CT Scans and Cancer Risks: A Systematic Review and Dose-response Meta-analysis.

BACKGROUND: There is still uncertainty on whether ionizing radiation from CT scans can increase the risks of cancer. This study aimed to identify the association of cumulative ionizing radiation from CT scans with pertaining cancer risks in adults. METHODS: Five databases were searched from their inception to November 15, 2020. Observational studies reporting cancer risks from CT scans in adults were included. The main outcome included quantified cancer risks as cancer case numbers in exposed/unexposed adult participants with unified converted measures to odds ratio (OR) for relative risk, hazard ratio. Global background radiation (2.4 mSv per year) was used as control for lifetime attribution risk (LAR), with the same period from incubation after exposure until survival to 100 years. RESULTS: 25 studies were included with a sum of 111,649,943 participants (mean age: 45.37 years, 83.4% women), comprising 2,049,943 actual participants from 6 studies with an average follow-up period as 30.1 years (range, 5 to 80 years); 109,600,000 participants from 19 studies using LAR. The cancer risks for adults following CT scans were inordinately increased (LAR adults, OR, 10.00 [95% CI, 5.87 to 17.05]; actual adults, OR, 1.17 [95%CI, 0.89 to 1.55]; combined, OR, 5.89 [95%CI, 3.46 to 10.35]). Moreover, cancer risks elevated with increase of radiation dose (OR, 33.31 [95% CI, 21.33 to 52.02]), and multiple CT scan sites (OR, 14.08 [95% CI, 6.60 to 30.05]). The risk of solid malignancy was higher than leukemia. Notably, there were no significant differences for age, gender, country, continent, study quality and studying time phrases. CONCLUSIONS: Based on 111.6 million adult participants from 3 continents (Asia, Europe and America), this meta-analysis identifies an inordinately increase in cancer risks from CT scans for adults. Moreover, the cancer risks were positively correlated with radiation dose and CT sites. The meta-analysis highlights the awareness of potential cancer risks of CT scans as well as more reasonable methodology to quantify cancer risks in terms of life expectancy as 100 years for LAR. PROSPERO TRIAL REGISTRATION NUMBER: CRD42019133487.

[Minimally invasive therapy for hallux valgus with deformity of little toe varus].

OBJECTIVE: To explore clinical effect of minimally corrective osteotomy for the treatment of hallux valgus with deformity of little toe varus through small incision. METHODS: From January 2013 to June 2016, 168 hallux valgus patients with deformity of little toe varus were treated by minimally corrective osteotomy through small incision. Among them, 7 males and 161 females were aged from 22 to 75 years old with an average of(59.3±3.5) years old. Preoperative clinical manifestation mainly focus on red and swollen of bunion, pain around with metatarsal bones, and diagnosed as hallux valgus with deformity of little toe varus through small incision. Operative time, postoperative complications, pre and post-operative IMA(angle between the first and the second metatarsal bones), HVA (hallux valgus angle), LDA(valgus angle of the fifth metatarsal bones), MPA(valgus angle of little toe), IM4-5 (angle between the forth and the fifth metatarsal bones) and PASA(fixed angle of proximal joint), postoperative AOFAS score were used to evaluate foot function. RESULTS: One hundred and sixty-eight patients were followed up for 6 to 48 months with an average of (28.6±3.2) months. All wounds were healed well without infection, sinus tract and other complications. Operative time ranged from 16 to 28 min with an average of (18.3±2.1) min. IMA, HVA, LDA, MPA and IM A 4-5 were (10.1±2.1)°, (32.6±4.2)°, (6.9±2.3)°, (18.5±5.2)°, (15.1±2.9)°preoperatively, improved to (8.3±2.2)°, (10.9±2.9)°, (2.7±0.4)°, (6.5±1.6)°, (8.9±1.8)° postoperatively, and had significant differences before and after operation. While there was no difference in PASA before (9.1±2.1)°and after operation(8.7±1.9)°. AOFAS score were improved from (31.6±3.9) before operation to(83.7±5.2) after operation, but no significant difference(P>0.05). According to AOFAS score, 147 patients obtained excellent results, 13 good, 6 moderate and 2 poor. CONCLUSIONS: Minimally corrective osteotomy for the treatment of hallux valgus with deformity of little toe varus through small incision could obtain satisfied clinical effect, and has advantages of small incision, no stitches, beautiful appearance, shorter operation time, and rapid recovery. It is worth popularization in clinical practise.