Neoantigen Cancer Vaccine for Immunologically Cold Microsatellite-stable Colorectal Cancer

PURPOSE/OBJECTIVE(S)

Immunotherapies, such as immune checkpoint inhibitors (ICIs), have revolutionized management of some cancers but have little benefit for microsatellite-stable colorectal cancer patients (MSS-CRC). This is, in part, due to the low mutations and neoantigen expression in this immunogenically "cold" MSS-CRC. Therefore, we aim to develop novel shared neoantigen-based therapeutic cancer vaccine to reinvigorate antitumor immunity and enhance the therapeutic benefit of radiotherapy in MSS-CRC.

MATERIALS/METHODS

To identify novel highly expressed and shared neoantigens, we collected 40 match-paired adjacent normal and tumor tissues from MSS-CRC patients for WES-seq, RNA-seq, and liquid chromatography-MS/MS (LC-MS/MS). By incorporating these databases, we established Neoantigen Discovery and Validation (NeoDiva) system to identify a cluster of highly expressed and shared neoantigens derived from non-coding regions and evaluate its immunogenicity by HLA-A*11 transgenic mice. We then develop a neoantigen-based therapeutic cancer vaccine by an engineered adenovirus-associated virus (AAV) to evaluate its therapeutic efficacy in combination with radiotherapy in MSS-CRC animal model.

RESULTS

We identified a cluster of highly expressed and shared neoantigens (HLA-A*11-restricted) derived from non-coding regions. The immunogenicity of these novel neoantigens was demonstrated by HLA-A*11 transgenic mice and ex vivo stimulation. Moreover, the engineered AAV-based neoantigen cancer vaccine significantly eradicates cancer cells, prevents distant metastasis, prolong survival period in combination with radiotherapy. By flow cytometry, ELISPOT and MHC-I-tetramer assay, we demonstrated the recruitment of tumor-infiltrating lymphocytes was remarkably increased and neoantigen-specific T cell response was enhanced. Moreover, these isolated neoantigen-specific T cells can recognize cancer cells and produce IFNg to kill cancer cells.

CONCLUSION

Neoantigens identified by our NeoDiVa platform, via the combination of radiotherapy and a novel AAV vaccine delivery system, boosted antigen-specific T-cell function and improve tumor control of limnologically "cold" MSS colorectal cancer in vivo. We are in the process of obtaining an IND and initiating Phase I/II clinical trial to validate safety and efficacy of these exciting findings.

Designing Patient-Centered Health Education Materials for Radiation Dermatitis in Breast Cancer Patients: A Pilot Study and Single-Center Clinical Trial

PURPOSE/OBJECTIVE(S)

For breast cancer patients receiving radiotherapy (RT), radiation dermatitis is the most commonly experienced discomfort. However, patients usually do not participate in the design of health education materials regarding radiation dermatitis. We designed a pilot study to investigate the unmet need of breast cancer patients who would be receiving RT at our department and created a patient-centered educational video. We initiated a single-arm clinical trial to evaluate the effectiveness of the video in improving patient and their family's knowledge of radiation dermatitis, alleviating their anxiety, and helping patients improve self-care skills during RT course.

MATERIALS/METHODS

The pilot study was executed in a radiation oncology department of a tertiary medical center in Taiwan. We designed a questionnaire to explore new breast cancer patients' idea of a comprehensive pre-RT health education. Enrolled patients would fill out an electronic questionnaire during their first visit at our outpatient clinic. They were asked to select at most two of the following items they considered most important for pre-RT health education: (1) The mechanism behind RT; (2) Self-care skills for irradiated skin; (3) Activities to be avoided during RT course; (4) The toxicity grading of radiation dermatitis. Given the above information, we created a 4-minute video set in a clinical scenario of a patient receiving pre-RT health education from a nurse. A single-arm clinical trial (IRB approval number: CMUH111-REC2-121) is currently recruiting. The video was launched on YouTube (Link: https://youtu.be/O1uTXpS_ed0) to give patients easy access to the video. Enrolled patients would complete Skindex-16 survey (translated into Chinese) at 3 timepoints: during their first visit at our clinic, in the middle of RT course, and at the first post-RT follow-up visit. Cronbach's alpha test was applied to determine the internal consistency of the questionnaires.

RESULTS

The pilot study included 19 patients with an average age of 46.6 (range: 34 to 69) years old. All patients' primary language was Chinese Mandarin. Most patients (84%) received at least secondary education. We found by surprise that RTOG skin toxicity grading was considered very important for most patients (79%), while less than half (42%) found the mechanism behind RT important. The internal validity of the Chinese version of Skindex-16 was good (Cronbach's alpha score = 0.87). For the recruiting trial, we have enrolled 10 patients and planned to close the trial upon enrolling 50 participants. The study result should be available before August 2023.

CONCLUSION

We suggest to actively involve patients in designing health education materials for patient-centered care. Toxicity grading of radiation dermatitis should be included in pre-RT health education for breast cancer patients. Whether the educational video helps reduce patients' anxiety and the incidence of severe radiation dermatitis will soon be answered by our ongoing clinical trial.

Late toxicities in concurrent chemoradiotherapy using high-dose-rate intracavitary brachytherapy plus weekly cisplatin for locally advanced cervical cancer: a historical cohort comparison against two previous different treatment schemes

PURPOSE

To determine the long-term toxicity of concurrent chemoradiotherapy (CCRT), using high-dose rate intracavitary brachytherapy (HDRICB) compared to radiation (RT) alone in patients with advanced cervical cancer using a control-cohort study.

METHODS

A total of 332 cases of Stage IIB-III disease were included in this comparative study. Seventy-three patients were treated with a 3-insertion schedule and labeled group A, whereas the other 146 patients with a 4-insertion schedule became group B. One hundred and thirteen patients treated by a 4-insertion protocol with concurrent weekly cisplatin were labeled group C.

RESULTS

The cumulative rate of grade 2 or above rectal complication was 13.7% for group A, 9.6% for the group B and 15.9% for group C (p = 0.76), whereas the grade 3 to 4 non-rectal radiation-induced intestinal injury was 6.8% for group A, 6.2% for group B and 9.7% for group C (p = 0.20). Grade 2 to 4 late bladder toxicity was higher in group C, with the cumulative rate being 5.5% for group A, 4.8% for group B and 15.0% for group C (p = 0.004). The independent factor for a rectal complication was the occurrence of a bladder complication (p = 0.01, hazard ratio 3.06). The independent factors for bladder complications were the use of CCRT (p = 0.01, hazard ratio 2.08), and the occurrence of rectal complications (p = 0.02, hazard ratio 2.77).

CONCLUSIONS

When treating advanced cervical cancer, HDRICB consisting of four 6 Gy insertions and weekly cisplatin shows a trend of increasing late bladder complications. The interval between drug administration and HDRICB should be kept long enough to avoid any synergistic effect of both regimens.

Comparing the relationship of Taxol-based chemotherapy response with P-glycoprotein and lung resistance-related protein expression in non-small cell lung cancer

Our aim was to compare Taxol-based chemotherapy response of non-small cell lung cancer (NSCLC) with P-glycoprotein (Pgp) or lung resistance protein expression (LRP). Immunohistochemical analyses were performed on multiple nonconsecutive sections of the biopsy specimens to detect Pgp and LPR expressions in 40 patients with advanced NSCLC before Taxol-based chemotherapy. The chemotherapy response was evaluated by clinical and radiological methods in the third month after completion of treatment. No significant differences of prognostic factors (age, sex, body weight loss, performance status, tumor size, tumor stage, and tumor cell type) were found between the 20 patients with good and the 20 patients with poor responses. The incidence difference of positive Pgp expressions between good and poor responses was significant, however, the difference of LRP expression was not. We concluded that Taxol-based chemotherapy response of patients with NSCLC was related to Pgp but not LPR expression.

Early stage cervical cancer with negative pelvic lymph nodes: pattern of failure and complication following radical hysterectomy and adjuvant radiotherapy

PURPOSE OF INVESTIGATION

The objective was to optimize the adjuvant treatment for patients with lymph node negative cervical cancer by analyzing patterns of failure and complications following radical hysterectomy and adjuvant radiotherapy.

METHODS

From September 1992 to December 1998, 67 patients with lymph node negative uterine cervical cancer (FIGO stage distribution: 50 Ib. 17 IIa), who had undergone radical hysterectomy and postoperative adjuvant radiotherapy with a minimum of three years of follow-up were evaluated. All patients received 50-58 Gy of external radiation to the lower pelvis followed by two sessions of intravaginal brachytherapy with a prescribed dose of 7.5 Gy to the vaginal mucosa. For 21 patients with lymphovascular invasion, the initial irradiation field included the whole pelvis for 44 Gy. The data were analyzed for actuarial survival (AS), pelvic relapse-free survival (PRFS), distant metastasis-free survival (DMFS), and treatment-related complications. Multivariate analysis was performed to assess the prognostic factors.

RESULTS

The respective five-year AS, PRFS, and DMFS for the 67 patients were 79%, 93% and 87%. Multivariate analysis identified two prognostic factors for AS: bulky tumor vs non-bulky tumor (p = 0.003), positive resection margin (p = 0.03). The independent prognostic factors for DMFS was bulky tumor (p = 0.003), while lymphatic permeation showed marginal impact to DMFS (p = 0.08). The incidence of RTOG grade 1-4 rectal and non-rectal gastrointestinal complication rates were 20.9% and 19.4%, respectively. The independent prognostic factor for gastrointestinal complication was age over 60 years (p = 0.047, relative risk 4.1, 95% CI 1.2 approximately 11.7). The incidence of non-rectal gastrointestinal injury for the patients receiving whole pelvic radiation and lower pelvic radiation was 28.5% and 15.2%, respectively (p = 0.25).

CONCLUSION

For patients with lymph node negative cervical cancer following radical hysterectomy, adjuvant lower pelvic radiation appears to be effective for pelvic control. It is also imperative to intensify the strategies of adjuvant therapy for some subgroups of patients.

Comparing whole body (18)F-2-deoxyglucose positron emission tomography and technetium-99m methylene diphosphonate bone scan to detect bone metastases in patients with breast cancer

PURPOSE

At present, bone metastases are usually assessed using conventional technetium-99m methylene diphosphonate whole-body bone scan, which has a high sensitivity but a poor specificity. However, positron emission tomography with (18)F-2-deoxyglucose (FDG-PET) can offer superior spatial resolution and improved specificity. We attempted to evaluate the usefulness of FDG-PET for detecting bone metastases in breast cancer and to compare FDG-PET results with bone scan findings.

PATIENTS

The study group comprised 48 patients with biopsy-proven breast cancer and suspected of having bone metastases who underwent bone scan and FDG-PET to detect the bone metastases. The final diagnosis of bone metastases was established by operative, histopathological findings or during a clinical follow-up longer than 1 year by additional radiographs or following FDG-PET/bone scan findings showing progressive widespread bone lesions.

RESULTS

A total of 127 bone lesions including 105 metastatic and 22 benign bone lesions found by either FDG-PET or bone scan were evaluated. Using FDG-PET, 100 metastatic and 20 benign bone lesions were accurately diagnosed, and using bone scan 98 metastatic and 2 benign bone lesions were accurately diagnosed. The diagnostic sensitivity and accuracy of FDG-PET were 95.2% and 94.5%, and of bone scan were 93.3% and 78.7%, respectively.

CONCLUSIONS

Our findings suggest that FDG-PET shows a similar sensitivity and a better accuracy than bone scan for detecting bone metastases in patients with breast cancer.

Differentiating benign and malignant pulmonary lesions with FDG-PET

The purpose of this retrospective study was to evaluate the efficacy of positron emission tomography (PET) with 18F-fluoro-2-deoxyglucose (FDG) to differentiate benign from malignant pulmonary lesions. Fifty-five patients, suspected of having primary pulmonary neoplasm based on chest radiographic findings, underwent FDG-PET scanning. Pathological diagnoses were obtained in 41 patients with a total of 43 pulmonary lesions. The other 14 patients (14 lesions) were followed-up clinically for at least four months. The standard uptake value (SUV) was determined in each patient. The SUV of the 15 benign and 40 malignant pulmonary lesions were 1.60+/-0.42 and 6.14+/-2.67, respectively. If SUV was > 2.50, the pulmonary lesion was considered as a malignant pulmonary lesion. FDG-PET could correctly detect 34 true-positive and 15 true-negative pulmonary lesions. However, 6 false-positive and one-false negative pulmonary lesions were misdiagnosed by FDG-PET. The sensitivity, specificity and accuracy of FDG-PET to differentiate between benign and malignant pulmonary lesions were 94%, 71% and 86%, respectively. FDG-PET can accurately detect malignant pulmonary lesions with a high sensitivity. However, false-positive FDG-PET findings caused by some inflammatory processes may decrease its specificity.

Retrospective comparison of the AJCC 5th edition classification for nasopharyngeal carcinoma with the AJCC 4th edition: an experience in Taiwan

OBJECTIVE

The aim of this study was to compare the new AJCC 5th edition classification system for nasopharyngeal carcinoma (NPC) with the AJCC 4th edition by re-evaluating the staging of patients treated in Taiwan.

METHODS

From 1992 through 1996, 117 NPC patients without distant metastasis were treated using complete courses of radiotherapy. All patients had complete CT examinations of the nasopharynx and neck. Each patient was re-staged according to the 5th edition of the AJCC classification system. Their overall survival (OS), loco-regional relapse-free survival (LRRFS), distant metastasis-free survival (DMFS) and disease-free survival (DFS) were compared between the two staging systems, using the Kaplan-Meier method, log-rank test, Wilcoxon test and Cox proportional hazard model.

RESULTS

After a median follow-up of 58.3 months, the 5-year OS for stage I, II, III and IV was 88, 86, 61 and 48%, respectively, according to the new staging. A more even distribution of patients was noted among the patients classified according to the AJCC 5th edition than the 4th edition. The distribution of stages I, II, III and IV was 13.7, 37.6, 15.4 and 33.3%, respectively, using the new staging system, whereas it was 0.8, 14.5, 20.5 and 64.2%, respectively, using the old staging system. More statistically significant differences among 5th edition stages and T classifications than the 4th edition were also noted.

CONCLUSIONS

The 5th edition of the AJCC staging system appears to have a more even distribution of patients and more statistically significant differences in predicting prognosis than the 4th edition, mostly in stages and T classification.

Intra-thoracic failure pattern and survival status following 3D conformal radiotherapy for non-small cell lung cancer: a preliminary report

BACKGROUND

To study the intra-thoracic failure pattern, clinical target volume (CTV) and survival status following 3D conformal radiotherapy (3DCRT) boost for non-small cell lung cancer (NSCLC).

METHODS

From May 1994 through June 1998, 33 patients (26 male, seven female) with NSCLC were treated with a complete course of radiotherapy (RT) in our institute. Group A included 10 patients receiving radical operation and adjuvant postoperative RT. The other 23 patients (groups B and C) received definitive radiotherapy as local treatment. Among them there were seven cases as group B (stage I-II) and 16 cases as group C (stage III). Fifteen (15/33) patients received chemotherapy. The radiotherapy strategy constituted conventional AP/PA radiotherapy (RT) 19.8-45 Gy (median 39.6 Gy) plus 3DCRT boost 6-34.2 Gy (median 20 Gy). The median total tumor dose was 59.6 Gy (ranging from 39.8 to 64.8 Gy). Patients were followed up regularly (6/33) or until their death (27/33). Nineteen patients received follow-up chest computed tomography (CT). The relationship between intra-thoracic failure found by chest CT and the initial RT and boost RT fields was analyzed. Local failure was defined as one of the following: clinical disease progression, CXR progression or relapse noted by CT. The overall survival (OS) and local failure free survival (LFF) were obtained using the Kaplan-Meier method.

RESULTS

Sixteen intra-thoracic failures were noted in 15 follow-up chest CT examinations, which included nine in-field relapses, three partial in-field relapses and four out-field relapses. The 2-year OS and LFF for groups A, B and C were 78.8/59.2, 14.2/16.7 and 6.2/7.1% respectively. RTOG grade III/IV complications included one pneumothorax (RTOG grade III).

CONCLUSION

Our retrospective study showed that selective omission of contralateral mediastinal lymph node station irradiation may be appropriate in RT for NSCLC. Chest wall and pleural relapses may not be a negligible cause of intra-thoracic failure after RT for NSCLC.

The prediction of late rectal complications following the treatment of uterine cervical cancer by high-dose-rate brachytherapy

PURPOSE

This study aimed to correlate patient, treatment, and dosimetric factors with the risk of late rectal sequelae in patients with uterine cervical cancer treated with external beam radiation therapy (EBRT) and high dose rate intracavitary brachytherapy (HDRICB).

METHODS AND MATERIALS

From September 1992 to December 1995, a total of 128 patients with uterine cervical cancer, who were treated and survived more than 12 months, were evaluated. After EBRT with 40-44 Gy/20-22 Fr/4-5 weeks to the whole pelvis, the dose was boosted up to 54-58 Gy with central shielding for patients with bilateral parametria of Stage IIb or greater. HDRICB consisted of three to four insertions at doses of 5-7.2 Gy (to Point A) at intervals of 1 week. Patient and treatment factors were analyzed using logistic regression analysis and the cumulative rectal biologic equivalent dose (CRBED) was calculated.

RESULTS

After 30-75 months of follow-up (median, 43 months), 38 patients (29.7%) had late rectal sequelae. Patients who had Stage IIb-IVa disease, cumulative rectal dose (external RT + total ICRU rectal dose) greeater than 65 Gy, or age greater than 70 years had a high risk of developing late rectal sequelae. When 110 Gy was used as the cut-off value, 19.6% (10 of 51) of patients whose CRBED was less than 110 Gy had rectal complications, while 36.4% (28/77) of patients whose CRBED was greater than 110 Gy developed rectal complications.

CONCLUSION

Risk factors of late rectal complications were advanced stage, age greater than 70 years, and cumulative rectal dose of greater than 65 Gy.

Implementation of stereotactic focal radiotherapy for intracranial arteriovenous malformations using a linear accelerator

A system of stereotactic focal radiotherapy using a linear accelerator has been developed in cooperation with a neurosurgeon. The treatment is delivered using a carefully calibrated 10 MV machine and the Cosman-Roberts-Wells (CRW) system. The precision of the method as well as its quality assurance is described. Eight patients with intracranial arteriovenous malformations (AVM) received irradiation from August 1990 to November 1991. The prescribed dose at the periphery of the AVM was 8 Gy per session, with six patients receiving two sessions and two patients receiving one session. The field size, encompassing the 90% isodose, ranged from 20 mm to 35 mm. In four patients, follow-up angiography was performed one year after the full course of therapy; total obliteration of the AVM was noted in three (75%) with a partial response in the other. In the other four patients, follow-up angiography was not performed; one patient, who had only one session of irradiation, experienced rebleeding six months later and died, and the other three patients had no further episodes of bleeding during their follow-up of 28, 18 and 14 months, respectively. Linear accelerator-based stereotactic focal radiotherapy can attain a precisely defined and reproducible dose distribution. The effects of this treatment may take one to two years to develop. Our preliminary study suggests that it is an effective alternative treatment for surgically inaccessible lesions. Patients with a small cavernous sinus dural AVM appear to have a better and more rapid response.

[Implementation of stereotactic focal radiotherapy using 10 MV x-ray]

Stereotactic focal irradiation is also called stereotactic radiosurgery by some neurosurgeons. This irradiation is used for the treatment of brain AVM (arterio-venous malformation) and small tumor. Application of stereotactic focal irradiation was developed with CRW (Cosman-Roberts-Wells) stereotactic device and two dimensional (2D) computer treatment planning system using 10 MV x-ray from a linear accelerator. This process of irradiation includes: (a) Identification and localization of a target volume in CRW stereotactic frame by CT scan or angiography. (b) To verify the alignment, a linear accelerator was used as a simulator to take portal films in anterior and lateral views. This was done to ascertain the angles between arc therapy, to encompass the target volume, and to exclude the critical organs such as lens at 0 degrees, 45 degrees, 90 degrees and 315 degrees couch angles. (c) A 2D computer treatment planning system was used to generate an isodose curve distribution for each couch angle. Then this was used to calculate the monitor unit per degree for rotation treatment. (d) 10 MV x-ray was used to implement the stereotactic focal radiotherapy.

Occurrence of nasopharyngeal carcinoma in aboriginals of Taiwan: report of 14 cases

The authors describe the rare occurrence of nasopharyngeal carcinoma (NPC) in 14 aboriginals of Taiwan (ABT), a minor ethnic group now accounting for less than 2% of the total population in Taiwan. The observation is epidemiologically unusual, representing a low-risk ethnic group in an NPC prevalent area. With regard to patient characteristics, symptomatology and pathology, we have not found any appreciable differences in reports from other geographic areas. Serological profiles of antiEBV-VCA (Epstein-Barr virus, viral capsid antigen) antibody in 7/9 patients available for review of IgA and 5/7 patients available for review of IgG were found significantly elevated, ranging respectively from 1:40-640/1:160-1280. Interestingly, 12 of the 14 patients were found to be exclusively from the Paiwan tribe residing in Pintung, a district in southern Taiwan. Since the exact prevalence of NPC in this minority remains unknown, it is not clear whether the apparent preponderance is real or merely causal due in part to geographic bias. To a lesser extent, however, our observations indicate that NPC is not an uncommon malignancy in Paiwan aboriginals of southern Taiwan.