Factors associated with cavity formation after stereotactic body radiation therapy for peripheral early-stage lung cancer.

PURPOSE: This retrospective study aimed to identify the factors associated with cavity formation after SBRT in peripheral early-stage lung cancer patients. We analyzed the occurrence of cavity changes after SBRT. MATERIALS AND METHODS: We examined 99 cases with T1-T2aN0 peripheral non-small cell lung cancer treated with SBRT from 2004 to 2021. Patients underwent respiratory function tests, including diffusing capacity for carbon monoxide (DLco), before treatment. The median observation period was 35 months (IQR 18-47.5 months). Treatment involved fixed multi-portal irradiation in 67% of cases and VMAT in 33%. The total radiation doses ranged from 42 to 55 Gy, delivered over 4 to 5 fractions. RESULTS: Cavity formation occurred in 14 cases (14.1%), appearing a median of 8 months after SBRT. The cavity disappeared in a median of 4 months after formation. High DLco and total radiation dose were identified as factors significantly associated with cavity formation. There have been no confirmed recurrences to date, but one patient developed a lung abscess. CONCLUSION: Although cavity formation after SBRT for peripheral early-stage lung cancer is infrequent, it can occur. This study showed high DLco and total radiation dose to be factors significantly associated with cavity formation. These findings can be applied to optimizing radiation therapy (RT) and improving patient outcomes. Further research is needed to determine the optimal radiation dose for patients with near-normal DLco for whom surgery is an option. This study provides valuable insights into image changes after RT.

Radiotherapy for ductal carcinoma of the prostate: an analysis based on the Japanese radiation oncology study group survey.

BACKGROUND: The clinical characteristics of prostate ductal carcinoma is still unclear, and treatment strategy has not yet been established due to its rarity. Therefore, we conducted a multicenter survey of radiation therapy for prostate ductal carcinoma in Japan. METHOD: Data of patients with ductal carcinoma of the prostate treated with radiation therapy between 1996 and 2018 were extracted from the database of each facility. RESULTS: Fifty-two treatment records of 41 patients were collected from nine institutions. The treatment purpose and situations were varied curative intent to palliation. Twenty-eight patients received curative treatments. The median follow-up period of these patients was 68 months. Androgen deprivation therapy was combined with radiation therapy in 26 cases (93%). X-ray and particle irradiation was used. Radiation dose range was 63-78 Gy; 5-year overall survival, progression-free survival and biochemical relapse-free survival were 87.0, 79.3 and 79.3%, respectively. One patient experienced Grade 3 radiation proctitis and one experienced Grade 3 radiation cystitis. There were no Grade 4 or worse adverse events. CONCLUSION: Most patient received similar treatment with adenocarcinoma of prostate, and the clinical results were compatible. For more reliable evidence, further studies are required.

Study of prostate-specific antigen levels during salvage radiotherapy after prostate cancer surgery.

BACKGROUND: Administration of adjuvant or salvage radiotherapy (RT) after prostate cancer (PCa) surgery is supported by clinical evidence and is a widely adopted strategy. On occasion, we detect changes in prostate-specific antigen (PSA) levels, such as a transient elevation or decline, during RT. Thus, we retrospectively investigated the frequency of changes in PSA levels, their associations with histopathological parameters, PSA doubling time (PSADT), and biochemical recurrence (BR) of PCa. METHODS: This study included 23 consecutive patients who underwent surgery for PCa between 2012 and 2019, received salvage RT without hormone therapy, and exhibited changes in PSA levels during RT. The prostatic bed was irradiated with a total dose of 64 to 66 Gy. BR was defined as consecutive PSA levels exceeding 0.2 ng/mL or having to start hormone therapy because of PSA elevation after salvage RT. RESULTS: During salvage RT after PCa surgery, PSA levels transiently increased in 11 patients (47.8%) and decreased in 12 (52.2%). When factors associated with BR were examined in patients with transient PSA elevation, seminal vesicle invasion and preoperative PSA values were identified as being statistically significant. When factors for BR were examined in patients with a decline in PSA levels, the Gleason score and PSADT were identified as being significant. Among the cases of a decline in PSA levels during salvage RT, those who received a radiation dose of less than 36 Gy did not experience BR. Similarly, patients who exhibited changes in PSA levels during salvage RT and did not have perineural invasion did not experience BR. CONCLUSION: This is the first study to examine the histopathological factors possibly affecting BR in patients undergoing salvage RT after PCa surgery. The results indicate that in patients with transient PSA elevation, seminal vesicle invasion is a significant risk factor. On the other hand, in patients with a decline in PSA levels during irradiation, the Gleason score and perineural invasion were found to be potential risk factors for BR. These findings suggest that a thorough examination of postoperative histopathological results may be necessary for the optimal management of patients with PCa.

Roles of Ki-67 and p16 as biomarkers for unknown primary head and neck squamous cell carcinoma.

PURPOSE: Treatment guidelines have not been established for unknown primary head and neck squamous cell carcinoma (SCC). For these patients, chemoradiotherapy (CRT) can provide a better prognosis than that for patients with other head and neck cancers. The presence of HPV in the tumor is associated with a better outcome. However, not all patients with HPV-positive unknown primary head and neck SCC experience good treatment outcomes in actual clinical settings. METHODS: We thus retrospectively determined the Ki-67 proliferation index and p16 expression status to assess the associations of these parameters with treatment outcomes of patients with unknown primary head and neck SCC. RESULTS: The subjects were 13 patients who underwent CRT after surgery or excision biopsy between 1999 and 2016. The 2- and 5-year overall survival (OS) rate was 76.9% and 68.4%, respectively. The prognostic factor was age. There was no significant difference in survival between patients with a high Ki-67 vs. low Ki-67 or between patients with p16-positive vs. p16-negative metastases OS. However, all p16-positive patients with low Ki-67 showed good locoregional control. CONCLUSIONS: The combination of ki67 expression and p16 expression status may allow prediction of local control more accurately than p16 expression status alone.

A long-surviving patient with advanced esophageal basaloid squamous cell carcinoma treated only with radiotherapy: case report and literature review.

BACKGROUND: Esophageal basaloid squamous cell carcinoma (EBSCC) is a rare malignant disease. Advanced EBSCC (AEBSCC) has a poorer prognosis than the more common esophageal squamous cell carcinoma, but no treatment policy has yet been established. This is the first reported case with AEBSCC treated only with radiotherapy. Thus, our long-surviving patient merits consideration. We therefore reviewed cases with the same stage of AEBSCC for further investigation. CASE PRESENTATION: An 85-year-old man with a chief complaint of difficulty swallowing foods was diagnosed with AEBSCC, cT3N1M0, stage III, by thorough examination. The basaloid carcinoma extended from the upper thoracic esophagus to the middle thoracic esophagus based on imaging studies, endoscopy and biopsy. Morphologically, the tumor was an elevated ulcerative area. We conducted radiotherapy to relieve symptoms, as the patient and his family refused aggressive treatment. He has remained alive without recurrence for 2 years, to date, after completing radiotherapy. CONCLUSIONS: Basaloid carcinoma might be highly sensitive to radiotherapy. Thus, radiotherapy for local control might be beneficial for elderly patients with complications and those refusing aggressive treatment.

Successful Pregnancy and Delivery After Radiation With Ovarian Shielding for Acute Lymphocytic Leukemia Before Menarche.

Total body irradiation is performed as a preconditioning regimen to inhibit graft-versus-host disease after bone marrow transplantation and to eradicate remaining tumor cells. However, these regimens result in delayed secondary sex characteristics and failure of ovarian function recovery, leading to amenorrhea and infertility. Herein, we report a case of an 11-year-old girl diagnosed with acute lymphocytic leukemia who received induction chemotherapy and prophylactic cranial irradiation. For bone marrow transplantation, she received total body irradiation of 12 Gy with uterine and ovarian shielding at 13 years of age. The patient remained in remission and menarche began at 14 years of age. At 23, she became pregnant and delivered a baby naturally with no abnormalities.

Solitary pulmonary metastasis from prostate cancer with neuroendocrine differentiation: a case report and review of relevant cases from the literature.

BACKGROUND: Solitary lung metastasis from prostate cancer is rare. There are few reports of such cases with neuroendocrine differentiation. CASE PRESENTATION: A 50-year-old man presented to our hospital with a chief complaint of dysuria. Histological examination revealed prostate cancer, which was classified as cT4 N0 M0, stage IV adenocarcinoma. Since the patient was at high risk, endocrine and radiation therapies were started. One year after starting radiation therapy, the patient developed bloody sputum. Chest radiography revealed a nodular shadow in his left lung (S5). Although 18-fluoro-2-deoxyglucose positron emission tomography revealed abnormal accumulation in the lesion, the cytological diagnosis was class IIIa, which did not yield a definitive diagnosis. Given that prostate specific antigen (PSA) was not elevated, a primary lung tumor was suspected, and thoracoscopic segmental resection of the lung was performed with lymph node dissection. The final pathological diagnosis was solitary lung metastasis from prostate cancer with neuroendocrine differentiation and mediastinal lymph node metastasis. The specimen showed a mixed pattern of conventional prostatic and neuroendocrine carcinomas. CONCLUSION: We herein report a case with neuroendocrine differentiation (NED), along with a review of the relevant literature, including histopathological findings. According to previous case reports, some patients with solitary lung metastasis from prostate cancer achieved relatively good long-term survival. We consider establishing the correct diagnosis and implementing an appropriate treatment plan to be essential in prostate cancer patients with oligometastases that have the potential to be neuroendocrine (NE) tumors.

Coronavirus disease 2019 (COVID-19) in patients before, during, or after lung irradiation, and serum SP-A and SP-D levels.

BACKGROUND: The correlation between COVID-19 and RT has not been determined to date and remains a clinical question. The aim of this study was to evaluate coronavirus disease 2019 (COVID-19) pneumonia before, during, and after radiation therapy (RT) regarding the radiation doses, radiation pneumonitis, and surfactant protein levels. METHODS: We evaluated patients diagnosed with COVID-19 before, during, or after RT for the lung between August 2020 and April 2022. In patients with breast cancer, the RT dose to the ipsilateral lung was determined. In all other patients, bilateral lung RT doses were determined. Patients diagnosed with COVID-19 after RT were evaluated to determine whether radiation pneumonitis had worsened compared with before RT. The serum levels of the surfactant proteins SP-A and SP-D were measured before, during, and after RT. RESULTS: The patients included in the study comprised three men (27.3%) and eight women (72.7%). The primary cancer sites were the breast (n = 7; 63.7%), lung (n = 2; 18.1%), esophagus (n = 1; 9.1%), and tongue (9.1%). COVID-19 was diagnosed before RT in four patients, during RT in two patients, and after RT in five patients. Six (54.5%) patients developed COVID-19 pneumonia. Radiation pneumonitis grade ≥2 was not identified in any patient, and radiation pneumonitis did not worsen after RT in any patient. No rapid increases or decreases in SP-A and SP-D levels occurred after the diagnosis of COVID-19 in all patients regardless of RT timing. CONCLUSIONS: COVID-19 did not appear to result in lung toxicity and surfactant protein levels did not change dramatically.

Bladder filling volume variation between the first and second day of planning computed tomography for prostate cancer radiation therapy and correlation with renal function.

AIM: During radiation therapy (RT) for prostate cancer, bladder filling helps exclude the organ from irradiation and reduces adverse effects. For RT planning, we performed computed tomography (CT) for 2 consecutive days to evaluate inter-day variations in organs such as the bladder. However, the patient factors that are associated with large intra-patient variations in bladder filling volume prior to RT are not known. METHODS: This was a retrospective study of 97 prostate cancer patients who underwent CT for 2 consecutive days for RT planning between March 2015 and March 2020 and with confirmed water intake volume before the scans. Patients consumed 500 ml of water immediately after urination and underwent CT 30 min after the start of water intake; CT was performed under similar conditions over 2 consecutive days. Patient information was collected from the medical records taken before CT. RESULTS: The median bladder filling volume was 102.8 cm3 (range: 31.7-774.0), and the median intra-patient bladder filling volume variation was 23.4 cm3 (range: 0.4-277.7). Univariate analysis revealed that the intra-patient variation was significantly larger in patients with an eGFR higher than the median (p = 0.003). No other factor showed correlations with the variation. As the larger bladder filling volume of the 2 consecutive days in patients increased (median 121.5 cm3 , range: 47.8-774.0), the intra-patient variation also increased. CONCLUSION: Patients with a higher eGFR show greater variation in bladder filling volume, and caution should be exercised when applying RT in these patients.

Radiation therapy for pelvic recurrent colorectal or gynecological cancer: is whole pelvic irradiation necessary?

BACKGROUND: Preoperative whole pelvic radiation therapy (RT) is used commonly for rectal cancer and is the standard field postoperatively in gynecological cancer. However, the ideal field (local vs. whole pelvis) has not been determined for local recurrence of these cancers. METHODS: We retrospectively reviewed the data for 52 patients who developed local tumor recurrence of rectal or gynecological cancer treated from 2013 to 2021. The initial treatment for all patients was total excision of the primary tumors without radiation therapy. Radiation therapy targets were surgical stumps, perianastomosis sites, and pelvic lymph nodes, classified according to the pelvic nodal volume atlas for radiation therapy. Patients were divided into the local recurrent tumor only radiation therapy group and the whole pelvis radiation therapy group. Whole pelvis radiation therapy included the common iliac lymph nodes or prophylactic lymph nodes below the L5/S1 junction. We recorded second recurrence after RT and the affected site(s) in each group. We also compared disease-specific survival using uni- and multivariate analyses. RESULTS: We found no significant differences between the groups regarding second recurrence or regarding the site(s) of recurrence. We also found no significant differences in disease-specific survival between the two RT groups. However, patients who did not receive chemotherapy after the initial surgery and before RT had significantly longer survival (P=0.015). CONCLUSIONS: In patients with locally recurrent rectal or gynecological cancer, we found no significant difference in second recurrence or survival between the local tumor only RT field and the whole pelvic RT field.

Isolated tuberculous liver abscess invading the abdominal wall: report of a case.

Isolated tuberculous liver parenchymal and subcapsular abscesses are unusual,^but an abdominal wall abscess secondary to a tubercular liver abscess is extremely rare. To our knowledge, there is only one reported case of an abdominal wall abscess occurring secondary to a subcapsular liver abscess. We report the first documented case of direct invasion of the abdominal wall from an isolated tuberculous liver parenchymal abscess, diagnosed by imaging, surgical, and pathological findings. Although ultrasonography and computed tomography showed nonspecific hypoechoic and hypodense findings with peripheral contrast enhancement, T2-weighted magnetic resonance imaging (MRI) revealed a heterogeneous mass with characteristic hypointensity, suggesting the presence of free radicals produced by macrophages during active phagocytosis in tuberculosis. Although our case is extremely unusual, when hypointensity on T2-weighted MRI is seen, the possibility of tuberculosis should be considered and the results of polymerase chain reaction, culture, and histopathological diagnosis must be taken into account to avoid needless invasive surgery.

Data management solution for large-volume computed tomography in an existing picture archiving and communication system (PACS).

Multidetector row computed tomography (MDCT) creates massive amounts of data, which can overload a picture archiving and communication system (PACS). To solve this problem, we designed a new data storage and image interpretation system in an existing PACS. Two MDCT image datasets, a thick- and a thin-section dataset, and a single-detector CT thick-section dataset were reconstructed. The thin-section dataset was archived in existing PACS disk space reserved for temporary storage, and the system overwrote the source data to preserve available disk space. The thick-section datasets were archived permanently. Multiplanar reformation (MPR) images were reconstructed from the stored thin-section datasets on the PACS workstation. In regular interpretations by eight radiologists during the same week, the volume of images and the times taken for interpretation of thick-section images with (246 CT examinations) or without (170 CT examinations) thin-section images were recorded, and the diagnostic usefulness of the thin-section images was evaluated. Thin-section datasets and MPR images were used in 79% and 18% of cases, respectively. The radiologists' assessments of this system were useful, though the volume of images and times taken to archive, retrieve, and interpret thick-section images together with thin-section images were significantly greater than the times taken without thin-section images. The limitations were compensated for by the usefulness of thin-section images. This data storage and image interpretation system improves the storage and availability of the thin-section datasets of MDCT and can prevent overloading problems in an existing PACS for the moment.

Association between unintentional splenic radiation and lymphopenia and high neutrophil/lymphocyte ratio after radiotherapy in patients with esophageal cancer.

BACKGROUND: Unintentional irradiation of the spleen may reduce absolute lymphocyte count (ALC), which can affect tumor immunity. Therefore, in the present study, we evaluated spleen dose-volume parameters associated with ALC and neutrophil/lymphocyte ratio (NLR) in patients with esophageal cancer. METHODS: This retrospective study evaluated patients who were diagnosed with stage I-IV esophageal cancer and who received radiotherapy at Nihon University Itabashi Hospital between January 2015 and March 2020. Spleen V5, V10, V20, and V30 and mean spleen dose, which are dose-volume histogram parameters correlated with ALC and NLR, were analyzed. RESULTS: In total, 89 esophageal cancer patients with a median age of 72 years (range, 51-92 years) were included in this research. Results showed that spleen V5, V10, and V20 and mean splenic dose were significantly correlated with a low ALC. Meanwhile, a significant association was observed between spleen V5 and V10 and a high NLR (P<0.05). In the linear regression analysis, spleen V5 and V10 were remarkably associated with a low ALC (P=0.006 and 0.008). Further, a correlation was noted between spleen V5 and a high NLR (P=0.019). Spleen V5 and V10 were remarkably associated with greater than grade 3 lymphopenia (P=0.024 and P=0.031). CONCLUSIONS: A correlation was observed between the irradiated volume of the spleen and ALC and NLR in patients with esophageal cancer. Furthermore, the spleen should be regarded as a high-risk organ, and the use of techniques in reducing spleen V5, V10 for the preservation of tumor immunity may be beneficial.

Whole-brain Radiation Therapy for Intracranial Metastases as Initial or Late Treatment.

BACKGROUND/AIM: We examined the difference between whole-brain radiation therapy (WBRT) for intracranial metastases (IM) from lung cancer as an initial and as a late treatment affecting overall survival (OS). PATIENTS AND METHODS: Thirty-three patients who presented with IM at initial examination who received WBRT as the initial treatment (initial WBRT group) and 47 patients without IM or with asymptomatic IM at initial examination who received WBRT after systemic therapy, between January 2014 and December 2020, were retrospectively analyzed. Patients' OS after WBRT were compared. RESULTS: Median OS was significantly longer in patients treated with systemic anticancer therapy after WBRT than in patients who were not (176 vs. 47 days, respectively; p<0.001), and systemic anticancer therapy after WBRT was a significant prognostic factor (p<0.001). CONCLUSION: Treatment with systemic anticancer therapy after WBRT may prolong the survival of patients who present with IM at initial examination.

Successful treatment of nonsmall cell lung cancer patients with leptomeningeal metastases using whole brain radiotherapy and tyrosine kinase inhibitors.

The efficacy of treatments in patients with nonsmall cell lung cancer (NSCLC) with leptomeningeal metastases (LMs) remains unclear. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) play an important role in the treatment of patients with NSCLC. However, few studies have investigated the efficacy of combination therapy with TKIs and whole brain radiotherapy (WBRT) in patients with NSCLC/LM. We report here the case of a male patient in his 60s with adenocarcinoma who underwent lobectomy of the right upper lobe. The cancer was classified as pT1bN1M0 Stage IIA, and a mutational analysis revealed the presence of an EGFR mutation. However, 6 months after standard chemotherapy, LM had developed and WBRT was administered. Gefitinib (250 mg/day) was administered after WBRT. The patient remained free of significant recurrent disease for 57 months after WBRT was administered. Combination therapy with TKIs and WBRT is associated with relatively long survival times in patients with LM.

A computer-assisted system for diagnostic workstations: automated bone labeling for CT images.

Although accurate information on thoracolumbar bone structure is essential when computed tomography (CT) images are examined, there is no automated method of labeling all the vertebrae and ribs on a CT scan. We are developing a computer-aided diagnosis system that labels ribs and thoracolumbar vertebrae automatically and have evaluated its accuracy. A candidate bone was extracted from the CT image volume data by pixel thresholding and connectivity analysis. All non-bony anatomical structures were removed using a linear discriminate of distribution of CT values and anatomical characteristics. The vertebrae were separated from the ribs on the basis of their distances from the centers of the vertebral bodies. Finally, the thoracic cage and lumbar vertebrae were extracted, and each vertebra was labeled with its own anatomical number by histogram analysis along the craniocaudal midline. The ribs were labeled in a similar manner, based on location data. Twenty-three cases were used for accuracy comparison between our method and the radiologist's. The automated labeling of the thoracolumbar vertebrae was concordant with the judgments of the radiologist in all cases, and all but the first and second ribs were labeled correctly. These two ribs were frequently misidentified, presumably because of pericostal anatomical clutter or high densities of contrast material in the injected veins. We are confident that this system can contribute usefully as part of a picture archiving and communication system workstation, though further technical improvement is required for identification of the upper ribs.

Risk Factors for Sacral Insufficiency Fractures in Cervical Cancer After Whole Pelvic Radiation Therapy.

AIM: To evaluate the incidence and risk factors of sacral insufficiency fractures (SIFs), particularly dose-volume histogram (DVH) parameters, in patients with cervical cancer after whole pelvic radiation therapy (WPRT). PATIENTS AND METHODS: The medical records of 61 patients with cervical cancer who underwent WPRT were retrospectively reviewed. The cumulative incidence of SIF, as well as the risk factors that could affect its incidence were assessed. RESULTS: Of the 61 patients, 11 (18%) were diagnosed with SIF, as revealed by computed tomography. Multivariate analysis revealed that abnormal body mass index (BMI) (more than 25 kg/m2 or below 18 kg/m2) and administration of five or more chemotherapy cycles were independently associated with SIF. A slight difference was observed in the D50% (the administered dose covering half of the sacrum) between patients with and those without SIF (p=0.052). CONCLUSION: Thus, the D50% of the sacrum should be particularly considered in patients with abnormal BMI and five or more cycles of chemotherapy.

Serum tumor marker levels at the development of intracranial metastasis in patients with lung or breast cancer.

BACKGROUND: Intracranial metastasis (IM) is observed in various cancers, including in lung and breast cancer, and its timely diagnosis is required for successful patient treatment. Various tumor serum markers, such as carcinoembryonic antigen (CEA), pro-gastrin-releasing peptide (ProGRP), neuron-specific enolase (NSE), and cancer antigen 15-3 (CA15-3), serve not only as prognostic indicators in lung and breast cancer but also as risk factors for IM development. This study is the first to assess a subgroup of cancer patients with IM that did not show elevated serum tumor marker levels. METHODS: This retrospective study included 53 patients with lung or breast cancer in which IM was detected by enhanced brain magnetic resonance imaging between January 2013 and December 2018. IM was classified into three types [parenchymal metastasis (PM), leptomeningeal metastasis and dural metastasis]. Serum CEA level was measured using an electrochemiluminescence immunoassay (ECLIA) or chemiluminescent immunoassay. Plasma ProGRP level was measured using a chemiluminescent enzyme immunoassay (CLEIA), and the serum NSE level was measured using ECLIA. The serum CA15-3 level was measured using CLEIA. Univariate and multivariate analyses were performed using Pearson's χ2 test and logistic regression analysis, respectively. RESULTS: Among the total 53 patients, 15 patients (28.3%) did not show elevated serum tumor marker levels. Univariate analysis showed that the patients with PM only significantly correlated with no increasing tumor marker level compared with other IM types (P=0.030), as well as female patients and patients without symptoms (P=0.010 and 0.046, respectively). Multivariate showed that the patients with PM only and female patients significantly correlated with no increasing tumor marker level (P=0.038 and 0.014, respectively). CONCLUSIONS: Our findings describe a subgroup of lung and breast cancer patients with IM that do not show elevated tumor marker levels, indicating the need for the identification of novel indicators for IM or increased monitoring of these patients.

Organizing pneumonia after thoracic radiotherapy followed by anti-PD-1 antibody treatment for patients with lung cancer: Three case reports.

Anti-PD-1 antibodies and thoracic radiation therapy (TRT) generate adverse events, including pneumonitis. However, there is limited information about potential overlapping toxicity of anti-PD-1 antibodies administered after TRT. Herein, we report three cases. The first case was of a man in his 80s with squamous cell lung cancer (cT2aN0M0 stage IB). Twelve months after TRT, tumor regrowth was observed, and the patient was administered nivolumab. Twenty-four months after TRT, computed tomography (CT) showed organizing pneumonia (OP). The second case was of a man in his 70s with squamous cell lung cancer. He underwent surgery for pT3N1M0 stage IIIA; however, mediastinum lymph node metastasis developed. Therefore, he received TRT for the mediastinum lymph node metastasis. One month after the completion of TRT, nivolumab was administered. Two months after TRT, an OP diagnosis was made. The third case was of a man in his 60s with an unknown type of lung cancer. He received TRT for cT4N2M0 stage IIIB. Fourteen months after TRT, tumor regrowth was observed, thus, nivolumab was administered. Twenty-seven months after TRT, an OP diagnosis was made. These case reports draw attention to OP after TRT and anti-PD-1 antibody administration despite low V20. Careful follow-up of such patients is advised considering synergistic adverse events.

Diameter of External Carotid Arteries in Patients With Mandibular Osteoradionecrosis.

BACKGROUND/AIM: To evaluate the association between osteoradionecrosis (ORN) of the mandible and stenosis of the external carotid artery after radiation therapy (RT) for head and neck cancer. PATIENTS AND METHODS: The computed tomography images of 42 patients (36 men, six women; median age, 64.5 years) treated with RT for head and neck cancer between January 2011 and December 2015 were reviewed. The cross-sectional diameters of the bilateral external carotid arteries were measured on contrast-enhanced images taken after completion of RT. RESULTS: Nine of the 42 included patients (21.4%) developed ORN after a median interval of 34 months from completion of RT. Univariate analysis revealed that external carotid artery diameter ≤ the median diameter was significantly associated with ORN development (p=0.008 and 0.013). In multivariate analysis, left external carotid artery diameter ≤ the median was significantly associated with ORN development (p=0.023). CONCLUSION: External carotid artery stenosis was significantly associated with ORN development.