Risk Factors for Symptomatic Radiation Pneumonitis after Stereotactic Body Radiotherapy (SBRT) for Early-Stage Lung Cancer

PURPOSE/OBJECTIVE(S)

To identify risk factors for symptomatic radiation pneumonitis (RP) after stereotactic body radiotherapy (SBRT) in patients with early-stage lung cancer.

MATERIALS/METHODS

We reviewed patients with clinical stage IA1-IIA non-small cell lung cancer treated by SBRT in our institution. The primary endpoint was grade ≥ 2 RP. To evaluate the relationship between clinical risk factors and grade ≥ 2 RP, the Gray test was used for univariate analysis and the Fine-Gray model for multivariate analysis. Dose parameters were univariate analyzed using the Fine-Gray model. Optimal thresholds for dose parameters were tested using receiver operating characteristic (ROC) curves.

RESULTS

Among a total of 244 patients analyzed. The median age of patients was 77 years. The median follow-up period was 48 months. The 4-year cumulative incidence of grade ≥ 2 RP was 15.3% for all patients. In univariate analysis, tumor size (p = 0.01), central tumor (p < 0.001), interstitial pneumonia (p = 0.002), biological effective dose (BED, α/β ratio of 10 Gy) (p = 0.017), lung volume (%) receiving at least 8 Gy (V8) (p = 0.012), V10 (p = 0.011), V20 (p = 0.022) and mean lung dose (MLD) (p = 0.014) were significantly associated with the risk of grade ≥ 2 RP. In multivariate analysis, central tumor (hazard ratio [HR], 3.77; 95% confidence interval [CI], 1.88-7.55; p < 0.001) and interstitial pneumonia (HR, 4.88; 95% CI, 1.77-13.43; p = 0.002) were significantly associated with the risk of grade ≥ 2 RP. ROC curve analysis showed that the optimal diagnostic thresholds for lung V8, V10, V20, and MLD were 19.5% (the area under the curve [AUC]-0.629), 16.7% (AUC-0.629), 7.9% (AUC-0.621), and 5.2 Gy (AUC-0.623). The incidence of RP2 was found to be significantly high for values higher than the ROC threshold. The 4-year cumulative incidence of grade ≥ 2 RP in the V10 ≤ 16.7% vs V10 > 16.7% groups were 10% vs. 27% (p = 0.0013).

CONCLUSION

Central tumor and interstitial pneumonia were significant risk factors for RP2 after SBRT. We recommend that lung V10 be kept below 16.7%.

Dosimetric Comparison of Automated Non-Coplanar Volumetric-Modulated Arc Therapy and Intensity-Modulated Proton Therapy in Angiosarcoma of the Scalp

PURPOSE/OBJECTIVE(S)

Angiosarcoma of the scalp (AS) is a rare tumor and has often been treated by total scalp irradiation (TSI). TSI is a challenging technique because of the target close to the organs at risks (OARs), located in the skin surface, and helmet-shape of the target. We performed the dosimetric comparison of automated non-coplanar volumetric-modulated arc therapy (HA) and intensity-modulated proton therapy (IMPT) in TSI for AS.

MATERIALS/METHODS

A planning study was performed on 20 patients with AS. The clinical target volume (CTV) 1 and CTV2 were defined as gross tumor volume with margin and entire scalp, respectively. For HA, planning target volume (PTV) 1 and PTV2 were defined as CTV1 and CTV2 with 5-mm margins, respectively. For IMPT, robust optimization was utilized which accounted for a 5-mm setup and a 3.5% range uncertainty and dose was prescribed to CTV1 robust and CTV2 robust. The prescription doses were 70 Gy and 56 Gy in 35 fractions to PTV1 (CTV1 robust) and PTV2 (CTV2 robust), respectively, using the simultaneous integrated boost technique. The HA plan was performed using a 6-MV photon beam machine and a 1-cm thick virtual bolus. The HA plan included three half non-coplanar and one full coplanar arc fields. The HA plan used collimator angles of 15°, 60°, 15°, and 120° in the beam with couch rotations of 0°, 45°, 90°, and 315°, respectively. The IMPT plan was performed using a compact proton beam machine dedicated to pencil beam scanning. The IMPT plan used gantry angles of 70°, 150°, 70°, 150°, and 30° in the beam with couch rotations of 0°, 0°, 180°, 180°, and 270°, respectively. The IMPT plan was optimized assuming a relative biological effectiveness of 1.1. The dose distribution and dosimetric parameters for each plan were evaluated.

RESULTS

All plans met the goals within the acceptable range in target volume coverage, conformity, and homogeneity. Table shows the dosimetric parameters of OARs in HA and IMPT plans. The doses receiving 0.1 cc of the volume for hippocampus, optic passway, eye, and lens in the IMPT plan were significantly lower than those in the HA plan. The IMPT plan showed a significant reduction in the percentage of brain volume receiving at least 5 Gy (V5 Gy) compared to the HA plan, while the HA plan showed a significant reduction of V10 Gy - V60 Gy and mean brain dose compared to the IMPT plan. The HA plan provided a shorter beam-on time (184 ± 9 s) than did the IMPT plan (446 ± 49 s).

CONCLUSION

The HA and IMPT plans demonstrated different strengths with respect to OARs sparing.

Effects of Radiation Doses on Clinical Recurrence in Patients with Biochemically Recurrent Prostate Cancer after Prostatectomy

PURPOSE/OBJECTIVE(S)

Salvage radiotherapy (SRT) to the prostate bed is the only curative treatment for patients with biochemical recurrence (BCR) after radical prostatectomy (RP). Although several systematic reviews indicated that a dose escalation in the range of 60-70 Gy improved biochemical control, the effects of radiation doses on clinical relapse after SRT remain unclear. Our aim was to investigate the relationship between radiation doses and clinical relapse-free survival (cRFS) after SRT.

MATERIALS/METHODS

We identified 295 eligible patients receiving SRT for biochemically recurrent prostate cancer after RP between 2005 and 2018 at 15 institutions. Sixteen patients (5%) received short-term (< 6 months) androgen deprivation therapy (ADT) following RP and/or concurrently with SRT. SRT was delivered to the prostate and seminal vesicle bed using photon beams at a median (range) dose of 66 Gy (61-85) in 1.8-3.0 Gy fractions. The primary outcome was cRFS. Clinical relapse was identified on radiological imaging and/or biopsy and included local recurrence, lymph node metastasis, and distant metastasis. In all analyses, doses were recalculated as an equivalent dose in 2-Gy fractions (EQD2) with α/β = 1.5 Gy. Clinical RFS between the EQD2 ≥ 66 Gy (n = 229) and EQD2 < 66 Gy (n = 66) groups were compared using the Log-rank test, followed by univariate and multivariate Cox regression analyses and a subgroup analysis.

RESULTS

The median follow-up duration was 73 months. Among patients with BCR (n = 119), 79 of 96 (82%) in the EQD2 ≥ 66 Gy group and 21 of 23 (91%) in the EQD2 < 66 Gy group received second salvage ADT (p = 0.36). Among all patients (n = 295), clinical relapse was identified in 22 (7%) patients after SRT. Six-year biochemical relapse-free survival (bRFS), cRFS, cancer-specific survival (CSS), and overall survival (OS) rates were 58%, 93%, 98%, and 94%, respectively. Six-year cRFS rates were 94% (95% confidence interval [CI], 90-97) in the EQD2 ≥ 66 Gy group and 87% (95% CI, 75-93) in the EQD2 < 66 Gy group (p = 0.020). The multivariate analysis revealed that EQD2 < 66 Gy, Gleason score ≥ 8, seminal vesicle involvement, and PSA at BCR ≥ 0.5 ng/ml correlated with clinical relapse (p = 0.0016, 0.014, 0.011, and 0.027, respectively). The subgroup analysis showed the consistent benefit of EQD2 ≥ 66 Gy in patients across most subgroups including PSA at BCR after RP, extracapsular extension, and age at SRT.

CONCLUSION

This large multi-institutional observational study demonstrated that a higher SRT dose (EQD2 ≥ 66 Gy) resulted in superior cRFS. The present result supports the dose recommendations in the 2023 National Comprehensive Cancer Network guidelines (64-72 Gy) even in terms of clinical relapse. Prospective trial is warranted to investigate an upper threshold for optimal SRT dose.

Cryptic species in a Vulnerable seabird: shorttailed albatross consists of two species

The occurrence of cryptic species within a threatened taxon is rare, but where they do occur, understanding species boundaries is essential for planning an effective conservation strategy. The short-tailed albatross Phoebastria albatrus is a Vulnerable seabird that mainly breeds on Torishima and the Senkaku Islands in the western North Pacific. Although it has been tacitly regarded as a single management unit with 2 breeding sites, the species is known to comprise 2 genetically separated populations (Senkaku-type and Torishima-type). However, morphological examination of birds from both populations has not been conducted owing to the difficulty in accessing the Senkaku Islands. In this study, we examined the morphological differences between immigrants from the Senkaku Islands to Torishima (Senkaku-type) and native birds on Torishima (Torishima-type) and found significant differences in morphological characteristics between the 2 bird types. In general, Torishima-type birds were larger than Senkaku-type birds, whereas Senkaku-type birds had relatively longer beaks. Based on the morphological differences found in this study as well as genetic and ecological differences revealed in previous studies, we believe that Senkaku- and Torishima-type birds should be classified as different cryptic species. To the best of our knowledge, this is the first case of cryptic species being identified in a threatened avian species.

Colorectal cancer treated by resection and extended lymphadenectomy: patterns of spread in left- and right-sided tumours

BACKGROUND

Whether tumour side affects the anatomical extent and distribution of lymph node metastasis in colon cancer is unknown. The impact of tumour side on the anatomical pattern of lymphatic spread in colon cancer was assessed.

METHODS

Patients with stage III colon cancer from a Japanese multi-institutional database who underwent extensive (D3) lymphadenectomy, which is similar in concept to complete mesocolic excision with central venous ligation, were divided into groups with right- and left-sided tumours. Based on location, mesenteric lymph nodes were categorized as paracolic (L1), intermediate (L2) or central (L3). The Kaplan-Meier method was used to evaluate disease-free survival (DFS) and overall survival (OS), and multivariable Cox models were used to evaluate the association between anatomical lymph node level, metastatic pattern and outcome.

RESULTS

A total of 4034 patients with stage III colon cancer (right 1618, left 2416) were included. Unadjusted OS was worse in patients with right colon cancer (hazard ratio 1·23, 95 per cent c.i. 1·08 to 1·40; P = 0·002), but DFS was similar. Right-sided tumours more frequently invaded L3 nodes than left-sided lesions (8·5 versus 3·7 per cent; P < 0·001). The proportion of patients with a skipped pattern of lymphatic spread was higher in right than in left colon cancer (13·7 versus 9·0 per cent; P < 0·001). In multivariable analysis, invasion of L3 nodes was associated with worse OS in left but not in right colon cancer. The presence of skipped metastasis was associated with worse DFS in left, but not right, colon cancer.

CONCLUSION

There are significant differences in the pattern of lymph node invasion between right- and left-sided stage III colon cancer, and in their prognostic significance, suggesting that tumour side may dictate the operative approach.

Status of the GroundBIRD Telescope

Our understanding of physics at very early Universe, as early as 10−35 s after the Big Bang, relies on the scenario known as the inflationary cosmology. Inflation predicts a particular polarization pattern in the cosmic microwave background, known as the B-mode yet the strength of such polarization pattern is extremely weak. To search for the B-mode of the polarization in the cosmic microwave background, we are constructing an off-axis rotating telescope to mitigate systematic effects as well as to maximize the sky coverage of the observation. We will discuss the present status of the GroundBIRD telescope.

Serum ferritin level is a prognostic marker in patients with peripheral T-cell lymphoma

INTRODUCTION

The prognostic value of serum ferritin level in patients with peripheral T-cell lymphoma (PTCL) remains unknown.

METHODS

We retrospectively analyzed clinical data from 78 consecutive patients with newly diagnosed PTCL that were treated with anthracycline-containing regimens between 1998 and 2011.

RESULTS

The patients consisted of 50 males and 28 females with a median age of 64 years (range, 16-83 years). The subtypes of PTCL were 39 PTCL, not otherwise specified and 39 angioimmunoblastic T-cell lymphoma (AITL). The median observation period for the surviving patients was 50 months. The overall survival (OS) was poorer in patients with serum ferritin level above the upper normal limit (n = 28), compared with patients with serum ferritin level within normal range (n = 50; 4-year OS: 23% vs. 72%; P < 0.001). In the multivariate analysis, poor performance status (P = 0.006) and elevated serum ferritin level (P = 0.018) were independent risk factors for poor OS.

CONCLUSION

Serum ferritin level is a useful prognostic marker for PTCL.