We investigated whether pulmonary metastases from historically considered radioresistant primaries would have inferior local control after radiation therapy than those from nonradioresistant nonlung ...primaries, and whether higher biologically effective dose assuming alpha/beta=10 (BED10) would be associated with superior local control.
We identified patients treated with radiation therapy for oligometastatic or oligoprogressive pulmonary disease to 1 to 5 lung metastases from nonlung primaries in 2013 to 2020 at a single health care system. Radioresistant primary cancers included colorectal carcinoma, endometrial carcinoma, renal cell carcinoma, melanoma, and sarcoma. Nonradioresistant primary cancers included breast, bladder, esophageal, pancreas, and head and neck carcinomas. The Kaplan-Meier estimator, log-rank test, and multivariable Cox proportional hazards regression were used to compare local recurrence-free survival (LRFS), new metastasis-free survival, progression-free survival, and overall survival.
Among 114 patients, 73 had radioresistant primary cancers. The median total dose was 50 Gy (IQR, 50-54 Gy) and the median number of fractions was 5 (IQR, 3-5). Median follow-up time was 59.6 months. One of 41 (2.4%) patients with a nonradioresistant metastasis experienced local failure compared with 18 of 73 (24.7%) patients with radioresistant metastasis (log-rank P = .004). Among radioresistant metastases, 12 of 41 (29.2%) patients with colorectal carcinoma experienced local failure compared with 6 of 32 (18.8%) with other primaries (log-rank P = .018). BED10 ≥100 Gy was associated with decreased risk of local recurrence. On univariable analysis, BED10 ≥100 Gy (hazard ratio HR, 0.263; 95% CI, 0.105-0.656; P = .004) was associated with higher LRFS, and colorectal primary (HR, 3.060; 95% CI, 1.204-7.777; P = .019) was associated with lower LRFS, though these were not statistically significant on multivariable analysis. Among colorectal primary patients, BED10 ≥100 Gy was associated with higher LRFS (HR, 0.266; 95% CI, 0.072-0.985; P = .047) on multivariable analysis.
Local control after radiation therapy was encouraging for pulmonary metastases from most nonlung primaries, even for many of those classically considered to be radioresistant. Those from colorectal primaries may benefit from testing additional strategies, such as resection or systemic treatment concurrent with radiation.
To explore predator-prey interactions between California killifish (Fundulus parvipinnis) and spionid polychaetes (Polydora cornuta and Streblospio benedicti) in saltmarsh creeks, we conducted a ...laboratory flume experiment to quantify whether killifish prey-patch selectivity varies with water flow. The flume included a 300-cm² area of defaunated sediment within which we centrally positioned 24 P. cornuta, 24 S. benedicti, or no worms as a control. We videotaped groups of three killifish for 50 min at one of six unidirectional flow speeds (3 cm s−1, 6 cm s−1, 9 cm s−1, 12 cm s−1, 15 cm s−1, or 18 cm s−1) and recorded their bite rate anywhere in the sediment vs. bites directed at the central patch containing worms (98 cm²). The number of bites anywhere in the 300-cm² sediment area increased as flow increased from 3 cm s−1 to 6 cm s−1 and declined linearly as flow increased further. The number of bites anywhere was lower in treatments with no worms than when either worm species was present. The percentage of bites directed at the central patch varied significantly with flow speed and worm presence. With defaunated sediment only, ∼ 33% of bites were directed at the central patch at all flows, consistent with a null model of nonselective foraging. When either worm species inhabited the central patch, ∼ 65% of bites were directed at the central patch at 3 cm s−1 and 6 cm s−1, with patch selection declining as flow increased. Despite differences in morphology and behavior, the two prey species elicited similar foraging activity by killifish. These results suggest the importance of hydrodynamics in driving these epibenthic predator-prey interactions.
Hydrodynamics and pollution affect estuarine populations, but their ecological effects have rarely been studied in combination. We conducted two laboratory experiments to quantify whether ...predator–prey interactions between California killifish,
Fundulus parvipinnis
, and the polychaete
Polydora cornuta
vary with flow speed and chlorpyrifos exposure. In one experiment, only
F. parvipinnis
was exposed to chlorpyrifos; in the other, only
P. cornut
a was exposed. The flume included a 300-cm
2
area of sediment with 24
P. cornuta
in a central patch (98 cm
2
). We videotaped groups of three killifish for 50 min at one of four flow speeds (6, 9, 12, or 15 cm/s) and recorded the proportion of bites directed at the prey patch. Unexposed killifish directed 70% of their bites at the prey patch at 6 cm/s, and prey-patch selection decreased as flow increased. Killifish exposed to chlorpyrifos directed 41% of their bites at the prey patch at 6 cm/s with reduced prey-patch selection relative to unexposed fish at 9 and 12 cm/s. At 15 cm/s, both exposed and unexposed fish displayed non-selective biting. Worms were videotaped to quantify their deposit- and suspension-feeding activities. Exposing worms to chlorpyrifos reduced total feeding activity by ~30%. Suspension feeding was more common at faster flow speeds, but the time worms spent suspension feeding relative to deposit feeding was unaffected by chlorpyrifos. No behavioral changes were noted in either species when the other was exposed to chlorpyrifos. This study highlights how hydrodynamic conditions can alter the relative importance of a toxicant’s effects on predator–prey interactions.
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