selected for unilateral radiotherapy over a 21-year period. METHODS AND MATERIALS Ipsilateral radiotherapy techniques were used in 228 of 642 patients with carcinoma of the tonsillar region from 1970 to 1991. Local control, regional lymph-node control (including contralateral failure), and survival were calculated for different degrees of tumor extent treated with these techniques. RESULTS Mean follow-up was 7 years. Cases tended to be T1 and T2, with N0 disease. The 3-year actuarial local control rate was 77% and cause-specific survival was 76%. Opposite neck failure was seen in 8 patients (crude rate of 3.5%). In the earlier period of the study, primary coverage was problematic in a proportion of cases and resulted in higher rates of local failure. CONCLUSION Appropriately selected cases of carcinoma of the tonsil show minimal risk of failure in the opposite neck with ipsilateral techniques. Patients should undergo computed tomography planning to ensure adequate target coverage.

Atypical clinical behavior of p16-confirmed HPV-related oropharyngeal squamous cell carcinoma treated with radical radiotherapy.

PURPOSE To report atypical clinical behavior observed in human papillomavirus (HPV)-related oropharyngeal carcinoma (OPC) treated with radiotherapy. METHODS AND MATERIALS A retrospective cohort study was conducted for all newly diagnosed OPC cases treated with radiotherapy on July 1, 2003 to April 30, 2009. HPV positivity was determined by p16 immunostaining in tumors. The incidence of additional malignancies and the pattern of distant metastases (DMs) were compared between the HPV-positive (HPV+) and HPV-negative (HPV-) cohorts. RESULTS HPV status was evaluated in 318 of 613 consecutive OPC cases (52%), showing 236 HPV+ and 82 HPV- patients. Compared with HPV-, HPV+ cases were less likely to have additional malignancies (prior: 11% vs. 20%, p = 0.038; synchronous: 1% vs. 9%, p = 0.001; metachronous: 6% vs. 16%, p = 0.003). Whereas the majority (10 of 12) of HPV- additional head-and-neck (HN) mucosal malignancies were in the oral cavity, there was none (0 of 7) in the HPV+ cohort (p < 0.001). HPV+ synchronous HN second primaries (SPs) were in the supraglottis, post-cricoid, and nasopharynx; metachronous HN SPs were in the glottis, supraglottis, and ethmoid plus glottis/post-cricoid region. All SPs that could be tested were HPV+. There was no difference in DM rate (10% vs. 15%, p = 0.272), but HPV+ DMs were more likely to involve multiple organs (46% vs. 0%, p = 0.005) and unusual sites. CONCLUSIONS This study reports atypical clinical behavior seen in HPV+ OPC, including multicentric lesions in HN mucosa and DM to multiple organs and unusual sites. The frequency of these events is low, but they may have clinical implications. The routine assessment of HPV status for all OPC is warranted.

Significance of Plk1 regulation by miR-100 in human nasopharyngeal cancer

Polo‐like kinase 1 (Plk1) is a critical regulator of many stages of mitosis; increasing evidence indicates that Plk1 overexpression correlates with poor clinical outcome, yet its mechanism of regulation remains unknown. Hence, a detailed evaluation was undertaken of Plk1 expression in human nasopharyngeal cancer (NPC), the cellular effects of targeting Plk1 using siRNA in combination with ionizing radiation (RT) and potential upstream microRNAs (miRs) that might regulate Plk1 expression. Using immunohistochemistry, Plk1 was observed to be overexpressed in 28 of 40 (70%) primary NPC biopsies, which in turn was associated with a higher likelihood of recurrence (p = 0.018). SiPlk1 significantly inhibited Plk1 mRNA and protein expression, and decreased Cdc25c levels in NPC cell lines. This depletion resulted in cytotoxicity of C666‐1 cells, enhanced by the addition of RT, mediated by G2/M arrest, increased DNA double‐strand breaks, apoptosis, and caspase activation. Immunofluorescence demonstrated that the G2/M arrest was associated with aberrant spindle formation, leading to mitotic arrest. In vivo, transfection of C666‐1 cells and systemic delivery of siPlk1 decreased tumour growth. MicroRNA‐100 (miR‐100) was predicted to target Plk1 mRNA, which was indeed underexpressed in C666‐1 cells, inversely correlating with Plk1 expression. Using luciferase constructs containing the 3′‐UTR of Plk1 sequence, we document that miR‐100 can directly target Plk1. Hence, our data demonstrate for the first time that underexpressed miR‐100 leads to Plk1 overexpression, which in turn contributes to NPC progression. Targeting Plk1 will cause mitotic catastrophe, with significant cytotoxicity both in vitro and in vivo, underscoring the important therapeutic opportunity of Plk1 in NPC.

Outcomes of HPV-related oropharyngeal cancer patients treated by radiotherapy alone using altered fractionation.

PURPOSE To report outcome of HPV-related [HPV(+)] oropharyngeal cancer (OPC) managed predominantly by altered-fractionation radiotherapy-alone (RT-alone). METHODS OPCs treated with RT-alone (n = 207) or chemoradiotherapy (CRT) (n = 151) from 2001 to 2008 were included. Overall survival (OS), local (LC), regional (RC) and distant (DC) control were compared for HPV(+) vs. HPV-unrelated [HPV(-)], by RT-alone vs. CRT, and by smoking pack-years (≤ 10 vs. >10). Multivariate analysis identified predictors. RESULTS HPV(+) (n = 277) had better OS (81% vs. 44%), LC (93% vs. 76%), RC (94% vs. 79%) (all p < 0.01) but similar DC (89% vs. 86%, p = 0.87) vs. HPV(-) (n = 81). HPV(+) stage IV CRT (n = 125) had better OS (89% vs. 70%, p < 0.01), but similar LC (93% vs. 90%, p = 0.41), RC (94% vs. 90%, p = 0.31) and DC (90% vs. 83%, p = 0.22) vs. RT-alone (n = 96). Both HPV(+) RT-alone (n = 37) and CRT (n = 67) stage IV minimal smokers had favorable OS (86% vs. 88%, p = 0.45), LC (95% vs. 92%, p = 0.52), RC (97% vs. 93%, p = 0.22), and DC (92% vs. 86%, p = 0.37). RT-alone and heavy-smoking were independent predictors for lower OS but not CSS in multivariate analysis. CONCLUSIONS Overall, HPV(+) RT-alone stage IV demonstrated lower survival but comparable disease control vs. CRT, but no difference was apparent among minimal smokers.

A Phase III placebo-controlled trial of oral pilocarpine in patients undergoing radiotherapy for head-and-neck cancer.

PURPOSE To test the hypothesis that the use of oral pilocarpine during and after radiotherapy (RT) for head-and-neck cancer would reduce the symptoms of post-RT xerostomia. METHODS AND MATERIALS One hundred thirty patients were randomized in a double-blind method to receive either pilocarpine (5-mg tablets) or placebo three times daily starting on Day 1 of RT and continuing for 1 month after treatment. The eligibility criteria included a planned dose of >50 Gy as radical or postoperative RT for head-and-neck cancer, with at least 50% of both parotid glands included in the treatment fields. The primary outcome measure was the severity of xerostomia as assessed by a patient-completed linear analog scale 3 months after RT. Secondary outcome measures included quality of life during therapy (as assessed by the McMaster University Head-and-Neck Questionnaire) and severity of mucositis during RT (as assessed using Radiation Therapy Oncology Group scales). RESULTS No difference was observed between the pilocarpine-treated patients and the placebo group in the severity of xerostomia score as assessed by linear analog scale at baseline and 1, 3, and 6 months after treatment (repeated measures analysis, p = 0.92). No difference was apparent in the severity of mucositis during RT; 56.3% of patients receiving pilocarpine had Grade III/IV mucositis compared with 50.8% treated with placebo. No difference in quality of life was noted between the treatment groups during or after RT. The questionnaire score at 3 months after RT was 5.0 (SD 1.0). in the pilocarpine group and 4.9 (SD 0.9) in the placebo group. CONCLUSION We were unable to detect a beneficial effect of pilocarpine on RT-induced xerostomia when administered during RT for head-and-neck cancer.

Spinal cord ependymomas: a retrospective analysis of 59 cases

PURPOSE To determine the outcome of patients with primary spinal ependymoma treated with postoperative radiotherapy and to identify clinical and treatment variables predictive of outcome. METHODS AND MATERIALS A retrospective chart review was undertaken of 59 spinal ependymoma patients referred to the Princess Margaret Hospital between 1958 and 1987. All patients were treated with radiation therapy to either the site of the primary tumor or the craniospinal axis. There were 23 female and 36 male patients with a median age of 37 years (range: 8-66 years). Median follow-up was 130 months (range: 1-371 months). Clinical variables including age, sex, length of symptoms, functional status, tumor location, and grade as well as treatment variables including extent of surgery, radiation dose and treatment volume were analyzed for influence on outcome. RESULTS Treatment was well-tolerated with no cases of radiation myelopathy identified. Overall actuarial survival at 5 and 10 years was 83% and 75%, respectively. Eleven patients had recurrent tumor with the 9/11 having a component of their recurrence within the treatment field. Median time to recurrence was 2 years with 9 of the 11 recurrences within the first 3 years. Tumor grade was the only independent variable identified as predictive of outcome. Patients with well differentiated tumors had a 5-year cause-specific survival of 97% compared to 71% for those with intermediate or poorly differentiated tumors (p = 0.005). CONCLUSION We conclude that postoperative irradiation for patients with spinal ependymomas is associated with a favorable outcome and that tumor grade is a major prognostic factor. Based on results of this series and a review of the literature, specific management recommendations are made for this rare tumor.