We published in May 10, 2022 a retrospective cohort study comparing the post-radiotherapy (post-RT) hemoglobin levels between patients with breast cancer who underwent intensity-modulated radiotherapy (IMRT) and those who underwent three-dimensional conformal radiotherapy (3D-CRT) in the Radiation Oncology Section of the Department of Radiological and Imaging Sciences of Southern Philippines Medical Center (ROS DORIS-SPMC) from October 2018 to March 2019. It came to our knowledge that the IMRT planning that was done on the patients included in our study was different from the IMRT planning that is currently being done since late 2020. Prior to late 2020, ROS DORIS-SPMC had been implementing forward-planned IMRT, wherein the weight of the multileaf collimator (MLC) segment was preselected at fixed values. In late 2020, ROS DORIS-SPMC started implementing inverse-planned IMRT, wherein the appropriate weights of the MLC segments are determined by an inverse optimization algorithm that creates a more uniform dose distribution throughout the target. Inverse-planned IMRT improves the dose homogeneity within the entire 3D-breast volume, while forward-planned IMRT mainly improves the dose distribution on the inframammary fold.1 Compared to 3D-CRT, however, forward-planned IMRT improves target homogeneity, albeit to a lesser degree than the homogeneity produced by the inverse technique.2 In the original article, we also stated that, for both IMRT and 3D-CRT, each dose fraction is given weekly within a span of 7 to 8 months. We recently confirmed that, among patients with breast cancer, each dose fraction of IMRT or 3D-CRT is given daily within a span of 33 days—28 days for conventional dose and 5 days for boost dose. In this corrigendum, we specify that the IMRT protocol used among the patients in our study was forward-planned IMRT, with all dose fractions given daily for 33 consecutive workdays, excluding weekends and holidays. We also describe here the original statements that we changed or removed because they have become irrelevant in light of the corrections. The table below shows the list of corrections.
Radiotherapy, Intensity-Modulated ; Radiotherapy, Conformal

PURPOSE: To evaluate the results of hypofractionated radiotherapy (HFX) for early glottic cancer. MATERIALS AND METHODS: Eighty-five patients with cT1-2N0M0 squamous cell carcinoma of the glottis who had undergone HFX, performed using intensity-modulated radiotherapy (IMRT, n = 66) and three-dimensional conformal radiotherapy (3D CRT, n = 19) were analyzed. For all patients, radiotherapy was administered at 60.75 Gy in 27 fractions. Forty-three patients received a simultaneous integrated boost (SIB) of 2.3–2.5 Gy per tumor fraction. RESULTS: The median follow-up duration was 29.9 months (range, 5.5 to 76.5 months). All patients achieved complete remission at a median of 50 days after the end of radiotherapy (range, 14 to 206 days). The 5-year rates for locoregional recurrence-free survival was 88.1%, and the 5-year overall survival rate was 86.2%. T2 stage was a prognostic factor for locoregional recurrence-free survival after radiotherapy (p = 0.002). SIB for the tumor did not affect disease control and survival (p = 0.191 and p = 0.387, respectively). No patients experienced acute or chronic toxicities of ≥grade 3. IMRT significantly decreased the dose administered to the carotid artery as opposed to 3D CRT (V₃₅, p < 0.001; V₅₀, p < 0.001). CONCLUSIONS: Patients treated with HFX achieved acceptable locoregional disease control rates and overall survival rates compared with previous HFX studies. A fraction size of 2.25 Gy provided good disease control regardless of SIB administration.
Carcinoma, Squamous Cell ; Carotid Arteries ; Follow-Up Studies ; Glottis ; Humans ; Radiotherapy ; Radiotherapy, Conformal ; Radiotherapy, Intensity-Modulated ; Retrospective Studies ; Survival Rate

PURPOSE: Thoracic re-irradiation (re-RT) of lung cancer has been challenged by the tolerance doses of normal tissues. We retrospectively analyzed local control, overall survival (OS) and toxicity after thoracic re-RT using highly conformal radiotherapy, such as intensity modulated radiotherapy and stereotactic body radiotherapy. MATERIALS AND METHODS: Thirty-one patients who received high-dose thoracic re-RT were analyzed. Doses were recalculated to determine biologically equivalent doses. The median interval to re-RT was 15.1 months (range, 4.4 to 56.3 months), the median initial dose was 79.2 Gy₁₀ (range, 51.75 to 150 Gy₁₀), and the median re-RT dose was 68.8 Gy₁₀ (range, 43.2 to 132 Gy₁₀). RESULTS: Eighteen (58.1%) and eleven (35.5%) patients showed loco-regional recurrence and distant metastasis, respectively, after 17.4 months of median follow-up. The 1-year and 2-year local control rates were 60.2% and 43.7%, respectively. The median loco-regional recurrence-free-survival (LRFS) was 15.4 months, and the median OS was 20.4 months. The cumulative and re-RT biologically equivalent dose for α/β=10 (BED₁₀) doses were the most significant prognostic factors. Cumulative BED₁₀ ≥145 Gy₁₀ and re-RT BED₁₀≥68.7 Gy₁₀ were significantly associated with longer OS (p=0.029 and p=0.012, respectively) and LRFS (p=0.003 and p=0.000, respectively). The most frequent acute toxicity was grade 1-2 pulmonary toxicity (41.9%). No acute grade 3 or higher toxicities occurred. CONCLUSION: Our results show that high-dose thoracic re-RT of lung cancer can be safely delivered using highly conformal radiotherapy with favorable survival and acceptable toxicity. An optimal strategy to select patients who would benefit from re-RT is crucial in extending the indications and improving the efficacy with a sufficiently high dose.
Follow-Up Studies ; Humans ; Lung Neoplasms ; Lung ; Neoplasm Metastasis ; Radiosurgery ; Radiotherapy ; Radiotherapy, Conformal ; Re-Irradiation ; Recurrence ; Retrospective Studies

PURPOSE: There is limited data on radiotherapy (RT) for hepatocellular carcinoma (HCC) in patients with Child-Pugh classification B (CP-B). This study aimed to evaluate the treatment outcomes of fractionated conformal RT in HCC patients with CP-B. MATERIALS AND METHODS: We retrospectively reviewed the data of HCC patients with CP-B treated with RT between 2009 and 2014 at 13 institutions in Korea. HCC was diagnosed by the Korea guideline of 2009, and modern RT techniques were applied. Fraction size was ≤ 5 Gy and the biologically effective dose (BED) ≥ 40 Gy₁₀ (α/β = 10 Gy). A total of 184 patients were included in this study. RESULTS: Initial CP score was seven in 62.0% of patients, eight in 31.0%, and nine in 7.0%. Portal vein tumor thrombosis was present in 66.3% of patients. The BED ranged from 40.4 to 89.6 Gy₁₀ (median, 56.0 Gy₁₀). After RT completion, 48.4% of patients underwent additional treatment. The median overall survival (OS) was 9.4 months. The local progression-free survival and OS rates at 1 year were 58.9% and 39.8%, respectively. In the multivariate analysis, non-classic radiation-induced liver disease (RILD) (p < 0.001) and additional treatment (p < 0.001) were the most significant prognostic factors of OS. Among 132 evaluable patients without progressive disease, 19.7% experienced non-classic RILD. Normal liver volume was the most predictive dosimetric parameter of non-classic RILD. CONCLUSION: Fractionated conformal RT showed favorable OS with a moderate risk non-classic RILD. The individual radiotherapy for CP-B could be cautiously applied weighing the survival benefits and the RILD risks.
Carcinoma, Hepatocellular ; Classification ; Disease-Free Survival ; Humans ; Korea ; Liver ; Liver Diseases ; Multivariate Analysis ; Portal Vein ; Radiotherapy ; Radiotherapy, Conformal ; Retrospective Studies ; Thrombosis ; Treatment Outcome

PURPOSE: This study was conducted to compare the outcome of three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) for the postoperative treatment of biliary tract cancer.MATERIALS AND METHODS: From February 2008 to June 2016, 57 patients of biliary tract cancer treated with curative surgery followed by postoperative 3D-CRT (n = 27) or IMRT (n = 30) were retrospectively enrolled.RESULTS: Median follow-up time was 23.6 months (range, 5.2 to 97.6 months) for all patients and 38.4 months (range, 27.0 to 89.2 months) for survivors. Two-year recurrence-free survival is higher in IMRT arm than 3D-CRT arm with a marginal significance (25.9% vs. 47.4%; p = 0.088). Locoregional recurrence-free survival (64.3% vs. 81.7%; p = 0.122) and distant metastasis-free survival (40.3% vs. 55.8%; p = 0.234) at two years did not show any statistical difference between two radiation modalities. In the multivariate analysis, extrahepatic cholangiocarcinoma, poorly-differentiated histologic grade, and higher stage were significant poor prognostic factors for survival. Severe treatment-related toxicity was not significantly different between two arms.CONCLUSIONS: IMRT showed comparable results with 3D-CRT in terms of recurrence, and survival, and radiotherapy toxicity for the postoperative treatment of biliary tract cancer.
Arm ; Biliary Tract Neoplasms ; Biliary Tract ; Cholangiocarcinoma ; Follow-Up Studies ; Humans ; Multivariate Analysis ; Radiotherapy ; Radiotherapy, Conformal ; Radiotherapy, Intensity-Modulated ; Recurrence ; Retrospective Studies ; Survivors

PURPOSE: To investigate the differences in treatment outcomes between two radiation techniques, intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT).MATERIALS AND METHODS: We retrospectively analyzed 160 (IMRT = 23, 3DCRT = 137) patients with stage I glottic cancer treated from January 2005 through December 2016. The IMRT was performed with TomoTherapy (16 patients), volumetric-modulated arc therapy (6 patients), and step-and-shoot technique (1 patient), respectively. The 3DCRT was performed with bilateral parallel opposing fields. The median follow-up duration was 30 months (range, 31 to 42 months) in the IMRT group and 65 months (range, 20 to 143 months) in the 3DCRT group.RESULTS: The 5-year overall survival and 3-year local control rates of the 160 patients were 95.7% and 91.4%, respectively. There was no significant difference in 3-year local control rates between the IMRT and 3DCRT groups (94.4% vs. 91.0%; p = 0.587). Thirteen of 137 patients in the 3DCRT group had recurrences. In the IMRT group, one patient had a recurrence at the true vocal cord. Patients treated with IMRT had less grade 2 skin reaction than the 3DCRT group, but this had no statistical significance (4.3% vs. 21.2%; p = 0.080).CONCLUSION: IMRT had comparable outcomes with 3DCRT, and a trend of less acute skin reaction in stage I glottic cancer patients
Follow-Up Studies ; Glottis ; Humans ; Laryngeal Neoplasms ; Radiotherapy, Conformal ; Radiotherapy, Intensity-Modulated ; Recurrence ; Retrospective Studies ; Skin ; Vocal Cords

PURPOSE: The objective of this study was to compare dosimetric characteristics of three-dimensional conformal radiotherapy (3D-CRT) and two types of intensity-modulated radiotherapy (IMRT) which are step-and-shoot intensity modulated radiotherapy (s-IMRT) and modulated arc therapy (mARC) for thoracic esophageal cancer and analyze whether IMRT could reduce organ-at-risk (OAR) dose. MATERIALS AND METHODS: We performed 3D-CRT, s-IMRT, and mARC planning for ten patients with thoracic esophageal cancer. The dose-volume histogram for each plan was extracted and the mean dose and clinically significant parameters were analyzed. RESULTS: Analysis of target coverage showed that the conformity index (CI) and conformation number (CN) in mARC were superior to the other two plans (CI, p = 0.050; CN, p = 0.042). For the comparison of OAR, lung V5 was lowest in s-IMRT, followed by 3D-CRT, and mARC (p = 0.033). s-IMRT and mARC had lower values than 3D-CRT for heart V30 (p = 0.039), V40 (p = 0.040), and V50 (p = 0.032). CONCLUSION: Effective conservation of the lung and heart in thoracic esophageal cancer could be expected when using s-IMRT. The mARC was lower in lung V10, V20, and V30 than in 3D-CRT, but could not be proven superior in lung V5. In conclusion, low-dose exposure to the lung and heart were expected to be lower in s-IMRT, reducing complications such as radiation pneumonitis or heart-related toxicities.
Esophageal Neoplasms ; Heart ; Humans ; Lung ; Radiation Pneumonitis ; Radiotherapy ; Radiotherapy, Conformal ; Radiotherapy, Intensity-Modulated

PURPOSE: This study aimed to assess complications and outcomes of a new approach, that is, combining short course radiotherapy (SRT), concurrent and consolidative chemotherapies, and delayed surgery. MATERIALS AND METHODS: In this single arm phase II prospective clinical trial, patients with T3-4 or N+ M0 rectal adenocarcinoma were enrolled. Patients who received induction chemotherapy or previous pelvic radiotherapy were excluded. Study protocol consisted of three-dimensional conformal SRT (25 Gy in 5 fractions in 1 week) with concurrent and consolidation chemotherapies including capecitabine and oxaliplatin. Total mesorectal excision was done at least 8 weeks after the last fraction of radiotherapy. Primary outcome was complete pathologic response and secondary outcomes were treatment related complications. RESULTS: Thirty-three patients completed the planned preoperative chemoradiation and 26 of them underwent surgery (24 low anterior resection and 2 abdominoperineal resection). Acute proctitis grades 2 and 3 were seen in 11 (33.3%) and 7 (21.2%) patients, respectively. There were no grades 3 and 4 subacute hematologic and non-hematologic (genitourinary and peripheral neuropathy) toxicities and perioperative morbidities such as anastomose leakage. Grade 2 or higher late toxicities were observed among 29.6% of the patients. Complete pathologic response was achieved in 8 (30.8%) patients who underwent surgery. The 3-year overall survival and local control rates were 65% and 94%, respectively. CONCLUSION: This study showed that SRT combined with concurrent and consolidation chemotherapies followed by delayed surgery is not only feasible and tolerable without significant toxicity but also, associated with promising complete pathologic response rates.
Adenocarcinoma ; Antineoplastic Combined Chemotherapy Protocols ; Arm ; Capecitabine ; Combined Modality Therapy ; Consolidation Chemotherapy ; Drug Therapy ; Humans ; Induction Chemotherapy ; Iran ; Proctitis ; Prospective Studies ; Radiotherapy ; Radiotherapy, Conformal ; Rectal Neoplasms

Intensity-modulated radiation therapy (IMRT) has been considered the most successful development in radiation oncology since the introduction of computed tomography into treatment planning that enabled three-dimensional conformal radiotherapy in 1980s. More than three decades have passed since the concept of inverse planning was first introduced in 1982, and IMRT has become the most important and common modality in radiation therapy. This review will present developments in inverse IMRT treatment planning and IMRT delivery using multileaf collimators, along with the associated key concepts. Other relevant issues and future perspectives are also presented.
Radiation Oncology ; Radiotherapy, Conformal

PURPOSE: Anaplastic thyroid cancer (ATC) is a rare tumor with a lethal clinical course despite aggressive multimodal therapy. Intensity-modulated radiotherapy (IMRT) may achieve a good therapeutic outcome in ATC patients, and the role of IMRT should be assessed. We retrospectively reviewed outcomes for ATC treated with three-dimensional conformal radiotherapy (3D-CRT) or IMRT to determine the optimal treatment option and explore the role of radiotherapy (RT). MATERIALS AND METHODS: Between December 2000 and December 2015, 41 patients with pathologically proven ATC received RT with a sufficient dose of ≥40 Gy. Among them, 21 patients (51%) underwent surgery before RT. Twenty-eight patients received IMRT, and 13 received 3D-CRT. Overall survival (OS) and progression-free survival (PFS), patterns of failure, and toxicity were examined. RESULTS: The median follow-up time for survivors was 38.0 months. The median and 1-year OS and PFS rates were 7.2 months and 29%, 4.5 months and 15%, respectively. Surgery significantly improved the prognosis (median OS: 10.7 vs. 3.9 months, p = 0.001; median PFS: 5.9 vs. 2.5 months, p = 0.007). IMRT showed significantly better PFS and OS than 3D-CRT, even in multivariate analysis (OS: hazard ratio [HR] = 0.30, p = 0.005; PFS: HR = 0.33, p = 0.005). Significantly higher radiation dose could be delivered with IMRT than 3D-CRT (EQD210 66 vs. 60 Gy, p = 0.005). Only 2 patients had grade III dermatitis after IMRT. No other severe toxicity ≥grade III occurred. CONCLUSION: Patients with ATC showed better prognosis through multimodal treatment. Furthermore, IMRT could achieve favorable survival rates by safely delivering higher dose than 3D-CRT.
Combined Modality Therapy ; Dermatitis ; Disease-Free Survival ; Follow-Up Studies ; Humans ; Multivariate Analysis ; Prognosis ; Radiotherapy ; Radiotherapy, Conformal ; Radiotherapy, Intensity-Modulated ; Retrospective Studies ; Survival Rate ; Survivors ; Thyroid Carcinoma, Anaplastic