A prospective randomised comparison of minor surgery in primary and secondary care. The MiSTIC trial

To determine whether there is equivalence in the competence of GPs and hospital doctors to perform a range of elective minor surgical procedures, in terms of the safety, quality and cost of care.

A prospective randomised controlled equivalence trial was undertaken in consenting patients presenting at general practices and needing minor surgery.

The study was conducted in the south of England.

Consenting patients presenting at general practices who needed minor surgery in specified categories for whom the recruiting doctor felt able to offer treatment or to be able to refer to a colleague in primary care.

On presentation to their GP, patients were randomised to either treatment within primary care or treatment at their local hospital. Evaluation was by assessment of clinical quality and safety of outcome, supplemented by examination of patient satisfaction and cost-effectiveness.

Two independent observers assessed surgical quality by blinded assessment of wound appearance, between 6 and 8 weeks postsurgery, from photographs of wounds. Other measures included satisfaction with care, safety of surgery in terms of recognition of and appropriate treatment of skin malignancies, and resource use and implications.

The 568 patients recruited (284 primary care, 284 hospital) were randomised by 82 GPs. In total, 637 skin procedures plus 17 ingrowing toenail procedures were performed (313 primary care, 341 hospital) by 65 GPs and 60 hospital doctors. Surgical quality was assessed for 273 (87%) primary care and 316 (93%) hospital lesions. Mean visual analogue scale score in hospital was significantly higher than that in primary care [mean difference=5.46 on 100-point scale; 95% confidence interval (CI) 0.925 to 9.99], but the clinical importance of the difference was uncertain. Hospital doctors were better at achieving complete excision of malignancies, with a difference that approached statistical significance [7/16 GP (44%) versus 15/20 hospital (75%), chi(2)=3.65, p=0.056]. The proportion of patients with post-operative complications was similar in both groups. The mean cost for hospital-based minor surgery was 1222.24 pounds and for primary care 449.74 pounds. Using postoperative complications as an outcome, both effectiveness and costs of the alternative interventions are uncertain. Using completeness of excision of malignancy as an outcome, hospital minor surgery becomes more cost-effective. The 705 skin procedures undertaken in this trial generated 491 lesions with a traceable histology report: 36 lesions (7%) from 33 individuals were malignant or premalignant. Chance-corrected agreement (kappa) between GP diagnosis of malignancy and histology was 0.45 (95% CI 0.36 to 0.54) for lesions and 0.41 (95% CI 0.32 to 0.51) for individuals affected by malignancy. Sensitivity of GPs for detection of malignant lesions was 66.7% (95% CI 50.3 to 79.8) for lesions and 63.6% (95% CI 46.7 to 77.8) for individuals affected by malignancy.

The quality of minor surgery carried out in general practice is not as high as that carried out in hospital, using surgical quality as the primary outcome, although the difference is not large. Patients are more satisfied if their procedure is performed in primary care, largely because of convenience. However, there are clear deficiencies in GPs' ability to recognise malignant lesions, and there may be differences in completeness of excision when compared with hospital doctors. The safety of patients is of paramount importance and this study does not demonstrate that minor surgery carried out in primary care is safe as it is currently practised. There are several alternative models of minor surgery provision worthy of consideration, including ones based in primary care that require all excised tissue to be sent for histological examination, or that require further training of GPs to undertake the necessary work. The results of this study suggest that a hospital-based service is more cost-effective. It must be concluded that it is unsafe to leave minor surgery in the hands of doctors who have never been trained to do it. Further work is required to determine GPs' management of a range of skin conditions (including potentially life-threatening malignancies), rather than just their recognition of them. Further economic modelling work is required to look at the potential costs of training sufficient numbers of GPs and GPs with special interests to meet the demand for minor surgery safely in primary care, and of the alternative of transferring minor surgery large-scale to the hospital sector. Different models of provision need thorough testing before widespread introduction.