Thirty-Year Experience of Radiotherapy for Primary Intraocular Lymphoma with and without Chemotherapy

PURPOSE/OBJECTIVE(S)

Primary intraocular lymphoma (PIOL) is a rare presentation of primary central nervous system lymphoma (PCNSL). We previously reported that ocular radiation therapy (RT) is an excellent option that can spare appropriate patients' upfront toxicity of whole brain radiotherapy (WBRT) and aggressive chemotherapy. A decade later, we expanded this series with almost double median follow up time.

MATERIALS/METHODS

We identified all patients seen at our institution from 1990-2022 treated for PCNSL or who received RT to the orbits. Detailed chart review was completed for cases with isolated ocular involvement at presentation (PIOL) who received RT to unilateral or bilateral orbits. Patients with disease on MRI brain or CSF cytology were excluded. Analysis included Kaplan-Meier method, log-rank-test, and Wilcoxon rank sum test. Overall survival (OS) was measured from diagnosis. Freedom-from-recurrence (FFR) measured time from RT start to first recurrence identified on imaging (parenchymal), slit-lamp exam (ocular), or biopsy.

RESULTS

A total of 75 patients were treated with RT to the orbits as part of management of PCNSL. 29 had PIOL with median follow up of 52 months from diagnosis. Of this subset, 22 (76%) received RT at our institution, median age at diagnosis was 65 (31-84) and 18 (62%) had bilateral disease. The majority were diagnosed by vitrectomy or vitreoretinal biopsy with B-cell lymphoma or unspecified lymphoma and 3 were clinically diagnosed. 17 patients received RT alone, 10 received RT after induction chemotherapy and 2 with induction and consolidation chemotherapy. Younger patients received chemotherapy (median age 60 vs 70, p = 0.03). RT dose ranged from 30 to 45 Gy, and 20 (69%) received 36 Gy, primarily with 1.8 Gy fractions. 22 (76%) received RT to bilateral orbits. 21 (72%) developed recurrence (Table 1), of which 6 (28.5%) recurred in a RT-treated eye and 11 (52.4%) isolated in the brain. 2 got salvage orbital RT and 4 got WBRT. Median OS was 5.4 years (95% CI 3.9, 7.6) and FFR was 8.4 months (95% CI 5.0, 25). There was no difference in OS (p = 0.4) or FFR (p = 0.3) between combined modality therapy versus RT alone.

CONCLUSION

In this updated experience, we demonstrate that RT alone remains an effective option for isolated PIOL, especially for those at risk of poor toleration of chemotherapy. Systemic therapy or WBRT can be utilized at recurrence, which primarily occurs in the brain. Future comparisons are needed to compare orbital RT to intravitreal therapies, and to investigate how these methods can complement each other to further improve management.

Trends in Utilization and Medicare Spending on Shorter vs. Longer Radiotherapy Courses for Breast and Prostate Cancer

PURPOSE/OBJECTIVE(S)

Evidence based research supports shorter, similarly efficacious, and potentially more cost-effective hypofractionated treatment regimens in many clinical scenarios for breast cancer (BC) and prostate cancer (PC). However, practice patterns of hospital-affiliated and standalone facilities vary considerably. We used the most recent Centers for Medicare and Medicaid Services data to assess trends in radiotherapy (RT) costs and practice patterns among episodes of BC and PC.

MATERIALS/METHODS

We performed a retrospective cohort analysis of all external beam episodes for BC and PC from 2015-2019. For patients with BC, receipt of shorter-course RT (SCRT) was defined as receiving 11-20 fractions of external beam radiation therapy (including IMRT), and conventional RT as >20 fractions. For patients with PC, SBRT was defined as receipt of <10 fractions and moderate hypofractionation as 10-30 fractions (SCRT defined as SBRT and moderate hypofractionation), and >30 fractions for conventional RT. Total Medicare spending were defined as the sum of winsorized payment for professional and technical services furnished during the episode in 2019 dollars. Multivariable logistic regression defined adjusted odds ratios (ORs) of receipt of SCRT over conventional RT by treatment modality, age, year of diagnosis, type of practice, as well as a time*treatment setting interaction term. Medicare spending was evaluated using multivariable linear regression controlling for duration of RT regimen (SCRT vs conventional) in addition to the covariables above.

RESULTS

Of 47,283 BC episodes and 45,917 PC episodes, 23,705 (50.13%) and 9,125 (19.87%) were SCRT, respectively. Median total spending for SCRT among BC episodes was $9,324 (IQR, $7,916-$10,921) vs. $13,372 (IQR, $11,511-$15,283) for conventional RT. Among PC episodes, median total spending was $12,917 (IQR, $9,551-$15,271) for SBRT, $18,944 (IQR, $16,530-$20,615) for moderate hypofractionation, and $26,935 (IQR, $25,062-$28,959) for conventional RT. For both cancers, total episode spending was reduced with SCRT utilization [(BC adjusted β, -$4,200; p<0.001), (PC adjusted β, -$8,747; p<0.001)], older age, and non-IMRT-based treatment. On logistic regression, receipt of SCRT was associated with older age among both BC and PC episodes (p<0.001), as well as treatment at hospital-affiliated over freestanding sites [(BC OR [95% CI], 1.41 [1.29-1.54], p<0.001), (PC OR, 1.64 [1.39-1.94], p<0.001)].

CONCLUSION

In this evaluation of all BC and PC RT episodes from 2015-2019, we found that shorter-course RT resulted in increased cost-savings vs. conventional RT. SCRT was also more common in hospital-affiliated sites. Further research is needed to devise payment incentives that encourage SCRT when clinically applicable in the two most common sites treated with RT, and to prospectively study cost-effective hypofractionation in other disease sites.

High-Dose-Rate Brachytherapy for Vaginal Rhabdomyosarcoma (RMS): Lessons Learned at a Single Institution

PURPOSE/OBJECTIVE(S)

Botryoid RMS is a rare pediatric tumor most commonly arising within the vaginal wall of girls under age three. Most patients are successfully treated with low-risk chemotherapy protocols but local treatment is required to minimize risk of local relapse. Intravaginal brachytherapy is an effective local therapy that can minimize sequelae in these very young patients.

MATERIALS/METHODS

We reviewed records of all patients with RMS who received intravaginal high-dose-rate brachytherapy from 2010-2022 at a single institution. All were treated with multiagent chemotherapy with or without minor surgical procedures, and had no gross disease prior to intravaginal brachytherapy. All patients underwent CT simulation under anesthesia and optimal-sized cylindrical applicators were chosen based on patient anatomy.

RESULTS

Twelve girls, median age 23 months (range 3-33), were treated with daily anesthesia. All were Stage 1 and 92% had Group III disease. A single patient had Group IIA disease based on up-front resection. Early in the series, 5 patients received 21 Gy in 7 fractions according to COG protocol guidelines. Subsequent patients received higher doses of 28-30 Gy in 7-10 fractions. Custom sized cylinders were used with diameters ranging from 1.2-1.6 cm and dose was prescribed to a median depth of 3 mm. Median mean dose to the rectum, bladder, uterus, and bilateral ovaries was 8.7 Gy, 7.2 Gy, 6.9 Gy, and 5.0 Gy, respectively. Median follow-up was 4 years (range 1-10). No acute or late side effects have occurred. At follow-up, three girls were of pubescent age, all three exhibited signs of puberty and two had reached menarche. Three girls (25%) suffered local relapse at a median of 15 months (range 5-16 months) after brachytherapy. One-year and five-year local control rates were 92% (95% CI 54-99%) and 70% (95% CI 32-89%), respectively. All relapses were in patients receiving 21 Gy and two were beyond full dose coverage of brachytherapy at the introitus and in the uterus. Subsequent patients receiving higher doses and full coverage of the vagina have had no local failures. Two of three patients who failed were cured with salvage therapy resulting in one-year and five-year overall survival rates of 100% and 86% (95% CI 33-98%), respectively.

CONCLUSION

Intravaginal high-dose-rate brachytherapy is an excellent option for local control of vaginal RMS with fewer long-term risks than external beam proton therapy or radical surgery. A dose of 28 Gy in 7 fractions prescribed to the entire vagina is necessary for optimal prevention of relapse. Longer follow-up is needed to confirm preservation of ovarian, reproductive, and sexual function.

Radiation in a New Era of Multiple Myeloma Management: Patterns of Utilization, Clinical, Radiologic, and Biochemical Outcomes, and Possible Genomic Correlates of Response

PURPOSE/OBJECTIVE(S)

Systemic therapies for multiple myeloma (MM) have advanced considerably, improving patient outcomes. Yet, the use of radiotherapy (RT) has remained heterogeneous, and even controversial, due to minimal data on outcomes. With the ultimate goal of guiding the design of prospective trials incorporating RT, we initiated a study of our institutional experience treating MM with RT since 1/1/2000. Here we report a preliminary feasibility analysis of an initial sample cohort, identifying patterns of RT utilization, outcomes, and impact of RT on radiographic and biochemical markers, with genomic characterization for more recently treated patients.

MATERIALS/METHODS

Five hundred six pathologically confirmed MM patients who received RT to 1190 sites between January 1, 2000, and June 1, 2022, were identified. Patient, disease, and treatment characteristics were analyzed for 50 consecutive patients treated in 2019 and tested for association with local and distant failure (LF, DF) using univariable and multivariable analysis. Genomic data was obtained via next generation sequencing using an institutional targeted sequencing panel.

RESULTS

Amongthe 50 patients analyzed (median 63 years), 90 lesions were treated with RT, 33% with concurrent systemic therapy, to median dose of 20 Gy (8-46 Gy) over a median of 5 fractions (1-25). RT Indications were pain (56%), critical structure involvement (25%), peri-operative (9%), salvage/consolidation (8%), and bridging therapy (2%). Median size of RT-treated lesions was 4.2 cm (1.4-7.9) and included non-vertebral bones (62%), spine (24%), and extramedullary sites (14%). The median number of lines of pre-RT therapy was 7 (1-14) and 51% had >9 lesions on imaging, 47% involving both medullary and extramedullary sites. With median follow-up of 12.4 months (0.5-46), LF occurred in 5% of treated sites and 89% had DF, most commonly in both medullary + extramedullary (51.4%) sites. Absolute decreases 1-week to 1-month post-RT were observed in % of marrow plasma cell (median 4.0%), M spike (0.30 g/dL), total protein (0.3 g/dL), K:L ratio (0.01), lesion size (1.5cm), and lesion SUV (3.1) but in this limited sample, none were significantly associated with disease control. A cohort of 62 RT-treated MM patients from 2016-2022 had genomic data available; most common tumor mutations were in TP53 (35%), HIST1 (34%), NRAS (34%), and KRAS (23%).

CONCLUSION

In this pilot analysis of a sampling cohort of RT-treated MM, we report on patterns of utilization, outcomes, and biochemical and radiographic correlates. At the meeting, we will present the full analysis of the >500 MM patients and further analyze emerging genomic data. We aim to characterize the role of RT in the modern era of systemic therapy to guide the design of future prospective trials and to inform novel approaches for incorporating RT into the treatment paradigm.

Risk of Sexual Dysfunction in Men Treated with Pelvic Radiation Therapy for Locally Advanced Rectal Cancer: 20 Years of Experience with 451 Patients

PURPOSE/OBJECTIVE(S)

Radiation therapy (RT) is commonly used in the treatment of locally advanced rectal cancer (LARC), but data on its impact on men's sexual health is limited. Given the rising incidence of rectal cancer in younger men, sexual function is an important quality of life factor. We hypothesized that men with LARC treated with RT would be at increased risk of sexual dysfunction compared to men who did not receive RT.

MATERIALS/METHODS

This is a single institution retrospective analysis of outcomes of men ≤50 years diagnosed with LARC between 1999 and 2019. Primary outcomes of erectile dysfunction (ED), ejaculatory dysfunction (EjD), and testosterone deficiency (TD) were assessed via ICD-9/10 codes, and TD was captured with free testosterone <300 ng/dL. Cumulative incidences were calculated with death as a competing risk and p values were calculated using Gray's test. Subdistribution hazard ratios from competing risk regression models were used.

RESULTS

The combined study sample included 451 men: 347 received RT as part of their multimodality treatment, and 104 did not. Median time to last follow up was 5.6 years (IQR 3.3-8.7). Age at diagnosis, stage, and medical comorbidities for sexual dysfunction were similar between the two groups (p>0.05). Cumulative incidence estimates are shown in Table 1, showing a higher cumulative incidence of ED in the RT group, but no difference in EjD or TD between the 2 groups. On univariable analysis, RT, smoking, dyslipidemia, peripheral artery disease, depression, prostate cancer/hyperplasia, closed or current ileostomy, and undergoing rectal cancer surgery were all independent risk factors for ED (p<0.05). On multivariable analysis, RT maintained statistical significance as an independent risk factor for ED (HR 3.87, 95% CI 1.93-7.75, p<0.001). Within the RT group, IMRT compared to 3D (HR 1.54, 95% CI 1.02-2.32, p = 0.040) and groin RT (HR 2.60, 95% CI 1.21-5.59, p = 0.014) were independent risk factors for ED. Within the RT group, groin RT also approached significance as a risk factor for TD (HR 3.61, 95% CI 0.98-13.3, p = 0.054). No RT dose thresholds to external genitals or penile bulb were identified that increased risks of ED, EjD, or TD.

CONCLUSION

RT for LARC independently increases risk of ED but not EjD or TD. IMRT might increase the risk of ED due to increased scatter dose to the genitals and including the inguinal nodes in the target volumes increases the dose to the genitals/testicles, which could translate into a higher risk for ED and TD. Future research on proton RT and prophylactic sildenafil is needed in men ≤50 to decrease the risk of ED.

Re-Irradiation for Diffuse Intrinsic Pontine Glioma with 3 Gy per Fraction

PURPOSE/OBJECTIVE(S)

Radiotherapy (RT) improves survival in pediatric diffuse intrinsic pontine glioma (DIPG). After recurrence, re-irradiation (re-RT) offers palliation of symptoms and extends life in patients after exhaustion of investigational options and clinical decline. Practice patterns vary in dose and fractionation for re-RT, with majority of reported cases treated with conventional fractionation. Given radiobiologic rationale for hypofractionation in glioblastoma, we hypothesized that treatment with 3 Gy per fraction is safe and effective for re-RT to the brainstem for DIPG.

MATERIALS/METHODS

We identified patients at our institution, ages 1-25, treated with re-RT to the brainstem for DIPG from 2012-2022. Patient demographics, treatment details, and clinical outcomes were reviewed from the medical record. Analysis was completed in R 4.2.2 using Kaplan-Meier method with log-rank test for survival estimates and Fisher's exact test for categorical variables.

RESULTS

A total of 22 patients received re-RT for DIPG. All patients had received 54-59.4 Gy with conventional fractionation at the time of diagnosis. Re-RT dose was initially 20-24 Gy in 2-Gy fractions (n = 6) and continued at 30-36 Gy in 3-Gy fractions (n = 14). Two patients did not complete re-RT due to continued clinical decline from disease progression after 1-2 fractions. Of the 20 that completed re-RT, 11 were female, median age was 5 years (3-14), median interval since initial RT was 8 months (3-20), 12 (60%) received concurrent bevacizumab, and OS from diagnosis was 18 months. Median OS from start of re-RT for patients treated with 3 Gy per fraction was 8.2 months and 13 (93%) clinically improved to taper pre-treatment steroid dose down (n = 9) or off (n = 4) within 2 months after re-RT. For those treated with 2 Gy per fraction, median OS from re-RT was 7.5 months and 3 (75%) improved to taper steroids down (n = 2) or off (n = 1). Overall, 2 patients were not on steroids, 2 were maintained at same steroid dose, and 0 required increase from pre-treatment steroid dose within 6 weeks after re-RT. There was no significant difference in OS from re-RT (p = 0.2) or steroid taper (p = 0.4) between fractionation groups. No patients developed radionecrosis of normal brain tissue.

CONCLUSION

Patients receiving re-RT achieved extended survival comparable to published outcomes and majority experienced clinical improvement to allow steroid taper. While radionecrosis is a reported risk in prior published series, our experience demonstrates the safety and effectiveness of using 3 Gy per fraction to 30-36 Gy for meaningful palliation in this population.

Very Low Dose Radiation Therapy for Indolent Lymphomas: Comparing "Big Boom" (4 Gy x 1) vs. "Boom Boom" (2 Gy x 2)

PURPOSE/OBJECTIVE(S)

Indolent lymphomas are exquisitely sensitive to radiation therapy (RT). Programs of 2 Gy x 2 were shown to be highly effective in controlling irradiated site(s). During the COVID-19 pandemic, the International Lymphoma Radiation Oncology Group (ILROG) proposed guidelines that offered substitution of the Boom Boom (BB) (2 Gy x 2) regimen with Big Boom (Big B) of 4 Gy x 1. This report compares our center's experience with both regimens.

MATERIALS/METHODS

We included patients with indolent lymphomas in this retrospective single institution study. After April 2020 both options of very low dose and choice of a standard full dose of 24 Gy were discussed with the patient. Patients were treated with a definitive or palliative intent depending on disease stage and prior therapy exposure. Patients treated with 24 Gy are not included in this report. Toxicity was reported as per CTCAE v4.0. Overall response rate (ORR) was assessed with Lugano PET criteria at the initial post-RT imaging. Differences between the two groups were examined using the Fisher's exact test and Mann-Whitney test.

RESULTS

We evaluated a total of 471 lesions in 386 patients, including 172 lesions (37%) treated with 4 Gy x 1 and 299 lesions (63%) treated with 2 Gy x 2. Table 1 summarizes the patient and treatment characteristics. Age at the time of RT and sex were not significantly different between the two groups. The BB cohort was more likely to have follicular lymphomas (FL) (66% vs 54%, p = 0.011), though the proportion of higher-grade FL was similar between cohorts. The ORR was similar (Big B = 86%, BB = 87%) at the first post-RT evaluation (median of 2.23 months from RT for both cohorts). There was no significant difference in the rate of complete response, partial response, stable disease, or progressive disease between the cohorts at initial post-RT imaging. For both regimens, no directly related short-term side effects were observed.

CONCLUSION

Both the 4 Gyx1 and 2 Gyx2 regimens demonstrated excellent ORR at the initial post-RT imaging assessment among patients with indolent lymphomas. While longer term follow-up is required to confirm durability of these findings, our initial experience suggests that 4 Gyx1 regimen recommended by ILROG during the pandemic is an effective treatment approach.

Salvage Radiotherapy as a Bridge for Relapsed Secondary CNS Lymphoma

PURPOSE/OBJECTIVE(S)

Secondary CNS lymphoma (SCNSL) is a challenging clinical scenario observed in 2-5% of non-Hodgkin lymphoma patients, for which a standard of care has not been defined. We studied the indications for, and outcomes of SCNSL patients referred for radiotherapy (RT).

MATERIALS/METHODS

We identified patients with aggressive B cell lymphoma who received brain RT for SCNSL between 1999-2023 at a tertiary cancer center. Patients were grouped and analyzed by RT indication. Overall survival (OS) was determined from RT start using the Kaplan-Meier method. OS analysis comparing patients who did and did not receive therapy after RT was landmarked at 60 days from start of RT to minimize immortal time bias. "SCNSL-directed therapy" is defined as systemic therapy for the treatment of SCNSL, as opposed to CNS prophylaxis.

RESULTS

We identified 99 SCNSL patients treated with RT. To account for the heterogeneity of RT referrals, we focused on the most common indication: salvage of radiographic progression after SCNSL-directed systemic therapy (n = 58). Among this group, median age was 62 (interquartile range [IQR]: 48-69) and 86% had diffuse large B cell histology. At initial lymphoma diagnosis, 10% of patients had CNS involvement, 90% received Rituximab-based therapy, and 25% received prior CNS prophylaxis. For SCNSL directed therapy, 90% received methotrexate (MTX)-based regimen. Median time from initial SCNSL diagnosis to RT was 4.4 months (IQR 1.7-7.0), with a median of 2.0 lines of therapy prior to RT (IQR 1.0-3.0). 86% of patients were symptomatic at RT with median KPS of 70 (IQR: 60-80). RT targets included whole brain (86%) and partial brain (14%). 1 patient had craniospinal RT. Median RT dose was 30 Gy (IQR: 24-30) over 10 fractions. Median OS for the entire salvage cohort was 3.5 months (m). Landmark analysis 2m post RT showed that median OS differed when patients were stratified by receipt of further therapy: CAR-T (9.4m, n = 4), hematopoietic cell transplant (8.5m, n = 6), other systemic therapy (4.4m, n = 17), no systemic therapy (0.6m, n = 10) (p = 0.0004). 29% of patients who received further therapy after RT achieved long term survival.

CONCLUSION

In our cohort, most SCNSL patients are referred for salvage RT, with a median OS of 3.5m. 86% of patients had neurologic symptoms after having failed a median of 2 lines of SCNSL-directed therapy; the clinical urgency of this scenario implies that without RT, patients may not have been suitable candidates for further therapy. However, among patients for whom RT was successfully used to bridge to additional therapy, 29% could achieve long-term survival. This study supports further investigation of RT as a combined modality strategy for relapsed/refractory SCNSL, including with emerging cellular therapies.

Genomic analysis and clinical correlations of non-small cell lung cancer (NSCLC) brain metastasis (BM)

2008

Background: Approximately 30% of patients with NSCLC present with BM, and up to 50% of patients ultimately develop BM. While modern NSCLC-directed agents yield excellent systemic response, most patients require focal treatment. Prior reports of BM genomics have been limited by low numbers, missing clinical data, and lack of matched specimens. Here, we report the largest cohort to date of molecularly profiled NSCLC BM samples with clinical correlates. Methods: Clinical data and outcomes for 244 patients with NSCLC and resected BM were identified, and BM samples were assessed with one of four versions (341, 410, 468, 505) of MSK-IMPACT, a custom FDA-approved next generation sequencing-based tumor sequencing assay. 51 (20.9%) patients had matched primary site tissue, and 44 (18%) patients had matched tissue from another metastatic site or CSF. Genomic alterations were filtered for driver variants using OncoKB. Results: Median age was 66 years (range 31-91), and median follow-up was 2.3 years (IQR 1.3-4.3). Adenocarcinoma was the most common histology (183, 78%). Half presented with a single BM, and 121 (51%) patients were treatment naive. Most (197, 83%) received adjuvant stereotactic radiosurgery (SRS) to the resection site and 28% received SRS to additional BM. After resection, 130 (55.1%) had CNS progression, often regional (54, 42%). SRS to new BMs (32%) was the most common salvage treatment. Median overall survival from BM diagnosis was 2.5 years (95%CI 2.1-3.2). Median CNS-progression-free survival was 1.2 years (95%CI 0.9-1.4). The most frequently altered genes in BM samples were TP53 (72%), CDKN2A (34%), KRAS (31%), KEAP1 (26%), and EGFR (21%). CDKN2A was more frequently altered in BM samples when compared to NSCLC primary samples (34% vs 14%, p = 0.003, q = 0.034). With regard to overrepresented gene sets, cell cycle pathway alterations were enriched in BM (56% vs 31%, p = 0.002, q = 0.022). BM samples had a significantly higher fraction of genome altered relative to the primary samples (p < 0.0001, q < 0.0001). After grouping patients based on type of CNS progression, we found that EGFR alterations were enriched in patients with leptomeningeal failures when compared to both patients without progression (42% vs 18%, p = 0.03, q = 0.93) and to patients with either local or regional progression (42% vs 19%, p = 0.03, q = 0.9). Conclusions: In the largest-ever assembled cohort of genomically-profiled NSCLC BM, we found significant enrichment for CDKN2A and cell cycle pathway alterations in BM compared to extracranial disease, as well as a higher fraction of genome altered, in BMs compared to matched primary tumor controls. We also observed EGFR alteration enrichment in patients who develop LMD, suggesting specific biologic underpinnings driving patterns of CNS failure. Further investigation into the role of systemic therapy and time course will elucidate potential mechanisms for CNS failure in patients with NSCLC.

Safety of opioid prescribing among older cancer survivors

BACKGROUND

Cancer survivors receive more long-term opioid therapy (LTOT) than people without cancer, but the safety of LTOT prescribing is unknown.

METHODS

Opioid-naive adults aged ≥66 years who had been diagnosed in 2008-2015 with breast, lung, head and neck, or colorectal cancer were identified with data from Surveillance, Epidemiology, and End Results cancer registries linked with Medicare claims. Survivors with 1 or more LTOT episodes (≥90 consecutive days) occurring ≥1 year after their cancer diagnosis and before censoring at hospice entry, another cancer diagnosis, 6 months before death, or December 2016 were included. The safety of prescribing during the first 90 days of the first LTOT episode was measured during follow-up. As a positive safety indicator, the proportion of survivors with concurrent nonopioid pain management was measured. Indicators of less safe prescribing were the proportion of survivors with a high average daily opioid dose (≥90 morphine milligram equivalents) and the proportion of survivors with concurrent benzodiazepine dispensing. Multivariable logistic regression analyses were conducted to identify clinical predictors of each safety outcome.

RESULTS

In all, 3628 cancer survivors received LTOT during follow-up (median duration, 4.9 months; interquartile range, 3.5-8.0 months). Seventy-two percent of the survivors received multimodal pain management concurrently with LTOT. Eight percent of the survivors had high-dose opioid prescriptions; 25% of the survivors received benzodiazepines during LTOT. Multivariable analyses identified variations in safety measures by multiple clinical factors, although none were consistently significant across outcomes.

CONCLUSIONS

To improve safe LTOT prescribing for survivors, efforts should focus on increasing multimodal pain management and reducing inappropriate benzodiazepine prescribing. Different clinical predictors of each outcome suggest different drivers of safe prescribing.

The rate and risk of secondary pelvic malignancies (SPM) in patients treated with definitive radiation for locally advanced rectal cancer

12065

Background: With a rising incidence of younger patients diagnosed with rectal cancer, the long-term toxicity of cancer-related therapy is becoming even more relevant. Risk of SPM is a known potential consequence of both chemotherapy (chemo) and radiation therapy (RT), yet the rate of SPM in patients with rectal cancer is still not defined. We sought to further investigate factors associated with and outcomes of SPM after RT for rectal cancer. Methods: Patients diagnosed with stage II-III rectal cancer treated with chemo and/or RT from 1995-2019 were included in a retrospective study. Patients treated with palliative intent and those who survived < 5 years from treatment were excluded. RT-associated SPM was defined as a cancer occurring ³5 years after RT completion. Cumulative incidence (CI) of SPM was analyzed using a landmark analysis at 5 years with death as a competing risk. For patients with CT simulation scans available, dosimetric analyses evaluated doses to the organs developing SPM. Kaplan Meier analysis was used to evaluate overall survival among patients who developed an SPM. Results: A total of 2,700 patients were included (RT = 978; chemo = 1722). Demographic characteristics were equivalent apart from age, which was higher in the RT group (61 vs 59 years, p < 0.001). Five (0.3%) chemo patients developed an SPM, all within 5-10 years after treatment for rectal cancer, vs 48 (4.9%) RT patients. The 8-year CI of developing an SPM in the RT group was 4% (95% CI 2.4-6.2) and increased to 17% at 15 years (95% CI 12.1-21.8) and 21% at 20 years (95% CI 14.8-27.7). Most (89%) RT patients had received chemotherapy (most commonly 5-FU or FOLFOX). The median time to SPM was 108 months (interquartile range [IQR], 84-140). After pelvic RT, the most common SPM histology was endometrial (38%), followed by prostate (31%), bladder (23%), sarcoma (4.2%), and other gynecologic cancers (4.2%). Seven patients had CT simulations for dosimetric analyses: median of maximum dose to the organ with SPM was 5301cGy (IQR, 4928-5427), median of mean dose was 4551 cGy (IQR, 4476-4751). None of the patients who developed endometrial cancer had Lynch syndrome. Median OS for patients with SPM after RT was 5.1 years with 5-yr OS of 58% (95% CI 43-77); 44 out of 48 patients needed at least one treatment modality for their SPM, and 8 received trimodality treatment [surgery, chemo and RT]. Conclusions: The CI of SPM increased from 4% at 8 years to 17% at 15 years and 21% at 20 years following pelvic RT for rectal cancer. Endometrial cancer was the most common SPM and survival following treatment of SPM was favorable. These data serve as a foundation for future prospective studies evaluating ways to reduce SPM such as proton therapy.

Opioid safety among high-risk cancer survivors

e19169

Background: To mitigate risks of opioid-related harms, ASCO’s pain management guidelines for cancer survivors recommend that opioids be used in conjunction with other pharmacologic and non-pharmacologic approaches. The guidelines also recommend caution when prescribing opioids and benzodiazepines concurrently. We evaluated these 2 metrics of safe prescribing as applied to chronic opioid therapy (COT) among older survivors of head and neck cancer (HNC) and lung cancer (LC), two growing populations with high pain burden and prevalent risk factors for opioid-related harms (e.g., opioid use during treatment, history of substance use, distress). Methods: Using SEER-Medicare, we identified opioid-naïve adults diagnosed 2008-2015 with HNC or LC. We restricted analyses to survivors with ≥1 COT episode (≥90 days) occurring ≥1 year after cancer diagnosis and ≤120 days prior to hospice entry or cancer-related death (survivorship period). We report 2 opioid safety metrics during the survivorship period: 1) the proportion of survivors with non-opioid pain management (≥1 dispensing for a non-opioid, non-benzodiazepine pain medication or ≥1 claim for pain management procedure) concurrent with the first 90 days of the first COT episode and 2) the proportion of survivors with 0 dispensings for benzodiazepines within the first 90 days of the first COT episode. Results: Among opioid-naïve HNC (N = 5,500) and LC (N = 21,090) patients, 306 HNC (5.6%) and 927 LC survivors (4.4%) received COT during follow-up. Median duration of first survivorship COT episode was 5.2 and 4.9 months for HNC and LC, respectively. 64% of HNC survivors received non-opioid pain management concurrent with their first COT episode; 55% received an analgesic and 24% underwent a procedure. 75% of LC survivors received non-opioid pain management concurrent with their first COT episode; 67% received an analgesic and 35% underwent a procedure. 79% of HNC and 81% of LC survivors did not receive benzodiazepines during the first COT episode. Conclusions: Among older survivors of LC and HNC, less than 6% receive COT. However, of those, one-half of HNC survivors and more than a third of LC survivors receive guideline-discordant care by using COT without other pain management strategies or while using benzodiazepines. To minimize opioid-related harms, efforts should focus on improving safe COT prescribing practices for survivors. [Table: see text]

The role of cancer in marijuana and prescription opioid use in the United States: A population-based analysis from 2005 to 2014

BACKGROUND

For patients with cancer, marijuana may be an alternative to prescription opioid analgesics. This study analyzed self-reported marijuana and prescription opioid use among people with cancer over a 10-year time period.

METHODS

Population-based data sets from the US National Health and Nutrition Examination Survey between 2005 and 2014 were compiled for respondents aged 20 to 60 years. Respondents with cancer and respondents without cancer were propensity score-matched (1:2) by demographics to compare substance use. Outcomes included current marijuana and prescription opioid use (ie, within the past 30 days). Pearson chi-square tests and logistic regressions were performed; a 2-tailed P value < .05 was significant.

RESULTS

There were 19,604 respondents, and 826 people with cancer were matched to 1652 controls. Among the respondents with cancer, 40.3% used marijuana within the past year, and 8.7% used it currently. Respondents with cancer were significantly more likely to use prescription opioids (odds ratio [OR], 2.43; 95% CI, 1.68-3.57; P < .001). Cancer was not associated with current marijuana use in a multivariable conditional logistic regression but was associated with current opioid use (OR, 1.82; 95% CI, 1.17-2.82; P = .008). Among all survey respondents, the odds of marijuana use significantly increased over time (OR, 1.05; 95% CI, 1.01-1.10; P = .012), whereas the odds of opioid use did not significantly change. There were no significant differences in the longitudinal odds of marijuana or opioid use over time between respondents with a cancer diagnosis and those without one.

CONCLUSIONS

This population-based analysis revealed a considerable proportion of respondents with cancer self-reporting marijuana use (40.3%) and a significantly higher prevalence of opioid use among respondents with cancer. In the midst of an opioid epidemic, an evolving political landscape, and new developments in oncology, quantifying the prevalence of opioid and marijuana use in the US population, especially among patients with cancer, is particularly relevant. Although opioid use did not significantly change from 2005 to 2014 among all respondents, marijuana use did increase, likely reflecting increased availability and legislative changes. A cancer diagnosis did not significantly affect longitudinal opioid or marijuana use.

Cost-effectiveness of nivolumab for treatment of platinum-resistant recurrent or metastatic squamous cell carcinoma of the head and neck

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Background: The Checkmate 141 randomized trial found that patients with platinum-refractory, recurrent or metastatic (R/M) squamous-cell carcinoma of the head and neck (SCCHN) treated with nivolumab had significantly longer overall survival than those treated with standard, single-agent therapy. However, nivolumab is more expensive than standard treatment. We conducted a cost-effectiveness analysis of nivolumab for the treatment of R/M SCCHN. Methods: We constructed a Markov model to simulate treatment with nivolumab or other single-agent therapy (docetaxel, cetuximab, or methotrexate) for patients with R/M SCCHN. Transition probabilities including disease progression, survival, and toxicity were derived from clinical trial data, while costs (in 2016 US dollars) and health utilities were estimated from the literature. Incremental cost-effectiveness ratios (ICERs), expressed as dollar per quality-adjusted life-year (QALY), were calculated with values less than $100,000/QALY considered cost-effective from a healthcare payer perspective. We conducted one-way and probabilistic sensitivity analyses to examine model uncertainty. Results: Our base-case model found that treatment with nivolumab increased overall cost by $59,000 and improved effectiveness by 0.2443 QALYs compared to single-agent therapy, leading to an ICER of $241,100/QALY. In sensitivity analyses, the model was most sensitive to the cost of nivolumab and assumptions about survival. Nivolumab would become cost-effective if the cost per cycle decreased from $13,432 to $5,716. If we assumed that all patients alive at the end of the Checkmate 141 trial were cured of their disease then nivolumab was still not considered cost-effective (ICER $160,000/QALY). Probabilistic sensitivity analysis also demonstrated relative stability of the cost-effectiveness model and found that treatment with nivolumab was cost-effective 0% of the time at a willingness-to-pay threshold of $100,000/QALY. Conclusions: While nivolumab significantly improves overall survival, at the current cost it would not be considered a cost-effective treatment option for patients with R/M SCCHN.