The modern landscape of radiotherapy in thyroid malignancies.

Thyroid carcinoma is the most common malignancy of the endocrine system and accounts for nearly 1.5% of all new cancer cases in India. The incidence of thyroid cancers is on the rise secondary to multiple factors including the widespread use of radiological imaging. Surgery remains the cornerstone of treatment, and radioactive iodine therapy plays a pivotal role in differentiated thyroid cancer. Radiation therapy appears to be an underutilized treatment modality. In this review, we have summarized the role of radiation in the treatment of thyroid cancer.

MYCN immunohistochemistry as surrogate marker for MYCN-amplified spinal ependymomas.

MYCN (master regulator of cell cycle entry and proliferative metabolism) gene amplification defines a molecular subgroup of spinal cord ependymomas that show high-grade morphology and aggressive behavior. Demonstration of MYCN amplification by DNA methylation or fluorescence-in situ hybridization (FISH) is required for diagnosis. We aimed to (i) assess prevalence and clinicopathological features of MYCN-amplified spinal ependymomas and (ii) evaluate utility of immunohistochemistry (IHC) for MYCN protein as a surrogate for molecular testing. A combined retrospective-prospective study spanning 8 years was designed during which all spinal cord ependymomas with adequate tissue were subjected to MYCN FISH and MYCN IHC. Among 77 spinal cord ependymomas included, MYCN amplification was identified in 4 samples from 3 patients (3/74, 4%) including two (1st and 2nd recurrences) from the same patient. All patients were adults (median age at diagnosis of 32 years) including two females and one male. The index tumors were located in thoracic (n = 2) and lumbar (n = 1) spinal cord. One of the female patients had neurofibromatosis type 2 (NF2). All four tumors showed anaplastic histology. Diffuse expression of MYCN protein was seen in all four MYCN-amplified samples but in none of the non-amplified cases, thus showing 100% concordance with FISH results. On follow-up, the NF2 patient developed widespread spinal dissemination while another developed recurrence proximal to the site of previous excision. To conclude, MYCN-amplified spinal ependymomas are rare tumors, accounting for ~ 4% of spinal cord ependymomas. Within the limitation of small sample size, MYCN IHC showed excellent concordance with MYCN gene amplification.

Platelet-to-albumin ratio and radiation-induced lymphopenia-prognostic biomarker for carcinoma esophagus.

BACKGROUND: Esophageal cancer has a poor survival outcome with 5-year OS at 16.7% despite treatment. Some inflammation-based prognostic indicators like the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been previously studied as potential biomarker for predicting outcome in esophageal cancer. Recently, platelet-to-albumin ratio (PAR) has been reported as a promising prognostic factor in gastrointestinal malignancies. METHODS: We performed a retrospective analysis of prospectively treated patients of carcinoma esophagus to evaluate the prognostic significance of inflammation-based prognostic indicators-neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and a composite inflammation-nutrition index: platelet-to-albumin ratio (PAR) in esophageal cancer. Based on previous studies, the optimal cut-off value of PAR was kept at 5.7 × 10^9, and 2.62 for NLR. RESULTS: A total of 71 patients of locally advanced esophageal cancer treated between 2019 and 2022, with either neoadjuvant or definitive chemoradiotherapy, were included. Median follow-up time was 19 months [range: 7-44 months]. Median OS and PFS in our study cohort were 11.3 months [range: 7-23 months] and 7.8 months [range: 3-17 months], respectively. In univariate analysis, lower PAR was found to be significantly correlated with shorter survival time (HR = 2.41; 1.3-4.76; p = 0.047). There was no association found between the OS and the NLR [HR = 1.09; 0.95-1.26; p = 0.222]. Univariate and multivariate linear and logistic regressions found no association between V15, V10, V5, or V2 of spleen and nadir lymphocyte count or between Dmax or Dmean and nadir lymphocyte counts. CONCLUSION: Present analysis found a trend toward an inverse association between PAR and OS. PAR, in the not-so-distant future, may evolve as a novel, convenient, and inexpensive prognostic indicator in esophageal cancer.

Trichilemmal carcinoma metastatic to parotid gland: First report of fine needle aspiration cytology features.

Trichilemmal carcinoma is a rare malignant cutaneous adnexal neoplasm arising from the outer root sheath of the hair follicle. Majority of cases occur on sun-exposed sites such as the face, scalp and neck, making them easily amenable to being biopsied and subjected to histological examination for definitive diagnosis. Thus, cytological features of trichilemmal carcinoma have not been described till date. Trichilemmal carcinoma is a low-grade malignancy, albeit with potential to metastasize to regional lymph nodes and distant sites. We report the case of trichilemmal carcinoma of scalp that metastasized to cervical lymph nodes and parotid gland and underwent fine-needle aspiration cytology (FNAC) from the parotid lesion. The aspirate showed tightly cohesive cell clusters with sharp borders. Tumour cells ranged from basaloid with scant cytoplasm to those with abundant cytoplasm. Nuclei were vesicular, with inconspicuous to prominent nuclei. Intercellular bridges, masses of keratin, and fragments of desmoplastic stroma were present, closely recapitulating histological features of trichilemmal carcinoma, which enabled diagnosis as metastasis. Cell block showed similar tumour fragments with evidence of differentiation towards outer root sheath. FNAC is the first-line investigation to obtain a tissue diagnosis of masses in the head and neck region. Although rarely encountered, the lack of knowledge of cytological features of trichilemmal carcinoma may hamper its FNAC diagnosis at metastatic sites. When intraparotid metastases occur, they may be mistaken as primary salivary gland carcinoma. Thus, awareness of the cytological features of this tumour must be raised among cytopathologists to enable accurate diagnosis and further management.

No Doppler Single Position-Lateral Intercostal Artery Perforator Flap (NDSP-LICAP): a Safe and Versatile Flap for Breast Oncoplasty in Resource-Limited Setting.

INTRODUCTION: The lateral intercostal artery perforator flap (LICAP) has emerged as one of the safest and less morbid flaps for lateral and central breast defects. We hereby describe a reproducible no Doppler single position (NDSP) technique to harvest it in single position without handheld Doppler, making it a versatile flap for lateral breast defects in resource-limited setting also. MATERIALS AND METHODS: With this technique, we performed a total of 22 LICAP turnover flaps over a period of 18 months from January 2020 to June 2021. In all 22 cases, the indication of flap was to fill the post-breast conservation surgery (BCS) defects in outer quadrant of breast. All LICAP flaps were harvested by surface marking of anatomical landmarks and without handheld Doppler. RESULTS: Out of 22 LICAP turnover flaps, thirteen were harvested for left breast and nine for right breast. The median width and length of the flap were 12.2 cm and 19.6 cm, respectively. The additional mean operative time was 41 min. All LICAP flaps survived well, and grade 1 Clavien-Dindo morbidity was documented in four cases. Mean hospital stay was 2.6 days. All patients received radiotherapy on their stipulated schedule. Early cosmetic outcome was good, and long-term outcomes are awaited. CONCLUSION: NDSP-LICAP flap is a workhorse for lateral breast defects. Precise knowledge of perforators and anatomical landmarks can be used for harvesting these flaps, thus avoiding ultrasound Doppler and dedicated training for perforator localization. This technique has short learning curve without the need for any plastic surgery training. The early cosmetic outcomes are good.

Hypo-fractionated accelerated radiotherapy with concurrent and maintenance temozolomide in newly diagnosed glioblastoma: updated results from phase II HART-GBM trial.

BACKGROUND: Glioblastoma (GBM) patients have poor survival outcomes despite treatment advances and most recurrences occur within the radiation field. Survival outcomes after dose escalation through hypofractionated accelerated RT(HART) were evaluated in this study. We previously reported the study's initial results showing similar survival outcomes with acceptable toxicities. Updated results after 5 years are being analysed to determine long-term survival trends. PATIENTS AND METHODS: 89 patients of newly diagnosed GBM after surgery were randomized to conventional radiotherapy (CRT) or HART. CRT arm received adjuvant RT 60 Gy in 30 fractions over 6 weeks and the HART arm received 60 Gy in 20 fractions over 4 weeks, both with concurrent and adjuvant temozolomide. RESULTS: 83 patients were eligible for analysis. After a median follow-up of 18.9 months, the median OS was 26.5 months and 22.4 months in the HART and CRT arms respectively. 5 year OS was 18.4% in the HART arm versus 3.8% in the CRT arm. This numerical difference in overall survival between the two arms was not statistically significant. The median PFS was not significantly different. CONCLUSION: The long-term results of the trial support HART as a promising treatment option with comparable survival outcomes to the current standard of care. Phase III trials are required for further validation of this regimen which has the potential to become the new standard of care in GBM.

Systematic Review and Individual Patient Data Analysis of Uncommon Variants of Glioblastoma: An Analysis of 196 Cases.

Objectives: Different variant of GBM has been reported viz. Epithelioid Glioblastoma (GBM-E), Rhabdoid GBM (GBM-R), Small cell GBM (GBM-SC), Giant cell GBM (GBM-GC), GBM with neuro ectodermal differentiation (GBM-PNET) with unknown behavior. Materials: We conducted a systematic review and individual patient data analysis of these rare GBM variants. We searched PubMed, google search, and Cochrane library for eligible studies till July 1st 2016 published in English language and collected data regarding age, sex, subtype and treatment received, Progression Free Survival (PFS), Overall Survival (OS). Statistical Package for social sciences (SPSS) v16 software was used for all statistical analysis. Results: We retrieved data of 196 patients with rare GBM subtypes. Among these GBM-GC is commonest (51%), followed by GBM-R (19%), GBM-PNET (13%), GBM-SC (9%) and GBM-E (8%). Median age at diagnosis was 38, 40, 43.5, 69.5 and 18 years, respectively. Male: female ratio was 2:1 for GBM-E, and 1:3 for GBM-SC. Maximal safe resection followed by adjuvant local radiation was used for most of the patients. However, 6 patients with GBM-PNET, 3 each of GBM-E, GBM-SC received adjuvant craniospinal radiation. Out of 88 patients who received chemotherapy, 64 received Temozolomide alone or combination chemotherapy containing Temozolomide. Median PFS and OS for the entire cohort were 9 and 16 months. In univariate analysis, patient with a Gross Total Resection had significantly better PFS and OS compared to those with a Sub Total Resection [23 vs. 13 months (p-0.01)]. Median OS for GBM PNET, GBM-GC, GBM-SC, GBM-R and GBM-E were 32, 18.3, 11, 12 and 7.7 months, respectively (P = 0.001). Interestingly, 31.3%, 37.8% of patients with GBM-E, GBM-R had CSF dissemination. Conclusion: Overall cohort of rarer GBM variant has equivalent survival compared to GBM not otherwise specified. However, epithelioid and Rhabdoid GBM has worst survival and one third shows CSF dissemination.

A systematic review exploring the role of modern radiation for the treatment of Hereditary or Familial Breast Cancer.

The diagnosis of hereditary or familial breast cancers influences the locoregional approach to breast cancer, with most patients undergoing mastectomy to avoid or minimize the use of adjuvant radiation therapy. We evaluated the current literature about known high- and moderate-penetrance genes and studied their impact on local control, toxicities, and contralateral breast cancers after adjuvant radiation therapy. The aim is to encourage the safe use of adjuvant radiation therapy when indicated in concordance with the updated guidelines.

Molecular Characterization of IDH Wild-type Diffuse Astrocytomas: The Potential of cIMPACT-NOW Guidelines.

IDH wild-type (wt) grade 2/3 astrocytomas are a heterogenous group of tumors with disparate clinical and molecular profiles. cIMPACT-NOW recommendations incorporated in the new 2021 World Health Organization (WHO) Classification of Central Nervous System (CNS) Tumors urge minimal molecular criteria to identify a subset that has an aggressive clinical course similar to IDH -wt glioblastomas (GBMs). This paper describes the use of a panel of molecular markers to reclassify IDH -wt grade 2/3 diffuse astrocytic gliomas (DAGs) and study median overall survival concerning for to IDH -wt GBMs in the Indian cohort. IDH -wt astrocytic gliomas (grades 2, 3, and 4) confirmed by IDHR132H immunohistochemistry and IDH1/2 gene sequencing, 1p/19q non-codeleted with no H3F3A mutations were included. TERT promoter mutation by Sanger sequencing, epidermal growth factor receptor amplification, and whole chromosome 7 gain and chromosome 10 loss by fluorescence in situ hybridization was assessed and findings correlated with clinical and demographic profiles. The molecular profile of 53 IDH -wt DAGs (grade 2: 31, grade 3: 22) was analyzed. Eleven cases (grade 2: 8, grade 3: 3) (20.75%) were reclassified as IDH -wt GBMs, WHO grade 4 ( TERT promoter mutation in 17%, epidermal growth factor receptor amplification in 5.5%, and whole chromosome 7 gain and chromosome 10 loss in 2%). Molecular GBMs were predominantly frontal (54.5%) with a mean age of 36 years and median overall survival equivalent to IDH -wt GBMs (18 vs. 19 mo; P =0.235). Among grade 2/3 DAGs not harboring these alterations, significantly better survival was observed for grade 2 versus grade 3 DAGs (25 vs. 16 mo; P =0.002). Through the incorporation of a panel of molecular markers, a subset of IDH -wt grade 2 DAGs can be stratified into molecular grade 4 tumors with prognostic and therapeutic implications. However, IDH -wt grade 3 DAGs behave like GBMs irrespective of molecular profile.

Treatment outcomes and prognostic factors in locally advanced non-small cell lung cancer - An experience from normal India.

Context: Chemoradiation is the standard of care in locally advanced non-small cell lung cancer (LA-NSCLC). Clinical presentation, disease course, and available treatment options are challenges to overcome. Little is known about the ideal timing and interaction of the two modalities, its relevance in day-to-day decision-making and the treatment outcome. Aims: The study evaluates the demographic profile, treatment pattern, outcome, and radiotherapy (RT) practice and patient care of LA-NSCLC at a tertiary cancer center. Setting and Design: This is a retrospective study from a tertiary cancer centre. Archives of patients of LA-NSCLC treated between June 2016 and June 2018 were included in our study. Materials and Methods: Clinical, demographic characteristics, treatment patterns, and outcomes were recorded. RT practice and patient care process including the integration of RT with other specialties, waiting time, and compliance to treatment were documented and analyzed. Statistical Analysis: Overall survival (OS) and progression-free survival (PFS) were the primary endpoints of the study. Log-rank test was used for univariate analysis for the factors on OS, and Cox's proportional hazards model was used for multivariate analysis for cofactors on OS. Results: Two hundred and thirty-two patients of lung cancer were treated during the study period. Fifty-four patients were squamous cell carcinoma, 108 were adenocarcinoma, and 12 were others. Out of 59 patients of LA-NSCLC, 34 underwent definitive chemoradiation. The median follow-up was 11 months (0.7-29), median overall treatment time was 44 days, median PFS was 8.9 months (range: 1.6-28.6), and median OS was 9.4 months (1.7-44.8). Time to start any oncological intervention was 1 month (0.1-4.3) and time to start RT was 2.1 months (0.1-5.4). Adherence to treatment was 91.2%. Age ≥65 and performance status ≥2 were significant for OS on univariate analysis and none on multivariate analysis. Conclusions: One-third of the cases of NSCLC present in LA stage and a third are suitable for definitive chemoradiation and only 20% undergo the planned treatment.

Demography, patterns of care, and survival outcomes in patients with salivary duct carcinoma: an individual patient data analysis of 857 patients.

Aim: Salivary duct carcinoma (SDC) is a rare and aggressive malignancy. The optimal treatment protocols are debated. Methodology: A systematic search and individual patient data analysis of published cases of SDC was performed. SPSS v21 was used for statistical analysis. Results: Data of 857 patients available. Median overall survival (OS) and progression-free survival (PFS) of the entire cohort 42 months and 24 months. Nodal involvement, males, primary size >5 cm, androgen receptor (AR) negativity significantly worse OS. Patients with surgery had a favorable median PFS (p = 0.000) and OS (p = 0.077). Patients with adjuvant radiation had better PFS (30 vs 18 months; p = 0.077). Conclusion: SDC has modest survival. Surgery and adjuvant radiation should be advocated for all patients. AR expression appears prognostic for survival.

Rosette Forming Glioneural Tumor Treated with Conformal Radiation.

Rosette forming glioneural tumors (RGNT) are a rare type of low-grade brain tumor included in 2007 in WHO classification. Given the benign nature of the disease, a complete surgical excision has been considered optimum. However, a handful of cases have reported the locally aggressive nature of RGNT. In addition, radiation may also be considered for a tumor located in areas where surgical excision is difficult. We present a similar case, where surgical risk was weighed against resection and we treated the patient with conformal radiation.

A systematic review and meta-analysis of the impact of radiation-related lymphopenia on outcomes in pancreatic cancer.

Background: Pancreatic cancer is a devastating disease with a 5-year survival rate of 5-10%. Radiation is commonly used in neoadjuvant and adjuvant settings to improve local control. Studies have shown that circulating lymphocyte count depletion after radiation has been associated with poor tumor control and inferior overall survival (OS) outcomes. Method: To better understand the impact of radiation-associated lymphopenia in pancreatic cancer, the authors undertook this systematic review and meta-analysis of clinical studies that have reported radiation-related lymphopenia in pancreatic cancer. Results: A systematic methodology search of PubMed, Embase and the Cochrane Library resulted in 2969 abstracts. Nine studies fulfilled the inclusion criteria. Six studies reported on outcomes in patients undergoing definitive chemoradiation and three studies comparing outcomes in stereotactic body radiotherapy versus definitive chemoradiation. The patients with severe lymphopenia were at increased risk of death with a pooled hazard ratio of 2.33 (95% CI: 1.79, 3.03; I2: 36%; p < 0.001) compared with patients with no severe lymphopenia. The odds of developing severe lymphopenia were 1.12 (95% CI: 0.45, 2.79; I2: 95%; p < 0.81). The pooled mean difference for OS was -6.80 months (95% CI: -10.35, -3.24; I2: 99%; p < 0.002), suggesting that patients who develop grade 3 or 4 lymphopenia have inferior median OS outcomes. Limiting the mean splenic dose to less than 9 Gy as well as various spleen dosimetric parameters such as visit (V)10 <32%, V15 <23% and V20 <15.4% can reduce the incidence of severe lymphopenia. Conclusion: Radiation-related lymphopenia is associated with an increased hazard of death and inferior median OS. Spleen dosimetric parameters correlate with the incidence of severe lymphopenia and with sub-optimal survival outcomes. There is a need to validate these findings in prospective studies.

A Systematic Review and Meta-analysis of the Impact of Radiation-Related Lymphopenia on Outcomes in High-Grade Gliomas.

Supriya MallickIntroduction Malignant gliomas are the most common primary malignant brain tumors and are typically treated with maximal safe surgical resection followed by chemoradiation. One of the unintended effects of radiation is depletion of circulating lymphocyte pool, which has been correlated with inferior overall survival outcomes. Methods A comprehensive and systematic searches of the PubMed, Cochrane Central, and Embase databases were done to assess the studies that have reported radiation-related lymphopenia in high-grade gliomas. Hazard ratios (HRs), odds ratios (OR), and mean differences were represented with Forest plots comparing patients with severe lymphopenia and no severe lymphopenia. Review Manager Version 5.3 (The Nordic Cochrane Centre, Copenhagen, Denmark) was used for the analysis. Results Nineteen studies were included in the final systematic review and 12 studies were included in the meta-analysis. The odds of developing severe lymphopenia were 0.39 (95% CI:0.19, 0.81, I 2 = 94%, p = 0.01). Patients with severe lymphopenia were at increased risk of death with a pooled HR = 2.19 (95% CI: 1.70, 2.83, I 2 = 0%, p <0.00001) compared to patients with no severe lymphopenia. The mean difference in survival between patients with severe lymphopenia and no severe lymphopenia was -6.72 months (95% CI: -8.95, -4.49, I 2 = 99%, p <0.00001), with a better mean survival in the no severe lymphopenia group. Conclusion Radiation-induced severe lymphopenia was associated with poor overall survival and increased risk of death. Photon therapy, larger planning target volume, higher brain dose, higher hypothalamus dose, and female gender were associated with increased risk of severe lymphopenia.

Low-dose radiation therapy for COVID-19 pneumonia: a pilot study.

OBJECTIVES: The World Health Organization (WHO) has declared coronavirus disease 2019 (COVID-19) as pandemic in March 2020. Currently there is no specific effective treatment for COVID-19. The major cause of death in COVID-19 is severe pneumonia leading to respiratory failure. Radiation in low doses (<100 cGy) has been known for its anti-inflammatory effect and therefore, low dose radiation therapy (LDRT) to lungs can potentially mitigate the severity of pneumonia and reduce mortality. We conducted a pilot trial to study the feasibility and clinical efficacy of LDRT to lungs in the management of patients with COVID-19. METHODS: From June to Aug 2020, we enrolled 10 patients with COVID-19 having moderate to severe risk disease [National Early Warning Score (NEWS) of ≥5]. Patients were treated as per the standard COVID-19 management guidelines along with LDRT to both lungs with a dose of 70cGy in single fraction. Response assessment was done based on the clinical parameters using the NEWS. RESULTS: All patients completed the prescribed treatment. Nine patients had complete clinical recovery mostly within a period ranging from 3 to 7 days. One patient, who was a known hypertensive, showed clinical deterioration and died 24 days after LDRT. No patients showed the signs of acute radiation toxicity. CONCLUSION: The results of our pilot study suggest that LDRT is feasible in COVID-19 patients having moderate to severe disease. Its clinical efficacy may be tested by conducting randomized controlled trials. ADVANCES IN KNOWLEDGE: LDRT has shown promising results in COVID-19 pneumonia and should be researched further through randomized controlled trials.

Glioblastoma with Primitive Neuroectodermal Component Treated with Adjuvant Radiotherapy and Temozolomide: A Pooled Analysis of 23 Patients.

AIM: Glioblastoma (GBM) is one of the most aggressive neoplasms of the central nervous system with dismal survival. In recent years, different variants of GBM have been described in the literature. GBM with areas of neuroectodermal differentiation (GBM-PNET) is a relatively new entity in GBM. Presence of the neuroectodermal component increases the propensity of systemic dissemination as with other intracranial primitive neuroectodermal tumors (PNET). The optimal treatment for these patients remains a controversy, with authors reporting local radiotherapy to craniospinal irradiation and chemotherapy. We intend to analyze the pattern of care for GBM with neuroectodermal component. MATERIALS AND METHODS: We retrieved data of four patients with GBM-PNET treated in our institute; data were also retrieved from published series to derive treatment and outcome results. RESULTS: In this series, we report the outcome of a series of four patients of GBM-PNET treated with adjuvant radiotherapy and temozolomide. All but one patient underwent gross total resection of the tumor. Adjuvant hypofractionated radiation with concurrent and adjuvant temozolomide was used in all cases. The median follow-up was 12.9 months in the present series. One patient experienced local recurrence 18 months after the treatment. A review of published literature on GBM-PNET was done; studies with details of patient outcome were used for an independent analysis. Twenty-three patients were identified, and the pooled analysis revealed a median progression free and overall survival of 10 and 25, months respectively. Extent of surgery, local radiation vs. craniospinal irradiation, and age at presentation had no impact on the survival. CONCLUSION: GBM PNET is a new entity with only few cases reported so far. Clinical behavior and treatment outcome of these tumors are not different from conventional GBM. However, these patients are at higher risk of CSF dissemination. Hence, an individualized treatment approach is best suited.

A Systematic Review of Radiation-Related Lymphopenia in Genito-urinary Malignancies.

BACKGROUND: The impact of radiation-related lymphopenia on clinical outcomes has been reported in various solid malignancies such as high grade gliomas, head and neck cancers, thoracic malignancies and gastro-intestinal malignancies but its impact is not clearly known in the context of common genito-urinary (GU) malignancies. METHODOLOGY: To better understand the effect of radiation-associated lymphopenia in prostate and bladder cancer, we undertook this systematic review of clinical studies that have studied radiation-related lymphopenia in GU malignancies. A systematic methodology search of PubMed, Embase, and Cochrane library resulted in 2125 abstracts. Ten studies fulfilled the inclusion criteria which included any prospective, retrospective study or cohort study of prostate, urinary bladder, kidney, ureter, urethra, penile cancer in humans, and radiation should be part of treatment and intent has to be in definitive or adjuvant settings. Finally the study should have data on radiation-related lymphopenia. RESULTS: Four studies reported on the cancer-specific outcomes related to the lymphopenia. The incidence of low lymphocyte counts were documented in all the studies. Three studies analyzed the factors associated with the Lymphocyte depletion. Pooled incidence of severe lymphopenia was 29.25% and mild to moderate lymphopenia was 60.75%. Bone marrow volume receiving 40 Gy was associated with the incidence of lymphopenia. CONCLUSION: One-third of the patients suffer from severe lymphopenia after radiation in prostate and bladder cancer. There are no clear data to support the correlation between severe lymphopenia and disease outcomes. Bone marrow dosimetry can affect the incidence and severity of lymphopenia. There is need of prospective datasets to identify the impact of radiation-related lymphopenia in GU malignancies focusing on long-term side effects, recurrence rates, and overall survival.