The Diagnosis and Treatment Approach for Oligo-Recurrent and Oligo-Progressive Renal Cell Carcinoma.

One-third of renal cell carcinomas (RCCs) without metastases develop metastatic disease after extirpative surgery for the primary tumors. The majority of metastatic RCC cases, along with treated primary lesions, involve limited lesions termed "oligo-recurrent" disease. The role of metastasis-directed therapy (MDT), including stereotactic body radiation therapy (SBRT) and metastasectomy, in the treatment of oligo-recurrent RCC has evolved. Although the surgical resection of all lesions alone can have a curative intent, SBRT is a valuable treatment option, especially for patients concurrently receiving systemic therapy. Contemporary immune checkpoint inhibitor (ICI) combination therapies remain central to the management of metastatic RCC. However, one objective of MDT is to delay the initiation of systemic therapies, thereby sparing patients from potentially unnecessary burdens. Undertaking MDT for cases showing progression under systemic therapies, known as "oligo-progression", can be complex in considering the treatment approach. Its efficacy may be diminished compared to patients with stable disease. SBRT combined with ICI can be a promising treatment for these cases because radiation therapy has been shown to affect the tumor microenvironment and areas beyond the irradiated sites. This may enhance the efficacy of ICIs, although their efficacy has only been demonstrated in clinical trials.

A multi-institutional survey of the quality of life after treatment for uterine cervical cancer: a comparison between radical radiotherapy and surgery in Japan.

This study aimed to research the post-treatment quality of life (QOL) between radiotherapy (RT)- and operation (OP)-treated early cervical cancer survivors, using separate questionnaires for physicians and patients. We administered an observational questionnaire to patients aged 20-70 years old with Stages IB1-IIB cervical cancer who had undergone RT or OP and without recurrence as outpatients for ≥6 months after treatment. We divided 100 registered patients equally into two treatment groups (n = 50 each). The average age was 53 and 44 years in the RT and OP groups, respectively. The RT group included 34 and 66% Stage I and II patients, respectively, whereas the OP group included 66 and 34% Stage I and II patients, respectively. The OP group included 58% of patients with postoperative RT. Combination chemotherapy was performed in 84 and 48% of patients in the RT and OP groups, respectively. On the physicians' questionnaire, we observed significant differences in bone marrow suppression (RT) and leg edema (OP). On the patients' questionnaire, significantly more patients had dysuria and leg edema in the OP group than in the RT group, and severe (Score 4-5) leg edema was significantly higher in the post-operative RT group than in the OP only group. The frequency of sexual intercourse decreased after treatment in both groups. On the patients' questionnaire, there were no significant differences between the two groups regarding sexual activity. These findings are useful to patients and physicians for shared decision-making in treatment choices. The guidance of everyday life and health information including sexual life after treatment is important.

Factors related to primary cancer death and non-primary cancer death in patients treated with stereotactic body radiotherapy for pulmonary oligometastases.

Cancer-specific death (CSD) and non-cancer-specific death (non-CSD) after stereotactic body radiotherapy (SBRT) for pulmonary oligometastases have not been studied in detail. The aim of this study was to determine the cumulative incidences of CSD and non-CSD and to reveal prognostic factors. Data from a large survey of SBRT for pulmonary oligometastases were used for analyses, and patients with unknown cause of death were excluded from current analyses. CSD was primary cancer death and non-CSD was non-primary cancer death including a series of cancer treatment-related deaths. Cumulative incidences were calculated using the Kaplan-Meier method and a stratified Cox regression model was used for multivariate analyses (MVA). Fifty-two patients with an unknown death were excluded and a total of 1326 patients was selected. CSD and non-CSD occurred in 375 and 109 patients, respectively. The median OS period was 53.2 months and the cumulative incidences of 1-, 3-, and 5-year CSD vs. non-CSD rates were 6.5% vs. 2.3%, 29.5% vs. 8.6%, and 41.2% vs. 11.0%, respectively. In MVA, the incidence of CSD was related to performance status (1 vs. 0; p < 0.001, 2-3 vs. 0; p = 0.011), oligometastatic state (sync-oligometastases vs. oligo-recurrence, p = 0.026) and maximum tumor diameter (p = 0.009), and the incidence of non-CSD was related to age (p = 0.001), sex (p = 0.030), performance status (2-3 vs. 0; p = 0.002), and irradiated tumor-located lung lobe (left lower lobe vs. other lobes, p = 0.036). CSD was main cause of death, but non-CSD was not rare after SBRT. Prognostic factors for CSD and non-CSD were different, and an understanding of the factors would help in treatment.

Analyses of the local control of pulmonary Oligometastases after stereotactic body radiotherapy and the impact of local control on survival.

BACKGROUND: Successful local therapy for oligometastases may lead to longer survival. The purpose of this multicentre retrospective study was to investigate factors affecting the local control (LC) of pulmonary oligometastases treated by stereotactic body radiotherapy (SBRT) and to investigate the impact of LC on survival. METHODS: The inclusion criteria included 1 to 5 metastases, the primary lesion and other extrathoracic metastases were controlled before SBRT, and the biological effective dose (BED10) of the SBRT was 75 Gy or more. The Cox proportional hazards model was used for analyses. RESULTS: Data of 1378 patients with 1547 tumours from 68 institutions were analysed. The median follow-up period was 24.2 months. The one-year, 3-year and 5-year LC rates were 92.1, 81.3 and 78.6%, respectively, and the 1-year, 3-year and 5-year overall survival rates were 90.1, 60.3 and 45.5%, respectively. Multivariate analysis for LC showed that increased maximum tumour diameter (p = 0.011), type A dose calculation algorithm (p = 0.005), shorter overall treatment time of SBRT (p = 0.035) and colorectal primary origin (p < 0.001 excluding oesophagus origin) were significantly associated with a lower LC rate. In the survival analysis, local failure (p < 0.001), worse performance status (1 vs. 0, p = 0.013; 2-3 vs. 0, p < 0.001), oesophageal primary origin (vs. colorectal origin, p = 0.038), squamous cell carcinoma (vs. adenocarcinoma, p = 0.006) and increased maximum tumour diameter (p < 0.001) showed significant relationships with shorter survival. CONCLUSIONS: Several factors of oligometastases and SBRT affected LC. LC of pulmonary oligometastases by SBRT showed a significant survival benefit compared to patients with local failure.

Analyses of local control and survival after stereotactic body radiotherapy for pulmonary oligometastases from colorectal adenocarcinoma.

This study is a subset analysis of a retrospective multicenter study performed in Japan and its purpose was to investigate the effectiveness of stereotactic body radiotherapy (SBRT) for pulmonary oligometastases from colorectal cancer. Local control (LC), freedom from further metastases, relapse-free survival and overall survival (OS) after SBRT were retrospectively analyzed. The Kaplan-Meier method was used to estimate lifetime data and the log-rank test was performed as univariate analyses. The Cox proportional hazards model was applied in multivariate analyses. Data for 330 patients with 371 tumors were used for analyses. The median follow-up period was 25.0 months. The 3-year LC, freedom from further metastases, relapse-free survival and OS rates were 64.9, 34.9, 24.9 and 63.4%, respectively. The results of multivariate analyses showed that a higher LC rate was associated with no history of local therapy for oligometastases (P = 0.01), SBRT without concurrent chemotherapy (P < 0.01), type B calculation algorithm (P < 0.01) and higher biological effective radiation doses (≥115 Gy, P = 0.04). A longer OS was associated with no history of local therapy for oligometastases (P = 0.04), a more recent period of SBRT (2010-15, P = 0.02), tumor located in the upper or middle lobe (P < 0.01) and higher biological effective radiation doses (≥115 Gy, P = 0.01). In conclusion, OS after SBRT was good, but LC rate was relatively low. The use of high biological effective radiation doses can improve both LC and OS outcomes.

Significant reduction of oncologic pulmonary death by local control for pulmonary oligometastases treated with stereotactic body radiotherapy.

BACKGROUND AND PURPOSE: The rate of oncologic pulmonary death after stereotactic body radiotherapy for pulmonary oligometastases has never been reported. The purpose of current study was to investigate the rate of freedom from oncologic pulmonary death (FOPD) and to analyze factors affecting for FOPD. MATERIALS AND METHODS: The inclusion criteria for this retrospective study were that SBRT was performed between 2004 and 2015, the number of metastases was 5 or less, the primary lesion and extrathoracic metastases needed to be controlled before SBRT and a biological effective dose (BED10) of 75 Gy or more was needed. The Kaplan-Meier estimator and the log-rank test were used to calculate and compare the stratified rates of FOPD. The Cox proportional hazards model was used for multivariate analyses (MVA). Primary disease death from a non-oncologic pulmonary cause was censored in model 1 and was excluded in model 2. RESULTS: A total of 1172 patients with 1315 tumors were enrolled. During a median follow-up period of 24.5 months, oncologic pulmonary deaths accounted for 101 of 221 primary disease deaths. The 1-year, 3-year and 5-year FOPD rates in model 1 were 98.2%, 89.4% and 84.0%, respectively. MVA for FOPD revealed that local failure of the irradiated tumor, squamous cell carcinoma pathology, and chemotherapy after SBRT had significant relationships with lower FOPD rates in both model 1 and model 2. CONCLUSIONS: Successful local control of pulmonary oligometastases by SBRT contributed to a higher FOPD rate.

Stereotactic Body Radiotherapy for Pulmonary Oligometastases from Esophageal Cancer: Results and Prognostic Factors.

BACKGROUND/AIM: The aim of this multi-center retrospective study was to investigate the results of stereotactic body radiotherapy (SBRT) for pulmonary oligometastases from esophageal cancer. PATIENTS AND METHODS: Oligometastases from the esophagus were identified from a dataset of a Japanese survey. The Kaplan-Meier method and Cox regression were applied to perform analyses. RESULTS: A total of 114 patients with 132 pulmonary oligometastases were collected. The 3-year local control rate, freedom from further metastasis (FFFM) rate and overall survival (OS) rate were 70.2%, 25.3% and 37.5%, respectively. Performance status (PS) (PS 1 vs. PS 0, p<0.01), disease-free interval (p=0.03) and history of local therapy for metastasis (p=0.01) had significant relationships with FFFM and only PS was an independent prognostic factor for OS (PS 1 vs. PS 0, p=0.02; PS 2-3 vs. PS 0, p=0.04). CONCLUSION: SBRT for pulmonary oligometastases from esophageal cancer provided good local control and survival.

Pulmonary Oligometastases Treated by Stereotactic Body Radiation Therapy: A Nationwide Survey of 1,378 Patients.

AIM: This study was performed to confirm the superior overall survival (OS) after pulmonary oligo-recurrence compared to pulmonary sync-oligometastases in a large nationwide study. PATIENTS AND METHODS: Patients that met the following criteria were included: 1 to 5 lung-only metastases at the beginning of stereotactic body radiation therapy (SBRT) was performed between January 2004 and June 2015, and the biological effective dose (BED) of SBRT was 75 Gy or more. The parameters included in the analyses were age, gender, ECOG PS, primary lesion, pathology, oligoetastatic state, SBRT date, chemotherapy before SBRT, chemotherapy concurrent SBRT, chemotherapy after SBRT, maximum tumor diameter, number of metastases, field coplanarity, dose prescription, BED10, OTT of SBRT. RESULTS: In total, 1,378 patients with 1,547 tumors were enrolled. Oligo-recurrence occurred in 1,016 patients, sync-oligometastases in 118, and unclassified oligometastases in 121. The three-year OS was 64.0% for oligo-recurrence and 47.5% for sync-oligometastasis (p<0.001). In the multivariate analysis, the hazard ratio (HR) for sync-oligometastases versus oligo-recurrence was 1.601 (p=0.014). Adverse events of Grade 5 were occurred in 3 patients. CONCLUSION: This is the first nationwide to indicate that the OS of patients with pulmonary oligo-recurrence is better than that of patients with sync-oligometastases.

Oligometastases: history and future vision of breast cancer.

Oligometastases, oligo-recurrence, sync-oligometastases and metachronous oligometastases were proposed based on the spectrum theory. This review article, first, described the history of cancer theory. Second, we described the history of the concepts of oligometastases, oligo-recurrence and sync-oligometastases. Finally, we prospect future visions of breast cancer of oligometastases.

Phase II Study of Concurrent Chemoradiotheapy Using Nedaplatin for Locally Advanced Uterine Cervical Carcinoma (KGROG0501): Final Results.

AIM: This phase II study using nedaplatin evaluated the effectiveness and safely of concurrent chemoradiotherapy for locally advanced uterine cervical carcinoma. PATIENTS AND METHODS: Patients met the following eligibility criteria,: International Federation of Gynecology and Obstetrics (FIGO) stage Ib, IIa, IIb with bulky tumor (≥40 mm) or pelvic lymph node swelling (≥10 mm), in FIGO stage IIIa, IIIb or IVa. Treatment adopted external radiation therapy combined with intracavitary brachyhtherapy using weekly nedaplain at 30 mg/m2 totaling five cycles. The primary endpoint was 3-year overall survival. RESULTS: From June 2005 to May 2010, 45 eligible patients with uterine cervical carcinoma were registered. Histopathology was squamous cell carcinoma in 36 and adenocarcinoma in nine. The median follow-up period was 39 months. The 3-year overall survival rate was 73.0% (95% confidence interval=56.2-84.2%). No severe acute or late toxicities occurred. CONCLUSION: This phase II study showed external radiation therapy combined with intracavitary brachyhtherapy using weekly nedaplain to be effective and safe.

Re-irradiation for oligo-recurrence from esophageal cancer with radiotherapy history: a multi-institutional study.

BACKGROUND: Neoadjuvant chemoradiotherapy following surgery has recently become a standard therapy. The purpose of the present study was to determine the effectiveness and toxicity of re-irradiation for oligo-recurrence in lymph nodes from esophageal cancer treated by definitive radiotherapy or by surgery with additional radiotherapy. METHODS: We reviewed retrospectively 248 patients treated with (chemo)radiotherapy for oligo-recurrence in lymph nodes from esophageal cancer in five Japanese high-volume centers between 2000 and 2015. Thirty-three patients in whom re-irradiation was performed were enrolled in this study, and the results for patients in whom re-irradiation was performed were compared with the results for other patients. RESULTS: Median maximum lymph node diameter was 22 mm. Median total radiation dose was 60 Gy. The median calculated biological effective dose using the LQ model with α/ß = 10 Gy (BED10) in patients in whom re-irradiation was performed was significantly lower than the median BED10 in others. There was no different factor except for BED10, histology and irradiation field between patients with a past irradiation history and patients without a past irradiation history. The median observation period in surviving patients in whom re-irradiation was performed was 21.7 months. The 3-year overall survival rate in the 33 patients with a past irradiation history was 17.9%, with a median survival period of 16.0 months. Overall survival rate and local control rate in patients with a past irradiation history were significantly worse than those in patients without a past irradiation history (log-rank test, p = 0.016 and p = 0.0007, respectively). One patient in whom re-irradiation was performed died from treatment-related gastric hemorrhage. CONCLUSIONS: Results in the present study suggested that re-irradiation for oligo-recurrence in lymph nodes from esophageal cancer treated by definitive radiotherapy or by surgery with additional radiotherapy might be acceptable but unsatisfactory.

Dose Escalation Improves Outcome in Stereotactic Body Radiotherapy for Pulmonary Oligometastases from Colorectal Cancer.

AIM: To evaluate the efficacy of stereotactic body radiotherapy (SBRT) for pulmonary metastasis from colorectal cancer. PATIENTS AND METHODS: Data for 104 lesions from 93 patients who underwent SBRT for pulmonary oligometastases from colorectal cancer at ten Institutions were retrospectively analyzed. Toxicity was graded according to the Common Terminology Criteria for Adverse Events v4.0. RESULTS: The median calculated biological effective dose using the linear-quadratic model with α/ß of 10 Gy (BED10) was 105.6 Gy. Adjuvant chemotherapy after SBRT was performed in 47 patients. The median observation period was 28 months. The 3- and 5-year local control rates were 65.2% and 56.2%, respectively. The 3- and 5-year overall survival rates were 55.9% and 42.7%, respectively. Only two patients had grade 3 radiation pneumonitis. In multivariate analysis for local control, primary site, age, adjuvant chemotherapy after SBRT and BED10 were selected as prognostic factors. CONCLUSION: Dose escalation and adjuvant chemotherapy might improve local control in SBRT for pulmonary oligometastases from colorectal cancer.

Definitive salvage radiation therapy and chemoradiation therapy for lymph node oligo-recurrence of esophageal cancer: a Japanese multi-institutional study of 237 patients.

BACKGROUND: This study evaluated the treatment results of lymph node (LN) oligo-recurrence in esophageal cancer patients treated with salvage radiotherapy (RT) in a multi-institutional retrospective study. METHODS: Eligibility criteria for this retrospective analysis were: the primary lesion of esophageal cancer was controlled; from one to five LN recurrences; total RT dose ≥45 Gy to exclude palliative RT; without recurrence other than LN; and salvage RT for LN recurrence was given between January 2000 and April 2015. The median follow-up time for the 93 living patients was 29.6 months. RESULTS: Two hundred thirty-seven patients were matched in five hospitals. The 3-year overall survival (OS) was 37%, local control was 45%, progression-free survival was 24%, and esophageal cancer-specific survival was 42%. On univariate analysis for OS, combined chemotherapy (p = 0.000055), disease-free interval (DFI) ≥12 months (p = 0.0013), LN max diameter ≤22 mm (p = 0.0052), and Karnofsky performance status ≥80% (p = 0.030) were associated with a significantly better prognosis. On multivariate analysis, significant differences were seen for combined chemotherapy (p = 0.000018), DFI (p = 0.0027), and LN max diameter (p = 0.018). CONCLUSIONS: LN oligo-recurrence following treatment for esophageal cancer was not a terminal-stage event. Moreover, cure may be possible by chemoradiation therapy with a long DFI (≥12 months) and small size (≤22 mm).

Oligo-recurrence predicts favorable prognosis of brain-only oligometastases in patients with non-small cell lung cancer treated with stereotactic radiosurgery or stereotactic radiotherapy: a multi-institutional study of 61 subjects.

BACKGROUND: To investigate the prognostic value of oligo-recurrence in patients with brain-only oligometastases of non-small cell lung cancer (NSCLC) treated with stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT). METHODS: Patients treated with SRS or SRT for brain-only NSCLC oligometastases in 6 high-volume institutions in Japan between 1996 and 2008 were reviewed. Eligible patients met 1), 2), and 4) or 1), 3), and 4) of the following: 1) NSCLC with 1 to 4 brain metastases on magnetic resonance imaging (MRI) treated with SRS or SRT; 2) control of the primary lesions (thorax) at the time of SRS or SRT for brain metastases (patients meeting this criterion formed the oligo-recurrence group); 3) with SRS or SRT for brain metastases, concomitant treatment for active primary lesions (thorax) with curative surgery or curative stereotactic body radiotherapy (SBRT), or curative chemoradiotherapy (sync-oligometastases group); and 4) Karnofsky performance status (KPS) ≥70. RESULTS: The median overall survival (OS) of all 61 patients was 26 months (95 % CI: 17.5-34.5 months). The 2-year and 5-year overall survival rates were 60.7 and 15.7 %, respectively. Stratified by oligostatus, the sync-oligometastases group achieved a median OS of 18 months (95 % CI: 14.8-21.1 months) and a 5-year OS of 0 %, while the oligo-recurrence group achieved a median OS of 41 months (95 % CI: 27.8-54.2 months) and a 5-year OS of 18.6 %. On multivariate analysis, oligo-recurrence was the only significant independent factor related to a favorable prognosis (hazard ratio: 0.253 (95 % CI: 0.082-0.043) (p = 0.025). CONCLUSIONS: The presence of oligo-recurrence can predict a favorable prognosis of brain-only oligometastases in patients with NSCLC treated with SRS or SRT.

Lung stereotactic radiotherapy for oligometastases: comparison of oligo-recurrence and sync-oligometastases.

BACKGROUND: Oligometastases can be divided into sync-oligometastases and oligo-recurrence. The difference is whether the primary site is uncontrolled or controlled. The goal of this multicenter study was to evaluate treatment outcomes and factors affecting survival after stereotactic body radiotherapy for pulmonary oligometastases. METHODS: The information after stereotactic body radiotherapy from January 2004 to April 2014 was retrospectively collected. Ninety-six patients (65 males, 31 females) were enrolled. Ten cases (10%) were sync-oligometastases, 79 cases (82%) were oligo-recurrences and 7 (7%) were unclassified oligometastases with <6 months of disease-free interval. The median disease-free interval between initial therapy and stereotactic body radiotherapy was 24 months. The median calculated biological effective dose was 105.6 Gy. RESULTS: The median follow-up period was 32 months for survivors. The 3-year overall survival and relapse-free survival rates were 53% and 32%, respectively. No Grade 5 toxicity occurred. The median overall survival was 23.9 months for sync-oligometastases and 66.6 months for oligo-recurrence (P = 0.0029). On multivariate analysis, sync-oligometastases and multiple oligometastatic tumors were significant unfavorable factors for both overall survival and relapse-free survival. CONCLUSIONS: In stereotactic body radiotherapy for oligometastatic lung tumors, the state of oligo-recurrence has the potential of a significant prognostic factor for survival.

Stereotactic Body Radiotherapy Results for Pulmonary Oligometastases: A Two-Institution Collaborative Investigation.

AIM: The current study investigated outcomes and prognostic factors of pulmonary oligometastases at two Institutions. PATIENTS AND METHODS: SBRT (stereotactic body radiotherapy) as performed for pulmonary oligometastases from January 2004 to April 2014, and patients with a biologically effective dose (BED10) ≥ 75 Gy were registered in the study. Control of the primary tumor was not a criterion: we included both oligo-recurrence and sync-oligometastases. RESULTS: A total of 34 patients were enrolled in the study. The median overall survival was 20 months (range=1-119 months) and the 2-year overall survival rate was 65.7% [95% confidence interval (CI)=48.3-83.1%]. The two-year local control rate was 79.1% (95% CI=62.4-95.8%). Stratified by oligo status, the 2-year overall survival rate of the oligo-recurrence group was 68.5% (95% CI=50.3-86.7%), while that of the group with sync-oligometastases was 50.0% (95% CI=1.0-99.0%). These rates were significantly different (p=0.037). No grade 5 early- or late-adverse events were recognized in the current study. CONCLUSION: SBRT for pulmonary oligometastases achieved good results and there was no serious adverse event. The oligo-recurrence group, in particular, achieved fairly good results.

Treatment outcomes of patients with FIGO Stage I/II uterine cervical cancer treated with definitive radiotherapy: a multi-institutional retrospective research study.

The purpose of this study was to analyze the patterns of care and outcomes of patients with FIGO Stage I/II cervical cancer who underwent definitive radiotherapy (RT) at multiple Japanese institutions. The Japanese Radiation Oncology Study Group (JROSG) performed a questionnaire-based survey of their cervical cancer patients who were treated with definitive RT between January 2000 and December 2005. A total of 667 patients were entered in this study. Although half of the patients were considered suitable for definitive RT based on the clinical features of the tumor, about one-third of the patients were prescribed RT instead of surgery because of poor medical status. The RT schedule most frequently utilized was whole-pelvic field irradiation (WP) of 30 Gy/15 fractions followed by WP with midline block of 20 Gy/10 fractions, and high-dose-rate intracavitary brachytherapy (HDR-ICBT) of 24 Gy/4 fractions prescribed at point A. Chemotherapy was administered to 306 patients (46%). The most frequent regimen contained cisplatin (CDDP). The median follow-up time for all patients was 65 months (range, 2-135 months). The 5-year overall survival (OS), pelvic control (PC) and disease-free survival (DFS) rates for all patients were 78%, 90% and 69%, respectively. Tumor diameter and nodal status were significant prognostic indicators for OS, PC and DFS. Chemotherapy has potential for improving the OS and DFS of patients with bulky tumors, but not for non-bulky tumors. This study found that definitive RT for patients with Stage I/II cervical cancer achieved good survival outcomes.

Oligo-Recurrence of Osteosarcoma Patients: Treatment Strategies for Pulmonary Metastases.

BACKGROUND: Distant metastases from osteosarcoma most commonly occur in the lungs. Osteosarcoma can be cured by complete surgical resection of all metastatic lesions if the number is limited (oligo-recurrence: ≤ 5 metastatic or recurrent lesions with controlled primary lesions). This study aimed to clarify the prognostic factors for osteosarcoma patients with pulmonary metastasis and determine their oligo-recurrence status. METHODS: Patients with conventional osteosarcoma who underwent definitive surgery for the primary lesion and at least one thoracotomy for pulmonary metastases were recruited to this retrospective study. Clinicopathological information was collected on each thoracotomy from 1976 to 2011, and was then analyzed statistically. We counted the number of resected nodules that were pathologically confirmed as metastatic lesions from osteosarcoma. RESULTS: In total, 151 thoracotomies in 71 patients were analyzed. Forty-seven patients (66 %) underwent up to two thoracotomies, and the maximum number of thoracotomies was six. The median number of resected nodules on each thoracotomy was two, and the median total size of metastatic lesions was 20 mm. Incomplete surgical remission [relative risk (RR) 3.42], a less than 1-year interval from a previous thoracotomy (RR 1.97), more than three resected nodules (RR 2.42); and total size of more than 30 mm for pulmonary metastases (RR 2.19) were independent predictors of increased risk of tumor death by multivariate analysis. CONCLUSIONS: We propose that factors contributing to oligo-recurrence of patients with pulmonary metastatic osteosarcoma include complete surgical remission, an interval from a previous thoracotomy, number of resected nodules, and total size of pulmonary metastases.