Ten-Year Outcomes of Moderately Hypofractionated (70 Gy in 28 fractions) Intensity Modulated Radiation Therapy for Localized Prostate Cancer

PURPOSE

Long-term outcomes with hypofractionated radiation therapy for prostate cancer are limited. We report 10-year outcomes for patients treated with intensity modulated radiation therapy (IMRT) for localized prostate cancer with 70 Gy in 28 fractions at 2.5 Gy per fraction.

METHODS AND MATERIALS

The study included 854 consecutive patients with localized prostate cancer treated with moderately hypofractionated IMRT and daily image guidance at a single institution between 1998 and 2012. Patients with a single intermediate risk factor were considered to have favorable intermediate-risk (FIR) disease, and those with multiple intermediate risk factors were considered unfavorable (UIR). Biochemical relapse-free survival, clinical relapse-free survival, and overall survival were analyzed using Kaplan-Meier analysis. Prostate cancer-specific mortality (PCSM) was analyzed using competing risk regression. All grade ≥3 genitourinary (GU) and gastrointestinal (GI) toxicities were recorded using Common Terminology Criteria for Adverse Event version 4.03, and cumulative incidence rates of GU and GI toxicity were calculated.

RESULTS

The median follow-up was 11.3 years (maximum, 19 years). For patients with low-risk (LR), FIR, UIR, and high-risk (HR) disease, the 10-year biochemical relapse free survival rates were 88%, 78%, 71%, and 42%, respectively, (P < .0001). The 10-year clinical relapse free survival were 95%, 91%, 85%, and 72% for patients with LR, FIR, UIR, and HR, respectively, (P < .0001). For all patients, the 10-year actuarial overall survival rate was 69% (95% confidence interval, 66%-73%), and the 10-year PCSM was 6.8% (95% confidence interval, 5.1%-8.6%) overall. For patients with LR, FIR, UIR and HR disease, the 10-year PCSM rates were 2%, 5%, 5%, and 15%. Long-term grade ≥3 GU or GI toxicity remained low with 10-year cumulative incidences of 2% and 1%, respectively.

CONCLUSIONS

High-dose moderately hypofractionated IMRT with daily image guidance for localized prostate cancer demonstrates favorable 10-year oncologic outcomes with a low incidence of toxicity. This fractionation schedule appears to be acceptable for patients across all risk groups.

Investigation of brachial plexus dose that exceeds RTOG constraints for apical lung tumors treated with four- or five-fraction stereotactic body radiation therapy

PURPOSE/OBJECTIVESS

We sought to determine the rate of brachial plexopathy (BPX) in patients exceeding RTOG dose constraints for treatment of apical lung tumors.

MATERIALS/METHODS

Patients with apical lung tumors treated with four- or five-fraction SBRT were identified from a prospective registry. Dosimetric data were obtained for ipsilateral subclavian vein (SCV) and anatomic BP (ABP) contours. Cumulative equivalent dose in 2 Gy equivalents (EQD2) was calculated for the SCV contour in patients with a history of prior ipsilateral RT. Five-fraction SBRT RTOG constraints of D0.03cc ≤32.0 Gy and D3cc ≤30.0 Gy were used. BPX was graded according to Common Terminology Criteria for Adverse Events 3.0.

RESULTS

A total of 64 patients met inclusion criteria. Median follow-up was 21 months. Six patients (9.4%) had prior ipsilateral conventional fractionated RT with varying degrees of overlap with subsequent SBRT field. Eleven patients without prior ipsilateral RT exceeded D0.03cc ≤32.0 Gy to SCV (mean 43.8 Gy ± 5.8). No BPX was observed in these patients. Out of the six patients who had prior ipsilateral RT, three patients exceeded D0.03cc ≤32.0 Gy to SCV (44.2 Gy ± 11.3), with two of these patients developing Grade 2 BPX within one year of SBRT. The EQD2 cumulative maximum point dose to BP was 122.6 Gy and 184.7 Gy for the two patients who developed Grade 2 BPX. The D0.03cc was >10 Gy higher to the ABP contour than the SCV contour in 14 patients.

CONCLUSION

Without a history of prior ipsilateral RT, no BPX was observed at 21 month follow-up in 11 patients who exceeded the RTOG five-fraction BP constraint. This observation is hypothesis generating and more experience with longer follow-up is necessary to validate these findings. For tumors located in close proximity to apical structures, there was substantial variation in dose between the ABP and SCV contours.

Effect of Tumor Location and Dosimetric Predictors for Chest Wall Toxicity in Single-Fraction Stereotactic Body Radiation Therapy for Stage I Non-Small Cell Lung Cancer

PURPOSE

Dosimetric parameters to limit chest wall toxicity (CWT) are not well defined in single-fraction (SF) stereotactic body radiation therapy (SBRT) phase 2 trials. We sought to determine the relationship of tumor location and dosimetric parameters with CWT for SF-SBRT.

METHODS AND MATERIALS

From a prospective registry of 1462 patients, we identified patients treated with 30 Gy or 34 Gy. Gross tumor volume was measured as abutting, ≤1 cm, 1 to 2 cm, or >2 cm from the chest wall. CWT was prospectively graded according to Common Terminology Criteria for Adverse Events version 3.0, with grade 2 requiring medical therapy, grade 3 requiring procedural intervention, and grade 4 being disabling pain. Grade 1 CWT or radiographic rib fracture was not included. Logistic regression analysis was used to identify the parameters associated with CWT and calculate the probability of CWT with dose.

RESULTS

This study included 146 lesions. The median follow-up time was 23.8 months. The 5-year local control, distant metastasis, and overall survival rates were 91.8%, 19.2%, and 28.7%, respectively. Grade 2 to 4 CWT was 30.6% for lesions abutting the chest wall, 8.2% for ≤1 cm from the chest wall, 3.8% for 1 to 2 cm from the chest wall, and 5.7% for >2 cm from the chest wall. Grade ≥3 CWT was 1.4%. Tumor abutment (odds ratio [OR]: 6.5; P = .0005), body mass index (OR: 1.1; P = .02), rib D1cc (OR: 1.01/Gy; P = .03), chest wall D1cc (OR: 1.08/Gy; P = .03), and chest wall D5cc (OR: 1.10/Gy; P = .01) were significant predictors for CWT on univariate analysis. Tumor abutment was significant for CWT (OR: 7.5; P = .007) on multivariate analysis. The probability of CWT was 15% with chest wall D5cc at 27.2 Gy and rib D1cc at 30.2 Gy.

CONCLUSIONS

The rate of CWT with SF-SBRT is similar to the rates published for fractionated SBRT, with most CWT being low grade. Tumor location relative to the chest wall is not a contraindication to SF-SBRT, but the rates increase significantly with abutment. Rib D1cc and chest wall D1cc and D5cc may be used as predictors of CWT.

Trends in Radiation Oncology Residency Applicant Interview Experiences and Post-Interview Communication

PURPOSE

To report trends in applicant interview experiences and post-interview communication (PIC) between the 2016 and 2018 radiation oncology interview cycles.

METHODS AND MATERIALS

An anonymous survey was sent to all 203 residency applicants to a single institution during the 2018 Match, and the results were compared to a similar 2016 survey.

RESULTS

Response rates in 2018 and 2016 were 53% and 56%, respectively. Applicants from 2018 were asked less frequently than 2016 applicants about where else they were interviewing (71% vs 84%, P = .024) and how highly they planned to rank a program (11% vs 23%, P = .018). A higher proportion of 2018 programs explicitly discouraged PIC (median, 53% vs 33%, P < .0001), and more 2018 respondents chose not to send any thank-you notes/emails (42% vs 17%, P < .0001). When comparing 2018 results to 2016, no significant differences were observed in the proportion of applicants who notified their top program that they would rank that program highly (54% vs 60%, P = .354). No difference was observed in the rate of reported distress associated with a sense of obligation to send PIC (49% vs 46%, P = .664), and similar rates of respondents said they would feel relieved if PIC was discouraged (94% vs 89%, P = .223). Most respondents again reported that they would prefer a policy to actively discourage applicants from notifying their top programs of their high rank (60% vs 66%, P = .974).

CONCLUSIONS

Compared to 2016, respondents in 2018 reported that fewer programs are engaging in potential Match violations, and more are actively discouraging PIC, possibly as a result of increased awareness from recent publications. A similar number of applicants continued to engage in "gamesmanship," but more are choosing not to send thank-you notes/emails. Most respondents continue to prefer a policy discouraging PIC.

The Residency Match: Interview Experiences, Postinterview Communication, and Associated Distress

BACKGROUND

Interview experiences and postinterview communication during the residency match process can cause distress for applicants, and deserve further study.

OBJECTIVE

We both quantified and qualified the nature of various interview behaviors during the 2015-2016 National Resident Matching Program (NRMP) Match and collected applicant perspectives on postinterview communication and preferences for policy change.

METHODS

An anonymous, 31-question survey was sent to residency candidates applying to 8 residency programs at a single academic institution regarding their experiences at all programs where they interviewed.

RESULTS

Of 6693 candidates surveyed, 2079 (31%) responded. Regarding interview experiences, applicants reported being asked at least once about other interviews, marital status, and children at the following rates: 72%, 38%, and 17%, respectively, and such questions arose at a reported mean of 25%, 14%, and 5% of programs, respectively. Female applicants were more frequently asked about children than male applicants (22% versus 14%, P < .0001). Overall, 91% of respondents engaged in postinterview communication. A total of 70% of respondents informed their top program that they had ranked it highly; 70% of this subset reported associated distress, and 78% reported doing this to improve match success. A total of 71% would feel relief if postinterview communication was actively discouraged, and 51% would prefer applicants to be prohibited from notifying programs of their rank.

CONCLUSIONS

Applicants to several residency programs reported being asked questions that violate the NRMP Code of Conduct. The majority of applicants would prefer postinterview communication to be more regulated and less prevalent.

Radical Prostatectomy, External Beam Radiotherapy, or External Beam Radiotherapy With Brachytherapy Boost and Disease Progression and Mortality in Patients With Gleason Score 9-10 Prostate Cancer

IMPORTANCE

The optimal treatment for Gleason score 9-10 prostate cancer is unknown.

OBJECTIVE

To compare clinical outcomes of patients with Gleason score 9-10 prostate cancer after definitive treatment.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study in 12 tertiary centers (11 in the United States, 1 in Norway), with 1809 patients treated between 2000 and 2013.

EXPOSURES

Radical prostatectomy (RP), external beam radiotherapy (EBRT) with androgen deprivation therapy, or EBRT plus brachytherapy boost (EBRT+BT) with androgen deprivation therapy.

MAIN OUTCOMES AND MEASURES

The primary outcome was prostate cancer-specific mortality; distant metastasis-free survival and overall survival were secondary outcomes.

RESULTS

Of 1809 men, 639 underwent RP, 734 EBRT, and 436 EBRT+BT. Median ages were 61, 67.7, and 67.5 years; median follow-up was 4.2, 5.1, and 6.3 years, respectively. By 10 years, 91 RP, 186 EBRT, and 90 EBRT+BT patients had died. Adjusted 5-year prostate cancer-specific mortality rates were RP, 12% (95% CI, 8%-17%); EBRT, 13% (95% CI, 8%-19%); and EBRT+BT, 3% (95% CI, 1%-5%). EBRT+BT was associated with significantly lower prostate cancer-specific mortality than either RP or EBRT (cause-specific HRs of 0.38 [95% CI, 0.21-0.68] and 0.41 [95% CI, 0.24-0.71]). Adjusted 5-year incidence rates of distant metastasis were RP, 24% (95% CI, 19%-30%); EBRT, 24% (95% CI, 20%-28%); and EBRT+BT, 8% (95% CI, 5%-11%). EBRT+BT was associated with a significantly lower rate of distant metastasis (propensity-score-adjusted cause-specific HRs of 0.27 [95% CI, 0.17-0.43] for RP and 0.30 [95% CI, 0.19-0.47] for EBRT). Adjusted 7.5-year all-cause mortality rates were RP, 17% (95% CI, 11%-23%); EBRT, 18% (95% CI, 14%-24%); and EBRT+BT, 10% (95% CI, 7%-13%). Within the first 7.5 years of follow-up, EBRT+BT was associated with significantly lower all-cause mortality (cause-specific HRs of 0.66 [95% CI, 0.46-0.96] for RP and 0.61 [95% CI, 0.45-0.84] for EBRT). After the first 7.5 years, the corresponding HRs were 1.16 (95% CI, 0.70-1.92) and 0.87 (95% CI, 0.57-1.32). No significant differences in prostate cancer-specific mortality, distant metastasis, or all-cause mortality (≤7.5 and >7.5 years) were found between men treated with EBRT or RP (cause-specific HRs of 0.92 [95% CI, 0.67-1.26], 0.90 [95% CI, 0.70-1.14], 1.07 [95% CI, 0.80-1.44], and 1.34 [95% CI, 0.85-2.11]).

CONCLUSIONS AND RELEVANCE

Among patients with Gleason score 9-10 prostate cancer, treatment with EBRT+BT with androgen deprivation therapy was associated with significantly better prostate cancer-specific mortality and longer time to distant metastasis compared with EBRT with androgen deprivation therapy or with RP.

A Multi-institutional Comparison of SBRT and IMRT for Definitive Reirradiation of Recurrent or Second Primary Head and Neck Cancer

PURPOSE

Two modern methods of reirradiation, intensity modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT), are established for patients with recurrent or second primary squamous cell carcinoma of the head and neck (rSCCHN). We performed a retrospective multi-institutional analysis to compare methods.

METHODS AND MATERIALS

Data from patients with unresectable rSCCHN previously irradiated to ≥40 Gy who underwent reirradiation with IMRT or SBRT were collected from 8 institutions. First, the prognostic value of our IMRT-based recursive partitioning analysis (RPA) separating those patients with unresectable tumors with an intertreatment interval >2 years or those with ≤2 years and without feeding tube or tracheostomy dependence (class II) from other patients with unresected tumors (class III) was investigated among SBRT patients. Overall survival (OS) and locoregional failure were then compared between IMRT and SBRT by use of 2 methods to control for baseline differences: Cox regression weighted by the inverse probability of treatment and subset analysis by RPA classification.

RESULTS

The study included 414 patients with unresectable rSCCHN: 217 with IMRT and 197 with SBRT. The unadjusted 2-year OS rate was 35.4% for IMRT and 16.3% for SBRT (P<.01). Among SBRT patients, RPA classification retained an independent association with OS. On Cox regression weighted by the inverse probability of treatment, no significant differences in OS or locoregional failure between IMRT and SBRT were demonstrated. Analysis by RPA class showed similar OS between IMRT and SBRT for class III patients. In all class II patients, IMRT was associated with improved OS (P<.001). Further subset analysis demonstrated comparable OS when ≥35 Gy was delivered with SBRT to small tumor volumes. Acute grade ≥4 toxicity was greater in the IMRT group than in the SBRT group (5.1% vs 0.5%, P<.01), with no significant difference in late toxicity.

CONCLUSIONS

Reirradiation both with SBRT and with IMRT appear relatively safe with favorable toxicity compared with historical studies. Outcomes vary by RPA class, which informs clinical trial design. Survival is poor in class III patients, and alternative strategies are needed.

Volume, Dose, and Fractionation Considerations for IMRT-based Reirradiation in Head and Neck Cancer: A Multi-institution Analysis

PURPOSE

Limited data exist to guide the treatment technique for reirradiation of recurrent or second primary squamous carcinoma of the head and neck. We performed a multi-institution retrospective cohort study to investigate the effect of the elective treatment volume, dose, and fractionation on outcomes and toxicity.

METHODS AND MATERIALS

Patients with recurrent or second primary squamous carcinoma originating in a previously irradiated field (≥40 Gy) who had undergone reirradiation with intensity modulated radiation therapy (IMRT); (≥40 Gy re-IMRT) were included. The effect of elective nodal treatment, dose, and fractionation on overall survival (OS), locoregional control, and acute and late toxicity were assessed. The Kaplan-Meier and Gray's competing risks methods were used for actuarial endpoints.

RESULTS

From 8 institutions, 505 patients were included in the present updated analysis. The elective neck was not treated in 56.4% of patients. The median dose of re-IMRT was 60 Gy (range 39.6-79.2). Hyperfractionation was used in 20.2%. Systemic therapy was integrated for 77.4% of patients. Elective nodal radiation therapy did not appear to decrease the risk of locoregional failure (LRF) or improve the OS rate. Doses of ≥66 Gy were associated with improvements in both LRF and OS in the definitive re-IMRT setting. However, dose did not obviously affect LRF or OS in the postoperative re-IMRT setting. Hyperfractionation was not associated with improved LRF or OS. The rate of acute grade ≥3 toxicity was 22.1% overall. On multivariable logistic regression, elective neck irradiation was associated with increased acute toxicity in the postoperative setting. The rate of overall late grade ≥3 toxicity was 16.7%, with patients treated postoperatively with hyperfractionation experiencing the highest rates.

CONCLUSIONS

Doses of ≥66 Gy might be associated with improved outcomes in high-performance patients undergoing definitive re-IMRT. Postoperatively, doses of 50 to 66 Gy appear adequate after removal of gross disease. Hyperfractionation and elective neck irradiation were not associated with an obvious benefit and might increase toxicity.

The importance of the need for better systemic therapy in the definitive treatment of high-risk prostate cancer regardless of whether the initial treatment modality was external beam radiation, I-125 brachytherapy, or radical prostatectomy

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Background: While androgen deprivation therapy (ADT) is a common form of systemic therapy for treating high-risk prostate cancer (HRCaP), distant metastases development remains the predominate form of failure. We present a description of the sites of failure after treatment of HRCaP with External Beam Radiation (EBRT), I-125 Brachytherapy (PB), or Radical Prostatectomy (RP). This is accompanied by an analysis of prostate cancer-specific mortality (PCSM) after clinical failure. Methods: The study includes 2186 patients with HRCaP according to NCCN guidelines (684 EBRT, 409 PB, and 1093 RP). The association of PCSM with clinical and pathologic variables was assessed with Fine and Gray regression with non-PCSM mortality treated as a competing event. Results: The median f/u is 52 months. Overall, there were 323 clinical failures (sites of first failures: 287 distant (DM), 34 local (LF), 2 DM + LF). The median time to the diagnosis of DM was 44 months. ADT was used in 93% of EBRT, 53% of PB and 19% of RP patients. Further details regarding the development of DM is shown in Table 1. The type of initial treatment was not associated with PCSM after DM (Table 1). The only factor significantly associated with PCSM was Gleason Score (p = 0.0372). Conclusions: DM is the primary mode of failure after definitive treatment of HRCaP. The type of initial definitive treatment did not affect PCSM after DM. The cure rates of all forms of definitive treatment of HRCaP would benefit from better systemic therapy. [Table: see text]

Dosimetric differences between local failure and local controlled non-small cell lung cancer patients treated with stereotactic body radiotherapy: A matched-pair study

INTRODUCTION

Concerns were raised about the accuracy of pencil beam (PB) calculation and potential underdosing of medically inoperable non-small cell lung cancer (NSCLC) treated with stereotactic body radiation therapy (SBRT). From our institutional series, we designed a matched-pair study where each local failure and controlled patient was matched based upon several clinical factors, to investigate the dose difference between the matched-pair.

METHODS

Eighteen pairs of NSCLC patients, treated with 50 Gy in five fractions, were selected. These patients were matched based on treatment intent, tumour size, histology and clinical follow-up. All PB calculated clinical plans were retrospectively recalculated with a MC algorithm. The D₉₉ and D_Mean of the gross tumour volume (GTV) and D₉₅ and D_Mean of the planning tumour volume (PTV) from PB and Monte Carlo (MC) calculation were compared between local failures and controls using the Mann-Whitney test.

RESULTS

The mean PB calculated D95 of PTV was 50.4 Gy for both failures and controls (P = 0.85), indicating no planning differences between the groups. From MC calculations, the mean (±SD) of GTV D₉₉ , GTV D_Mean , PTV D₉₅ , PTV D_Mean were 47.6 ± 2.6/46.3 ± 2.4, 50.4 ± 2.1/49.8 ± 1.6, 44.4 ± 2.7/43.6 ± 3.1, 48.7 ± 2.4/48.2 ± 2.4 Gy for failure/controlled groups, respectively, and there was no significant difference between two groups (all P > 0.1). The dose differences between MC and PB calculations were in agreement with other literatures and there was no significant difference between two groups.

CONCLUSIONS

While PB algorithms may overestimate tumour doses relative to MC algorithms, our matched-pair study did not find dose differences between local failure and local controlled cases.

Three or More Courses of Stereotactic Radiosurgery for Patients with Multiply Recurrent Brain Metastases

BACKGROUND

Although patients with brain metastasis are treated with primary stereotactic radiosurgery (SRS), the use of salvage therapies and their consequence remains understudied.

OBJECTIVE

To study the intracranial recurrence patterns and salvage therapies for patients who underwent multiple SRS courses.

METHODS

A retrospective review was performed of 59 patients with brain metastases who underwent ≥3 SRS courses for new lesions. Cox regression analyzed factors predictive for overall survival.

RESULTS

The median age at diagnosis was 52 years. Over time, patients underwent a median of 3 courses of SRS (range: 3-8) to a total of 765 different brain metastases. The 6-month risk of distant intracranial recurrence after the first SRS treatment was 64% (95% confidence interval: 52%-77%). Overall survival was 40% (95% confidence interval: 28%-53%) at 24 months. Only 24 patients (41%) had a decline in their Karnofsky Performance Status ≤70 at last office visit. Quality of life was preserved among 77% of patients at 12 months, with 45% experiencing clinically significant improvement during clinical follow-up. Radiation necrosis developed in 10 patients (17%). On multivariate analysis, gender (males, Hazard Ratio [HR]: 2.0, P < .05), Karnofsky Performance Status ≤80 (HR 3.2, P < .001), extracranial metastases (HR: 3.6, P < .001), and a distant intracranial recurrence ≤3 months from initial to repeat SRS (HR: 3.8, P < .001) were associated with a poorer survival.

CONCLUSION

In selected patients, performing ≥3 SRS courses controls intracranial disease. Patients may need salvage SRS for distant intracranial relapse, but focal retreatments are associated with modest toxicity, do not appear to negatively affect a patient's performance status, and help preserve quality of life.

Pain flare after stereotactic radiosurgery for spine metastases

PURPOSE

Understanding of pain flare (PF) following spine stereotactic radiosurgery (sSRS) is lacking. This study sought to determine the incidence and risk factors associated with PF following single fraction sSRS.

MATERIALS/METHODS

An IRB-approved database was compiled to include patients who underwent sSRS. Patient and disease characteristics as well as treatment and dosimetric details were collected retrospectively. Pain relief post-sSRS was prospectively collected using the Brief Pain Inventory (BPI). These factors were correlated to the development of PF (defined as an increase in pain within 7 days of treatment which resolved with steroids). Survival was calculated using Kaplan-Meier analysis and logistic regression was utilized to evaluate the association between the clinical and treatment factors and occurrence of PF.

RESULTS

A total of 348 patients with 507 treatments were included. Median age and prescription dose were 59 years and 15 Gy (range: 7-18), respectively, and 62% of patients were male. Renal cell carcinoma (24%), lung cancer (14%), and breast cancer (11%) were the most common histologies, and 74% had epidural disease and 43% had thecal sac compression. The most common location of metastases was in the cervical/thoracic spine (59%), followed by lumbar spine (32%), and sacral spine (9%). Most common reason for treatment was pain (73%), followed by pain and neurological deficit (13%), asymptomatic disease (10%), and neurologic deficit only (3%). Median time to pain relief was 1.8 months. Median overall survival, time to radiographic failure, and time to pain progression were 13.6 months, 26.5 months, and 56.6 months, respectively. Only 14.4% of treatments resulted in the development of PF. Univariate analysis showed that higher Karnofsky performance score (KPS) (OR=1.03, p=0.03), female gender (OR=1.80, p=0.02), higher prescription dose (OR=1.30, p=0.008), and tumor location of cervical/thoracic spine vs lumbar spine (OR=1.81, p=0.047) were predictors for the development of PF. On multivariate analysis, higher consult KPS (OR=1.03, p=0.04), female gender (OR=1.93, p=0.01), higher prescription dose (OR=1.27, p=0.02), and tumor location of cervical/thoracic spine vs lumbar spine (OR=1.81, p=0.05) remained predictors of PF. No other dosimetric parameters were associated with the development of PF.

CONCLUSION

PF is an infrequent complication of sSRS. Predictors for the development of PF include higher consult KPS, female gender, higher prescription dose, and cervical/thoracic tumor location. Dose to the spinal cord was not a predictor of PF. Since a minority (14.4%) of treatments result in PF, we do not routinely utilize prophylactic steroid treatment; however, prophylactic steroids may be considered in female patients with cervical/thoracic metastases receiving higher dose sSRS.

A matched comparison of human papillomavirus-induced squamous cancer of unknown primary with early oropharynx cancer

OBJECTIVES/HYPOTHESIS

Patients with human papillomavirus (HPV)-induced cancer of unknown primary (CUP) are generally excluded from clinical trials, despite surgical series reporting detection rates of occult oropharynx primaries of >80%. We performed a matched-pair analysis to compare outcomes between T0N1-3M0 HPV+ CUP and T1-2N1-3M0 HPV+ oropharynx known primary (OPX).

STUDY DESIGN

Retrospective cohort study at a single institution.

METHODS

Patients with early T stage, node positive HPV+ OPX or CUP treated with curative intent between 1998 and 2016 were identified. For a subgroup of CUP patients with an unknown HPV status, we imputed HPV status and included patients with a >80% probability of being HPV+. Cohorts were matched based on patient demographics using a nearest neighbor propensity technique. After matching, patients were grouped according to either a favorable or unfavorable risk stratification designations per current NRG Oncology clinical trial enrollment criteria. Disease-free survival (DFS) and overall survival (OS) were calculated using Kaplan-Meier analysis.

RESULTS

Of 298 patients with T1-2N1-3 OPX, 48 were matched to 48 HPV+ CUP patients (32 with confirmed and 16 imputed HPV status). Median follow-up for CUP (34.1 months) and OPX (27.8 months) patients were similar (P = .23).There were no significant differences between the CUP and OPX groups for 3-year DFS (89% vs. 85%, P = .44), and 3-year OS (91% vs. 91%, P = .11), respectively.

CONCLUSIONS

Patients with T0N+M0 HPV-induced CUP have similar survival outcomes to matched patients with T1-2N+M0 HPV+ OPX. These patients can reasonably be included in clinical trials investigating the role of treatment deintensification and risk stratified similar to patients with early-stage known primary OPX cancer.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1379-1385, 2018.

Tumor Control and Toxicity for Common Stereotactic Body Radiation Therapy Dose-Fractionation Regimens in Stage I Non-Small Cell Lung Cancer

PURPOSE

To examine the impact of stereotactic body radiation therapy (SBRT) dose on outcomes in early-stage non-small cell lung cancer in a large single-institution series.

METHODS AND MATERIALS

We reviewed 600 patients treated from 2003 to 2012 for early-stage non-small cell lung cancer. The SBRT dose was at physician discretion on the basis of tumor size and location. Peripheral tumors were treated to 60 Gy in 3 fractions (homogeneous planning), 48-50 Gy in 4-5 fractions, or 30-34 Gy in 1 fraction. Central tumors were treated to 50 Gy in 5 fractions, 60 Gy in 8 fractions, or 50 Gy in 10 fractions. Patient, tumor, and treatment factors were assessed for their impact on patterns of failure, toxicity, and survival.

RESULTS

An SBRT dose of 54-60 Gy in 3 fractions was associated with a statistically significant lower rate of local failure (LF) (4.3% at 2 years) compared with 30-34 Gy in 1 fraction (21%), 48-50 Gy in 4-5 fractions (15.5%), and 50-60 Gy in 8-10 fractions (13.3%). Lower pre-SBRT hemoglobin and higher positron emission tomography standardized uptake value were also associated with LF. Nodal failure, distant failure, and overall survival were similar between fractionation groups. Pulmonary toxicity (crude rate, any grade) was slightly higher for 3 fractions (5.0%) compared with 1 (3.2%) or 4-5 fractions (3.8%). Chest wall toxicity was also higher for 3 (23.7%) compared with 1 (8.6%) or 4-5 (7.7%) fraction regimens.

CONCLUSIONS

Although higher biologically equivalent dose SBRT (150-180 Gy₁₀) may be associated with slightly lower LF, it was also associated with mildly increased toxicity and no difference in other patterns of failure or overall survival.

Secondary Urethral Malignancies Following Prostate Brachytherapy

OBJECTIVE

To understand urethral secondary malignancies among patients treated with brachytherapy (BRT) for primary prostate cancer.

PATIENTS AND METHODS

Institutional retrospective review identified 13 patients evaluated from 2003 to 2014 with urethral cancer and history of BRT monotherapy for prostate cancer. All patients were biochemically free of their primary disease and radiation-associated secondary malignancies (RASMs) were confirmed pathologically to be histologically distinct from primary tumor. BRT characteristics, patient age, presentation, staging workup, and clinical course were evaluated.

RESULTS

The mean time from BRT to presenting symptoms of hematuria, urinary retention, and/or renal failure was 71 months. Symptom onset to RASM diagnosis interval was 24 months. Mean time from BRT to RASM diagnosis was 95 months. Eighty-five percent of patients had an undetectable prostate-specific antigen level (<0.2 ng/mL) at last follow-up. Types of RASM included sarcomatoid carcinoma (6), small cell carcinoma (2), urothelial carcinoma with squamous differentiation (2), squamous cell carcinoma (1), rhabdomyosarcoma (1), and urothelial carcinoma (1). A majority of patients were diagnosed with advanced disease with either distant metastases (54%) or local progression (23%). Ten patients died during this study period with median time to death after RASM diagnosis of 6 months.

CONCLUSION

RASMs localized to the posterior urethra displayed advanced disease and high mortality rates. Refractory lower urinary tract symptoms, hematuria, and history of prostate BRT should raise suspicion for urethral RASMs. Further studies are warranted to determine patient and disease characteristics that correlate with disease-specific mortality of secondary urethral malignancies.

Prognostic factors associated with benefit to post-operative chemotherapy: A National Cancer Data Base analysis

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Background: Addition of chemotherapy to adjuvant radiation (RT) confers an OS benefit and is recommended in HNSCC patients with nodal extracapsular extension (ECE) and positive surgical margins based on pooled data. The purpose of this study is to retrospectively evaluate a larger patient data set in an attempt to confirm this observation and to assess current patterns of practice. Methods: The National Cancer Data Base (NCDB) was queried to identify patients with HNSCC who were treated with primary definitive surgery followed by adjuvant RT between 2004 and 2012. For patients treated with surgery and post-operative RT with or without chemotherapy, the effect of the systemic therapy on OS was explored using multivariable Cox proportional hazards modeling and stratified by patient and disease factors. Results: 6,351 patients were identified meeting study criteria; 3157 patients (49.7%) received adjuvant RT alone, and 3194 patients (50.3%) received adjuvant chemoradiotherapy (CRT). An increase in chemotherapy usage was observed over time (6% of patients in 2004; 16% in 2012). No difference was seen in OS by use of CRT (median OS 8.3 years in patients without CRT vs. 9.4 years in patients with CRT, p = 0.0893). On multivariate analysis OS was improved in younger patients, patients with less co-morbidity, oropharynx, lower T and lower N. OS was also improved in patients given chemotherapy if either ECE or positive surgical margins were present (HR 1.166, p = 0.0438) but not in those with negative surgical margins and no ECE (HR 1.037, p = 0.5888). Nonetheless, chemotherapy was given to 38% of post-operative patients without these risk factors and not given to 35% of patients with risk factors. Conclusions: This NCDB analysis confirms an OS benefit with addition of chemotherapy to post-operative RT in HNSCC patients with ECE or positive surgical margins but not in patients without these risk factors, consistent with current guidelines. National practice patterns, however, do not mirror these recommendations. These results are subject to limitations of retrospective analysis of a large database and further studies are needed to better elucidate high risk factors benefiting from intensifying adjuvant therapy.

Skeletal-related events and mortality among men diagnosed with advanced prostate cancer: The impact of alternative measures of radiation to the bone

PURPOSE/OBJECTIVE(S)

Skeletal-related events (SREs), which include radiation to the bone (RtB), can occur among patients with bone metastasis (BM). There is a recognized potential for misclassification of RtB when using claims data. We compared alternative measures of RtB to better understand their impact on SRE prevalence and SRE-related mortality.

METHODS AND MATERIALS

We analyzed data for stage IV prostate cancer (PCa) cases identified between 2005 and 2009 in the Surveillance, Epidemiology, and End Results registry linked with Medicare claims. We created two measures of RtB: 1) a literature-based measure requiring the presence of a prior claim with a BM code; 2) a new measure requiring either that the BM code coincided with the radiation episode or that the duration of the radiation episode was less than or equal to 4 weeks. We estimated adjusted hazard ratios of an SRE using both measures among stratified samples: no metastasis (M0), metastasis to bone (M1b) and other sites (M1c).

RESULTS

The study sample included 5,074 men with stage IV PCa (median age 77 years), of whom 22% had M0, 54% had M1b, and 24% had M1c disease at time of PCa diagnosis. Based on Approaches 1 and 2, the proportion with probable RtB was 5% and 8% among M0, 30% and 30% among M1b, and 25% and 27% among M1c patients. Among M0 patients, the adjusted hazard ratio (AHR) associated with an SRE was 1.27 when using Approach 1 (95% confidence interval, CI: 0.95-1.7) and 1.49 when using Approach 2 (95% CI: 1.14-1.96). However, the impact of SREs on mortality did not differ between both approaches among M1b and M1c patients.

CONCLUSION

We found that alternative measures used to define RtB as SRE in claims data impact conclusions regarding the effect of SREs on mortality among M0 but not M1 patients.

Intensity modulated radiation therapy with pulsed reduced dose rate as a reirradiation strategy for recurrent central nervous system tumors: An institutional series and literature review

BACKGROUND

Pulsed reduced dose rate (PRDR) is a reirradiation technique that potentially overcomes volume and dose limitations in the setting of previous radiation therapy for recurrent central nervous system (CNS) tumors. Intensity modulated radiation therapy (IMRT) has not yet been reported as a PRDR delivery technique. We reviewed our IMRT PRDR outcomes and toxicity and reviewed the literature of available PRDR series for CNS reirradiation.

METHODS AND MATERIALS

A total of 24 patients with recurrent brain tumors received PRDR reirradiation between August 2012 and December 2014. Twenty-two patients were planned with IMRT. Linear accelerators delivered an effective dose rate of 0.0667 Gy/minute. Data collected included number of prior interventions, diagnosis, tumor grade, radiation therapy dose and fractionation, normal tissue dose, radiation therapy planning parameters, time to progression, overall survival, and adverse events.

RESULTS

The median time to PRDR from completion of initial radiation therapy was 47.8 months (range, 11-389.1 months). The median PRDR dose was 54 Gy (range, 38-60 Gy). The mean planning target volume was 369.1 ± 177.9 cm³. The median progression-free survival and 6-month progression-free survival after PRDR treatment was 3.1 months and 31%, respectively. The median overall survival and 6-month overall survival after PRDR treatment was 8.7 months and 71%, respectively. Fifty percent of patients had ≥4 chemotherapy regimens before PRDR. Toxicity was similar to initial treatment, including no cases of radiation necrosis.

CONCLUSION

IMRT PRDR reirradiation is a feasible and appropriate treatment strategy for large volume recurrent CNS tumors resulting in acceptable overall survival with reasonable toxicity in our patients who were heavily pretreated. Prospective studies are necessary to determine the optimal timing of PRDR reirradiation, the role of concurrent systemic agents, and the ideal patient population who would receive the maximal benefit from this treatment approach.

SUMMARY

Intensity modulated radiation therapy (IMRT) has not yet been reported as a pulsed reduced dose rate (PRDR) delivery technique for recurrent brain tumors and may allow for safe and comprehensive reirradiation for large volume tumors. We reviewed our IMRT PRDR outcomes and toxicity and reviewed the literature of available PRDR series for recurrent central nervous system tumors. We conclude that IMRT PRDR reirradiation is a feasible and appropriate treatment strategy for large volume recurrent brain tumors resulting in acceptable overall survival with reasonable toxicity in our patients who were heavily pretreated.