Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

Example input: Abstract: Some patients converted from ventricular fibrillation to organized rhythms by defibrillation - trained ambulance technicians(EMT - Ds) will refibrillate before hospital arrival.The authors analyzed 271 cases of ventricular fibrillation managed by EMT - Ds working without paramedic back - up.Of 111 patients initially converted to organized rhythms, 19(17 % ) refibrillated, 11(58 % ) of whom were reconverted to perfusing rhythms, including nine of 11(82 % ) who had spontaneous pulses prior to refibrillation.Among patients initially converted to organized rhythms, hospital admission rates were lower for patients who refibrillated than for patients who did not(53 % versus 76 % , P = NS), although discharge rates were virtually identical(37 % and 35 % , respectively).Scene - to - hospital transport times were not predictively associated with either the frequency of refibrillation or patient outcome.Defibrillation - trained EMTs can effectively manage refibrillation with additional shocks and are not at a significant disadvantage when paramedic back - up is not available.
Example output: Ventricular Fibrillation
Example explanation: This term is directly present in the abstract and it is one of the main topic in it. So can be chosen as the medical subject heading.
Q: Abstract: Ninety-six patients with disseminated malignant melanoma received thrice weekly intramuscular injections of leukocyte A recombinant interferon (rIFN-alpha A, Roferon-A, Hoffmann La Roche) at doses of 12 X 10(6) U/m2 or 50 X 10(6) U/m2 with or without cimetidine as an immunorestorative agent. Four patients, two with prior chemotherapy, demonstrated either a complete response (3 months, soft tissue metastasis) or exceptionally durable response durations (months) of 29+ (soft tissue; lung lesion), 31+ (soft tissue), and 35+ (soft tissue; liver lesions). None of these patients had particularly characteristic clinical parameters. As noted previously, using chemotherapy, a small proportion of patients with advanced malignant melanoma, despite prior therapy, may achieve prolonged objective regression with rIFN-alpha A.
A:
Adult