Prompt Pain Relief: Advanced Practice Provider Led Rapid Access Palliative Radiotherapy Clinic

PURPOSE/OBJECTIVE(S)

Patients (pts) commonly present to radiation oncology with painful bone metastases requiring urgent palliative radiotherapy (RT). Unfortunately, the pre-existing scheduling workflow for palliative referrals can be inefficient, causing significant delays before pts are seen by a radiation oncologist (RO). Our institution implemented an alternative workflow, which led to the creation of an advanced practice provider (APP) led Rapid Access Palliative RT Clinic (PRC). We investigated the impact of the PRC in reducing time from referral to consultation for pts in need of palliative RT.

MATERIALS/METHODS

In March 2022, we initiated an outpatient APP led PRC focused on the APP driving consultations supervised by the weekly on-call RO. Pts are offered a variety of options for consultation such as virtual, in clinic with reserved simulation time, and when appropriate virtual simulation, using diagnostic imaging for RT planning, and same day treatment requiring only one visit to the department. The clinic provides a point of contact that fosters multidisciplinary interaction and proactive continuity of care and follow up. Following institutional review board approval, pts who received palliative RT for painful bone metastases from June 2021 to December 2022 were retrospectively reviewed. Data was collected with respect to when the referral was placed for palliative RT and when the pts was seen for consultation by a provider. The cohort of pts seen between June 2022 and December 2022 represented the PRC cohort. A comparison cohort of pts treated between June 2021 and December 2021 represented the pre-PRC cohort. Unpaired T-test was used to analyze time from referral to consultation (TTC) between groups. P value < 0.05 was considered statistically significant.

RESULTS

During the pre-PRC period, 91 patients were treated, including 12 inpatients and 79 outpatients, while during the PRC period, 101 pts were treated, including 7 inpatients and 94 outpatients. The median dose was 8 Gy in 1 fraction for both cohorts. During the PRC period, there was a 19% increase in outpatients treated for bone metastases. Restricted to just outpatients, the average TTC was 10.4 days (SD 10.2) for pre-PRC cohort versus 6.3 days (SD 6.6) for the PRC cohort, which was statistically significant (p = 0.003). This was a 39% reduction in TTC. During the PRC period, 17 pts were not seen in the APP led PRC while 77 were seen in the PRC. The most common reason was an erroneous referral for curative intent treatment instead of palliative bone treatment. During the PRC period, those pts seen in the APP led PRC had an average TTC of 5.1 days (SD 4.6) versus 11.5 days (SD 10.64) for those not seen in the PRC (p = 0.03) with a 56% reduction in TTC.

CONCLUSION

The APP led PRC clinic significantly decreased time from referral to consultation for pts requiring urgent palliative RT for painful bone metastases. Further research is underway to determine if the PRC increases referrals, patients treated, patient satisfaction, and the impact on staffing RO.

Radiotherapy Utilization and Outcomes on a Contemporary Trial for Pediatric High-Risk Hodgkin Lymphoma Study

PURPOSE/OBJECTIVE(S)

Contemporary trials in pediatric Hodgkin lymphoma (cHL) evaluate strategies to reduce radiotherapy (RT) utilization while maintaining excellent progression-free survival (PFS). An alternative strategy is to irradiate selective sites at higher risk of relapse, and/or use proton therapy (PT) to minimize exposure to healthy tissue. We investigated the use of PT and photon therapy (XRT) and associated early outcomes among patients receiving involved site RT (ISRT) to high-risk sites on the Children's Oncology Group (COG) trial AHOD1331 (NCT021664643).

MATERIALS/METHODS

This multicenter randomized, open-label phase 3 study enrolled patients 2-21 years (yrs) with previously untreated cHL: stages IIB + bulk, IIIB, IVA, IVB. Patients were randomized to 5 cycles of either ABVE-PC (doxorubicin, bleomycin, vincristine, etoposide, prednisone, cyclophosphamide) or the brentuximab vedotin (BV) containing regimen BV-AVE-PC given every 21 days. ISRT to 21 Gy was given to bulky mediastinal adenopathy and slow responding lesions (SRL) defined by 5-point score 4 or 5 on PET-CT after 2 cycles. ISRT could be delivered as 3D conformal XRT (3D), intensity modulated XRT (IMRT), or proton therapy (PT). Utilization of RT was compared by mode and by study enrollment midpoint among irradiated patients. Severe acute toxicity assessment included any incident grade 3 or higher toxicity during the ISRT period, except for neuropathy.

RESULTS

Among 587 eligible patients who were enrolled across 153 institutions between March 2015 and August 2019 with a median follow up of 43.1 months, the 3-yr PFS was 82.5% (90% CI, 78.3%-85.9%) with ABVE-PC and 92.5% (90% CI 89.5%-94.6%) with BV-AVE-PC (p = 0.0002). There was no difference in ISRT receipt or modality by study arm (p = 0.33). Among those who received RT 69.7% received it due to bulky mediastinal adenopathy, 6.6% due to SRL, and 23.7% for both. Overall, 317 (54.0%) patients received protocol RT of which 28.7% received 3D, 44.8% received IMRT, and 26.5% received PT. PT utilization increased over the course of the study from 21.5% among the first 50% of irradiated patients to 31.5% in the second half of irradiated patients (p = 0.045). The 3-yr progression-free survival rates overall by RT were comparable: PT (88.0%, 90% CI 80.6% - 92.7%%); XRT (87.1%, 90% CI 82.9%-90.4%) (p = 0.85). No difference in PFS was observed between 3D versus IMRT (p = 0.65). No differences were observed in severe acute toxicities (8.33% vs. 8.15%, p = 0.96) between PT and XRT.

CONCLUSION

Selective use of RT results in excellent outcomes for pediatric patients with high-risk HL and combination chemotherapy inclusive of the novel agent BV. Over the course of the study, PT utilization increased as an RT modality. Early results suggest that PT does not compromise disease control and has similar acute toxicity as XRT. Long term follow-up (>10 years) is needed to evaluate for secondary malignancies and cardiac toxicity among the different RT modalities.

Consolidative Radiotherapy for Residual PET-Avid Disease on Day +30 Post CAR T-Cell Therapy in Non-Hodgkin Lymphoma

PURPOSE/OBJECTIVE(S)

Up to30% of non-Hodgkin lymphoma (NHL) patients achieve a partial response (PR) to anti-CD19 Chimeric Antigen Receptor T-cell Therapy (CART) on day +30. Most PR patients relapse and only 30% achieve spontaneous complete response (CR) without additional therapies. This study is the first to report on the role of consolidative radiotherapy (cRT) for PR PET-avid disease on day +30 post-CART in NHL.

MATERIALS/METHODS

Aretrospective review across 3 institutions from 2018 to 2022 identified 60 patients with B-cell NHL who received CART and achieved PR (Deauville 4-5) with <5 PET-avid disease sites on day +30. Progression-free survival (PFS) was defined from CART infusion to any disease progression. Overall survival (OS) was defined from CART infusion to death. Local relapse-free survival (LRFS), calculated based on the total number of PR sites, was defined from CART infusion to local relapse (LR) in the PR site identified on day +30. cRT was defined as comprehensive (compRT) - treated all PR PET-avid sites - or focal (focRT).

RESULTS

Followingday +30 PET scan, 45 PR patients were observed and 15 received cRT. Only one patient received consolidative systemic therapy and belonged to the cRT group. Prior to CART, bridging RT was given to 13 patients (9 in observation group and 4 in cRT group). There were no significant differences in the pre-CART and day +30 baseline characteristics, including the median size and SUVmax of the PR sites, between the two groups. However, the median number of PR sites on day +30 was higher in the cRT group (2 [range 1-3] vs 1 [range 1-3], p = 0.003). The median equivalent 2 Gy dose was 39.1 (Interquartile range 36.8-41) Gy, and the most common cRT regimen was 37.5 Gy in 15 fractions. The median follow-up was 21 months. Among the observed patients, 15 (33%) achieved spontaneous CR, and 27 (60%) experienced disease progression with all relapses involving the initial PR sites. Among patients who received cRT, 10 (67%) achieved CR, and 3 (20%) had disease progression with no relapses in the radiated PR sites. None of the 10 cRT patients achieving CR relapsed or required subsequent therapies. The 2-year PFS was 80% and 37% (p = 0.012) and the 2-year OS was 78% and 43% (p = 0.12) in the cRT and observation groups, respectively. Patients consolidated with compRT (n = 12) had superior 2-year PFS (92% vs 37%, p = 0.003) and 2-year OS (86% vs 43%, p = 0.048) compared to observed or focRT patients (n = 48). There were no grade 3+ RT-related toxicities. A total of 90 PR sites were identified; 64 were observed and 26 received cRT. Fourteen (22%) observed PR sites achieved spontaneous sustained CR and 42 (66%) experienced LR. Twenty-four (92%) PR sites consolidated with cRT achieved sustained CR and none experienced LR. The 2-year LRFS was 100% in the cRT sites and 31% in the observed sites (p<0.001).

CONCLUSION

NHL patients who achieve PR by PET to CART are at high risk of local progression. cRT for residual PET-avid disease on day +30 post-CART appears to alter the pattern of relapse and improve LRFS and PFS.

Predictors of Local Control with Palliative Radiotherapy for Multiple Myeloma

PURPOSE/OBJECTIVE(S)

Palliative radiotherapy (RT) is employed for patients with multiple myeloma to improve or prevent symptoms. However, the optimal dose fractionation is not well defined. The role of cytogenetics in informing RT warrants further study. We performed an institutional analysis of patients with multiple myeloma receiving palliative RT and assessed factors associated with local progression, with a focus on dose fractionation and cytogenetic abnormalities.

MATERIALS/METHODS

We queried a prospectively maintained, departmental database for consecutive patients who received palliative RT for multiple myeloma at our institution from 2015 to 2020. Double- and triple-hit were defined as the presence of two and three high-risk cytogenetic abnormalities. RT dose fractionation data were extracted from the database. Follow-up imaging was used to evaluate for progression.

RESULTS

A total of 239 patients with 362 treated lesions were included. Twenty-five patients (10.4%) with 39 lesions had double-hit cytogenetics, and 4 patients (1.7%) with 7 lesions were triple-hit. Patients had the following number of lesions treated with RT: 1 (156, 65.3%), 2 (53, 22.2%), 3 (17, 7.1%), or >3 (13, 5.4%). The most commonly targeted sites were spine (125, 34.5%), abdomen/pelvis (67, 18.5%), and lower extremity (53, 14.6%). Most lesions received doses of 20 Gy/5 fx (132, 36.5%), 8 Gy/1 fx (93, 25.7%), or 30 Gy/10 fx (48, 13.3%). RT equivalent dose in 2 Gray fractions (EQD2) was <2000 cGy for 126 lesions (34.8%) and ≥2000 cGy for 236 lesions (65.2%). At a median follow-up of 4.3 years, the risk of local progression on a per lesion basis at 1 and 4 years was 7.8% (95% CI: 5.5-11.1) and 13.4% (10.3-17.5), respectively. No cytogenetic abnormalities were correlated with local progression. Factors significant on univariate analysis included female sex [hazard ratio (HR): 1.94 (1.02-3.71), p = .045], LDH at diagnosis [HR per 10 units/liter: 1.04 (1.09-1.08), p = .016], and number of treated lesions [HR per lesion: 1.38 (1.02-1.89), p = .039]. These three covariates were included on multivariable analysis, and the only covariate to approach significance was number of treated lesions [HR for >3 versus 1: 2.43 (0.88-6.74), p = .059]. In the overall cohort, EQD2 did not impact risk of progression. Among those with >3 treated lesions, EQD2 ≥2000 cGy was associated with a significantly lower risk of progression [HR: 0.05 (0.01-0.23), p<.001]. Double- and triple-hit status were not correlated with progression. Median overall survival in all patients was 4.1 years versus 1.5 and 0.6 years in those with double- and triple-hit disease, respectively.

CONCLUSION

In this large, institutional study of patients with multiple myeloma, palliative RT achieves durable long-term local control. Patients with high disease burden may be at increased risk of progression at treated sites. This group may benefit from an EQD ≥2000 cGy. Cytogenetics, including double- and triple-hit status, do not appear to influence RT response.

The Role of Radiation Therapy in the Management of Gray Zone Lymphoma

PURPOSE/OBJECTIVE(S)

Gray zone lymphoma (GZL) is a relatively rare disease predominantly affecting young adults with purportedly poor outcomes with current treatment approaches. The role of radiation therapy (RT) in the management of GZL is not well established. This is the largest study to report on the outcomes of GZL patients treated with and without RT.

MATERIALS/METHODS

A retrospective review of 30 patients with GZL treated across 3 institutions from 2009 to 2021 was performed. Event-free survival (EFS) was defined from initiation of frontline chemotherapy (CHT) to disease progression/relapse, initiation of salvage therapy, or death. Local control (LC) was defined from RT start date to in-field recurrence.

RESULTS

The median age was 32 (range: 18-86) years, and 16 (53%) patients had early stage (I-II) disease. Bulky mediastinal disease was present in 63% of patients, and the median tumor diameter was 10 (range: 1.5-18) cm. Patients received ABVD (20%), RCHOP (33%), or REPOCH (47%) as frontline CHT. Among 25 patients with interim PET/CT scan, there were 6 rapid early responders and 14 slow early responders (SER), with 2-year EFS of 33% and 24%, respectively (p = 0.13). After the completion of CHT, 15 (50%) patients achieved complete response (CR) and 10 (33%) achieved partial response (PR), with 2-year EFS of 46% and 10%, respectively (p = 0.004). RT was given to 9 patients in CR (n = 3) or in PR (n = 6). The median RT dose was 36 (30.6-48.6) Gy, at 1.8-2 Gy/fraction. Those receiving RT had bulkier disease at diagnosis (p = 0.049) and lower rates of CR following CHT (p = 0.03). After RT, 3/6 (50%) PR patients converted to CR. At a median follow-up of 4 years, the 2-year EFS was 26% for all patients, 33% for RT and 23% for noRT (p = 0.44). Among patients who did not receive upfront RT and experienced progression (n = 17), 16 (94%) relapsed in pre-existing sites. The 5-year OS was 80% for all patients, 88% for RT and 78% for no RT (p = 0.63). Patients who achieved PR to CHT and received RT had better 2-year EFS (17% vs 0%, p = 0.007) compared to patients who did not receive RT. Similarly, patients with SER who received RT had superior 2-year EFS (33% vs 13%, p = 0.038). Patients with bulky mediastinal disease had a 2-year EFS of 43% with RT and 11% without RT (p = 0.08). After 1st line treatment, 22 (73%) patients relapsed and 18 were successfully salvaged with a sustained CR. The most common salvage regimen involved high dose CHT followed by hematopoietic cell transplantation (HCT) (n = 15). RT was given for 7 patients in the relapsed/refractory setting (consolidative peri-HCT n = 4; definitive salvage n = 3) and 5 (71%) achieved a sustained CR. Among the 16 patients who received RT in the upfront (n = 9) or salvage (n = 7) setting, 3 patients experienced in-field recurrence translating to 2-year LC of 79%.

CONCLUSION

GZL patients have high risk of relapse and maximal upfront combined modality therapy should be considered. RT provides good local control and improves EFS particularly for SER, PR, and bulky mediastinal disease.

Change in Blood Counts after Palliative Radiotherapy for Multiple Myeloma

PURPOSE/OBJECTIVE(S)

Radiation therapy (RT) can provide effective palliation and prevent symptomatic local progression of multiple myeloma (MM). However, RT is sometimes avoided due to concerns for secondary impact to bone marrow, potentially decreasing blood cell counts and precluding ability to receive future systemic therapies. We reviewed a series of MM patients who received palliative RT to assess changes in blood counts from pre-RT to post-RT, hypothesizing that blood counts would not significantly decline after treatment with modern RT volumes and techniques.

MATERIALS/METHODS

We utilized a prospectively maintained departmental database and included patients who received palliative RT for MM from 2015 to 2020. Lab values immediately pre-RT (within one month of RT start date) and post-RT (within three months of RT completion) including hemoglobin, lymphocytes, neutrophils, and platelets were collected. Statistical differences from pre-RT to post-RT were assessed using t-tests. ANOVA was used to compare change in blood counts between common dose fractionation regimens (30 Gy in 10 Fractions, 20 Gy in 5, and 8 Gy in 1).

RESULTS

A total of 334 MM patients receiving 424 courses of RT were included in this analysis. The median age at start of first treatment was 67 (IQR: 60-76) years. One-hundred ninety-five (58%) were male. Median RT dose was 20 (IQR: 8-24.5) Gy delivered over a median 5 (IQR: 1-5) fractions. Between pre-RT and post-RT, there was no significant change in hemoglobin (+0.1 g/dL (IQR: -0.8, +0.5), p = .076), lymphocyte counts (-0.3*10^9 cells/L (IQR: -0.6, 0), p = .435), or neutrophil counts (-0.1*10^9 cells/L (IQR: -1.1, +0.9), p = .310). In contrast, platelet counts significantly decreased from pre-RT (median 165*10^9 cells/L, IQR: 112-210) to post-RT (median 146, IQR: 93-194) by a median of 17.5 *10^9 cells/L (IQR: -52.5, +14.0, p<0.0001). There were no differences in changes in hemoglobin, neutrophils, or platelets between the common dose fractionations. However, there was a significantly greater drop in lymphocytes after 30 Gy in 10 fractions (p = .039, mean lymphocyte count change (in 10^9 cells/L) for 30 Gy in 10: -0.87, 20 Gy in 5: -0.47, and 8 Gy in 1: -0.27).

CONCLUSION

In this large dataset of patients receiving modern palliative RT for MM, hemoglobin, lymphocytes, and neutrophils did not significantly decline from pre-RT to post-RT. In contrast, there was a statistically significant drop in platelet count by a median 17.5*10^9 cells/L from pre-RT to post-RT, which may or may not be clinically significant depending on clinical context. Patients receiving 30 Gy in 10 fractions had greater drops in lymphocytes than those receiving lower doses. Further analyses will be performed to determine clinical, dosimetric, and volumetric predictors of decline in blood counts after radiation.

Consolidative Radio therapy in Place of Autologous Stem Cell Transplant in Patients with Low-Risk Relapsed/Refractory (R/R) Classic Hodgkin Lymphoma (cHL) Treated with Nivolumab plus Brentuximab Vedotin: CheckMate 744

PURPOSE/OBJECTIVE(S)

Standard of care treatment for patients with relapsed and refractory classic Hodgkin lymphoma (RRHL) involves second line therapy followed by high dose therapy and autologous stem cell transplant (HDT/ASCT) and carries with it significant costs and toxicities to the patient. Some patients with RRHL may not require such intensive therapy, especially in the era of targeted chemotherapy and checkpoint inhibitors. CheckMate 744 (NCT02927769) evaluated a novel second-line therapy that omits HDT/ASCT by combining brentuximab vedotin (BV) and a nivolumab (N) followed by consolidative ISRT for low risk RRHL.

MATERIALS/METHODS

Pts were aged 5-30 y and had one prior treatment without HDT/ASCT. Low-risk RRHL were those at relapse without B symptoms or extranodal disease, limited sites of relapse (≤4 sites of disease above the diaphragm or ≤3 sites above/below the diaphragm) AND with initial Stage IA, IIA with relapse <1 year if they received ≤3 cycles of chemotherapy and no RT OR Stage IA/B, IIA/B, IIIA ≥ 1 year. Patients received 4 cycles of N + BV induction. Patients with complete metabolic response (CMR) received an additional 2 cycles of N + BV before RT consolidation. Patients with suboptimal response received 2 cycles of BV + bendamustine intensification. Those patients achieving CMR proceeded to RT consolidation. RT was delivered to a dose of 30-30.6 Gy at 1.5-1.8 Gy/fraction to an ISRT volume.

RESULTS

Among 28 pts treated, the median age (range) was 17 (6-27) years old and 64% of patients were aged < 18 y. Most (79%) pts had stage II disease at diagnosis and 82% had relapsed ≥ 12 months after first line treatment. Of 27 pts continuing in study after induction N + BV, 6 received bendamustine + BV intensification, and 92.9% achieved complete metabolic response. Twenty-two patients received RT consolidation. RT consolidation was delivered using 3D-CRT, IMRT, or proton therapy. After a median (range) follow-up of 31.8 (2.2-55.1) months, the 3-y event-free survival rate and progression-free survival were 86.9% (69.5-94.7%) and 95% (76.7-99%), respectively.

CONCLUSION

A novel combination of N + BV followed by ISRT was an effective second line therapy. This treatment regimen allowed patients to forgo high dose therapy and transplant in favor of consolidative radiotherapy using ISRT. Larger studies challenging the role of high dose therapy and transplant are needed for RRHL.

Local Control after Low-Dose Radiation for Two Rare Forms of Indolent Non-Hodgkin Lymphoma

PURPOSE/OBJECTIVE(S)

Small lymphocytic lymphoma (SLL) and lymphoplasmacytic lymphoma (LPL) are two rare subsets of indolent non-Hodgkin lymphoma (NHL). National guidelines recommend 24-30 Gy for localized SLL. However, based on data for follicular and marginal zone lymphoma, lower dose RT (4 Gy) has been increasingly utilized. We reviewed our experience with SLL and LPL and hypothesized that low dose RT would provide excellent local control.

MATERIALS/METHODS

We retrospectively reviewed patients at three tertiary cancer centers who had been treated with RT for SLL or LPL. Response to RT was classified using the World Health Organization response criteria and by examining available PET and CT imaging. Radiographic response was assessed at first imaging follow-up and clinical response was recorded if no imaging was performed. Time to best response was noted, and Kaplan Meier estimates and cumulative incidence tests were performed to determine progression-free survival (PFS) and local progression (LP), respectively.

RESULTS

From 2014-2022, 16 patients with 18 sites of SLL (n = 13) or LPL (n = 5) were treated with RT and available to review. Five sites of SLL represented diffuse large B-cell lymphoma transformation and were excluded from analysis. In total, eight sites of SLL (seven patients) and five sites of LPL (five patients) were treated with doses ranging from 4 to 30 Gy in 2 to 12 fractions (median 20 Gy). Four sites of disease received 4 Gy in 2 fractions, one of which (SLL) progressed approximately four months after RT. This site was successfully salvaged with 24 Gy in 12 fractions. There were no other LP. Toxicity overall was low: one patient experienced grade 2 mucositis after 25 Gy in 10 fractions to the maxillary sinus and palate and the remainder of patients experienced grade 1 or no toxicity. Of 10 symptomatic sites, seven (5/7 SLL and 2/3 LPL) attained at least partial relief after RT. A complete response (CR) was achieved in 14% of SLL disease sites and 60% of LPL sites. Partial response was achieved in 57% of SLL and 40% of LPL sites, and 29% of SLL sites were deemed to be stable. One patient with SLL died after their first RT treatment, but this was unrelated to RT. The median time to best response was 284 days (IQR 189-292 days) for SLL and 131 days (IQR 106-166 days) for LPL. 4 Gy in 2 fractions did not result in any CR, yet one patient from the LPL group exhibited a striking CR after 8 Gy in 2 fractions. PFS at one year was 51% for SLL and 100% for LPL - cumulative incidence of LP at two years was 15% and 0% respectively.

CONCLUSION

In this cohort of patients with two types of indolent NHL, one patient progressed locally after 4 Gy, while none progressed after higher doses. LPL sites achieved more complete responses than SLL sites, and RT was tolerated extremely well. These results indicate that similar to other indolent lymphomas, clinical judgment should be used when deciding between 4 Gy or higher doses of RT. For SLL in particular, higher doses of RT are more likely to provide durable local control and CR.

Prompt Pain Relief from Bone Metastases: Mature Results from the Virtual Simulation Program

PURPOSE/OBJECTIVE(S)

Rapidpain relief for patients with bone metastases can be a challenge due to the lengthy and complex radiotherapy workflow. The purpose of this study was to evaluate the time (in days) between initial radiation oncology consultation and start of palliative radiation treatment after implementing an alternative virtual simulation palliative workflow.

MATERIALS/METHODS

Patients meeting strict criteria were selected for virtual simulation, which included only those with painful bone metastases who were recommended palliative radiotherapy using standard AP/PA or opposed lateral fields. A recent (within 30 days) diagnostic CT scan clearly visualizing the target volume was required for treatment planning. For comparison, a reference group of 40 consecutive patients with bone metastases that underwent in-person CT simulation prior to virtual simulation implementation was reviewed.

RESULTS

Forty-five patients were treated for painful bone metastases as part of the virtual simulation program from May 2021 to October 2022. Regarding travel distance, 23 patients lived locally (<50 miles from treatment center) and 22 patients were distant (≥50 miles from treatment center). Average time from consult to treatment for all virtual simulation patients was 3.7 days compared to 7.5 days for in-person CT simulation patients (3.8 days sooner on average, p = <0.001). For outpatient treatments, average time from consult to treatment for distant virtual simulation patients was 4.0 days compared to 8.9 days for distant in-person CT simulation patients (4.9 days sooner on average, p = 0.003).

CONCLUSION

The virtual simulation program decreased the time from consult to start of treatment for patients recommended palliative radiotherapy for painful bone metastases by over 50%. This benefit was most significant for outpatients traveling ≥ 50 miles for treatment. Virtual simulation-based planning can be considered for patients anxious to proceed with radiotherapy quickly, or in underserved settings with limited transportation options to regional treatment centers.

Consolidative proton therapy after chemotherapy for patients with Hodgkin lymphoma

Background

We investigated early outcomes for patients receiving chemotherapy followed by consolidative proton therapy (PT) for the treatment of Hodgkin lymphoma (HL).

Patients and methods

From June 2008 through August 2015, 138 patients with HL enrolled on either IRB-approved outcomes tracking protocols or registry studies received consolidative PT. Patients were excluded due to relapsed or refractory disease. Involved-site radiotherapy field designs were used for all patients. Pediatric patients received a median dose of 21 Gy(RBE) [range 15–36 Gy(RBE)]; adult patients received a median dose of 30.6 Gy(RBE) [range, 20–45 Gy(RBE)]. Patients receiving PT were young (median age, 20 years; range 6–57). Overall, 42% were pediatric (≤18 years) and 93% were under the age of 40 years. Thirty-eight percent of patients were male and 62% female. Stage distribution included 73% with I/II and 27% with III/IV disease. Patients predominantly had mediastinal involvement (96%) and bulky disease (57%), whereas 37% had B symptoms. The median follow-up was 32 months (range, 5–92 months).

Results

The 3-year relapse-free survival rate was 92% for all patients; it was 96% for adults and 87% for pediatric patients (P = 0.18). When evaluated by positron emission tomography/computed tomography scan response at the end of chemotherapy, patients with a partial response had worse 3-year progression-free survival compared with other patients (78% versus 94%; P = 0.0034). No grade 3 radiation-related toxicities have occurred to date.

Conclusion

Consolidative PT following standard chemotherapy in HL is primarily used in young patients with mediastinal and bulky disease. Early relapse-free survival rates are similar to those reported with photon radiation treatment, and no early grade 3 toxicities have been observed. Continued follow-up to assess late effects is critical.

Beam-specific planning volumes for scattered-proton lung radiotherapy

This work describes the clinical implementation of a beam-specific planning treatment volume (bsPTV) calculation for lung cancer proton therapy and its integration into the treatment planning process. Uncertainties incorporated in the calculation of the bsPTV included setup errors, machine delivery variability, breathing effects, inherent proton range uncertainties and combinations of the above. Margins were added for translational and rotational setup errors and breathing motion variability during the course of treatment as well as for their effect on proton range of each treatment field. The effect of breathing motion and deformation on the proton range was calculated from 4D computed tomography data. Range uncertainties were considered taking into account the individual voxel HU uncertainty along each proton beamlet. Beam-specific treatment volumes generated for 12 patients were used: a) as planning targets, b) for routine plan evaluation, c) to aid beam angle selection and d) to create beam-specific margins for organs at risk to insure sparing. The alternative planning technique based on the bsPTVs produced similar target coverage as the conventional proton plans while better sparing the surrounding tissues. Conventional proton plans were evaluated by comparing the dose distributions per beam with the corresponding bsPTV. The bsPTV volume as a function of beam angle revealed some unexpected sources of uncertainty and could help the planner choose more robust beams. Beam-specific planning volume for the spinal cord was used for dose distribution shaping to ensure organ sparing laterally and distally to the beam.

Protons safely allow coverage of high-risk nodes for patients with regionally advanced non-small-cell lung cancer

Our objective was to determine if protons allow for the expansion of treatment volumes to cover high-risk nodes in patients with regionally advanced non-small-cell lung cancer. In this study, 5 consecutive patients underwent external-beam radiotherapy treatment planning. Four treatment plans were generated for each patient: 1) photons (x-rays) to treat positron emission tomography (PET)-positive gross disease only to 74 Gy (XG); 2) photons (x-rays) to treat high-risk nodes to 44 Gy and PET-positive gross disease to 74 Gy (XNG); 3) protons to treat PET-positive gross disease only to 74 cobalt gray equivalent (PG); and 4) protons to treat high-risk nodes to 44 CGE and PET-positive gross disease to 74 CGE (PNG). We defined high-risk nodes as mediastinal, hilar, and supraclavicular lymph nodal stations anatomically adjacent to the foci of PET-positive gross disease. Four-dimensional computed tomography was utilized for all patients to account for tumor motion. Standard normal-tissue constraints were utilized. Our results showed that proton plans for all patients were isoeffective with the corresponding photon (x-ray) plans in that they achieved the desired target doses while respecting normal-tissue constraints. In spite of the larger volumes covered, median volume of normal lung receiving 10 CGE or greater (V10Gy/CGE), median V20Gy/CGE, and mean lung dose were lower in the proton plans (PNG) targeting gross disease and nodes when compared with the photon (x-ray) plans (XG) treating gross disease alone. In conclusion, proton plans demonstrated the potential to safely include high-risk nodes without increasing the volume of normal lung irradiated when compared to photon (x-ray) plans, which only targeted gross disease.

Safety of proton therapy treatment for prostate cancer patients with unilateral hip replacements

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Background: Determine the feasibility of proton therapy for prostate cancer patients who have undergone unilateral hip replacement.

Methods: From January, 2007 to March, 2008 5 patients with localized (4) or locally recurrent (1) prostate cancer and previous unilateral hip replacement underwent hip avoiding proton therapy. The median target dose was 78 Cobalt Gray Equivalent (Range 74CGE to 82CGE). All patients were treated in the supine position without a rectal balloon. Median maximum (1cc) dose to the normal femoral head was 51.47CGE (Range 43.82CGE to 64.50CGE). All patients signed informed consent and were registered to either the IRB approved UFPTI PR01, PR02 or Outcome Tracking (OTP) Protocols.

Results: With a median follow up of 28 (range 15 to 39) months, no patient experienced grade 2 or higher late rectal toxicity. No patient experienced grade 3 or higher late urinary toxicity. Two patients experienced grade 2 urinary toxicity by virtue of having been placed on medication (tamsulosin) for urinary obstructive symptoms. No patient has reported hip fracture, hip pain or other skeletal event in the normal hip.

Conclusions: Our experience suggests that patients with unilateral hip replacements can be treated with hip avoiding proton therapy without an increased risk of urinary, rectal or skeletal complications.

No significant financial relationships to disclose.

The role of FDG-PET imaging and involved field radiotherapy in relapsed or refractory diffuse large B-cell lymphoma

We examined the role of fluorodeoxyglucose-positron emission tomography (FDG-PET) and the addition of involved field radiotherapy (IFRT) as potential modifiers of salvage therapy. From January 2000 to June 2007, 83 patients with chemosensitive relapsed or primary refractory diffuse large B-cell lymphoma (DLBCL) underwent FDG-PET scans following second-line chemotherapy before high-dose therapy with autologous stem cell rescue (HDT/ASCR). We evaluated the prognostic value of having a negative FDG-PET scan before HDT/ASCR and whether IFRT improved the outcomes. Median follow-up was 45 months, and the 3-year PFS, disease-specific survival (DSS) and OS were 72, 80 and 78%, respectively. Multivariate analysis revealed that a positive FDG-PET scan had worse PFS (hazard ratio=(HR) 3.4; P=0.014), DSS (HR=7.7; P=0.001) and OS (HR=5.4; P=0.001), and that patients not receiving IFRT had worse PFS (HR=2.7; P=0.03) and DSS (HR=2.8, P=0.059). Patients who received IFRT had better local control with fewer relapses within prior involved sites compared with those that did not receive IFRT (P=0.006). These outcomes confirm the important prognostic value of FDG-PET scans before undergoing HDT/ASCR. It also suggests that the role of IFRT should be evaluated further.

Complementation of the radiosensitive M059J cell line

M059J is a radiosensitive cell line established from a human glioblastoma tumor that fails to express the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs, now known as PRKDC). Another cell line, M059K, established from the same tumor is radioresistant. Neither M059J nor M059K cells have been fully characterized, beyond the lack of expression of PRKDC and low expression of ATM in M059J cells. To determine whether its radiosensitive phenotype is due to a defect in the gene that encodes PRKDC, we show here that M059J cells can be complemented with the PRKDC gene by introducing a fragment of human chromosome 8 containing a copy of the human PRKDC gene. Two hybrid cell lines that retain an extra copy of PRKDC display active kinase activity and are radioresistant, demonstrating that the primary defect in M059J cells is in PRKDC. In addition, these cell lines derived from M059J cells provide us with a closer genetic match to M059J than M059K cells in studies to elucidate the function of DNA-PK.