Utilization and predictors of postmastectomy radiation receipt in an Oncology Center in Zimbabwe.

PURPOSE: Few sub-Saharan African studies have ascertained utilization for postmastectomy radiation (PMRT) for breast cancer, the second most common cancer among African women. We estimated PMRT utilization and identified predictors of PMRT receipt in Zimbabwe. METHODS: Retrospective patient cohort included non-metastatic breast cancer patients treated from 2014 to 2019. PMRT eligibility was assigned per NCCN guidelines. Patients receiving chemotherapy for non-metastatic disease were also included. The primary endpoint was receipt of PMRT, defined as chest wall with/without regional nodal radiation. Predictors of receiving PMRT were identified using logistic regression. Model performance was evaluated using the c statistic and Hosmer-Lemeshow test for goodness-of-fit. RESULTS: 201 women with localized disease and median follow-up of 11.4 months (IQR 3.3-17.9) were analyzed. PMRT was indicated in 177 women and utilized in 59(33.3%). Insurance coverage, clinical nodal involvement, higher grade, positive margins, and hormone therapy receipt were associated with higher odds of PMRT receipt. In adjusted models, no hormone therapy (aOR 0.12, 95% CI 0.043, 0.35) and missing grade (aOR 0.07, 95% CI 0.01, 0.38) were associated with lower odds of PMRT receipt. The resulting c statistic was 0.84, with Hosmer-Lemeshow p-value of 0.93 indicating good model fit. CONCLUSION: PMRT was utilized in 33% of those meeting NCCN criteria. Missing grade and no endocrine therapy receipt were associated with reduced likelihood of PMRT utilization. In addition to practice adjustments such as increasing hypofractionation and increasing patient access to standard oncologic testing at diagnosis could increase postmastectomy utilization.

Prostate cancer-specific mortality burden by risk group among men with localized disease: Implications for research and clinical trial priorities.

OBJECTIVE: To estimate contemporary population-based patterns of the relative burden of prostate cancer-specific mortality (PCSM) attributable to each N0M0 prostate cancer risk-group, that may guide prioritization in research, trial design, and clinical practice. METHODS: We categorized 2004-2015 Surveillance, Epidemiology, and End Results database patients by risk group (low, favorable intermediate, unfavorable intermediate, high, and very highrisk). Using the Fine-Gray method, we calculated the relative burden of 10-year PCSM attributable to each risk group. RESULTS: Among N = 337 162 men (6.8-year median follow-up; median age 65 years), the relative proportion of low-, favorable intermediate-, unfavorable intermediate-, high-, and very high-risk diagnoses were 29.9% (N = 100 969), 31.1% (N = 104 696), 17.9% (N = 60 360), 18.1% (N = 61 023), and 3.0% (N = 10 114). Within 10 years of diagnosis, among patients who died of prostate cancer (N = 15 064), 5.0% (N = 746) had low-risk, 13.7% (N = 2060) had favorable intermediate-risk, 16.1% (N = 2429) had unfavorable intermediate-risk, 47.8% (N = 7196) had high-risk, and 17.5% (N = 2633) had very high-risk disease at diagnosis. Patients aged 65 and older accounted for 51.9% of all diagnoses and 72.3% of 10-year PCSM. Although black patients accounted for 15.0% of low-risk diagnoses, they accounted for 20.6% of 10-year PCSM. White patients accounted for 80.3% of low-risk diagnoses and 75.7% of 10-year PCSM. CONCLUSION: Although high-risk and very high-risk disease account for one-fifth of diagnoses, they account for two-thirds of 10-year PCSM. Older patients and black patients with low-risk disease accounted for a disproportionately large proportion of deaths. These findings support targeting research toward high-risk disease and ensuring adequate representation of older and black men in clinical trials.

Are Staging Computed Tomography (CT) Scans of the Chest Necessary in Pancreatic Adenocarcinoma?

BACKGROUND: There is no consensus on the use of chest imaging in pancreatic ductal adenocarcinoma (PDAC) patients. Among PDAC patients, we examined the use of chest computed tomography (CT) over time and determined whether the use of chest CT led to a survival difference or change in management via identification of indeterminate lung nodules (ILNs). METHODS: Retrospective clinical data was collected for patients diagnosed with PDAC from 1998 to 2014. We examined the proportion of patients undergoing staging chest CT scan and those who had ILN, defined as ≥ 1 well-defined, noncalcified lung nodule(s) ≤ 1 cm in diameter. We determined time to overall survival (OS) using multivariate Cox regression. We also assessed changes in management of PDAC patients who later developed lung metastasis only. RESULTS: Of the 2710 patients diagnosed with PDAC, 632 (23%) had greater than one chest CT. Of those patients, 451 (71%) patients had ILNs, whereas 181 (29%) had no ILNs. There was no difference in median overall survival in patients without ILNs (16.4 [13.6, 19.0] months) versus those with ILN (14.8 [13.6, 15.8] months, P = 0.18). Examining patients who developed isolated lung metastases (3.3%), we found that staging chest CTs did not lead to changes in management of the primary abdominal tumor. CONCLUSIONS: Survival did not differ for PDAC patients with ILNs identified on staging chest CTs compared with those without ILNs. Furthermore, ILN identification did not lead to changes in management of the primary abdominal tumor, questioning the utility of staging chest CTs for PDAC patients.

Development and Validation of a Novel TP53 Mutation Signature That Predicts Risk of Metastasis in Primary Prostate Cancer.

INTRODUCTION: Prostate tumors with TP53 gene mutations are molecularly heterogenous, and the presence of TP53 gene mutations has been linked to inferior outcomes. We developed an RNA-based gene signature that detects underlying TP53 gene mutations and identifies wild-type prostate tumors that are analogous to TP53-mutant tumors. MATERIALS AND METHODS: Using genomic expression profiles from The Cancer Genome Atlas, we developed a mutation signature score to predict prostatic tumors with a molecular fingerprint similar to tumors with TP53 mutations. Area under the receiver operating characteristic curve assessed model accuracy in predicting TP53 mutations, and Cox regression models measured association between the signature and progression-free survival and metastasis-free survival (MFS). RESULTS: The TP53 signature score achieved an area under the receiver operating characteristic curve of 0.84 in the training and 0.82 in the validation cohorts for predicting an underlying mutation. In three retrospective cohorts, a high score was prognostic for poor 5-year MFS: 46% versus 81% (hazard ratio [HR], 3.05; P < .0001; Johns Hopkins University cohort), 64% versus 83% (HR, 2.77; P < .0001; Mayo Clinic cohort), and 71% versus 97% (HR, 6.8; P = .0001; Brigham and Women's Hospital cohort). The signature also identified TP53 wild-type tumors molecularly analogous to TP53 mutant tumors, wherein high signature score correlated with worse 5-year MFS (50% vs. 82%; HR, 3.05; P < .0001). CONCLUSIONS: This novel mutational signature predicted tumors with TP53 mutations, identified TP53 wild-type tumors analogous to mutant tumors, and was independently associated with poor MFS. This signature can therefore be used to strengthen existing clinical risk-stratification tools.

Accuracy of Pathologic Diagnosis in Patients With Lymphoma and Survival: A Prospective Analysis From Botswana.

PURPOSE: With intense HIV epidemics, southern African countries have a high burden of classic Hodgkin lymphoma (CHL) and non-Hodgkin lymphoma (NHL). However, suboptimal access to pathology resources limits subtype classification. We sought to assess the diagnostic accuracy of specimens classified as lymphoma and to determine association between discordant pathologic diagnosis and overall survival. METHODS: Seventy patients with CHL or NHL and treated at three Botswana hospitals from 2010 to 2016 were analyzed. Local pathologic assessment relied primarily on morphology. All cases underwent secondary US hematopathology review, which is considered gold standard. RESULTS: The median follow-up was 58 months. The overall reclassification rate was 20 of 70 cases (29%). All 20 CHL cases were correctly classified in Botswana, and mixed cellularity was the most common subtype, diagnosed in 11 (55%) cases. Of 47 confirmed NHL cases, diffuse large B-cell lymphoma was the final US diagnosis in 28 cases (60%), another aggressive B-cell NHL in nine (19%), an indolent B-cell NHL in six (13%), and T-cell NHL in four (9%). Common types of diagnostic discordance included NHL subtype reclassification (11 of 20, 55%) and CHL reclassified as NHL (7 of 20, 35%). Concordant versus discordant diagnosis after secondary review was associated with improved 5-year overall survival (60.1% v 26.3%, P = .0066). Discordant diagnosis was independently associated with increased risk of death (adjusted hazard ratio 2.733; 95% CI, 1.102 to 6.775; P = .0300) even after stratifying results by CHL versus NHL. CONCLUSION: In this single prospective cohort, discordant pathologic diagnosis was associated with a nearly three-fold increased risk of death. Limited access to relatively basic diagnostic techniques impairs treatment decisions and leads to poor patient outcomes in low-resource countries.